Boronic ester-based crosslinked polymers with improved processability

Abstract

To provide a process for preparing crosslinked polymers in which the crosslinking is realized via a post-processing curing step.SOLUTION: The present invention relates to a process for preparing a crosslinked polymer composition containing exchangeable pendant links and exchangeable crosslinks, by boronic ester metathesis reactions. The process can realize a thermoplastic polymer comprising pendant boronic ester groups, which contains an additive as a crosslinking agent that melts and thus crosslinks in a polymer matrix at a temperature, called the temperature of dissociation, higher than a processing temperature thereof. The temperature of dissociation is reached in a later curing step only.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for preparing crosslinked polymers, particularly vitrimers, with improved processability. [Background technology]

[0002] Like thermosetting polymers, vitrimers have a crosslinked structure that gives them advantageous mechanical properties, but they have the ability to flow at high temperatures and therefore can be recycled as thermoplastic polymers.

[0003] In the invention described in applications WO2017 / 029413 and WO2017 / 029412, vitrimers containing exchangeable boronic ester bonds were developed. As fully explained in WO2017 / 029413 and WO2017 / 029412, in particular on pages 2 to 4 of WO2017 / 029413, the metathesis reaction of boronic esters allows for an exchange reaction between substituents on the boronic ester rings and can be represented as follows:

[0004] [ka]

[0005] Crosslinked polymers such as vitrimers are useful for preparing recyclable materials that can be heated to a temperature at which they become liquid without suffering from the destruction or degradation of their structure. However, the melt viscosity of such crosslinked polymers decreases slowly with temperature and may require higher temperatures and / or shear forces and / or processing times compared to thermoplastics. Therefore, there is a need for a method to improve the processability of crosslinked polymers, especially vitrimers. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] WO2017 / 029413 [Patent Document 2] WO2017 / 029412

Non-Patent Literature

[0007]

Non-Patent Literature 1

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Summary of the Invention

[0008] Surprisingly, the inventors of the present invention have developed a method for preparing crosslinked polymers, where crosslinking is achieved through a post-processing curing step. Such an approach allows the polymer to be produced as a thermoplastic, which is easier to mold and store and transport as needed, and then at a later stage to a crosslinked polymer, in particular a vitrimer, with exchangeable bonds at the appropriate time for use. This method utilizes additives as crosslinking agents, which melt in the polymer matrix at a temperature called the dissociation temperature, which is higher than the processing temperature, and thus crosslinks. Said dissociation temperature is only reached in a later curing step. [Means for solving the problem]

[0009] The present invention provides a method for preparing a crosslinked polymer composition having exchangeable side group attachments and exchangeable crosslinks by a boronic ester metathesis reaction, comprising: (a) A mixture M containing a thermoplastic polymer containing pendant boronic ester groups and molecules of additive A is heated to a temperature T mix heating to The boronic ester side groups are represented by the following formulae EB-1 and EB-2:

[0010] [ka]

[0011] (In the formula, Rx, Rv, and Rw may be the same or different, and each represents a hydrogen atom or a group containing carbon. or two together form an aliphatic or aromatic ring, Ry is a carbon-containing group, and Ry is bonded to the boron atom of the dioxaborolane or dioxaborinane ring by a covalent bond via a carbon atom; Ry is further attached to the polymer either directly by a covalent bond or through a functional group G covalently attached to the polymer, or ○ The substituents selected from Rx, Rw, Rv, {Rx, Rw}, or {Rx, Rv} are attached to the polymer by a covalent bond or through a functional group G that is covalently attached to the polymer. are independently selected from the group consisting of dioxaborolane and dioxaborinane of - the molecules of additive A are capable of reacting with the boronic ester side groups of the thermoplastic polymer to form a crosslinked polymer composition containing exchangeable side group bonds and crosslinks by a boronic ester metathesis reaction, and forming intermolecular non-covalent interactions with other molecules of additive A and / or the thermoplastic polymer, at a temperature T mix and wherein the molecules of Additive A can be associated with each other and / or associated with the thermoplastic polymer by non-covalent interactions, and the molecules of Additive A each independently have two boronic ester functional groups capable of reacting with the boronic ester side groups of a thermoplastic polymer, and two or more functional groups F, which may be the same or different, selected from the group consisting of amide functional groups of the formula -NH-C(O)-, urea functional groups of the formula -NH-C(O)-NH-, and carbamate functional groups of the formula -OC(O)-NH- where T mix is higher than the glass transition temperature or melting temperature of the thermoplastic polymer used in step (a) and the initial dissociation temperature T of the crosslinker in the mixture of step (a) dis(i) and (b) recovering a composition comprising the polymer of step (a) and Additive A that is not crosslinked; (c) increasing the temperature T c and curing the non-crosslinked composition of step (b). Including, Here, T c is expressed by the following formula: T c ≧(T dis(i) + Tdis(f) ) / 2 Fulfilling In the formula, T dis(i) is the initial dissociation temperature in step (a), T dis(f) is the final dissociation temperature of additive A in the mixture of step (c), Initial dissociation temperature T dis(i) is the temperature at which the intermolecular non-covalent interactions formed by the molecules of additive A in the mixture of step (a) begin to break down, and Final dissociation temperature T dis(f) is the temperature at which the intermolecular non-covalent interactions formed by the molecules of additive A in the mixture of step (c) are completely destroyed; It concerns the method.

[0012] According to some embodiments, each molecule of Additive A contains two identical boronic ester functional groups.

[0013] According to some embodiments, the molecules of additive A are identical and have the formula (IA):

[0014] [ka]

[0015] is a molecule of During the ceremony, Ar1 is an aromatic group; F1 and F2 are the same or different and are selected from the group consisting of -NH-C(O)-, -C(O)-NH-, -NH-C(O)-NH-, -OC(O)-NH-, and -NH-C(O)-O-; a, b, i, and j are the same or different and are natural numbers equal to 0 or 1; When a is 1, - R2 is a C1-C4 alkanediyl or a C1-C4 alkenediyl, said alkanediyl or alkenediyl being optionally substituted with one or more halogens, and R3 is H, or - R2 further forms an aromatic group together with R3, provided that i=0, said aromatic group being optionally substituted by one or more halogens, When a is 0, the F1 group is bonded directly to a carbon atom of the boronic ester and R3 is H; When b is 1, - R4 is a C1-C4 alkanediyl or a C1-C4 alkenediyl, said alkanediyl or alkenediyl being optionally substituted with one or more halogens, and R5 is H, or - R4 further forms an aromatic group together with R5, provided that j=0, said aromatic group being optionally substituted by one or more halogens, When b is 0, the F2 group is bonded directly to a carbon atom of the boronic ester and R5 is H; R1 and R6 are the same or different and each is a carbon-containing group.

[0016] According to some embodiments, the molecules of additive A are identical and have the formula (IB):

[0017] [ka]

[0018] is a molecule of During the ceremony, Ar2 and Ar3 are the same or different and each is an aromatic group; F'1 and F'2 are the same or different and are selected from the group consisting of -NH-C(O)-, -C(O)-NH-, -NH-C(O)-NH-, -OC(O)-NH-, and -NH-C(O)-O-; a, b, i, and j are the same or different and are natural numbers equal to 0 or 1; When a is 1, - R'2 is a C1-C4 alkanediyl or a C1-C4 alkenediyl, said alkanediyl or alkenediyl being optionally substituted with one or more halogens, and R'3 is H, or - R'2 further forms an aromatic group together with R'3, provided that i=0, said aromatic group being optionally substituted by one or more halogens; When a is 0, the F'1 group is directly attached to a carbon atom of the boronic ester and R'3 is H; When b is 1, - R'4 is a C1-C4 alkanediyl or a C1-C4 alkenediyl, said alkanediyl or alkenediyl being optionally substituted with one or more halogens, and R'5 is H, or - R'4 further forms an aromatic group together with R'5, provided that j=0, said aromatic group being optionally substituted by one or more halogens; When b is 0, the F'2 group is directly attached to a carbon atom of the boronic ester and R'5 is H; R7 is a carbon-containing group.

[0019] According to some embodiments, step (b) comprises shaping the non-crosslinked polymer composition, for example by extrusion, injection, compression, molding, or thermoforming.

[0020] According to some embodiments, steps (a) and (b) are achieved simultaneously by extrusion.

[0021] According to some embodiments, step (c) is carried out for a time ranging from 1 minute to 1 hour, preferably from 2 minutes to 30 minutes, even more preferably from 5 minutes to 20 minutes.

[0022] According to some embodiments, the mixture of step (a) comprises 0.05 to 10% by weight, preferably 0.1 to 3.5% by weight, more preferably 0.5 to 1.5% by weight of additive A relative to the weight of the thermoplastic polymer or blend thereof.

