Thermally-conducting, electrically-insulating fluoropolymer composite materials, tubings made therefrom, and systems including such materials and tubings

Abstract

The present disclosure relates to a thermally-conductive, electrically-insulating polymer composite material. The material includes a continuous polymeric phase including a fluorinated polymer phase having a total fluoropolymer content of at least 50 wt%, the fluorinated polymer phase including a functional polymer, the functional polymer comprising reactive functional groups; and optionally, a thermoplastic fluoropolymer, the thermoplastic fluoropolymer being miscible with the functional polymer; and phase-separated from the fluorinated polymer phase, an elastomeric polymer; and dispersed within the continuous polymeric phase, a thermally-conductive, electrically-insulating filler. The materials of the disclosure can be formed into tubes, and used, for example, in thermal management systems and methods, especially for magnetic resonance instruments.

Description

THERMALLY-CONDUCTING, ELECTRICALLY-INSULATING FLUOROPOLYMER COMPOSITE MATERIALS, TUBINGS MADE THEREFROM, AND SYSTEMS INCLUDING SUCH MATERIALS AND TUBINGS Cross-Reference to Related Applications

[0001] This application claims the benefit of priority of U.S. Provisional Patent Application no.63 / 514,976, filed July 21, 2023, which is hereby incorporated herein by reference in its entirety. Background of the Disclosure 1. Field

[0002] The present disclosure relates to thermally-conducting, electrically-insulating polymer composite materials, tubings made therefrom, and systems including such materials and tubings. 2. Technical Background

[0003] The present disclosure relates to thermally-conducting, electrically-insulating polymer composite materials, tubings made therefrom, and systems including such materials and tubings.

[0004] Tubings are often used in heat transfer applications, for example, in conducting a thermal transfer fluid like a coolant between a hot zone (e.g., a hot area of an apparatus that is desired to be cooled) and a cool zone (e.g., a heat sink, a heat exchanger, or merely a cooler environment). Such tubings must, of course, be able to resist the hot temperatures in the relevant hot zone, and are desirably thermally-conductive to allow for efficient heat transfer into and out of the thermal transfer fluid. But, depending on the particular application, they may have a variety of other stringent requirements.

[0005] For example, magnetic resonance imaging (MRI) systems produce images using strong magnetic field gradients, which are generated using a series of superconducting magnetic coils. During operation, significant heat is generated by the magnetic coils themselves, as well as by other components of the gradient subsystem. In order to dissipate this heat away from the system, e.g., in order to maintain a desired temperature, coolant tubes made of copper are conventionally positioned near the heat-generating components and configured to carry coolant water to cool the heat-generating components. However, copper tubing presents a serious drawback: it interferes with the magnetic field, which can reduce signal-to-noise ratio and even provide distorted images. To overcome this limitation, a copper tubing needs to be actively shielded. Additionally, copper tubing is stiff and heavy and susceptible to corrosion by deionized water, which are also undesirable characteristics of a coolant tubing.

[0006] Further improvements in tubings for heat transfer are required.Summary of the Disclosure

[0007] In various aspects, the disclosure provides thermally-conducting and electrically- insulating polymer composite materials that can advantageously be formed into tubings. The materials and tubings can be flexible, resistant to a variety of fluids, especially various coolant fluids, and stable to high continuous use temperatures. Accordingly, the tubings can be useful in the transfer of heat at a first location into a working fluid disposed within the tubing, conducting the heated working fluid to a second location, and the transfer of heat at the second location out of the working fluid disposed within the tubing.

[0008] One aspect of the disclosure relates to a thermally-conductive, electrically- insulating polymer composite material, comprising: a continuous polymeric phase comprising a fluorinated polymer phase having a total fluoropolymer content of at least 50 wt%, the fluorinated polymer phase comprising; a functional polymer, the functional polymer comprising reactive functional groups; and optionally, a thermoplastic fluoropolymer, the thermoplastic fluoropolymer being miscible with the functional polymer; and phase-separated from the fluorinated polymer phase, an elastomeric polymer; and dispersed within the continuous polymeric phase, a thermally-conductive, electrically- insulating filler.

[0009] Another aspect of the disclosure is a tubing comprising at least one annular layer of a thermally-conductive, electrically-insulating polymer composite material of the disclosure.

[0010] Another aspect of the disclosure is a method for transferring heat from a heat source, the method comprising providing a tubing of the disclosure positioned in substantial thermal communication with the heat source at a first position, the tubing having a working fluid disposed therein; and transferring heat from the heat source through the tubing and into the working fluid.

[0011] Another aspect of the disclosure is a thermal management system for cooling a heat source, the system comprising: a tubing according to any of embodiments 72-80, in substantial thermal communication with the heat source at a first position; and a source of a working fluid configured to conduct the working fluid through the tubing

[0012] Another aspect of the disclosure is a magnetic resonance instrument, e.g., a magnetic resonance imaging instrument, comprising a gradient coil assembly and a tubing of the disclosure in substantial thermal communication with the gradient coil assembly at a first position; and a source of a working fluid configured to conduct the working fluid through the tubing.

[0013] Another aspect of the disclosure is a method of thermal management for a magnetic resonance instrument comprising a gradient coil assembly, the method comprising providing a tubing of the disclosure positioned in substantial thermal communication with the gradient coil assembly at a first position, the tubing having a working fluid disposed therein; and transferring heat from the gradient coil assembly through the tubing and into the working fluid.

[0014] Other aspects of the disclosure will be evident to the person of ordinary skill in the art from the present specification. Brief Description of the Drawings

[0015] Various aspects of the disclosure are illustrated by the drawings, in which:

[0016] FIG.1 is a schematic view of a material according to one embodiment of the disclosure;

[0017] FIG.2 is a schematic cross-sectional view of a tubing according to one embodiment of the disclosure.

[0018] FIG.3 is a schematic view of a thermal management system according to one embodiment of the disclosure.

[0019] The person of ordinary skill in the art will appreciate that the drawings are schematic in nature, and are not necessarily to scale and may omit particular components that are not germane to the discussion of the figure. Detailed Description

[0020] The present inventors have noted a number of limitations of existing tubing materials, especially of the copper tubings typically used in magnetic resonance imaging apparatuses. The present inventors note that to overcome the above limitations, it is desirable to replace copper tubing with a polymeric tubing. However, that tubing has to that exhibit a proper suite of thermal, mechanical, electrical, physical and magnetic properties.

[0021] The present disclosure provides thermally-conductive, electrically-insulating polymer composite materials suitable for formation into tubing and use in cooling applications, such as cooling of magnet coils in MRI instruments.

[0022] Thus, in various aspects, the disclosure provides thermally-conducting and electrically-insulating polymer composite materials that can advantageously be formed into tubings. The materials and tubings can be flexible, resistant to a variety of fluids, especially various coolant fluids, and stable to high continuous use temperatures. Accordingly, the tubings can be useful in the transfer of heat at a first location into a working fluid disposed within the tubing, conducting the heated working fluid to a second location, and the transfer of heat at the second location out of the working fluid disposed within the tubing.

[0023] Such materials and tubings can be especially desirable in a variety of uses. For example, in various aspects of the disclosure, tubings formed of the materials described herein can be used as coolant tubes used in medical diagnostic equipment such as magnetic resonance imaging systems. But the materials and tubings described herein can find a variety of uses, especially in thermal management applications in which a high rate of heat transfer through the tube wall is advantageous but the electrical properties of metallic tubings are undesirable.

[0024] One aspect of the disclosure is a thermally-conductive, electrically-insulating polymer composite material. The polymer composite material includes a continuous polymeric phase that includes a fluorinated polymer phase that has a total fluoropolymer content of at least 50 wt%. The fluorinated polymer phase comprising a functional polymer comprising reactive functional groups, and, optionally, a thermoplastic fluoropolymer that is miscible with the functional polymer; and, phase-separated from the thermoplastic fluoropolymer and the functional polymer, an elastomeric polymer; and dispersed within the continuous polymeric phase, a thermally-conductive filler. This is shown in partial cross- sectional schematic view in FIG.1, in which polymer composite material 100 includes a continuous polymeric phase 102 in which a thermally-conductive, electrically-insulating filler 104 is disposed. As used herein, the continuous polymeric phase is continuous with respect to the filler. As noted above, the continuous polymeric phase itself can have phase separation of an elastomeric polymer from the thermoplastic fluoropolymer / functional polymer phase, as determined by microscopy. For example, in the schematic view of FIG. 1, the continuous polymeric phase 102 includes a fluorinated polymer phase 106, and, phase-separated therefrom, a elastomeric polymer phase 108. While the elastomeric polymer phase 108 is shown in FIG.1 as being a discontinuous phase dispersed within a continuous phase of the fluorinated polymer phase 106, the person of ordinary skill in the art will appreciate that other arrangements are possible, such as co-continuous phases.

[0025] Notably, the fluorinated polymer phase has a high total fluoropolymer content of at least 50 wt%. That is, at least 50 wt% of the fluorinated polymer phase is made up of fluoropolymer(s). The person of ordinary skill in the art will appreciate that suchfluoropolymers can have a substantial content of non-fluorinated residues. In various embodiments, the fluorinated polymer phase has a total fluoropolymer content of at least 60 wt%, e.g., at least 70 wt%. In various embodiments, the fluorinated polymer phase has a total fluoropolymer content of at least 80 wt%, e.g., at least 90 wt%. In various embodiments, the fluorinated polymer phase has a ratio of hydrogen atoms to fluorine atoms of no more than 2, for example, no more than 1.5, or no more than 1, or no more than 0.5.

[0026] In various embodiments, the fluorinated polymer phase has a peak melting temperature of at least 190 °C. For example, in various embodiments, the fluorinated polymer phase has a peak melting temperature of at least 200 °C., e.g., at least 210 °C or at least 220 °C. Peak melting temperatures are measured according to ASTM D 4591.

[0027] In various embodiments, the fluorinated polymer phase has a melt flow rate in the range of 5-50 g / 10 min as measured by ASTM D3159 at 297 ºC and 47 N, e.g., in the range of 5-40 g / 10 min, 5-30 g / 10 min, or 5-20 g / 10 min, or 10-50 g / 10 min, or 10-40 g / 10 min, or 10-30 g / 10 min, or 10-20 g / 10 min, or 20-50 g / 10 min, or 20-40 g / 10 min, or 20-30 g / 10 min, or 30-50 g / 10 min, or 30-40 g / 10 min.

[0028] The thermoplastic fluoropolymer is an optional component of the fluorinated polymer phase. In some cases, for example, a functional fluoropolymer can be used in the absence of a separate thermoplastic fluoropolymer. Notably, as the amount of thermoplastic fluoropolymer is reduced (or even eliminated), the amount of functional fluoropolymer can be increased in order to provide an overall continuous polymeric phase with a desirably high total fluoropolymer content as described above.

[0029] In various embodiments, however, the thermoplastic fluoropolymer is present.

[0030] In various embodiments, the thermoplastic fluoropolymer of the continuous polymeric phase has a peak melting temperature of at least 190 °C. For example, in various embodiments, the thermoplastic fluoropolymer of the continuous phase has a peak melting temperature of at least 200 °C., e.g., at least 210 °C or at least 220 °C. Peak melting temperatures are measured according to ASTM D 4591.