[0023] According to some embodiments, step (c) is carried out by compression molding, injection molding, and oven curing.

[0024] According to some embodiments, a thermoplastic polymer that does not bear any pendant boronic ester groups is further added during step (a).

[0025] According to some embodiments, step (a) comprises the following substeps: (a1) providing a thermoplastic polymer comprising pendant boronic ester groups and optionally a thermoplastic polymer not carrying any pendant boronic ester groups, or a blend thereof, as defined in any one of claims 1 to 9; (a2) providing an additive A as defined in any one of claims 1 to 9; (a3) The thermoplastic polymer of step (a1) and the additive A of step (a2) are processed at a processing temperature T mix The step of mixing Including, Here, T mix is higher than the glass transition temperature or melting temperature of the thermoplastic polymer provided in step (a1) and the initial dissociation temperature T of the crosslinker in the mixture in step (a3). dis(i) is equal to or lower than

[0026] definition The terms "polymer", "linear polymer" and "branched polymer" have the definitions given in WO2017 / 0294123, page 15, line 18 to page 16, line 7, the teachings of which are incorporated herein by reference. According to the present invention, polymer refers to both linear and branched polymer chains.

[0027] A "boronic ester" according to the present invention refers to a group that includes a dioxaborolane or dioxaborinane moiety.

[0028] A "dioxaborolane moiety" according to the present invention has the formula:

[0029] [ka]

[0030] It is of the following.

[0031] A "dioxaborinane moiety" according to the present invention has the formula:

[0032] [ka]

[0033] It is of the following.

[0034] The boronic ester group according to the present invention is a dioxaborolane or dioxaborinane:

[0035] [ka]

[0036] where Ry, Rx, Rw, and Rv are as defined below.

[0037] The term "side group" as used herein refers to a side group of a polymer chain, i.e., a substituent that is neither oligomeric nor polymeric. A side group is not integrated into the main chain of a polymer. The term "boronic ester side group" as used herein refers to a boronic ester group (EB1) or (EB2) that is directly covalently bonded to a polymer building block by one and only one of its substituents Ry, Rx, Rw, Rz, {Rx, Rw}, or {Rx, Rv}, or that is bonded through a functional group G.

[0038] The substituent attached to the polymer chain may be Ry as defined below, and the boronic ester group is then said to be attached to the polymer by the boron atom of the dioxaborolane or dioxoborinane group.

[0039] The substituents attached to the polymer chain may be Rx, Rw, Rv, or, if they together form an aliphatic or aromatic ring, {Rx, Rw} or {Rx, Rv}, as defined below, and the boronic ester group is then said to be attached to the polymer by a carbon atom of the dioxaborolane or dioxoborinane group.

[0040] "Crosslinking" or polymer chain crosslinking has the definition given in WO2017 / 029413, page 18, line 6 to page 19, line 9, the teachings of which are incorporated herein by reference. It consists in creating covalent chemical bonds between polymer chains that are not initially bonded to one another by covalent bonds. Crosslinking involves an increase in connectivity through covalent bonds between the various chains that make up the polymer. Crosslinking of linear or branched polymer chains can involve an increase in the molecular dimensions of the chains, especially in their molar mass, resulting in a crosslinked polymer network. Crosslinking of the crosslinked polymer network involves an increase in the mass fraction of insoluble material in a good non-reactive solvent according to the definition given in WO2017 / 029413.

[0041] Crosslinking of the composition can be assessed by using dynamic mechanical analysis (DMA) where crosslinking is assessed by the appearance of a rubbery plateau above the glass transition or melting temperature of the thermoplastic polymer at a frequency of 1 Hz.

[0042] "Glass transition temperature", T g is defined as the temperature at which the damping or loss factor value, tan δ, is at a maximum value according to dynamic mechanical analysis at 1 Hz. The damping or loss factor, tan δ, is defined as the ratio of the loss modulus E" to the storage modulus E' (Mechanical Properties of Solid Polymers, Authors: IM Ward, J. Sweeney; Editors: Wiley-Blackwell; Edition: 3rd Edition; Print ISBN: 9781444319507; DOI: 10.1002 / 9781119967125).

[0043] When a blend of thermoplastic polymers is used in step (a), the relevant glass transition temperature (T g ) or melting temperature (T m ) has the highest T among all thermoplastic polymers present in the blend with a content of at least 8% by weight, in particular at least 4% by weight, more particularly at least 2% by weight, relative to the total weight of the blend. g Or T m When the polymer is amorphous, the glass transition temperature (T g ), and when the polymer is semi-crystalline it is understood to refer to the melting temperature.

[0044] "Initial dissociation temperature" of additive A, T dis(i) is the temperature at which some intermolecular non-covalent bonds formed by molecules of additive A with other molecules of additive A or with the thermoplastic polymer in the considered mixture, which may be the mixture of step (a), in particular step (a3), the composition resulting from step (b), or the composition of step (c), begin to break. In other words, the aggregates of molecules of additive A with other molecules of additive A or with the thermoplastic polymer begin to break at a temperature T dis(i) It starts to dissociate at T dis(i) will depend on the nature of the thermoplastic polymer provided in step (a) with which additive A is mixed, and on the amount of said additive A.

[0045] T dis(i) is preferably determined by VT-FTIR experiments according to the method described in the "Methods" section below. When VT-FTIR experiments are not available, the temperature T dis(i) may be determined by rheology using temperature sweep experiments according to the method described in the "Methods" section below.

[0046] "Final dissociation temperature" of additive A, T dis(f)is the temperature at which all intermolecular non-crosslinked bonds formed by molecules of additive A with other molecules of additive A or with the thermoplastic polymer in the considered mixture, which may be the mixture of step (a), in particular step (a3), the composition resulting from step (b), or the composition of step (c) are completely broken. In other words, the aggregates of molecules of additive A with other molecules of additive A or with the thermoplastic polymer break down completely at a temperature T dis(f) completely dissociates.

[0047] Therefore, T dis(f) will depend on the nature of the thermoplastic polymer provided in step (a) that is mixed with additive A, and on the amount of said additive A.

[0048] T dis(f) is typically determined by VT-FTIR experiments according to the method described in the "Methods" paragraph below. When VT-FTIR experiments are not available, the temperature T dis(f) may be determined rheologically using temperature sweep experiments according to the method described in the "Methods" section below.

[0049] By definition, for additive A in mixture M, the final dissociation temperature T dis(f) is the initial dissociation temperature T dis(i) Strictly higher than.

[0050] A "carbon-containing group" according to the present invention is a hydrocarbon-based group, and thus consists primarily of carbon and hydrogen atoms, which may contain one or more heteroatoms and / or may be substituted by one or more halogens. The group preferably contains 1 to 50, more preferably 1 to 18, even more preferably 1 to 12 carbon atoms.

[0051] A "heteroatom" according to the present invention refers to an atom of sulfur, nitrogen, oxygen, boron, phosphorus, or silicon. When replacing a carbon atom, such as a methylene group, nitrogen is in the form of -NH- or -N(C1-C6 alkyl)-, and sulfur is in the form of -S-, -SO-, or -SO2-.

[0052] "Halogen" according to the present invention refers to a fluorine, chlorine, bromine or iodine atom.

[0053] The carbon-containing groups can be aliphatic or aromatic.

[0054] "Aliphatic" according to the present invention refers to an "alkyl", "alkenyl", "alkanediyl", "alkenediyl" or "cycloalkyl" group. The valency of the group will be determined on an individual basis.

[0055] In the context of the present invention, aliphatic groups may contain heteroatoms, in particular ester, amide, ether, thioether, secondary or tertiary amine, carbonate, urethane, carbamide or anhydride functional groups. Where applicable, aliphatic groups may be substituted, in particular by halogen, -Rz, -OH, -NH2, -NHRz, -NRzR'z, -C(O)-H, -C(O)-Rz, -C(O)-OH, -C(O)-NRzR'z, -C(O)-O-Rz, -OC(O)-Rz, -OC(O)-O-Rz, -OC(O)-N(H)-Rz, -N(H)-C(O)-O-Rz, -O-Rz, -SH, -S-Rz, -SS-Rz, -C(O)-N(H)-Rz, -N(H)-C(O)-Rz groups, where Rz, R'z are the same or different and represent a C1 to C50 alkyl group.

[0056] An "alkyl" group according to the present invention refers to a saturated linear or branched hydrocarbon chain, preferably containing 1 to 50 carbon atoms, more preferably 1 to 18 carbon atoms, even more preferably 1 to 12 carbon atoms. According to the present invention, disregarding the conventional meaning of the term, an "alkyl" group may contain one or more heteroatoms. Thus, the term "alkyl" in the context of the present invention also includes "heteroalkyl", which is an alkyl group as defined above, containing one or more heteroatoms.

[0057] An "alkenyl" group according to the present invention refers to an unsaturated linear or branched hydrocarbon chain, preferably containing 1 to 50 carbon atoms, more preferably 1 to 18 carbon atoms, even more preferably 1 to 12 carbon atoms. According to the present invention, disregarding the conventional meaning of the term, an "alkenyl" group may contain one or more heteroatoms. Thus, the term "alkenyl" in the context of the present invention also includes "heteroalkenyl", which is an alkenyl group as defined above containing one or more heteroatoms.

[0058] An "alkanediyl" group according to the present invention refers to a divalent saturated linear or branched hydrocarbon chain, preferably containing 1 to 50 carbon atoms, more preferably 1 to 18 carbon atoms, even more preferably 1 to 12 carbon atoms. According to the present invention, the "alkanediyl" group may contain one or more heteroatoms, regardless of the strict meaning of the term. Thus, the term "alkanediyl" in the context of the present invention also includes "heteroalkanediyl", which is an alkanediyl group as defined above, containing one or more heteroatoms.

[0059] An "alkenediyl" group according to the present invention refers to a divalent unsaturated linear or branched hydrocarbon chain, preferably containing 1 to 50 carbon atoms, more preferably 1 to 18 carbon atoms, even more preferably 1 to 12 carbon atoms, such as a vinylene (ethenylene) group or a propenylene group. According to the present invention, the "alkenediyl" group may contain one or more heteroatoms, regardless of the strict meaning of the term. Thus, the term "alkenediyl" in the context of the present invention also includes "heteroalkenediyl", which is an alkenediyl group as defined above, containing one or more heteroatoms.

[0060] A "cycloalkyl" group according to the present invention refers to a cyclic alkyl chain, which may be saturated or partially unsaturated, but is not aromatic, preferably containing 3 to 10 carbon atoms in the ring. The cyclic alkyl chain may contain one or more heteroatoms; in this case it will be specifically referred to as a "heterocycloalkyl". The group may contain multiple rings, thus including fused, linked, or spiro rings. Examples include cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl, pyrrolidinyl, piperidinyl, piperazinyl, or morpholinyl groups. Where applicable, the cycloalkyl group may be substituted in particular by halogen, -Rz, -OH, -NH2, -NHRz, -NRzR'z, -C(O)-H, -C(O)-Rz, -C(O)-OH, -C(O)-NRzR'z, -C(O)-O-Rz, -OC(O)-Rz, -OC(O)-O-Rz, -OC(O)-N(H)-Rz, -N(H)-C(O)-O-Rz, -O-Rz, -SH, -S-Rz, -SS-Rz, -C(O)-N(H)-Rz, -N(H)-C(O)-Rz groups, Rz, R'z being identical or different and representing a C1-C50 alkyl group. Where applicable, the cycloalkyl group may be divalent; in this case it is preferably referred to as an "alicyclic" group.

[0061] "Aromatic" according to the present invention refers to a monovalent or polyvalent group containing an aromatic hydrocarbon group. The valency of the group is determined on an individual basis.

[0062] The aromatic group may contain heteroatoms; in this case it is referred to as a "heteroaromatic" group. In particular, it may contain ester, amide, ether, thioether, secondary or tertiary amine, carbonate, urethane, carbamide, or anhydride functional groups. The aromatic group may contain one or more rings that are fused or covalently linked. If applicable, the aromatic ring may in particular be substituted by halogen, -Rz, -OH, -NH2, -NHRz, -NRzR'z, -C(O)-H, -C(O)-Rz, -C(O)-OH, -C(O)-NRzR'z, -C(O)-O-Rz, -OC(O)-Rz, -OC(O)-O-Rz, -OC(O)-N(H)-Rz, -N(H)-C(O)-O-Rz, -O-Rz, -SH, -S-Rz, -SS-Rz, -C(O)-N(H)-Rz, -N(H)-C(O)-Rz groups, Rz, R'z being identical or different and representing a C1 to C50 alkyl group, or by a functional group selected from among polymerizable functional groups.

[0063] The term "aromatic" includes "aryl aromatic" groups, which are groups that, as defined, contain at least one aromatic group and at least one aliphatic group. The aliphatic group may be attached to one part of the molecule and the aromatic group to another part of the molecule. A group may contain two aromatic groups, each attached to one part of the molecule and connected between them by an aliphatic chain.

[0064] "Aryl" according to the present invention refers to an aromatic hydrocarbon group. The term "aryl" includes aralkyl and alkyl-aryl groups. The aromatic hydrocarbon group may be substituted, in particular one or more times, with halogen, -Rz, -OH, -NH2, -NHRz, -NRzR'z, -C(O)-H, -C(O)-Rz, -C(O)-OH, -C(O)-NRzR'z, -C(O)-O-Rz, -OC(O)-Rz, -OC(O)-O-Rz, -OC(O)-N(H)-Rz, -N(H)-C(O)-O-Rz, -O-Rz, -SH, -S-Rz, -SS-Rz, -C(O)-N(H)-Rz, -N(H)-C(O)-Rz groups, where Rz, R'z are the same or different and represent a C1-C50 alkyl group.

[0065] "Alkyl-aryl" according to the present invention refers to an alkyl group, as defined above, attached to the remainder of the molecule through an aromatic group, as defined above.

[0066] "Aralkyl" according to the present invention refers to an aryl group, as defined above, attached to the remainder of the molecule through an aliphatic group, as defined above.

[0067] "Heteroaryl" according to the present invention refers to an aryl group in which at least one of the atoms of the aromatic ring is a heteroatom. "Heteroalkyl-aryl" according to the present invention refers to an alkyl-aryl group as defined, substituted with at least one heteroatom.

[0068] "Heteroaralkyl" according to the present invention refers to an aralkyl group, as defined, substituted with at least one heteroatom. [Brief description of the drawings]

[0069] [Figure 1] Analytical results for heating a P / 1 mixture at 1 wt.%, as defined in the Examples. FIG. 1A is a graph of VT-FTIR heating of a P / 1 mixture at 1 wt.%, with 3 min isotherms every 5° C., where α is the normalized intensity of the hydrogen-bonded NH stretching band at 3292 cm-1. FIG. 1B is a graph of a rheological temperature sweep experiment performed at 1 rad / s: heating a P / 1 mixture at 1 wt.%, at 10° C. / min. FIG. 1C is a graph of the DSC of the first heating of a pure 1. FIG. 1D is a graph of the DSC of the first heating of a P / 1 mixture at 1 wt.%, both DSC experiments were performed with a ramp of 10° C. / min. [Diagram 2]Analytical results for mixtures of 1 and P and mixtures of 2 and P as defined in the examples. Figure 2A is a graph showing the force required to keep the screw speed constant as a function of extrusion time for mixtures of 1 and P and mixtures of 2 and P (solid and dashed lines, respectively). Both extrusions were carried out at 100°C. Figure 2B is a graph showing normalized stress-relaxation performed at 100°C (normalized relaxation modulus as a function of time) for polymer P with 1% by weight of 1 and 2 after extrusion at 100°C (solid and dashed lines, respectively) and polymer P with 1% by weight of 1 after extrusion and compression molding at 220°C for 10 minutes (dashed line). [Diagram 3] 1 is a graph showing the DMA of the material obtained after extrusion (i.e. after steps (a) and (b)) of polymer P with 1% by weight of 1 (black solid line), of the material obtained after extrusion and compression molding (10 min at 220° C., black dotted line) of polymer P with 1% by weight of 1 (i.e. after steps (A), (b) and (c)) as defined in the examples, and of the latter material after recycling (light grey dashed line). The frequency is 1 Hz. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0070] The method of the present invention comprises the following steps: (a) - a thermoplastic polymer as defined herein, and Additive A as defined herein A mixture M containing mix heating the mixture to In the formula, T mix is higher than the glass transition temperature or melting temperature of the thermoplastic polymer used in step (a); and T mix is the initial dissociation temperature T of additive A in the mixture of step (a). dis(i) and (b) recovering the composition comprising the polymer of step (a) that is not crosslinked and additive A; (c) subjecting the non-crosslinked composition of step (b) to a temperature T cto provide a crosslinked polymer composition. c But the following: T c ≧(T dis(i) +T dis(f) ) / 2 In the formula, T dis(i) is the initial dissociation temperature of additive A in the mixture of step (a), T dis(f) is the final dissociation temperature of additive A in the composition of step (c); Includes.