[0031] Based on the description herein, the person of ordinary skill in the art can determine an appropriate fluoropolymer for use as the thermoplastic fluoropolymer of the continuous polymeric phase. For example, in various embodiments, the thermoplastic fluoropolymer is poly(ethylene-co-tetrafluoroethylene) (ETFE). In various embodiments, the thermoplastic fluoropolymer is poly(tetrafluoroethylene-co-hexafluoropropylene). In various embodiments, the thermoplastic fluoropolymer includes (or is) poly(tetrafluoroethylene-co- hexafluoropropylene) (“FEP”). However, the person of ordinary skill in the art will appreciate that other thermoplastic fluoropolymers are available for use in the materials describedherein. For example, in various embodiments, thermoplastic fluoropolymer can include (or be) polyvinylidenefluoride (PVF), poly(tetrafluoroethylene-co-perfluoro(alkyl vinyl ether)) (PFA), polyvinylidene difluoride (PVDF), polychlorotrifluoroethlylene (PCTFE), tetrafluoroethylene / hexafluoropropylene / ethylene copolymer (HTE), chlorotrifluoroethylene / vinylidenefluoride copolymer, chlorotrifluoroethylene / hexafluoropropylene, ethylene / chlorotrifluoroethylene copolymers (ECTFE), ethylene / trifluoroethylene copolymers, tetrafluoroethylene / propylene copolymers (TFE / P), tetrafluoroethylene / hexafluoropropylene copolymers (FEP / HFP), and / or hexafluoropropylene / tetrafluoroethylene / vinylidene copolymer (THV).

[0032] In some embodiments, however, the thermoplastic fluoropolymer includes significant content of non-fluorinated residues. For example, in various embodiments, the thermoplastic fluoropolymer includes in the range of 5-70 wt% non-fluorinated residues, e.g., in the range of 5-50 wt%, or 5-30 wt%, or 10-70 wt%, or 10-50 wt%, or 10-30 wt%. Such materials can remain substantially chemically inert, yet be more flexible and more easily processed than fully fluorinated materials.

[0033] In various embodiments, the thermoplastic fluoropolymer includes (or is) poly(ethylene-co-tetrafluoroethylene) (“ETFE”).

[0034] To provide for ease of processing, in various embodiments it can be desirable for the thermoplastic fluoropolymer to have a melt flow rate in the range of 5-50 g / 10 min as measured by ASTM D3159 at 297 ºC and 47 N, e.g., in the range of 5-40 g / 10 min, 5-30 g / 10 min, or 5-20 g / 10 min, or 10-50 g / 10 min, or 10-40 g / 10 min, or 10-30 g / 10 min, or 10- 20 g / 10 min, or 20-50 g / 10 min, or 20-40 g / 10 min, or 20-30 g / 10 min, or 30-50 g / 10 min, or 30-40 g / 10 min.

[0035] In order to provide material suitable for a variety of thermal transfer applications, it can be desirable for the thermoplastic fluoropolymer to have a continuous use operating temperature rating of at least 100 °C, e.g., at least 150 °C at least 180 °C or at least 200 °C.

[0036] As noted above, when present, the thermoplastic fluoropolymer is substantially miscible with the functional polymer. This can be determined by melt blending the functional polymer with the thermoplastic fluoropolymer in the relative amounts present in the thermally-conductive, electrically-insulating polymer composite material, allowing the blend to cool, and determining whether there is substantial phase separation (e.g., greater than 5 wt% of the functional polymer). Desirably, the functional polymer is miscible with the thermoplastic fluoropolymer in the relative amounts present in the thermally-conductive, electrically-insulating polymer composite material, i.e., there is no visible phase separation of the functional polymer from the thermoplastic fluoropolymer.

[0037] However, as noted above, when the functional polymer component is substantially fluorinated, it can be acceptable to omit the thermoplastic fluoropolymer from the composition. Accordingly, in various embodiments as otherwise described herein, the thermoplastic fluoropolymer is not present in the continuous polymeric phase.

[0038] The polymer composite material also includes a functional polymer that is a thermoplastic polymer that is substantially miscible with the thermoplastic fluoropolymer and comprises reactive functional groups. The functional groups of the functional polymer can vary. In various embodiments, the reactive functional groups of the functional polymer include (or are) hydroxyl groups, carboxylate groups, a carboxylic acid group, an ester group, a carbonate group, an anhydride group, an epoxy group and / or amine groups. For example, in various embodiments, the functional groups of the functional polymer include (or are) hydroxyl groups. In various embodiments, the functional groups of the functional polymer include (or are) amine groups. In various embodiments, the functional groups of the functional polymer include (or are) anhydride groups. The person of ordinary skill in the art will appreciate that a variety of reactive groups can be used. The functional group(s) may be located at any position on the functional polymer. For example, the functional group may be at the end of the polymer chain, within the polymer chain, or extending from a side chain that extends from the backbone of the polymer. The reactive functional groups can provide the functional polymer, for example, with the capability to affect adhesion with other materials, such as another polymer, a liquid resin, a glass or a ceramic, or a metal, for example, upon heating of the materials in contact with one another.

[0039] In various embodiments, the functional polymer is a functional fluoropolymer. This can be desirable in order to provide a continuous polymeric phase with a desirably high degree of fluorination, as well as from the from the standpoint of miscibility with any thermoplastic fluoropolymer present in the continuous polymeric phase. For example, in various embodiments the functional polymer can be a functional ETFE or a functional FEP, i.e., a ETFE or an FEP that bears the functional groups. But other fluoropolymers, such as those listed above, can also be suitably provided as functional fluoropolymers.

[0040] The person of ordinary skill in the art will appreciate that functional fluoropolymers can be made in a variety of ways. For example, in various embodiments, the functional fluoropolymer is a copolymer. For example, a fluorinated monomer (in some cases together with a non-fluorinated monomer) can be copolymerized with a functional monomer bearing the desired functionality to provide the functional fluoropolymer. In various embodiments, for example, the functional monomer is an anhydride-bearing monomer such as itaconic anhydride or maleic anhydride. As an alternative, graft polymerization can be used to graft functional monomers onto an already-formedfluoropolymer. Example compounds for grafting onto and thereby becoming part of the fluoropolymer are maleic acid and maleic anhydride. Maleic anhydride can be halogen- substituted, e.g., dichloromaleic anhydride and difluoromaleic anhydride. Grafting may be brought about by using a grafting compound comprising a linking group (including, but not limited to an unsaturated or saturated hydrocarbon group which is involved in addition or association of radicals (particularly an organic group having an a,b-unsaturated double bond at its terminal), an amino group or a phenol group which is involved in nucleophilic reaction, a peroxy group or an azo group. A variety of such polymers are known in the art, and the person of ordinary skill in the art can select a particular one depending on desired adhesion and compatibility properties.

[0041] Functional fluoropolymers can also be provided by treatment of a fluoropolymer in order to form the functional groups thereon. For example, in various embodiments, the functional polymer is a fluoropolymer that has been treated with an oxidant, a plasma (e.g., using a corona treatment), or with some other chemical treatment to provide the functional groups. Various treatments using oxidation, plasma and reactive nitrogenous reagents are known to functionalize fluoropolymers.

[0042] In various embodiments, the functional fluoropolymer includes a reaction product of (i) a monomer containing an anhydride, (ii) ethylene, and (iii) tetrafluoroethylene. In this embodiment, the reaction product may be generally referred to as functionalized ETFE. Furthermore the monomer containing the anhydride may be hydrolyzed such that the functionalized ETFE of this embodiment contains a carboxylic acid functional group, or otherwise modified via conventional carboxylate chemistries to provide other functional groups, e.g., carboxamides, hydroxyalkyl carboxylates, etc. In another embodiment, the functional polymer is a poly(ethylene-tetrafluoroethylene) copolymer comprising hydroxyl or amine reactive functional groups.

[0043] As described above, the continuous polymeric phase of the polymer composite material also includes, phase separated from the thermoplastic fluoropolymer and the functional polymer, an elastomeric polymer. The person of ordinary skill in the art will, based on the present disclosure, select a desirable elastomeric polymer in view of desired overall material properties and compatibility in the thermoplastic fluoropolymer. In various embodiments, the elastomeric polymer is a thermosetting elastic polymer.

[0044] For example, in various embodiments, the elastomeric polymer is a fluoroelastomer. A variety of fluoroelastomers are known and can be adapted for use in the materials of the disclosure; the person of ordinary skill in the art will appreciate that some fluorinated polymers become elastomeric only upon crosslinking, and will suitably crosslinkthem for use in the materials of the disclosure. Certain examples of the fluoroelastomer include, but are not limited to, one or more of the following fluoropolymers: a TFE / P copolymer, a tetrafluoroethylene / propylene / vinylidenefluoride copolymer, a vinylidenefluoride / hexafluoropropylene copolymer, a vinylidenefluoride / hexafluoropropylene / tetrafluoroethylene copolymer, a vinylidenefluoride / tetrafluoroethylene / perfluoroalkylvinylether copolymer, a vinylidenefluoride / hexafluoropropylene / tetrafluoroethyene / perfluoroalkylvinylether copolymer, a vinylidenefluoride / hexafluoropropylene / perfluoroalkylvinylether copolymer, a tetrafluoroethylene / ethylene / perfluoroalkylvinylether copolymer, a vinylidenefluoride / hexafluoropropylene / tetrafluoroethylene / ethylene / perfluoroalkylvinyl ether copolymer, a vinylidenefluoride / chlorotrifluoroethylene copolymer, or a 1,1,1,2-tetrafluoro-2- propene / vinylidene fluoride copolymer. In certain embodiments, the fluoroelastomer is a copolymer of tetrafluoroethylene / propylene (TFE / P) or an FKM fluoropolymer or a fluorosilicone rubber. The FKM fluoropolymer is a fluoropolymer defined by ASTM D1418. The FKM fluoropolymer includes Type 1, Type 2, Type 3, Type 4, and Type 5 FKM fluoropolymers.

[0045] But other elastomers can be used. For example, in various embodiments, the elastomeric polymer is a silicone rubber, or ethylene-propene-diene monomer (EPDM) rubber, or chlorosulfonated polyethylene rubber, or hydrogenated acrylonitrile-butadiene rubber (HNBR).

[0046] Depending on the type of elastomer, it can be desirable in some embodiments (e.g., thermosetting elastomeric polymers) for the elastomeric polymer to be crosslinked to at least a degree (e.g., lightly or highly). The person of ordinary skill in the art can use conventional techniques to provide such crosslinking, such as using peroxide-curing or other free radical curing, alone or in combination with a crosslinker, or without using chemical agents such as by electron beam irradiation. For example, chemical curing agents include radical sources like peroxides. Specific examples of an organic peroxide include, but are not limited to, dicumyl peroxide, 1,3-bis(tert-butylperoxyisopropyl)benzene, tert-butylcumyl peroxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, tert- butylperoxybenzoate, 2,5-dimethyl-2,5-dibenzoyl peroxyhexane, di-tert-butyl peroxide, 2,5- dimethyl-2,5-di-tert-butyl peroxyhexane and dibenzoyl peroxide and combinations thereof. But other free radical sources (e.g., in the form of thermal initiators) can be used. In various embodiments, the crosslinker is an unsaturated polyfunctional compound. In certain embodiments, the unsaturated polyfunctional compound is a triallyl derivative of cyanuric acid. Specific examples include triallyl cyanurate (TAC), triallyl isocyanurate (TAIC), triallylisocyanurate oligomer, trimethallyl isocyanurate (TMAIC) or combinations thereof. In various embodiments, various fluoroelastomers can be cured using a bisphenol.

[0047] In various other embodiments, crosslinking of the fluoroelastomer is effected by radiation such as ultraviolet radiation, infrared radiation, electron beam radiation, x-ray radiation, an irradiating plasma, a discharging corona, gamma radiation and / or any combination of these.

[0048] Of course, the person of ordinary skill in the art will appreciate that other elastomers (e.g., meeting the definition of ASTM D-156611) can also or alternatively be used. Desirable elastomers, while phase-separated from the thermoplastic fluoropolymer and the functional polymer, are desirably compatible in that they are dispersible in the thermoplastic fluoropolymer / functional polymer mixture.

[0049] In various embodiments of the thermally-conductive, electrically-insulating polymer composite materials of the disclosure, the thermoplastic fluoropolymer is poly(ethylene-co-tetrafluoroethylene); the functional polymer is modified poly(ethylene-co- tetrafluoroethylene) copolymer comprising anhydride reactive functional groups; and the elastomeric polymer is poly(vinylidene fluoride-hexafluoropropylene) type-1 FKM rubber.

[0050] Of course, the materials of the disclosure can include other components. For example, it can be desirable to include other polymers in the material to tune its properties. However, in many embodiments it is desirable for the total amount of thermoplastic fluoropolymer, functional polymer and elastomeric polymer to make up at least 75 wt% of the continuous phase, e.g., at least 90 wt% or at least 95 wt%.

[0051] The person of ordinary skill in the art can select amounts of thermoplastic fluoropolymer, functional fluoropolymer and elastomeric polymer to provide desired properties to the continuous phase and to the overall material. Notably, as the amount of thermoplastic fluoropolymer is reduced (or even eliminated), the amount of functional fluoropolymer can be increased in order to provide an overall continuous polymeric phase with a desirably high total fluoropolymer content as described above.

[0052] In various embodiments, the thermoplastic fluoropolymer is present in the continuous polymeric phase in an amount up to 90 wt%, e.g., in the range of 5-90 wt%, or 10-90 wt%, or 25-90 wt%, or 40-90 wt%, or 50-90 wt%. In various embodiments, the thermoplastic fluoropolymer is present in the continuous polymeric phase in an amount up to 80 wt%, e.g., in the range of 5-80 wt%, or 10-80 wt%, or 25-80 wt%, or 40-80 wt%, or 50-80 wt%. In various embodiments, the thermoplastic fluoropolymer is present in the continuous polymeric phase in an amount up to 70 wt%, e.g., in the range of 5-70 wt%, or 10-70 wt%, or 25-70 wt%, or 40-70 wt%, or 50-70 wt%. In various embodiments, the thermoplasticfluoropolymer is present in the continuous polymeric phase in an amount up to 50 wt%, e.g., in the range of 5-50 wt%, or 10-50 wt%, or 25-50 wt%. In various embodiments, the thermoplastic fluoropolymer is present in the continuous polymeric phase in an amount up to 25 wt%, e.g., in the range of 5-25 wt%, or 10-25 wt%. In various embodiments, the thermoplastic fluoropolymer is present in the continuous polymeric phase in an amount up to 10 wt%, e.g., in the range of 1-10 wt%, or in the range of 3-10 wt%. However, as noted above, in various embodiments the thermoplastic fluoropolymer is absent from the continuous polymeric phase.

[0053] In various embodiments, the functional polymer is present in the continuous polymeric phase in an amount in the range of 5-90 wt%, e.g., 10-90 wt%, or 25-90 wt%, or 40-90 wt%, or 5-75 wt%, or 10-75 wt%, or 25-75 wt%, or 40-75 wt%. In various embodiments, the functional polymer is present in the continuous polymeric phase in an amount in the range of 5-50 wt%, or 10-50 wt%, or 15-50 wt%, or 25-50 wt%, or 5-30 wt%, or 10-30 wt%, or 15-30 wt%, or 20-30 wt%. In various embodiments, the functional polymer is present in the continuous polymeric phase in an amount in the range of 5-20 wt%, e.g., 7- 20 wt%, or 10-20 wt%, or 13-20 wt%, or 5-15 wt%, or 7-15 wt%, or 10-15 wt%.

[0054] In various embodiments, the elastomeric polymer is present in the continuous polymeric phase in an amount in the range of 3-50 wt%, e.g., 5-50 wt%, or 10-50 wt%, or 20-50 wt%, or 3-40 wt%, or 5-40 wt%, or 10-40 wt%, or 20-40 wt%. In various embodiments, the elastomeric polymer is present in the continuous polymeric phase in an amount in the range of 3-30 wt%, e.g.,5-30 wt%, or 7-30 wt%, or 10-30 wt%, or 3-20 wt%, or 5-20 wt%, or 7-20 wt%, or 10-20 wt%. In various embodiments, the elastomeric polymer is present in the continuous polymeric phase in an amount in the range of 3-18 wt%, e.g., 5-18 wt%, or 7-18 wt%, or 10-18 wt%, or 3-15 wt%, or 5-15 wt%, or 7-15 wt%, or 10-15 wt%.

[0055] As noted above, the thermally-conductive, electrically insulating polymer composite material also includes, dispersed within the continuous polymeric phase, a thermally-conductive, electrically-insulating filler. The person of ordinary skill can provide thermally-conductive fillers that provide a desired degree of thermal conductivity while maintaining electrical resistivity and maintaining good material properties for the overall polymer composite material.

[0056] For example, in various such embodiments, the thermally-conductive, electrically- insulating filler includes (or is) boron nitride. In various embodiments, the boron nitride is hexagonal boron nitride. The boron nitride can be provided in a variety of forms, e.g., amorphous boron nitride, boron nitride of the hexagonal system, having a laminated structure of hexagonal-shaped meshed layers); or a turbotrain boron nitride, havingrandomly oriented layers; platelet boron nitride; boron nitride fibers; boron nitride agglomerates; boron nitride nanotubes. In various embodiments, the boron nitride is in a hexagonal form, a platelet form, or a turbostratic form. In various embodiments, the boron nitride is in a hexagonal form.

[0057] The person of ordinary skill in the art can select a particle size of the boron nitride to provide good dispersion within the continuous polymeric phase and good physical properties of the overall material. In various embodiments, a d50 particle size of the boron nitride is in the range of 0.05 microns to 500 microns; or from 0.5 microns to 250 microns; from 1 microns to 150 microns; from 5 microns to 100 microns or from 10 microns to 50 microns. In various embodiments, the boron nitride has a d50 particle size of at least 50 microns (e.g., 50-600 microns, or 50-400 microns, or 50-250 microns, or 50-150 microns, or 100-600 microns, or 100-400 microns, or 100-250 microns).

[0058] In various embodiments, the boron nitride comprises irregularly shaped agglomerates of hexagonal boron nitride platelets, having a d50 particle size of at least 50 μm (e.g., 50-600 microns, or 50-400 microns, or 50-250 microns, or 50-150 microns, or 100- 600 microns, or 100-400 microns, or 100-250 microns).

[0059] The boron nitride component can, for example, comprise crystalline or partially crystalline boron nitride particles made by processes known in the art. These include spherical boron nitride particles in the micron size range produced in a process utilizing a plasma gas as disclosed in U.S. Pat. No.6,652,822; hexagonal boron nitride comprising spherical boron nitride agglomerates is formed from irregular non-spherical boron nitride particles bound together by a binder and subsequently spray-dried, as disclosed in U.S. Patent Publication No.2001 / 0021740; boron nitride powder produced from a pressing process as disclosed in U.S. Pat. Nos.5,898,009 and 6,048,511; boron nitride agglomerated powder as disclosed in U.S. Patent Publication No.2005 / 0041373; boron nitride powder having high thermal diffusivity as disclosed in U.S. Patent Publication No.2004 / 0208812A1; and highly delaminated boron nitride powder as disclosed in U.S. Pat. No.6,951,583. These also include boron nitride particles of the platelet morphology.

[0060] In various embodiments, the boron nitride is in the form of spherical agglomerates of hexagonal boron nitride platelets. In one embodiment of spherical boron nitride powder, the agglomerates have a d50 particle size in the range of 10-500 microns.

[0061] In various embodiments, the boron nitride is in the form of platelets having an average length along the b-axis of at least about 1 micron, and typically 1-20 microns, and a thickness of no more than about 5 microns. In various embodiments, the boron nitride is in the form of platelets having an average aspect ratio of from about 50 to about 300.

[0062] In various embodiments, the boron nitride particles comprise hexagonal boron nitride platelets having an aspect ratio of from about 10 to about 300. In another embodiment, the boron nitride particles have an oxygen content from 0.2 to 2.5 wt. %. In another embodiment, the hexagonal boron nitride particles have a graphitization index of less than 7.

[0063] In various embodiment, the boron nitride is coated (i.e., surface-treated) to improve compatibility with and dispersion in the continuous polymeric phase. Examples of surface coating materials for the boron nitride powder include, but are not limited to, reactive silane, isohexadecane, liquid paraffin, non-ionic surfactants, dimethylpolysiloxane (or dimethicone), a mixture of completely methylated, linear siloxane polymers which have been terminally blocked with trimethylsiloxy units, a silazane compound possessing perfluoroalkyl groups, a titanate coupling agent, a zirconate coupling agent, a zirconium aluminate coupling agent, an aluminate coupling agent, and mixtures thereof. In one embodiment, the boron nitride is coated in a reactive silane which may covalently bond to the boron nitride particles and to the surrounding continuous polymeric phase, e.g., the siloxane residues.

[0064] Boron nitride is available from a variety of commercial sources, including Saint Gobain Ceramics, 3M, Sintec Keramic, Kawasaki Chemicals, and Momentive Performance Materials.

[0065] A variety of other thermally-conductive, electrically-insulating fillers are known in the art and can be used in addition to or instead of boron nitride. For example, in various embodiments, the thermally-conductive, electrically-insulating filler includes (or is) one or more of aluminum nitride and alumina. But the person of ordinary skill in the art is familiar with a variety of other thermally-conductive, electrically-insulating fillers that could be used, such as silicon nitride, silicon carbide or beryllium oxide.