[0071] Thermoplastic Polymers The thermoplastic polymer used in step (a) has the following formulas EB-1 and EB-2:

[0072] [ka]

[0073] (In the formula, Rx, Rv, and Rw are the same or different, each of which represents a hydrogen atom or a group containing carbon, or two of which together form an aliphatic or aromatic ring; and Ry is a carbon-containing group, and Ry is bonded to the boron atom of the dioxaborolane or dioxaborinane ring by a covalent bond through a carbon atom. and wherein the boronic ester pendant groups are independently selected from the group consisting of dioxaborolane and dioxaborinane.

[0074] When Rx and Rv together form an aliphatic or aromatic ring, the corresponding group is designated {Rx, Rv}. The same applies to the group formed by Rx and Rw.

[0075] Each boronic ester side group is bounded by either one or more carbon atoms of the dioxaborolane or dioxaborinane ring, i.e., R x , R w , and / or R, if applicable vor by the boron atom of the dioxaborolane or dioxaborinane ring, i.e. R y Thus, - Ry is further attached to the polymer by a covalent bond, either directly or via a functional group G covalently attached to the polymer; or The substituent selected from Rx, Rw, Rv, {Rx, Rw}, or {Rx, Rv} is attached to the polymer by a covalent bond or via a functional group G which is covalently attached to the polymer.

[0076] Preferably, Rx, Rw and Rv are the same or different and each represents an alkyl, alkenyl, aryl, aralkylalkyl-aryl or cycloalkyl group. The alkyl, alkenyl, aryl, aralkylalkyl-aryl or cycloalkyl group may contain heteroatoms, in particular selected from O, N, S or Si, and / or may be substituted. One or more, preferably 1 to 4 methylene units of the alkyl, alkenyl, aryl, aralkylalkyl-aryl or cycloalkyl group may be optionally replaced by -O-, -S-, -C(O)-, -SO2-, -NH- or -N(C1-C6 alkyl)-. In particular, Rx and / or Rw and / or Rv together form an aliphatic or aromatic ring.

[0077] In particular, these Rx, Rw and Rv groups are halogen, -Rz, -OH, -NH2, -NHRz, -NRzR'z, -C(O)-H, -C(O)-Rz, -C(O)-OH, -C(O)-NRzR'z, -C(O)-O-Rz, -OC(O)-Rz, -OC(O)-O-Rz, -OC(O)-N(H)-Rz, -N(H)-C(O)-O-Rz, -O-Rz, -SH, -S-Rz, -SS-Rz, -C(O)-N(H)-Rz, -N(H)-C(O)-Rz groups, where Rz and R'z are the same or different, and are each a C1 to C 50 It may be substituted by a functional group specifically selected from those representing alkyl groups.

[0078] In particular, the Rx, Rw, and Rv groups may contain an ester, amide, carbamate, ether, thioether, secondary or tertiary amine, carbonate, urethane, carbamide (i.e., a urea functional group of the formula -NH-C(O)-NH-), or anhydride functional group.

[0079] Preferably, Ry represents an alkyl, alkenyl, aryl, aralkyl, alkyl-aryl or cycloalkyl group. The alkyl, alkenyl, aryl, aralkyl, alkyl-aryl or cycloalkyl group may contain heteroatoms, in particular heteroatoms selected from among O, N, S or Si, and / or may be substituted. One or more, preferably 1 to 4 methylene units of the alkyl, alkenyl, aryl, aralkyl, alkyl-aryl or cycloalkyl group are optionally replaced by -O-, -S-, -C(O)-, -SO2-, -NH- or -N(C1-C6 alkyl)-. In particular, the Ry group is a halogen, -Rz, -OH, -NH2, -NHRz, -NRzR'z, -C(O)-H, -C(O)-Rz, -C(O)-OH, -C(O)-NRzR'z, -C(O)-O-Rz, -OC(O)-Rz, -OC(O)-O-Rz, -OC(O)-N(H)-Rz, -N(H)-C(O)-O-Rz, -O-Rz, -SH, -S-Rz, -SS-Rz, -C(O)-N(H)-Rz, -N(H)-C(O)-Rz group, in which Rz and R'z are the same or different and are C1 to C 50 It may be substituted by a functional group selected in particular from those representing alkyl groups. In particular, this Ry group may comprise an ester, amide, carbamate, ether, thioether, secondary or tertiary amine, carbonate, urethane, carbamide (i.e. a urea functional group of formula -NH-C(O)-NH-) or anhydride functional group.

[0080] Each boronic ester side group is preferably attached to the polymer chain or to a functional group G covalently attached to the polymer via Rx and / or Ry, as defined below. When their substituents {Rx, Rw} or {Rx, Rv} together form an aliphatic or aromatic ring, the boronic ester side group may be attached to the polymer chain or to a functional group G covalently attached to the polymer chain, as defined below, via their substituents {Rx, Rw} or {Rx, Rv} and / or Ry.

[0081] The boronic ester side groups may in particular be selected from among the boronic ester groups described in Example 1 of WO2017 / 029413, the contents of which are incorporated by reference.

[0082] According to some embodiments, EB-1 and EB-2 are:

[0083] [ka]

[0084] is selected from the group consisting of In the formula, the wavy line represents the point of attachment to a functional group G that is directly attached to the polymer by a covalent bond.

[0085] As a non-limiting example, the functional group G may be a group resulting from the reaction of a thiol functional group with an alkene bond of a polydienes, such as polybutadiene, polyisoprene and their copolymers, an alkene bond of vinyl copolymers having alkene side groups, or an alkene bond of polyolefins obtained by ring-opening metathesis polymerization (ROMP) or by acyclic diene metathesis (ADMET) (Charles E. Hoyle, Christopher N. Bowman, Angew. Chem. Int. Ed. 2010, 49, 1540-1573; Kemal Arda Gunay, Patrick Theato, Harm-Anton Klok, Journal of Polymer Science Part A: Polymer Chemistry 2013, 51, 1-28). The functional group G may be a group resulting from the radical grafting of maleimide or methacrylic, acrylic, styrenic or maleic ester functional groups, for example onto polyethylene and polypropylene (G. Moad, Prog. Polym. Sci. 1999, 24, 81-142; Elisa Passagliaa, Serena Coiai, Sylvain Augier, Prog. Polym. Sci. 2009, 34, 911-947). The functional group G may be a group resulting from the reaction of an isocyanate functional group with an alcohol, amine, or thiol pendant group on the polymer (Kemal Arda Gunay, Patrick Theato, Harm-Anton Klok, Journal of Polymer Science Part A: Polymer Chemistry 2013, 51, 1-28; Charles E. Hoyle, Andrew B. Lowe, Christopher N. Bowman, Chem. Soc. Rev., 2010, 39, 1355-1387).The functional group G may be the result of a Michael addition of an electrophilic alkene group with a nucleophile such as a thiol, a primary or secondary amine, or a phosphine (Brian D. Mather, Kalpana Viswanathan, Kevin M. Miller, Timothy E. Long, Prog. Polym. Sci. 2006, 31, 487-531). Among electrophilic alkene groups, non-limiting examples include acrylates, acrylamides, maleimides, methacrylates, and vinyl sulfones. The functional group G may be the result of a nucleophilic substitution or ring-opening reaction with a nucleophilic functional group such as an alcohol, a thiol, an amine, or a carboxylic acid (Kemal Arda Gunay, Patrick Theato, Harm-Anton Klok, Journal of Polymer Science Part A: Polymer Chemistry 2013, 51, 1-28). These nucleophilic functional groups can open epoxides present in the backbone of the polymer, as for example in epoxidized natural rubber, or can open epoxide side groups, as for example in vinyl copolymers prepared with glycidyl methacrylate. The functional group G can be an ester, thioester, or amide functional group resulting from the reaction of an alcohol, thiol, or amine functional group with an ester side group, or an activated ester functional group. This approach is particularly used in vinyl polymers functionalized with ester side groups, such as poly(methyl methacrylate). Thus, the functional groups for covalently attaching molecules containing boronic ester functional groups to polymers are very numerous and varied, and the skilled person will know how to select the functional group that is selected depending on the functional groups present in the polymer and the grafting conditions (temperature, reaction medium (molten or in solution), kinetics, use of catalysts, etc.).

[0086] According to some embodiments, the thermoplastic polymer comprising two or more pendant boronic ester groups used in step (a) is as defined for thermoplastic polymers carrying a boronic ester functional group P1 in WO2017 / 029413, the contents of which are incorporated herein by reference, in particular on page 26, line 10 to page 30, line 2, and on page 37, line 30 to page 38, line 17.