[0066] The person of ordinary skill in the art can determine a loading of thermally- conductive, electrically-insulating filler that provides a desired degree of thermal performance together with necessary material properties. In various embodiments, the continuous polymeric phase is present in an amount of 10-90 wt% of the material, and the thermally-conductive, electrically-insulating filler is present in an amount of 10-90 wt% of the material. In various embodiments, the continuous polymeric phase is present in an amount in the range of 10-80 wt% (e.g., 10-70 wt%, or 10-60 wt%, or 10-50 wt%, or 10-40 wt%, or 10-30 wt%) and the material and the thermally-conductive, electrically-insulating filler is present in an amount in the range of 20-90 wt% (e.g., 30-90 wt%, or 40-90 wt%, or 50-90 wt%, or 60-90 wt% or 70-90 wt%) of the material. In various embodiments, the continuous polymeric phase is present in an amount in the range of 20-90 wt% (e.g., 20-80 wt%, or 20-70 wt%, or 20-60 wt%, or 20-50 wt%, or 20-40 wt%) and the material and the thermally- conductive, electrically-insulating filler is present in an amount in the range of 10-80 wt% (e.g., 20-80 wt%, or 30-80 wt%, or 40-80 wt%, or 50-80 wt%, or 60-80 wt%) of the material. In various embodiments, the continuous polymeric phase is present in an amount in the range of 30-90 wt% (e.g., 30-80 wt%, or 30-70 wt%, or 30-60 wt%, or 30-50 wt%) and the material and the thermally-conductive, electrically-insulating filler is present in an amount in the range of 10-70 wt% (e.g., 20-70 wt%, or 30-70 wt%, or 40-70 wt%, or 50-70 wt%) of the material. In various embodiments, the continuous polymeric phase is present in an amount in the range of 40-90 wt% (e.g., 40-80 wt%, or 40-70 wt%, or 40-60 wt%) and the material and the thermally-conductive, electrically-insulating filler is present in an amount in the range of 10-60 wt% (e.g., 20-60 wt%, or 30-60 wt%, or 40-60 wt%) of the material. In various embodiments, the continuous polymeric phase is present in an amount in the range of 50-90 wt% (e.g., 50-80 wt%, or 50-70 wt%) and the material and the thermally-conductive, electrically-insulating filler is present in an amount in the range of 10-50 wt% (e.g., 20-50 wt%, or 30-50 wt%) of the material. In various embodiments, the continuous polymeric phase is present in an amount in the range of 60-90 wt% (e.g., 60-80 wt%) and the material and the thermally-conductive, electrically-insulating filler is present in an amount in the range of 10-40 wt% (e.g., 20-40 wt%) of the material. In various embodiments, the continuous polymeric phase is present in an amount in the range of 70-90 wt% and the material and the thermally-conductive, electrically-insulating filler is present in an amount in the range of 10- 30 wt% of the material.

[0067] The present inventors have noted that beneficial material properties can be provided especially when the amount of thermally-conductive filler is no more than 40 wt% of the material. For example, in various embodiments, the continuous polymeric phase is present in an amount of 60-80 wt% of the material, and the thermally-conductive filler is present in an amount of 20-40 wt% of the material.

[0068] The present inventors have found that well-performing thermally-conductive, electrically-insulating polymer composite materials can be provided using the continuous polymeric phase and the thermally-conductive, electrically-insulating filler as the substantial components. For example, in various embodiments, the continuous polymeric phase and the thermally-conductive filler make up at least 75 wt% of the thermally-conductive, electrically-insulating polymer composite material, e.g., at least 90 wt%, or at least 95 wt%.

[0069] Moreover, the person of ordinary skill in the art will appreciate that a variety of other components can be present in the material. These can include, without limitation, one or more of metal oxides, smoke suppressants, flame retardants, boron containing compounds, anti-drip agents, fillers / reinforcements, minerals, other inorganic fillers such asC-nanotubes, flow aids / plasticizers, mold release compounds, antioxidants, impact modifiers, fibers / fibrous fillers, thermal stabilizers, nucleating agents, clarifying agents, crystallization suppressants / accelerators, colors / dyes / pigments, UV absorbers, light stabilizers, lubricants, anti-static agents, foaming agents, and anti-foaming agents. These can be selected by the person of ordinary skill in the art to provide desirable properties to the material, especially with the goal of maintaining thermal conductivity and electrical resistivity.

[0070] In many cases, it is important that the thermally-conductive, electrically-insulating material has relatively high thermal conductivity. The person of ordinary skill in the art can provide highly-conductive materials based on the present disclosure. For example, in various embodiments, the thermally-conductive, electrically-insulating material has a thermal conductivity of at least 0.3 W / m-K, e.g., in the range of 0.3-10 W / m-K, or 0.3-5 W / m-K, or 0.3-3 W / m-K, or 0.3-2 W / m-K. In various embodiments, the thermally-conductive, electrically-insulating material has a thermal conductivity of at least 0.5 W / m-K, e.g., in the range of 0.5-10 W / m-K, or 0.5-5 W / m-K, or 0.5-3 W / m-K, or 0.5-2 W / m-K. In various embodiments, the thermally-conductive, electrically-insulating material has a thermal conductivity of at least 0.7 W / m-K, e.g., in the range of 0.7-10 W / m-K, or 0.7-5 W / m-K, or 0.7-3 W / m-K, or 0.7-2 W / m-K. In various embodiments, the thermally-conductive, electrically-insulating material has a thermal conductivity of at least 1 W / m-K, e.g., in the range of 1-10 W / m-K, or 1-5 W / m-K, or 1-3 W / m-K, or 1-2 W / m-K. In various embodiments as described above, the thermally-conductive, electrically-insulating material has a thermal conductivity of greater than 0.25 W / m-K, e.g., greater than 0.27 W / m-K. In various embodiments as described above, the thermally-conductive, electrically-insulating material has a thermal conductivity of greater than 0.4 W / m-K, e.g., greater than 0.42 W / m-K. In various embodiments, thermal conductivities are quantified using the procedure of ASTM C177-19. In various embodiments, thermal conductivities are quantified using the procedure of ASTM D5470-12. In various embodiments, thermal conductivities are quantified using the procedure of ASTM C518-17.

[0071] In many cases, it is important that the thermally-conductive, electrically-insulating material has relatively high electrical resistivity. The person of ordinary skill in the art can provide highly-resistive materials based on the present disclosure. For example, in various embodiments, the thermally-conductive, electrically-insulating material has an electrical resistivity of at least 108ohms-cm, e.g., at least 1010ohms-cm, or at least 1012ohms-cm. Electrical resistivities are measured as described in ASTM D257-14(2021)e1.

[0072] Notably, the materials of the disclosure can be made to have relatively low flexural modulus, which can allow for flexible tubings to be made. In various embodiments, the materials of the disclosure have a flexural modulus of no more than 600 MPa, e.g., nomore than 550 MPa, or no more than 500 MPa. In various embodiments, the materials of the disclosure have a flexural modulus in the range of 300-600 MPa, e.g., 300-550 MPa, or 300-500 MPa, or 350-600 MPa, or 350-550 MPa, or 350-500 MPa, or 400-600 MPa, or 400- 550 MPa, or 400-500 MPa. Flexural modulus is measured on flex bars at 23 °C using ASTM D790.

[0073] The materials of the disclosure can in many embodiments be formed via extrusion into tubings having relatively low bend radii. For example, in various embodiments, a material of the disclosure, when formed via extrusion into a tubing having an inner diameter of 4.7 mm and a wall thickness of 0.67 mm, has a minimum bend radius of no more than 18 mm, e.g., no more than 17 mm, or no more than 15 mm. In various embodiments, a material of the disclosure, when formed via extrusion into a tubing having an inner diameter of 4.7 mm and a wall thickness of 0.67 mm, has a minimum bend radius in the range of 10-18 mm, e.g., 10-17 mm, or 10-15 mm, or 12-18 mm, or 12-17 mm, or 12-15 mm, or 13-18 mm, or 13-17 mm, or 13-15 mm.

[0074] The materials of the disclosure can be compounded and processed using techniques familiar to the person of ordinary skill in the art. For example, materials can be compounded by melt blending, although solution blending is also possible. Melt processing methods can be performed in a variety of types of equipment, such as twin-screw extruders (e.g., co-rotating and counter-rotating extruders), single screw extruders, co-kneaders, disc- pack processors and various other types of extrusion equipment. The person of ordinary skill in the art can select processing conditions, for example, by working at desirably low temperatures and / or shear rates and / or head pressure and / or residence time to avoid excessive degradation of the material. The blended material can be formed into pellets or granules for later processing into desired articles, or, in some cases, can be directly extruded into a desired shape (e.g., a tubing).

[0075] It can be desirable in some embodiments to crosslink the elastomeric polymer (e.g., partially or substantially completely) before it is compounded with the fluorinated polymer phase. The crosslinked material can be provided in a desirable particle size (e.g., by grinding) before formulation. Accordingly, the particle size of the provided elastomeric polymer can be used to control the size of the elastomer domains in the continuous polymeric phase.

[0076] In particular embodiments, the polymer composite materials according to the present invention, can also be shaped or fabricated into films, coatings, sheets, strips, tapes, ribbons and the like. The film, coating and sheet may be fabricated by any method known in the art, including blown bubble processes (e.g., simple bubble as well as biaxial orientationtechniques such trapped bubble, double bubble and tenter framing), cast extrusion, injection molding processes, thermoforming processes, extrusion coating processes, profile extrusion, and sheet extrusion processes. As noted above, the extrusion used to blend the material can in some cases also be used to form a desired shape of the material, e.g., a tubing.

[0077] In some embodiments as described above, the polymer composite material is crosslinked, e.g., by treatment with an e-beam, or by reaction of a peroxide or other free radical initiator, or with a crosslinker. The person of ordinary skill in the art will select an appropriate time for such crosslinking, recognizing that it is often desirable to perform such crosslinking after the material is formed into a desired shape (e.g., after it is formed into a tubing), as crosslinked materials will often be difficult to further shape. When e-beam treatment is used, in various embodiments the energy level is in the range of 1 to 50 MeV with total ionizing dosage in the range of 10 to 300 kGy.

[0078] While extrusion can be used to form articles from the materials of the disclosure as noted above and as described below with respect to tubings, the person of ordinary skill in the art will appreciate that a variety of other techniques can be used, for example, compression molding, injection molding, stamp molding, embossing, and blow molding.

[0079] As noted above, the materials of the disclosure can be especially useful in the formation of tubings for thermal transfer applications. Accordingly, another aspect of the disclosure is tubing comprising at least one annular layer of a thermally-conductive, electrically-insulating polymer composite material as described herein. FIG.2 provides a schematic cross-sectional view of such a tubing 220, which includes a single annular layer of a thermally-conductive, electrically-insulating polymer composite material 200.

[0080] The thickness of the annular layer of the thermally-conductive, electrically- insulating polymer composite material can vary. For example, in various embodiments, the layer thickness is in the range of 0.1-5 mm, e.g., 0.1-3 mm, or 0.1-2 mm, or 0.1-1.5 mm, or 0.1-1 mm. In various embodiments, the layer thickness is in the range of 0.25-5 mm, e.g., 0.25-3 mm, or 0.25-2 mm, or 0.25-1.5 mm, or 0.25-1 mm. In various embodiments, the layer thickness is in the range of 0.5-5 mm, or 0.5-3 mm, or 0.5-2 mm, or 0.5-1.5 mm, or 0.5-1 mm. In various embodiments, the layer thickness is in the range of 1-5 mm, e.g., 1-3 mm, or 1-2 mm.

[0081] The tubing can be provided with a variety of inner diameters. For example, in various embodiments, the tubing has an inner diameter in the range of 1-50 mm, e.g., in the range of 2-30 mm, or 2-20 mm, or 2-10 mm. In various embodiments, the tubing has an inner diameter in the range of 5-50 mm, e.g., in the range of 5-30 mm, or 5-20 mm, or 5-10mm. In various embodiments, the tubing has an inner diameter in the range of 10-50 mm, e.g., in the range of 10-30 mm, or 10-20 mm.

[0082] The person of ordinary skill in the art can select a thickness of the annular layer as well as overall tubing to provide a tubing with a desired thermal conductivity and desired physical properties (e.g., wall strength, flexibility, pressure drop, minimum bend radius, burst pressure, flex fatigue life, compression set, axial elongation, radial expansion, radial compression) for a desired application.

[0083] In various embodiments, the tubing is formed substantially of the material of the disclosure. For example, in various embodiments, a cross-section of the tubing is formed of at least 75 wt% of the material of the disclosure, e.g., at least 90 wt%, or at least 95 wt%. Of course, the person of ordinary skill in the art can include other layers in the tubing, such as an internal fluid contact layer or an exterior ink layer, but desirably such layers do not substantially affect the thermal conductivity of the tubing. And in sections of the tubing where heat transfer is not desired, the tubing can be further jacketed.

[0084] In various embodiments, a tubing of the disclosure has a minimum bend radius of no more than 18 mm, e.g., no more than 17 mm, or no more than 15 mm. For example, in various embodiments, a tubing of the disclosure has a minimum bend radius in the range of 10-18 mm, e.g., 10-17 mm, or 10-15 mm, or 12-18 mm, or 12-17 mm, or 12-15 mm, or 13-18 mm, or 13-17 mm, or 13-15 mm. In various such embodiments, the tubing has an inner diameter of 4.7 mm + / - 0.4 mm and a wall thickness of 0.7 + / - 0.15 mm.

[0085] The tubings of the disclosure can be prepared to exhibit not only high thermal conductivity and high electrical resistivity, but also a one or more of a variety of other properties, such as a high temperature rating for continuous operation, high flexibility, high flame retardance, high burst pressure, high dielectric strength, chemical inertness, especially to cooling fluids, and strong bondability to outer encapsulating materials such as another concentric polymer layer, braided polymer fibers, metal braids and wires, and with potting resins. The outer surface of the tubing can be modified using chemical and physical methods such as a chemical etch treatment, corona treatment or plasma treatment.

[0086] The person of ordinary skill in the art can use conventional methods to make the tubing, e.g., by extrusion. In various embodiments, the melt blending of the polymers and blends and any other additives, necessary or desirable to improve the properties of the tubing, may be compounded in an extruder by adding the components simultaneously at the throat or sequentially through different feeders located at different positions along the barrel of the extruder. The extrudate emanating from the extruder may be either fed directly to a separate extruder, or cooled and converted into pellets or granules for use in a futureoperation to make the tubing. Alternatively, the tubing may be directly extruded by feeding the components, and additives, directly into an extruder configured with a tubing extrusion die, where the components may be mixed immediately prior to extrusion.

[0087] The present inventors have determined that the tubings of the disclosure can be used in thermal management applications, for example, to cool a heat source. The tubings of the disclosure can have a high rate of thermal transfer through the thermally-conductive, electrically-insulating polymer composite material, while remaining electrically insulating, flexible and chemically inert. For example, another aspect of the disclosure is a method for transferring heat from a heat source. The method comprises providing a tubing of the disclosure positioned in substantial thermal communication with the heat source at a first position, the tubing having a working fluid (e.g., water) disposed therein and transferring heat from the heat source through the tubing and into the working fluid. The method can, in various embodiments, further include conducting the working fluid away from the first position. The working fluid can, in various embodiments, be conducted via the tubing to a second position, where heat can be conducted from the working fluid through the tubing to the surrounding atmosphere or to a cooler object, such as a heat exchanger, a radiator or a heat sink.

[0088] Similarly, another aspect of the disclosure is thermal management system for cooling a heat source. The thermal management system can include a tubing of the disclosure in substantial thermal communication with the heat source at a first position; and a source of a working fluid (e.g., water) configured to conduct the working fluid through the tubing. The source of the working fluid can be, for example, a water line provided with sufficient pressure to conduct water through the tubing; or can be a tank of working fluid (e.g., a coolant) with a pump configured to pump the working fluid through the tubing. In various embodiments the system can further include a heat exchanger, a radiator or a heat sink operatively coupled to the tubing and configured to remove heat from the working fluid at a second position different from the first position. The heat exchanger, radiator or heat sink can, for example, be provided in a substantially closed circuit with the tubing and the source of the working fluid.

[0089] The thermal management systems and methods of the disclosure can be applicable to a wide variety of heat sources. In various embodiments, the heat source is operating at a temperature, or has an operating temperature, in the range of 50-250 °C, e.g., in the range of 50-200 °C, or 50-150 °C, or 50-100 °C, or 75-250 °C, or 75-200 °C, or 75-150 °C, or 75-125 °C. or 100-250 °C, or 100-200 °C, or 100-150 °C, or 150-250 °C, or 150-200 °C. As the tubings of the disclosure can be made to be substantially electrically-insulating, they are especially useful with heat sources that are electrical or magnetic in nature. Forexample, in various embodiments, the heat source comprises one or more magnets, e.g., one or more electromagnets, such as magnetic coils. In various embodiments, the heat source comprises one or more electrical devices, such as a battery (or an anode or cathode thereof); an electric motor; a computing system or subsystem such as a computer circuit (integrated or otherwise); a lamp; and a laser. Of course, the person of ordinary skill in the art will identify other heat sources that can be suitably cooled by the methods and systems of the disclosure.

[0090] An example of such a system is shown in schematic view in FIG.3. Here, system 330 includes a heat source 340, and a tubing 320 of the disclosure in substantial thermal contact with the heat source at a first position 345, here, by being wound around the heat source. A source of working fluid 350 is configured to conduct the working fluid through the tubing. In the example of FIG.3, the system 330 further includes a heat exchanger 360 operatively coupled to the tubing and configured to remove heat from the working fluid at a second position 365 different from the first position 345. Here, the heat exchanger is provided in a substantially closed circuit with the tubing and the source of the working fluid.

[0091] The tubings of the disclosure can be made to be resistant to a variety of common fluids. Accordingly, a variety of different fluids can be used as the working fluid. The person of ordinary skill in the art, can, for example, select from a variety of coolants for use as the working fluid. In various embodiments, the working fluid comprises (or is) water. In various embodiments, the working fluid comprises (or is) a glycol, such as ethylene glycol or propylene glycol, which in some embodiments can be provided in combination with water.

[0092] The present inventors have determined that the tubings, methods and systems of the disclosure can be especially useful in heat management in magnetic resonance systems like magnetic resonance imaging systems. For example, during a patient scan, the gradient coil(s) of the gradient coil assembly that produce the magnetic field gradients dissipate large amounts of heat. The heat produced by the gradient coils can cause an increase in the temperature of the MRI system's patient bore and the magnet warm bore. Heating of the patient bore may reduce the amount of RF power that can be transmitted during imaging which in turn can affect the efficiency of the MRI system. In addition, an increase in temperature of the patient bore can be uncomfortable for a patient and may even become dangerous unless safety interlocks are designed to prevent overheating. Minimizing any increase in temperature of the patient bore is important to MRI scanner efficiency and safety. Similar issues apply to other types of magnetic resonance instruments. The heat produced by the gradient coil assembly of an magnetic resonance system (e.g., by the gradient coils themselves and / or by other components in the gradient coil assembly) may be removed using the methods and systems of the disclosure. Accordingly, in various embodiments ofthe methods and systems described herein, the heat source is a gradient coil assembly of a magnetic resonance instrument, e.g., a magnetic resonance imaging instrument.

[0093] Another aspect of the disclosure is a magnetic resonance instrument, e.g., a magnetic resonance imaging instrument, comprising a gradient coil assembly and a tubing of the disclosure in substantial thermal communication with the gradient coil assembly at a first position, and a source of a working fluid configured to conduct the working fluid through the tubing. The magnetic resonance instrument can be further configured as described above with respect to systems of the disclosure, and methods analogous to the methods of the disclosure can be used to cool the gradient coil assembly.

[0094] Various methods of cooling, cooling systems and MRI instruments are described, for example, in U.S. Patents nos.7015692, 7250766, 7301343, 7495444 and 8362774, each of which is hereby incorporated herein by reference in its entirety. Various embodiments of the disclosure as described herein can be configured as described in any of these references, using the tubings of the disclosure as a replacement for the coolant tubings described therein.

[0095] Various aspects of the disclosure are exemplified by the following non-limiting examples.

[0096] Nine formulations were compounded by twin screw extrusion.

[0097] The ETFE was a poly(ethylene-co-tetrafluoroethylene) thermoplastic having a melt flow rate in the range of 10-20 g / 10 min as measured by ASTM D3159 at 297 C and 47 N. The elastomeric polymer was a copolymer of tetrafluoroethylene / propylene (TFE / P). The functional polymer was functionalized ETFE formed with the reaction of ethylene, tetrafluoroethylene and itaconic anhydride.

[0098] Formulations 1 and 6-11 feed had a V-0 rating in a 50 W vertical burning test pursuant to UL 94.

[0099] Tubings were extruded from formulations 1, 2 and 6-11.

[0100] The flexural modulus of the ETFE material and Formulations 1-11 were measured on flex bars at room temperature using ASTM D790. Formulations 1-11 respectively exhibited flexural moduli of 716, 790, 470, 420, 525, 320, 330, 522, 480, 470 and 511 MPa. The data demonstrate how the addition of the elastomer helps decrease the flexural modulus of the overall material, including balancing out the increase in flexural modulus from the inclusion of the filler.

[0101] Samples were tested via lap shear testing for their bonding to an epoxy resin. A nylon control exhibited a failure at 84 lb load. Formulation 10 exhibited failure at a much higher load, 123.5 lb. When a sample of Formulation 10 was plasma treated or sodium etched, the load at failure was even higher (231.0 lb and 215.2 lb, respectively).

[0102] Impulse testing was conducted on Formulation I; it survived one million cycles at 145 psi at 60 C. Impulse testing was performed according to SAE J434 guidelines. Unaged hose assemblies with end fittings were bent through 180 degrees and connected to the apparatus. This test was conducted with oil temperature at 60 °C and pressure at 145 psi. Apulsating pressure was applied internally to the hose assembly at a rate of 604.0 psi / s. Once the pressure inside the tube reached 145 psi, that pressure was held for 0.6 seconds and then released. Altogether, this is one cycle and it lasts 1.2 seconds. The test was continued at a rate of 50 cycles per minutes until the sample fails or reached 1 million cycles.