[0087] The thermoplastic polymer and additive A react together to form crosslinks under the processing conditions described below via a boronate metathesis reaction as described on pages 28, lines 27 to 29, lines 9, pages 30, lines 4 to 32, lines 33, pages 39, lines 19 to 40, lines 19, and FIG. 2 of WO2017 / 029413, the contents of which are incorporated herein by reference. In particular, the molar ratio of [repeating units of the polymer that do not contain boronic ester side groups] / [repeating units of the polymer that contain boronic ester side groups] is preferably between 0.01 and 1000, more preferably between 0.1 and 250, and even more preferably between 1 and 100. The resulting crosslinks are exchangeable by a boronate metathesis reaction. The inventors believe that the exchange reaction between boronic esters allows for the cycling of crosslinks, which explains why the composition exhibits thermoplastic behavior when it is insoluble as a thermosetting composition per se.

[0088] The thermoplastic polymer may contain additional side groups, excluding the boronic ester groups, in particular these side groups may contain functional groups capable of forming non-covalent bonds, such as aryl groups, in particular phenyl groups, halogens, amide functional groups of the formula -NH-C(O)-, urea functional groups of the formula -NH-C(O)-NH-, and carbamate functional groups of the formula -OC(O)-NH.

[0089] The halogen atoms can form dipole-dipole interactions, and the aromatic rings can achieve pi-pi stacking.

[0090] In some embodiments, a blend of thermoplastic polymers containing pendant boronic ester groups as defined above is used in step (a).

[0091] In some embodiments, a blend of a thermoplastic polymer comprising pendant boronic ester groups as defined above and a thermoplastic polymer not comprising pendant boronic ester groups as defined above is used in step (a).

[0092] Additive A Additive A is a molecule capable of reacting with boronic ester side groups of a thermoplastic polymer to form a crosslinked polymer composition, preferably a crosslinked network, containing exchangeable side group bonds and crosslinks via a boronic ester metathesis reaction, and capable of forming intermolecular non-covalent interactions with other molecules of Additive A and / or with the thermoplastic polymer. To this end, each molecule of Additive A comprises: two boronic ester functional groups, each of which contains a dioxaborolane or dioxaborinane moiety, the two boronic ester functional groups being either both bonded to the remainder of the molecule through at least one carbon atom of the dioxaborolane or dioxaborinane ring, or both bonded to the remainder of the molecule through a boron atom of the dioxaborolane or dioxaborinane ring, and two or more F functional groups, which may be identical or different, selected from the group consisting of an amide functional group of the formula -NH-C(O)-, a urea functional group of the formula -NH-C(O)-NH-, and a carbamate functional group of the formula -OC(O)-NH-.

[0093] The molecules of additive A may also contain other functional groups capable of forming intermolecular non-covalent interactions, such as halogen atoms capable of forming dipole-dipole interactions, aliphatic groups capable of van der Waals interactions, and aromatic rings capable of achieving π-π stacking. Preferably, the molecules of additive A further contain an aromatic ring, in particular an optionally substituted phenyl group.

[0094] Preferably, each molecule of additive A contains two or more, in particular two identical F functional groups selected from the group consisting of an amide functional group of formula -NH-C(O)-, a urea functional group of formula -NH-C(O)-NH-, and a carbamate functional group of formula -OC(O)-NH-.

[0095] The molecules of additive A are preferably identical to each other.

[0096] Depending on the temperature, the molecules of additive A can "associate", meaning to form intermolecular non-covalent interactions with other molecules of additive A and / or with the thermoplastic polymer. With increasing temperature, the molecules will subsequently dissociate from other molecules of additive A and / or from the thermoplastic polymer. In the context of the present invention, additive A and the thermoplastic polymer in step (a) are heated to an initial dissociation temperature T dis(i) is the glass transition temperature (T g ) or melting temperature (T m ) is selected.

[0097] Examples of intermolecular non-covalent bonds include hydrogen bonds, particularly formed by urea, amide, and / or carbamate functional groups, π-π stacking when aromatic groups are present, Van der Waals interactions, dipole-dipole interactions, and coordinate bonds.

[0098] Thus, molecules of additive A are capable of forming intermolecular non-covalent interactions with other molecules of additive A and / or with the thermoplastic polymer by the presence of at least two or more F functional groups, which may be identical or different, selected from the group consisting of amide functional groups of the formula -NH-C(O)-, urea functional groups of the formula -NH-C(O)-NH-, and carbamate functional groups of the formula -OC(O)-NH-.

[0099] Initial dissociation temperature T dis(i)At temperatures below or equal to , the formation of such intermolecular non-covalent interactions prevents crosslinking between the molecules of Additive A and the thermoplastic polymer. In fact, when such intermolecular non-covalent interactions are formed, the molecules of Additive A are in a spatial orientation and configuration that renders the boronic ester functional groups unavailable for reaction with the pendant boronic ester groups of the thermoplastic polymer, and therefore crosslinking is not achieved.

[0100] The temperature T at which step (a) is carried out mix is T dis(i) Since it is lower than or equal to T mix The molecules of Additive A in the polymer are associated with each other and / or with the thermoplastic polymer via non-covalent interactions.

[0101] Preferably, each molecule of additive A independently comprises a Y radical between two boronic ester functional groups, Y being defined as the core of the molecule. Preferably, the core of the molecule of additive A presents a symmetry element selected from a mirror plane or a C2 rotation axis. Preferentially, the molecule presents not only its core Y but also a symmetry element selected from a mirror plane or a C2 rotation axis.

[0102] Preferably, the additive A molecule is of formula (IA) or (IB).

[0103] According to one embodiment, the additive A molecule has the formula (IA):

[0104] [ka]

[0105] is a molecule of the formula Ar1 is an aromatic group; F1 and F2 are the same or different and are selected from the group consisting of -NH-C(O)-, -C(O)-NH-, -NH-C(O)-NH-, -OC(O)-NH-, and -NH-C(O)-O-; a, b, i, and j are the same or different and are natural numbers equal to 0 or 1; When a is 1, - R2 is a C1-C4 alkanediyl or a C1-C4 alkenediyl, said alkanediyl or alkenediyl being optionally substituted with one or more halogens, and R3 is H, or - R2 further forms an aromatic group together with R3, provided that i=0, said aromatic group being optionally substituted by one or more halogens, when a is 0, F1 is bonded directly to a carbon atom of the boronic ester and R3 is H; When b is 1, - R4 is a C1-C4 alkanediyl or a C1-C4 alkenediyl, said alkanediyl or alkenediyl being optionally substituted with one or more halogens, and R5 is H, or - R4, with the provision that j=0, further forms together with R5 an aromatic group, said aromatic group being optionally substituted by one or more halogens, When b is 0, F2 is directly bonded to a carbon atom of the boronic ester and R5 is H; R1 and R6 are the same or different and each is a carbon-containing group preferably substituted with one or more halogens.

[0106] Preferably, the substituents are ultimately present on the Ar1 group, and R1 to R6 do not contain a functional group selected from the group consisting of -NH-C(O)-, -C(O)-NH-, -NH-C(O)-NH-, -OC(O)-NH-, and -NH-C(O)-O-. Thus, only F1 and F2 can be amide, urea, or carbamate functional groups.

[0107] Advantageously, Ar1 has a symmetry element selected from a mirror plane or a C2 axis of rotation. Ar1 is preferably, in its divalent form, an aryl or heteroaryl. More preferably, Ar1 is an unsubstituted phenylene. More preferably, Ar1 is an unsubstituted phenylene, with the boronic ester functional group in the para position, such that the molecule has the formula:

[0108] [ka]

[0109] This applies.

[0110] In all embodiments, Preferably, i=j.

[0111] Preferably, F1 and F2 are the same and are selected from amide, carbamate and urea functional groups.

[0112] Preferably, a=b.

[0113] R2 is preferably -CH2- or -CH2-CH2-, or, provided that i=0, R2 can form a phenylene with R3, which can be combined with a boronic ester to form the following formula:

[0114] [ka]

[0115] This falls under the category of

[0116] R4 is preferably -CH2- or -CH2-CH2-, or, provided that j=0, R4 can form a phenylene with R5, which can be combined with a boronic ester to form the following formula:

[0117] [ka]

[0118] This falls under the category of

[0119] R2 and R4 are preferably the same.

[0120] R1 and R6 may be broadly independently selected from carbon-containing groups. R1 and R6 are the same or different and preferably represent alkyl, alkenyl, aryl, cycloalkyl, heteroaryl, heteroalkyl or heterocycloalkyl groups, each of which may be substituted, in particular, by one or more halogen atoms. Preferentially, R1 and R6 are themselves crystalline, so that the melting point of their corresponding molecules is preferably higher than 0°C. R1 and R6 are the same or different and preferably represent cyclohexyl, an alkyl group containing 1 to 6 carbon atoms, or phenyl.

[0121] In particular, Ar1, F1, F2, i, j, R3, R5, a, b, R2, and R4 are selected such that the molecule presents a symmetry element selected from a mirror plane or a C2 rotation axis.

[0122] According to some embodiments, the additive A molecule is:

[0123] [ka]

[0124] [ka]

[0125] is selected from the group consisting of:

[0126] According to another embodiment, the additive A molecule has the formula (IB):

[0127] [ka]

[0128] is a molecule of the formula Ar2 and Ar3 are the same or different and each is an aromatic group; F'1 and F'2 are the same or different and are selected from the group consisting of -NH-C(O)-, -C(O)-NH-, -NH-C(O)-NH-, -OC(O)-NH-, and -NH-C(O)-O-; a, b, i, and j are the same or different and are natural numbers equal to 0 or 1; When a is 1, - R'2 is a C1-C4 alkanediyl or a C1-C4 alkenediyl, said alkanediyl or alkenediyl being optionally substituted with one or more halogens, and R'3 is H, or R'2 further forms an aromatic group with R'3, provided that i=0, said aromatic group being optionally substituted by one or more halogens, when a is 0, F'1 is bonded directly to a carbon atom of the boronic ester and R'3 is H; When b is 1, - R'4 is a C1-C4 alkanediyl or a C1-C4 alkenediyl, said alkanediyl or alkenediyl being optionally substituted with one or more halogens, and R'5 is H, or R'4 further forms together with R'5, provided that j=0, an aromatic group, said aromatic group being optionally substituted by one or more halogens, when b is 0, F'2 is directly bonded to a carbon atom of the boronic ester and R'5 is H; R7 is a carbon-containing group.

[0129] Preferably, the substituents are finally present on the Ar2, Ar3, R'2 to R'5 groups, and R7 does not contain a functional group selected from the group consisting of -NH-C(O)-, -C(O)-NH-, -NH-C(O)-NH-, -OC(O)-NH-, and -NH-C(O)-O-. Thus, only F'1 and F'2 can be amide, urea, or carbamate functional groups.

[0130] R7 can be broadly selected from carbon-containing groups. R7 is preferably a divalent form of an alkyl, alkenyl, aryl, cycloalkyl, heteroaryl, heteroalkyl, or heterocycloalkyl group, each of which may be substituted, in particular by one or more halogen atoms. R7 preferably represents phenylene. More preferably, R7 is unsubstituted phenylene, with F'1 and F'2 in the para position; thus the molecule has the formula:

[0131] [ka]

[0132] This applies.

[0133] Preferably, F'1 and F'2 are both amide or carbamate or urea functional groups.

[0134] Advantageously, F'1-R7-F'2 has a symmetry element chosen from a mirror plane or a C2 axis of rotation.

[0135] In all embodiments, Preferably, i=j.

[0136] Preferably, a=b.

[0137] R'2 is preferably -CH2- or -CH2-CH2-, or, provided that i=0, R'2 can form a phenylene together with R'3, which, together with the boronic ester, can be represented by the following formula:

[0138] [ka]

[0139] This falls under the category of

[0140] R'4 is preferably -CH2- or -CH2-CH2-, or, provided that j=0, R'4 can form a phenylene together with R'5, which, together with the boronic ester, can be represented by the following formula:

[0141] [ka]

[0142] This falls under the category of

[0143] R'2 and R'4 are preferably the same.

[0144] Ar2 and Ar3 are the same or different and are aryl or heteroaryl.Preferentially, Ar2 and Ar3 are themselves crystalline, and therefore the melting point of their corresponding molecules is preferably higher than 0°C.More preferably, Ar2 is unsubstituted phenylene.More preferably, Ar2 is unsubstituted phenylene.

[0145] In particular, Ar2, Ar3, F'1, F'2, i, j, R'2 to R'5, a, b, and R7 are selected such that the molecule presents a symmetry element selected from a mirror plane or a C2 rotation axis.

[0146] According to some embodiments, the additive A molecule is:

[0147] [ka]

[0148] is selected from the group consisting of:

[0149] The use of compounds of formula (IA) or of compounds of formula (IB) to obtain compositions comprising crosslinked polymers / vitrimers having exchangeable side bonds and crosslinks by boronic ester metathesis reactions depends on the nature of the atom through which the boronic ester functional side group is attached to the thermoplastic polymer.

[0150] Thus, the boronic ester pendant group of formula EB-1 or EM-2 is bound by at least one carbon atom of the dioxaborolane or dioxabrinane ring, i.e., R x , R w , and / or R, where applicable v The compound of formula (IA) is selected as the molecule of additive A when it is bonded to the thermoplastic polymer via

[0151] Thus, the boronic ester pendant group of formula EB-1 or EB-2 is bonded by the boron atom of the dioxaborolane or dioxaborinane ring, i.e., R y The compound of formula (IB) is selected as the molecule of additive A when it is bonded to the thermoplastic polymer via

[0152] Preferred embodiments of the method of the present invention Process (a) Preferably, the mixture of step (a) comprises from 0.05 to 10% by weight, preferably from 0.1 to 3.5% by weight, more preferably from 0.5 to 1.5% by weight of additive A relative to the weight of the thermoplastic polymer or blend thereof.

[0153] Advantageously, step (a) comprises the following successive substeps: (a1) providing a thermoplastic polymer comprising pendant boronic ester groups as defined herein; (a2) providing an additive A, as defined herein; (a3) The thermoplastic polymer of step (a1) and the additive A of step (a2) are processed at a processing temperature T mix The step of mixing where T mix is higher than the glass transition temperature or melting temperature of the thermoplastic polymer provided in step (a1) and the initial dissociation temperature T of additive A [in the mixture of step (a3)] dis(i) is equal to or lower than.

[0154] Advantageously, step (a3) ​​is carried out for a time ranging from 30 seconds to 2 hours, preferably from 1 minute to 1 hour, and even more preferably from 2 minutes to 30 minutes. It is understood that the duration of step (a3) ​​is set so that the thermoplastic polymer does not degrade during step (a3).

[0155] Processing temperature T mix is preferably equal to or lower than the glass transition temperature T of the thermoplastic polymer into which additive A is mixed. g or melting temperature T m and the initial dissociation temperature T of additive A in the mixture of step (a). dis(i) More preferably, between T g +5℃ or T m +5℃ to T dis(i) -5°C, and even more preferably T g +10℃ or T m +10℃ to T dis(i) between -10°C.

[0156] At the end of step (a), a non-crosslinked polymer composition is obtained, comprising a thermoplastic polymer or blends thereof in admixture with additive A. In other words, the non-crosslinked composition comprises a thermoplastic polymer containing pendant boronic ester groups, or blends thereof, or blends thereof with a thermoplastic resin not containing pendant boronic ester groups, into which additive A is admixed. The initial dissociation temperature T of additive A is dis(i) At temperatures below 0.1° C., the molecules of Additive A in the non-crosslinked polymer composition form non-covalent interactions with other molecules of Additive A and / or with the thermoplastic polymer, blocking exchange reactions by metathesis between the boronic ester substituents of the polymer and Additive A.

[0157] Process (b) In step (b), the non-crosslinked polymer composition is recovered. During recovery, the composition is typically shaped by methods known to those skilled in the art, including compression molding, injection molding, extrusion, blow molding, fiber spinning, powder coating, rotational molding, and thermoforming.

[0158] Steps (a) and (b) may be achieved simultaneously by extrusion, whereby the mixing in step (a) is carried out in an extruder.

[0159] Step (b) may include the addition of additives such as pigments, colorants, bluing agents, fillers, plasticizers, impact modifiers, fibers, flame retardants, antioxidants, lubricants, wood, glass, and metals in the non-crosslinked composition.

[0160] The non-crosslinked polymer recovered in step (b) may be stored, shipped, used in an appropriate application, granulated, dispersed in a resin, and the like.

[0161] All of the operations carried out in step (b) are carried out at the initial dissociation temperature T dis(i) The reaction is carried out at a temperature equal to or less than that.

[0162] Process (c) During the curing step, the non-crosslinked polymer composition recovered in step (b) is heated to a temperature T c In this process, Additive A plays the role of its cross-linking agent.

[0163] temperature T c Cross-linking can be induced at T c satisfies: T c ≧(T dis(i) +T dis(f) ) / 2, in the formula, T dis(i) is the initial dissociation temperature of the mixture of step (a), T dis(f) is the final dissociation temperature of additive A in the composition of step (c).