[0103] Various aspects and embodiments of the disclosure are further described by the following enumerated embodiments, which may be combined in any number and in any combination that is not logically or technically inconsistent. Embodiment 1. A thermally-conductive, electrically-insulating polymer composite material, comprising: a continuous polymeric phase comprising a fluorinated polymer phase having a total fluoropolymer content of at least 50 wt%, the fluorinated polymer phase comprising; a functional polymer, the functional polymer comprising reactive functional groups; and optionally, a thermoplastic fluoropolymer, the thermoplastic fluoropolymer being miscible with the functional polymer; and phase-separated from the fluorinated polymer phase, an elastomeric polymer; and dispersed within the continuous polymeric phase, a thermally-conductive, electrically- insulating filler. Embodiment 2. A thermally-conductive, electrically-insulating polymer composite material according to embodiment 1, wherein the fluorinated polymer phase has a total fluoropolymer content of at least 60 wt%, e.g., at least 70 wt%, or at least 80 wt%, or at least 90 wt%. Embodiment 3. A thermally-conductive, electrically-insulating polymer composite material according to embodiment 1 or embodiment 2, wherein the fluorinated polymer phase has a ratio of hydrogen atoms to fluorine atoms of no more than 2, for example, no more than 1.5, or no more than 1, or no more than 0.5. Embodiment 4. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-3, wherein the fluorinated polymer phase has a peak melting point of at least 190 °C, e.g., at least 200 °C, or at least at least 210°C or at least 220 °C.Embodiment 5. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-4, wherein the fluorinated polymer phase has a melt flow rate in the range of 5-50 g / 10 min as measured by ASTM D3159 at 297 ºC and 47 N, e.g., in the range of 5-40 g / 10 min, 5-30 g / 10 min, or 5-20 g / 10 min, or 10-50 g / 10 min, or 10-40 g / 10 min, or 10-30 g / 10 min, or 10-20 g / 10 min, or 20-50 g / 10 min, or 20-40 g / 10 min, or 20-30 g / 10 min, or 30-50 g / 10 min, or 30-40 g / 10 min. Embodiment 6. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-5, wherein the thermoplastic fluoropolymer is present. Embodiment 7. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-6, wherein the thermoplastic fluoropolymer has a peak melting point of at least 190 °C, e.g., at least 200 °C, or at least at least 210°C or at least 220 °C. Embodiment 8. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-7, wherein the thermoplastic fluoropolymer includes (or is) poly(ethylene-co-tetrafluoroethylene) (“ETFE”). Embodiment 9. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-8, wherein the thermoplastic fluoropolymer includes (or is) poly(tetrafluoroethylene-co-hexafluoropropylene) (“FEP”). Embodiment 10. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-9, wherein the thermoplastic fluoropolymer includes (or is) a thermoplastic fluoropolymer having in the range of 5-70 wt% non- fluorinated residues, e.g., in the range of 5-50 wt%, or 5-30 wt%, or 10-70 wt%, or 10-50 wt%, or 10-30 wt%. Embodiment 11. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-10, wherein the thermoplastic fluoropolymer includes (or is) polyvinylidenefluoride (PVF), poly(tetrafluoroethylene-co-perfluoro(alkyl vinyl ether)) (PFA), polyvinylidene difluoride (PVDF), polychlorotrifluoroethlylene (PCTFE), tetrafluoroethylene / hexafluoropropylene / ethylene copolymer (HTE), chlorotrifluoroethylene / vinylidenefluoride copolymer,chlorotrifluoroethylene / hexafluoropropylene, ethylene / chlorotrifluoroethylene copolymers (ECTFE), ethylene / trifluoroethylene copolymers, tetrafluoroethylene / propylene copolymers (TFE / P), tetrafluoroethylene / hexafluoropropylene copolymers (FEP / HFP), and / or hexafluoropropylene / tetrafluoroethylene / vinylidene copolymer (THV). Embodiment 12. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-11, wherein the thermoplastic fluoropolymer has a melt flow rate in the range of 5-50 g / 10 min as measured by ASTM D3159 at 297 ºC and 47 N, e.g., in the range of 5-40 g / 10 min, 5-30 g / 10 min, or 5-20 g / 10 min, or 10-50 g / 10 min, or 10-40 g / 10 min, or 10-30 g / 10 min, or 10-20 g / 10 min, or 20-50 g / 10 min, or 20-40 g / 10 min, or 20-30 g / 10 min, or 30-50 g / 10 min, or 30-40 g / 10 min. Embodiment 13. A thermally-conductive electrically-insulating polymer composite material according to any of embodiments 1-12, wherein the thermoplastic fluoropolymer has a continuous use operating temperature rating of at least 100 °C, e.g., at least 150 °C, or at least 180 °C, or at least 200 °C. Embodiment 14. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-5, wherein the thermoplastic fluoropolymer is not present. Embodiment 15. A thermally-conductive electrically-insulating polymer composite material according to any of embodiments 1-14, wherein the functional groups of the functional polymer are hydroxyl groups, anhydride groups, carboxylate groups, and / or amine groups. Embodiment 16. A thermally-conductive electrically-insulating polymer composite material according to any of embodiments 1-15, wherein the functional groups of the functional polymer include (or are) anhydride groups. Embodiment 17. A thermally-conductive electrically-insulating polymer composite material according to any of embodiments 1-16, wherein the functional groups of the functional polymer include (or are) hydroxyl groups. Embodiment 18. A thermally-conductive electrically-insulating polymer composite material according to any of embodiments 1-17, wherein the functional groups of the functional polymer include (or are) amine groups.Embodiment 19. A thermally-conductive electrically-insulating polymer composite material according to any of embodiments 1-18, wherein the functional groups of the functional polymer include (or are) carboxylate groups. Embodiment 20. A thermally-conductive electrically-insulating polymer composite material according to any of embodiments 1-19, wherein the functional polymer is a functional fluoropolymer. Embodiment 21. A thermally-conductive electrically-insulating polymer composite material according to embodiment 20, wherein the functional polymer is a functional ETFE or a functional FEP, i.e., a ETFE or an FEP that bears the functional groups. Embodiment 22. A thermally-conductive electrically-insulating polymer composite material according to embodiment 20 or embodiment 21, wherein the functional fluoropolymer is a copolymer of a fluorinated monomer copolymerized with a functional monomer bearing the reactive functional group. Embodiment 23. A thermally-conductive electrically-insulating polymer composite material according to embodiment 22, wherein the functional monomer is an anhydride- bearing monomer such as itaconic anhydride or maleic anhydride. Embodiment 24. A thermally-conductive electrically-insulating polymer composite material according to embodiment 22, wherein the functional polymer is a copolymer of a monomer containing an anhydride (e.g., itaconic anhydride or maleic anhydride), (ii) ethylene, and (iii) tetrafluoroethylene. Embodiment 25. A thermally-conductive electrically-insulating polymer composite material according to embodiment 22, wherein the functional fluoropolymer is provided by graft polymerization of functional monomers onto an already-formed fluoropolymer. Embodiment 26. A thermally-conductive electrically-insulating polymer composite material according to embodiment 22, wherein the functional fluoropolymer is a fluoropolymer that has been treated with an oxidant, a plasma (e.g., using a corona treatment), or with some other chemical treatment to provide the functional groups.Embodiment 27. A thermally-conductive, electrically-insulating polymer composite material according to embodiment 21, wherein the functional polymer is modified poly(ethylene-co- tetrafluoroethylene) copolymer comprising hydroxyl or amine reactive functional groups. Embodiment 28. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-27, wherein the elastomeric polymer is a fluoroelastomer. Embodiment 29. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-27, wherein the elastomeric polymer is one or more of TFE / P copolymer, a tetrafluoroethylene / propylene / vinylidenefluoride copolymer, a vinylidenefluoride / hexafluoropropylene copolymer, a vinylidenefluoride / hexafluoropropylene / tetrafluoroethylene copolymer, a vinylidenefluoride / tetrafluoroethylene / perfluoroalkylvinylether copolymer, a vinylidenefluoride / hexafluoropropylene / tetrafluoroethyene / perfluoroalkylvinylether copolymer, a vinylidenefluoride / hexafluoropropylene / perfluoroalkylvinylether copolymer, a tetrafluoroethylene / ethylene / perfluoroalkylvinylether copolymer, a vinylidenefluoride / hexafluoropropylene / tetrafluoroethylene / ethylene / perfluoroalkylvinyl ether copolymer, a vinylidenefluoride / chlorotrifluoroethylene copolymer, or a 1,1,1,2-tetrafluoro-2- propene / vinylidene fluoride copolymer. Embodiment 30. A thermally-conductive, electrically-insulating polymer composite material according to embodiments 1-27, wherein the elastomeric polymer is an FKM fluoropolymer or a fluorosilicone rubber. Embodiment 31. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-27, wherein the elastomeric polymer is silicone rubber, or ethylene-propene-diene monomer (EPDM) rubber, or chlorosulfonated polyethylene rubber, or hydrogenated acrylonitrile-butadiene rubber (HNBR). Embodiment 32. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-31, wherein the elastomeric polymer is crosslinked.Embodiment 33. A thermally-conductive, electrically-insulating polymer composite material according to embodiment 32, wherein the elastomeric polymer is crosslinked and formed into particles before being compounded with the fluorinated polymer phase. Embodiment 34. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-7, 14, 32 and 33, wherein the thermoplastic fluoropolymer, if present, is poly(ethylene-co-tetrafluoroethylene); the functional polymer is modified poly(ethylene-co-tetrafluoroethylene) copolymer comprising anhydride reactive functional groups; and the elastomeric polymer is poly(vinylidene fluoride- hexafluoropropylene) type-1 FKM rubber. Embodiment 35. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-34, wherein the total amount of thermoplastic fluoropolymer, functional fluoropolymer and elastomeric polymer makes up at least 75 wt% of the continuous phase, e.g., at least 90 wt% or at least 95 wt%. Embodiment 36. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-35, wherein the thermoplastic fluoropolymer is present in the continuous polymeric phase in an amount up to 90 wt%, e.g., in the range of 5-90 wt%, or 10-90 wt%, or 25-90 wt%, or 40-90 wt%, or 50-90 wt%. Embodiment 37. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-35, wherein the thermoplastic fluoropolymer is present in the continuous polymeric phase in an amount up to 80 wt%, e.g., in the range of 5-80 wt%, or 10-80 wt%, or 25-80 wt%, or 40-80 wt%, or 50-80 wt%. Embodiment 38. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-35, wherein the thermoplastic fluoropolymer is present in the continuous polymeric phase in an amount up to 70 wt%, e.g., in the range of 5-70 wt%, or 10-70 wt%, or 25-70 wt%, or 40-70 wt%, or 50-70 wt%. Embodiment 39. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-35, wherein the thermoplastic fluoropolymer is present in the continuous polymeric phase in an amount up to 50 wt%, e.g., in the range of 5-50 wt%, or 10-50 wt%, or 25-50 wt%.Embodiment 40. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-35, wherein the thermoplastic fluoropolymer is present in the continuous polymeric phase in an amount up to 25 wt%, e.g., in the range of 5-25 wt%, or 10-25 wt%. Embodiment 41. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-35, wherein the thermoplastic fluoropolymer is present in the continuous polymeric phase in an amount up to 10 wt%, e.g., in the range of 1-10 wt%, or in the range of 3-10 wt%. Embodiment 42. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-41, wherein the functional polymer is present in the continuous polymeric phase in an amount in the range of 5-90 wt%, e.g., 10-90 wt%, or 25-90 wt%, or 40-90 wt%, or 5-75 wt%, or 10-75 wt%, or 25-75 wt%, or 40-75 wt%. Embodiment 43. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-41, wherein the functional polymer is present in the continuous polymeric phase in an amount in the range of 5-50 wt%, or 10-50 wt%, or 15- 50 wt%, or 25-50 wt%, or 5-30 wt%, or 10-30 wt%, or 15-30 wt%, or 20-30 wt%. Embodiment 44. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-41, wherein the functional polymer is present in the continuous polymeric phase in an amount in the range of 5-20 wt%, e.g., 7-20 wt%, or 10-20 wt%, or 13-20 wt%, or 5-15 wt%, or 7-15 wt%, or 10-15 wt%. Embodiment 45. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-44, wherein the elastomeric polymer is present in the continuous polymeric phase in an amount in the range of 3-50 wt%, e.g., 5-50 wt%, or 10-50 wt%, or 20-50 wt%, or 3-40 wt%, or 5-40 wt%, or 10-40 wt%, or 20-40 wt%. Embodiment 46. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-44, wherein the elastomeric polymer is present in the continuous polymeric phase in an amount in the range of 3-30 wt%, e.g.,5-30 wt%, or 7-30 wt%, or 10-30 wt%, or 3-20 wt%, or 5-20 wt%, or 7-20 wt%, or 10-20 wt%. Embodiment 47. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-44, wherein the elastomeric polymer is presentin the continuous polymeric phase in an amount in the range of 3-18 wt%, e.g., 5-18 wt%, or 7-18 wt%, or 10-18 wt%, or 3-15 wt%, or 5-15 wt%, or 7-15 wt%, or 10-15 wt%. Embodiment 48. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-47, wherein the thermally-conductive, electrically-insulating filler includes (or is) boron nitride, e.g., hexagonal boron nitride. Embodiment 49. A thermally-conductive, electrically-insulating polymer composite material according to embodiment 48, wherein the boron nitride has a d50 particle size in the range of 0.05 microns to 500 microns; or from 0.5 microns to 250 microns; from 1 microns to 150 microns; from 5 microns to 100 microns or from 10 microns to 50 microns. Embodiment 50. A thermally-conductive, electrically-insulating polymer composite material according to embodiment 48, wherein the boron nitride has a d50 particle size of at least 50 microns (e.g., 50-600 microns, or 50-250 microns, or 50-150 microns). Embodiment 51. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-50, wherein the thermally-conductive, electrically-insulating filler includes (or is) one or more of aluminum nitride and alumina. Embodiment 52. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-51, wherein the continuous polymeric phase is present in an amount of 10-90 wt% of the material, and the thermally-conductive, electrically-insulating filler is present in an amount of 10-90 wt% of the material. Embodiment 53. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-51, wherein the continuous polymeric phase is present in an amount in the range of 10-80 wt% (e.g., 10-70 wt%, or 10-60 wt%, or 10-50 wt%, or 10-40 wt%, or 10-30 wt%) and the material and the thermally-conductive, electrically-insulating filler is present in an amount in the range of 20-90 wt% (e.g., 30-90 wt%, or 40-90 wt%, or 50-90 wt%, or 60-90 wt% or 70-90 wt%) of the material. Embodiment 54. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-51, wherein the continuous polymeric phase is present in an amount in the range of 20-90 wt% (e.g., 20-80 wt%, or 20-70 wt%, or 20-60 wt%, or 20-50 wt%, or 20-40 wt%) and the material and the thermally-conductive,electrically-insulating filler is present in an amount in the range of 10-80 wt% (e.g., 20-80 wt%, or 30-80 wt%, or 40-80 wt%, or 50-80 wt%, or 60-80 wt%) of the material. Embodiment 55. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-51, wherein the continuous polymeric phase is present in an amount in the range of 30-90 wt% (e.g., 30-80 wt%, or 30-70 wt%, or 30-60 wt%, or 30-50 wt%) and the material and the thermally-conductive, electrically-insulating filler is present in an amount in the range of 10-70 wt% (e.g., 20-70 wt%, or 30-70 wt%, or 40-70 wt%, or 50-70 wt%) of the material. Embodiment 56. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-51, wherein the continuous polymeric phase is present in an amount in the range of 40-90 wt% (e.g., 40-80 wt%, or 40-70 wt%, or 40-60 wt%) and the material and the thermally-conductive, electrically-insulating filler is present in an amount in the range of 10-60 wt% (e.g., 20-60 wt%, or 30-60 wt%, or 40-60 wt%) of the material. Embodiment 57. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-51, wherein the continuous polymeric phase is present in an amount in the range of 50-90 wt% (e.g., 50-80 wt%, or 50-70 wt%) and the material and the thermally-conductive, electrically-insulating filler is present in an amount in the range of 10-50 wt% (e.g., 20-50 wt%, or 30-50 wt%) of the material. Embodiment 58. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-51, wherein the continuous polymeric phase is present in an amount in the range of 60-90 wt% (e.g., 60-80 wt%) and the material and the thermally-conductive, electrically-insulating filler is present in an amount in the range of 10- 40 wt% (e.g., 20-40 wt%) of the material. Embodiment 59. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-51, wherein the continuous polymeric phase is present in an amount in the range of 70-90 wt% and the material and the thermally- conductive, electrically-insulating filler is present in an amount in the range of 10-30 wt% of the material.Embodiment 60. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-59, wherein the amount of thermally-conductive filler is no more than 40 wt% of the material. Embodiment 61. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-60, the continuous polymeric phase and the thermally-conductive filler make up at least 75 wt% of the thermally-conductive, electrically- insulating polymer composite material, e.g., at least 90 wt%, or at least 95 wt%. Embodiment 62. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-61, having a thermal conductivity of at least 0.3 W / m-K, e.g., in the range of 0.3-10 W / m-K, or 0.3-5 W / m-K, or 0.3-3 W / m-K, or 0.3-2 W / m-K. Embodiment 63. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-61, having a thermal conductivity of at least 0.5 W / m-K, e.g., in the range of 0.5-10 W / m-K, or 0.5-5 W / m-K, or 0.5-3 W / m-K, or 0.5-2 W / m-K. Embodiment 64. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-61, having a thermal conductivity of at least 0.7 W / m-K, e.g., in the range of 0.7-10 W / m-K, or 0.7-5 W / m-K, or 0.7-3 W / m-K, or 0.7-2 W / m-K. Embodiment 65. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-61, having a thermal conductivity of at least 1 W / m-K, e.g., in the range of 1-10 W / m-K, or 1-5 W / m-K, or 1-3 W / m-K, or 1-2 W / m-K. Embodiment 66. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-65, having a thermal conductivity of greater than 0.25 W / m-K, e.g., greater than 0.27 W / m-K. Embodiment 67. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-65, having a thermal conductivity of greater than 0.4 W / m-K, e.g., greater than 0.42 W / m-K. Embodiment 68. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-67, having an electrical resistivity of at least 108ohms-cm, e.g., at least 1010ohms-cm, or at least 1012ohms-cm.Embodiment 69. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-68, having a flexural modulus of no more than 600 MPa, e.g., no more than 550 MPa, or no more than 500 MPa. Embodiment 70. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-68, having a flexural modulus in the range of 300-600 MPa, e.g., 300-550 MPa, or 300-500 MPa, or 350-600 MPa, or 350-550 MPa, or 350-500 MPa, or 400-600 MPa, or 400-550 MPa, or 400-500 MPa. Embodiment 71. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-70, that, when formed via extrusion into a tubing having an inner diameter of 4.7 mm and a wall thickness of 0.67 mm, has a minimum bend radius of no more than 18 mm, e.g., no more than 17 mm, or no more than 15 mm. Embodiment 72. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-70, that, when formed via extrusion into a tubing having an inner diameter of 4.7 mm and a wall thickness of 0.67 mm, has a minimum bend radius in the range of 10-18 mm, e.g., 10-17 mm, or 10-15 mm, or 12-18 mm, or 12-17 mm, or 12-15 mm, or 13-18 mm, or 13-17 mm, or 13-15 mm. Embodiment 73. A tubing comprising at least one annular layer of a thermally- conductive, electrically-insulating polymer composite material according to any of embodiments 1-72. Embodiment 74. A tubing according to embodiment 73, wherein the at least one annular layer has a thickness in the range of 0.1-5 mm, e.g., 0.1-3 mm, or 0.1-2 mm, or 0.1- 1.5 mm, or 0.1-1 mm. Embodiment 75. A tubing according to embodiment 73, wherein the at least one annular layer has a thickness in the range of 0.25-5 mm, e.g., 025-03 mm, or 0.25-2 mm, or 0.25-1.5 mm, or 0.25-1 mm. Embodiment 76. A tubing according to embodiment 73, wherein the at least one annular layer has a thickness in the range of 0.5-5 mm, or 0.5-2 mm, or, 0.5-1.5 mm, or 0.5- 1 mm.Embodiment 77. A tubing according to embodiment 73, wherein the at least one annular layer has a thickness in the range of 1-5 mm, e.g., 1-3 mm, or 1-2 mm. Embodiment 78. A tubing according to any of embodiments 73-77, having an inner diameter in the range of 2-50 mm, e.g., in the range of 2-30 mm, or 2-20 mm, or 2-10 mm. Embodiment 79. A tubing according to any of embodiments 73-77, having an inner diameter in the range of 5-50 mm, e.g., in the range of 5-30 mm, or 5-20 mm, or 5-10 mm. Embodiment 80. A tubing according to any of embodiments 73-77, having an inner diameter in the range of 10-50 mm, e.g., in the range of 10-30 mm, or 10-20 mm. Embodiment 81. A tubing according to any of embodiments 73-80, wherein a cross- section of the tubing is formed of at least 75 wt% of the material of the disclosure, e.g., at least 90 wt%, or at least 95 wt%. Embodiment 82. A tubing according to any of embodiments 73-81, wherein having a minimum bend radius of no more than 18 mm, e.g., no more than 17 mm, or no more than 15 mm. Embodiment 83. A tubing according to any of embodiments 73-81, wherein having a minimum bend radius in the range of 10-18 mm, e.g., 10-17 mm, or 10-15 mm, or 12-18 mm, or 12-17 mm, or 12-15 mm, or 13-18 mm, or 13-17 mm, or 13-15 mm. Embodiment 84. A tubing according to embodiment 79 or embodiment 83, wherein the tubing has an inner diameter of 4.7 mm + / - 0.4 mm and a wall thickness of 0.7 + / - 0.15 mm. Embodiment 85. A method for transferring heat from a heat source, the method comprising providing a tubing according to any of embodiments 73-84 positioned in substantial thermal communication with the heat source at a first position, the tubing having a working fluid disposed therein; and transferring heat from the heat source through the tubing and into the working fluid.Embodiment 86. The method of embodiment 85, further comprising conducting the conducting the working fluid away from the first position. Embodiment 87. The method of embodiment 85, further comprising conducting the working fluid via the tubing to a second position. Embodiment 88. The method of embodiment 87, wherein at the second position heat is conducted from the working fluid through the tubing to the surrounding atmosphere or to a cooler object, such as a heat exchanger, a radiator or a heat sink. Embodiment 89. A thermal management system for cooling a heat source, the system comprising: a tubing according to any of embodiments 73-84, in substantial thermal communication with the heat source at a first position; and a source of a working fluid configured to conduct the working fluid through the tubing. Embodiment 90. The thermal management system of embodiment 89, wherein the source of the working fluid is a water line provided with sufficient pressure to conduct water through the tubing; or is a tank of working fluid (e.g., a coolant) with a pump configured to pump the working fluid through the tubing. Embodiment 91. The thermal management system of embodiment 89 or embodiment 90, further including a heat exchanger, a radiator or a heat sink operatively coupled to the tubing and configured to remove heat from the working fluid at a second position different from the first position. Embodiment 92. The thermal management system according to embodiment 91, wherein the heat exchanger, radiator or heat sink is provided in a substantially closed circuit with the tubing and the source of the working fluid. Embodiment 93. The method or thermal management system according to any of embodiments 85-92, wherein the heat source is operating at a temperature, or has an operating temperature, in the range of 50-250 °C, e.g., in the range of 50-200 °C, or 50-150 °C, or 50-100 °C, or 75-250 °C, or 75-200 °C, or 75-150 °C, or 75-125 °C. or 100-250 °C, or 100-200 °C, or 100-150 °C, or 150-250 °C, or 150-200 °C.Embodiment 94. The method or thermal management system according to any of embodiments 85-92, wherein the heat sources is electrical or magnetic in nature. Embodiment 95. The method or thermal management system according to any of embodiments 85-92, wherein the heat source comprises one or more magnets, e.g., one or more electromagnets, such as magnetic coils. Embodiment 96. The method or thermal management system according to any of embodiments 85-92, wherein the heat source comprises one or more electrical devices, such as a battery (or an anode or cathode thereof); an electric motor; a computing system or subsystem such as a computer circuit (integrated or otherwise); a lamp; and a laser. Embodiment 97. The method or thermal management system according to any of embodiments 85-96, wherein the working fluid is a coolant. Embodiment 98. The method or thermal management system according to any of embodiments 85-96, wherein the working fluid comprises (or is) water. Embodiment 99. The method or thermal management system according to any of embodiments 85-96, the working fluid comprises (or is) a glycol, such as ethylene glycol or propylene glycol, e.g., provided in combination with water. Embodiment 100. The method or thermal management system according to any of embodiments 85-99, wherein the heat source is a gradient coil assembly of a magnetic resonance instrument, e.g., a magnetic resonance imaging instrument. Embodiment 101. A magnetic resonance instrument, e.g., a magnetic resonance imaging instrument, comprising a gradient coil assembly and a tubing according to any of embodiments 73-84 in substantial thermal communication with the gradient coil assembly at a first position; and a source of a working fluid configured to conduct the working fluid through the tubing. Embodiment 102. A method of thermal management for a magnetic resonance instrument comprising a gradient coil assembly, the method comprisingproviding a tubing according to any of embodiments 73-84 positioned in substantial thermal communication with the gradient coil assembly at a first position, the tubing having a working fluid disposed therein; and transferring heat from the gradient coil assembly through the tubing and into the working fluid. Embodiment 103. The magnetic resonance instrument or method of embodiment 101 or embodiment 102, as further described by any of embodiments 85-94 and 97-100.