[0164] T cIt is understood that the temperature is set to be below the temperature at which the thermoplastic polymer or blends thereof or Additive A begins to decompose, such decomposition temperatures being known to those skilled in the art.

[0165] Preferably, T c is T dis(f) Preferably, the T c is T dis(f) +50°C or less, preferably T dis(f) Equal to or lower than +40°C.

[0166] According to a preferred embodiment, step (c) is carried out for a time ranging from 1 minute to 1 hour, preferably from 2 minutes to 30 minutes, even more preferably from 5 minutes to 20 minutes. The duration of step (c) is determined so that the thermoplastic polymer reaches a temperature T c It is understood that the setting is made so as not to decompose.

[0167] Step (c) is typically carried out by compression molding, injection molding, and oven curing.

[0168] method Initial and final dissociation temperatures T of additive A dis(i) and T dis(f) Decision by conducting variable temperature Fourier transform infrared spectroscopy (VT-FTIR) experiments on the mixture of step (a); This method is the most accurate method.

[0169] A relevant mixture containing a thermoplastic polymer containing boronic ester side groups and Additive A as defined in the present invention is gradually heated over time by maintaining an isotherm for 3 minutes at 5° C. FTIR reveals stretching bands of non-covalent bonds formed by the molecules of Additive A, e.g., at 3292 cm -1By following the hydrogen-bonded NH stretching bands of the amide functional groups at 100° C., it gives molecular information on the degree of association of the molecules of Additive A. During the increase in temperature, the number of monitored non-covalent bonds decreases until their complete disappearance and therefore the normalized intensity α of the corresponding stretching band also drops to zero, indicating the dissociation of the molecules of Additive A in the mixture. The protocol used to perform this experiment (3 min isotherm) brings the system closer to equilibrium than the temperature sweep experiment in rheology described below and therefore gives information on the system at fine time intervals. Thus, the dissociation of the molecules of Additive A begins when the normalized intensity of the monitored stretching band starts to decrease (dashed line in FIG. 1A), the corresponding temperature being the initial dissociation temperature T of Additive A. dis(i) The final dissociation temperature of additive A, T dis(f) corresponds to the temperature at which this stretching band disappears, i.e., the normalized intensity α is equal to 0 (dashed circle in Figure 1A).

[0170] by conducting a temperature sweep experiment in rheology on the mixture of step (a); When VT-FTIR is not available, this less accurate method can be used.

[0171] A relevant mixture comprising a thermoplastic polymer containing boronic ester pendant groups and Additive A as defined herein is heated gradually over time, typically at 10° C. / min. The shear storage modulus (G′) and loss modulus (G”) are measured during heating at a frequency of 1 rad / sec. Upon heating, the shear storage (G′) and loss (G”) moduli decrease with temperature, indicating the expected flow of the system for a thermoplastic resin. From a temperature T (dashed line in FIG. 1B ), the storage modulus (G′ ; black curved solid line) increases. The loss modulus (G″ ; grey curved dashed line) also increases at slightly higher temperatures than for G′. This increase in storage and loss modulus reflects the crosslinking reaction occurring between the thermoplastic polymer and the dissociated Additive A. From the initial dissociation temperature T dis(i) is about 30° C. to 50° C. lower than the temperature at which the storage modulus G' begins to increase. EXAMPLES

[0172] Example 1 Synthesis of Additive 1 (according to the present invention)

[0173] [ka]

[0174] N-(2,3-dihydroxypropyl)cyclohexanecarboxamide. 3-Aminopropane-1,2-diol (2.0 g, 22 mmol) and triethylamine (3.26 mL, 0.024 mol) were dissolved in 15 mL of DMF and cooled to 0° C. under N2 atmosphere. In a separate flask, cyclohexanecarbonyl chloride (3.22 g, 22 mmol) was solubilized in 10 mL of DMF and added dropwise to the solution of 3-aminopropane-1,2-diol and triethylamine. The reaction was kept at 0° C. for 1 h and allowed to warm to room temperature for an additional 18 h. The reaction mixture was added to 300 mL of brine and extracted with 5×50 mL of 1-butanol. The organic fractions were combined and diluted with 0.5 M NaOH. (aq) 150mL, 0.5M HCl (aq) The mixture was washed with 150 mL of ethyl acetate and 150 mL of brine, then dried over anhydrous MgSO4. The solvent was removed under vacuum and the solid was washed with diethyl ether to give a white powder (1.72 g, yield=39%). 1 H NMR (400 MHz, DMSO-d6, 25℃, TMS) δ 7.71 (t, J = 5.8 Hz, 1H), 4.78 (s, 1H), 4.55 (d, J = 5.6 Hz, 1H), 3.44 (t, J = 5.7 Hz, 1H), 3.25 (s, 2H), 3.14 (ddd, J = 13.4, 6.0, 5.2 Hz, 1H), 2.96 (ddd, J = 13.4, 6.4, 5.5 Hz, 1H), 2.12 (ddd, J = 11.4, 8.1, 3.3 Hz, 1H), 1.78 - 1.52 (m, 5H), 1.41 - 1.02 (m, 5H). 13C NMR (101 MHz, DMSO-d6, 25℃) δ 175.76, 70.59, 63.61, 43.89, 41.94, 29.32, 25.49, 25.28. 13 Splitting of the cyclohexyl group peak was observed in C NMR.

[0175] [ka]

[0176] Crosslinker 1. N-(2,3-dihydroxypropyl)cyclohexanecarboxamide (1.76 g, 8.78 mmol), benzene-1,4-diboronic acid (0.728 g, 4.39 mmol), water (5 mL, 0.28 mol), and ethanol (5 mL, 0.109 mol) were added to a round bottom flask containing 90 mL of toluene. The flask was connected to a Dean-Stark apparatus and the mixture was heated to reflux. The reaction was cooled after three purges (45 mL) of purge liquid were exhausted. The solvent was removed under reduced pressure and the product was crystallized from acetonitrile / DMF after hot filtration to give Crosslinker 1 as a white solid (1.49 g, yield=60%). 1 H NMR (400 MHz, DMSO-d6, 25℃, TMS) δ 7.93 (t, J = 5.9 Hz, 2H), 7.73 (s, 4H), 4.68 - 4.56 (m, 2H), 4.33 (t, J = 8.6 Hz, 2H), 4.02 (dd, J = 9.1, 6.5 Hz, 2H), 3.41 - 3.19 (m, 4H), 2.12 (tt, J = 11.3, 3.4 Hz, 2H), 1.78 - 1.50 (m, 10H), 1.41 - 0.99 (m, 10H). 13 C NMR (101 MHz, DMSO-d6, 25 °C) δ 175.89, 133.81, 75.97, 68.23, 43.79, 42.01, 29.09, 25.44, 25.21. The carbon adjacent to the boron could not be observed. 13Splitting of the cyclohexyl group peak in C NMR was observed. ESI-MS: m / z C 26 H 38 B2N2O6H + Calculated value: 497.2989; Measured value: 497.2354.

[0177] Additive 1 structure:

[0178] [ka]

[0179] Example 2 Identifying processing temperatures and cure times for a given polymer matrix and additives In this example, the present inventors synthesized the additive 1 obtained in Example 1 and the polymer P having dioxaborolane side groups; n = 104 kg / mol, 5.7 mol% repeat units carrying dioxaborolane side groups, 86.4 mol% 2-ethylhexyl methacrylate; 7.9 mol% styrene; T g = 12 ° C.) was used. Polymer P had the following formula:

[0180] [ka]

[0181] has.

[0182] i) DSC (differential scanning calorimetry); First, the melting point of additive A is determined by DSC. From DSC (Figure 1C), 1 melts at 262 °C with a melting enthalpy of 192 J / g. This temperature is the limit at which the additive can be processed independently of the polymer matrix.

[0183] 1 and P (1% by weight of 1) were blended by extrusion at 100° C. for 10 min, and then DSC of the resulting mixture was performed (FIG. 1D). Due to the low mass loading, the signal is not very strong and the melting peak is visible between 175 and 215° C., with the peak at 193° C. being the reactive melting of 1 in P. It should be noted that the dissociation temperature of the polymer is about 70° C. lower than that of molecule 1 alone, reflecting the interactions occurring between the additive and the polymer matrix (e.g., van der Waals interactions, hydrogen bonding, π-π interactions, covalent coordinate bonds).