Claims

What is claimed is:

1. A thermally-conductive, electrically-insulating polymer composite material, comprising: a continuous polymeric phase comprising a fluorinated polymer phase having a total fluoropolymer content of at least 50 wt%, the fluorinated polymer phase comprising; a functional polymer, the functional polymer comprising reactive functional groups; and optionally, a thermoplastic fluoropolymer, the thermoplastic fluoropolymer being miscible with the functional polymer; and phase-separated from the fluorinated polymer phase, an elastomeric polymer; and dispersed within the continuous polymeric phase, a thermally-conductive, electrically- insulating filler.

2. A thermally-conductive, electrically-insulating polymer composite material according to claim 1, wherein the fluorinated polymer phase has a total fluoropolymer content of at least 80 wt%.

3. A thermally-conductive, electrically-insulating polymer composite material according to embodiment 1 or embodiment 2, wherein the fluorinated polymer phase has a ratio of hydrogen atoms to fluorine atoms of no more than 2, for example, no more than 1.5, or no more than 1, or no more than 0.

5.

4. A thermally-conductive, electrically-insulating polymer composite material according to claim 1, wherein the thermoplastic fluoropolymer is present.

5. A thermally-conductive, electrically-insulating polymer composite material according to claim 1, wherein the thermoplastic fluoropolymer includes (or is) poly(ethylene-co- tetrafluoroethylene) (“ETFE”).

6. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-5, wherein the thermoplastic fluoropolymer is not present.

7. A thermally-conductive electrically-insulating polymer composite material according to claim 1, wherein the functional groups of the functional polymer are hydroxyl groups, anhydride groups, carboxylate groups, and / or amine groups.

8. A thermally-conductive electrically-insulating polymer composite material according to claim 1, wherein the functional groups of the functional polymer include (or are) anhydride groups.

9. A thermally-conductive electrically-insulating polymer composite material according to claim 1, wherein the functional polymer is a functional fluoropolymer.

10. A thermally-conductive electrically-insulating polymer composite material according to claim 9, wherein the functional fluoropolymer is a copolymer of a fluorinated monomer copolymerized with a functional monomer bearing the reactive functional group.

11. A thermally-conductive electrically-insulating polymer composite material according to claim 10, wherein the functional monomer is an anhydride-bearing monomer such as itaconic anhydride or maleic anhydride.

12. A thermally-conductive electrically-insulating polymer composite material according to claim 9, wherein the functional polymer is a copolymer of a monomer containing an anhydride, (ii) ethylene, and (iii) tetrafluoroethylene.

13. A thermally-conductive electrically-insulating polymer composite material according to claim 9, wherein the functional fluoropolymer is provided by graft polymerization of functional monomers onto an already-formed fluoropolymer, or by treatment with an oxidant, or a plasma.

14. A thermally-conductive, electrically-insulating polymer composite material according to claim 1, wherein the elastomeric polymer is a fluoroelastomer.

15. A thermally-conductive, electrically-insulating polymer composite material according to claim 1, wherein the elastomeric polymer is an FKM fluoropolymer or a fluorosilicone rubber.

16. A thermally-conductive, electrically-insulating polymer composite material according to claim 1, wherein the elastomeric polymer is silicone rubber, or ethylene-propene-dienemonomer (EPDM) rubber, or chlorosulfonated polyethylene rubber, or hydrogenated acrylonitrile-butadiene rubber (HNBR).

17. A thermally-conductive, electrically-insulating polymer composite material according to claim 1, wherein the elastomeric polymer is crosslinked.

18. A thermally-conductive, electrically-insulating polymer composite material according to claim 1, wherein the elastomeric polymer is crosslinked and formed into particles before being compounded with the fluorinated polymer phase.

19. A thermally-conductive, electrically-insulating polymer composite material according to claim 1, wherein the thermoplastic fluoropolymer, if present, is poly(ethylene-co- tetrafluoroethylene); the functional polymer is modified poly(ethylene-co-tetrafluoroethylene) copolymer comprising anhydride reactive functional groups; and the elastomeric polymer is poly(vinylidene fluoride-hexafluoropropylene) type-1 FKM rubber.

20. A thermally-conductive, electrically-insulating polymer composite material according to claim 1, wherein the total amount of thermoplastic fluoropolymer, functional fluoropolymer and elastomeric polymer makes up at least 90 wt% of the continuous polymeric phase.

21. A thermally-conductive, electrically-insulating polymer composite material according to claim 1, wherein the thermoplastic fluoropolymer is present in the continuous polymeric phase in an amount in the range of 10-90 wt%.

22. A thermally-conductive, electrically-insulating polymer composite material according to claim 1, wherein the thermoplastic fluoropolymer is present in the continuous polymeric phase in an amount up to 10 wt%.

23. A thermally-conductive, electrically-insulating polymer composite material according to claim 1, wherein the functional polymer is present in the continuous polymeric phase in an amount in the range of 5-90 wt%.

24. A thermally-conductive, electrically-insulating polymer composite material according to claim 1, wherein the functional polymer is present in the continuous polymeric phase in an amount in the range of 10-30 wt%.

25. A thermally-conductive, electrically-insulating polymer composite material according to claim 1, wherein the elastomeric polymer is present in the continuous polymeric phase in an amount in the range of 3-50 wt%.

26. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-44, wherein the elastomeric polymer is present in the continuous polymeric phase in an amount in the range of 3-20 wt%.

27. A thermally-conductive, electrically-insulating polymer composite material according to claim 1, wherein the thermally-conductive, electrically-insulating filler includes (or is) boron nitride, e.g., hexagonal boron nitride.

28. A thermally-conductive, electrically-insulating polymer composite material according to claim 1, wherein the continuous polymeric phase is present in an amount in the range of 50-90 wt% and the thermally-conductive, electrically-insulating filler is present in an amount in the range of 10-50 wt% of the material.

29. A thermally-conductive, electrically-insulating polymer composite material according to claim 1, wherein the amount of thermally-conductive filler is no more than 40 wt% of the material.

30. A thermally-conductive, electrically-insulating polymer composite material according to claim 1, the continuous polymeric phase and the thermally-conductive filler make up at least 90 wt% of the thermally-conductive, electrically-insulating polymer composite material.

31. A thermally-conductive, electrically-insulating polymer composite material according to any of embodiments 1-69, having a thermal conductivity of at least 0.5 W / m-K.

32. A thermally-conductive, electrically-insulating polymer composite material according to claim 1, having a flexural modulus of no more than 550 MPa.

33. A thermally-conductive, electrically-insulating polymer composite material according to claim 1, that, when formed via extrusion into a tubing having an inner diameter of 4.7 mm and a wall thickness of 0.67 mm, has a minimum bend radius of no more than 17 mm.

34. A tubing comprising at least one annular layer of a thermally-conductive, electrically- insulating polymer composite material according to claim 1.

35. A method for transferring heat from a heat source, the method comprising providing a tubing according to claim 34 positioned in substantial thermal communication with the heat source at a first position, the tubing having a working fluid disposed therein; and transferring heat from the heat source through the tubing and into the working fluid.

36. A thermal management system for cooling a heat source, the system comprising: a tubing according to claim 34, in substantial thermal communication with the heat source at a first position; and a source of a working fluid configured to conduct the working fluid through the tubing.

37. A magnetic resonance instrument, e.g., a magnetic resonance imaging instrument, comprising a gradient coil assembly and a tubing according to claim 34 in substantial thermal communication with the gradient coil assembly at a first position; and a source of a working fluid configured to conduct the working fluid through the tubing.

38. A method of thermal management for a magnetic resonance instrument comprising a gradient coil assembly, the method comprising providing a tubing according to claim 34 positioned in substantial thermal communication with the gradient coil assembly at a first position, the tubing having a working fluid disposed therein; and transferring heat from the gradient coil assembly through the tubing and into the working fluid.

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