[0184] ii) VT-FTIR (variable temperature Fourier transform infrared spectroscopy); VT-FTIR was performed by maintaining the isotherm for 3 min every 5 °C (Figure 1A). FITR was 3292 cm -1 At 100°C, the melting starts at 100°C with a small amount of decomposed molecules. Melting continues gradually up to 200°C where the hydrogen-bonded amides can no longer be observed. This gives molecular information on the degree of aggregation of additive 1. Typically, this band drops and disappears when the number of hydrogen bonds is reduced, indicating melting and dissociation of 1 into the polymer matrix. The method used to perform this experiment (3 min isotherm) allows the system to be brought closer to equilibrium than the rheological experiments described below, and therefore gives information on the system at fine time intervals. Here, melting starts at 100°C with a small amount of decomposed molecules. Melting continues gradually up to 200°C where the hydrogen-bonded amides can no longer be observed. This allows the crosslinking temperature T c However, in this system, it is 150°C (T dis(i) +T dis(f) The curing step can be designed such that the curing temperature should be equal to or higher than 220° C. / 2. Thus, the curing step is designed to occur at 220° C. for 10 minutes. Crosslinking should occur at a temperature and for a duration such that the polymer does not decompose. This information is known to those skilled in the art.

[0185] iii) Rheology To prove and quantify the cross-linking reaction resulting from melting of 1 in P, a temperature sweep experiment was performed rheologically on a mixture of P and 1 with 1 wt % of 1 (Figure 1B). The samples were heated from 50 to 250° C. at 10° C. / min and the shear storage (G') and loss (G") moduli were measured at a frequency of 1 rad / s. From 50 to 160° C., both moduli decrease with temperature, indicating flow of the system, as expected for thermoplastics. From 160° C., the storage modulus (G') increases from 500 Pa to 16,000 Pa at 240° C. when a plateau is reached. This increase in the storage and loss moduli reflects the crosslinking reaction that occurs between the polymer P and the molten additive 1. From rheology and DSC, it is possible to infer the maximum temperature for processing P with 1 in the absence of crosslinking. In this example, 1 at a loading of 1 wt. % in P begins to crosslink at 160° C. in rheology (supported by melting at 175° C. from DSC, a less sensitive analysis).

[0186] Processing should preferably be carried out at a temperature at least 30° C. below the temperature at which G' begins to increase during a temperature sweep experiment performed at a frequency of 1 rad / s and a heating rate of 10° C. / min (FIG. 1B), preferentially at least 40° C. below the temperature at which G' begins to increase during a temperature sweep experiment performed at a frequency of 1 rad / s and a heating rate of 10° C. / min, and even more preferentially at least 60° C. below the temperature at which G' begins to increase during a temperature sweep experiment performed at a frequency of 1 Hz and a heating rate of 10° C. / min.

[0187] The above experiments - DSC, rheology, FTIR - make it possible to determine the processing temperature and curing conditions (temperature and duration) for a given additive in a given polymer matrix. For the example of the present invention, additive 1 at a loading of 1% by weight in P, we have to process the two components below or at 100°C. We choose 100°C for 10 minutes; the curing step is (T dis(i) +T dis(f) ) / 2, which in this system is 150° C. Therefore, we choose 220° C. for 10 minutes.

[0188] Example 3 The process of the present invention with the additive of the present invention or a comparative additive The inventors realise Additive 1 and Polymer P as disclosed in Example 2.

[0189] The inventors further discovered a compound of the formula:

[0190] [ka]

[0191] Use comparison additive 2 (counterexample).

[0192] According to the method of the present invention, the crosslinker 1 is mixed with the polymer P at a loading of 1% by weight at a temperature T mix The mixture is mixed at 100 rpm (revolutions per minute) and the mixture is extruded at a screw speed of 100 rpm (revolutions per minute). The torque required to keep the screw speed constant remains constant (Figure 2A: solid line). The torque required to rotate the screw is related to the viscosity of the melt.

[0193] In a counter example, the same experiment is performed - at the same molar loading, temperature, and screw speed - by using additive 2 instead of 1. The torque increases quickly, reaching a plateau that is more than twice the torque measured in the extrusion performed with 1 (FIG. 2A; dashed line). This clearly demonstrates that mixture P+2 starts to crosslink during extrusion under these conditions, whereas no crosslinking occurs during the extrusion of mixture P+1.

[0194] Rheological analysis further shows that the material processed with 2 crosslinks after extrusion (without the need for a curing step). Stress relaxation (Figure 2B) shows how long it takes the material to relax the stress at a given deformation, giving an indication of the viscosity / flowability of the material (i.e. the higher the viscosity, the longer the relaxation time). Functional polymer P extruded at 100 °C with 1% by weight of 1 completely relaxes the stress after about 100 seconds (solid line), giving a zero shear viscosity η0 = 120000 Pa·s and a relaxation time τ = 104 seconds. When the material obtained by extrusion of P and 1 at 100 °C is cured by compression molding (10 min at 220 °C), it no longer completely relaxes the stress within 10000 seconds - a residual stress of about 5% after 10000 seconds - which is typical for boronic ester-based vitrimers and constitutes direct evidence of the transformation of the material into a vitrimer (dashed line). The material extruded with 2, without any curing step, does not fully relieve stress within 10,000 seconds, showing a residual stress of 14% after 10,000 seconds (dotted line).

[0195] These two experiments show that the mixture polymer P+1 does not crosslink after extrusion at 100° C., whereas the mixture polymer P+2 is already crosslinked after extrusion.

[0196] The significant stress relaxation of the cured material at 100 °C (polymer P + 1 wt % was extruded and then compression molded; Figure 2B, dashed line), combined with the presence of a rubbery plateau in DMA (dynamic mechanical analysis) (Figure 3, black dotted line), is characteristic of a vitrimer.

[0197] To evaluate the recyclability of the vitrimers (cured materials) obtained in the examples, the vitrimers were mechanically tested (tensile tests), crushed and then mechanically recycled. Mechanical recycling was performed by cutting and chopping the samples into small pieces and compression molding them into the desired shape at 140° C. and 1 equivalent ton for 20 minutes. The recycled materials obtained were then characterized again by DMA (FIG. 3, grey dashed line) and tensile tests and compared to the vitrimers (Table 1).

[0198]

Table 1

Claims

1. 1. A method for preparing a crosslinked polymer composition having exchangeable side group attachments and exchangeable crosslinks by a boronic ester metathesis reaction, comprising: (a) A mixture M containing a thermoplastic polymer containing pendant boronic ester groups and molecules of additive A is heated to a temperature T mix heating to The boronic ester side groups are represented by the following formulae EB-1 and EB-2: 【Chemistry 1】 (In the formula, Rx, Rv, and Rw are the same or different, each of which represents a hydrogen atom or a group containing carbon, or two of which together form an aliphatic or aromatic ring; Ry is a carbon-containing group, and Ry is bonded to the boron atom of the dioxaborolane or dioxaborinane ring by a covalent bond via a carbon atom; Ry is further linked to the thermoplastic polymer by a covalent bond, either directly or via a functional group G covalently linked to the thermoplastic polymer, or - a substituent selected from Rx, Rw, Rv, {Rx, Rw}, or {Rx, Rv} is attached to the thermoplastic polymer by a covalent bond or through a functional group G that is covalently attached to the thermoplastic polymer. are independently selected from the group consisting of dioxaborolane and dioxaborinane of - the molecules of Additive A are capable of reacting with the boronic ester side groups of the thermoplastic polymer and forming intermolecular non-covalent interactions with other molecules of Additive A and / or the thermoplastic polymer to form a crosslinked polymer composition containing exchangeable side group bonds and crosslinks via a boronic ester metathesis reaction, at a temperature T mix The molecules of Additive A can be associated with each other and / or with the thermoplastic polymer by non-covalent interactions, and each of the molecules of Additive A can be independently two boronic ester functional groups capable of reacting with the pendant boronic ester groups of the thermoplastic polymer, and - two or more functional groups F, which may be the same or different, selected from the group consisting of an amide functional group of the formula -NH-C(O)-, a urea functional group of the formula -NH-C(O)-NH-, and a carbamate functional group of the formula -OC(O)-NH- having Here, T mix is higher than the glass transition temperature or melting temperature of the thermoplastic polymer used in step (a) and the initial dissociation temperature T of the crosslinker in the mixture of step (a) dis(i) and (b) recovering a composition comprising the uncrosslinked thermoplastic polymer of step (a) and additive A; (c) subjecting the crosslinked polymer composition to a temperature T c and curing the non-crosslinked composition of step (b). Including, Here, T c is represented by the following formula: T c ≧(T dis(i) +T dis(f) ) / 2 Fulfilling In the formula, T dis(i) is the initial dissociation temperature in step (a), and T dis(f) is the final dissociation temperature of additive A in the mixture of step (c), The initial dissociation temperature T dis(i) is the temperature at which the intermolecular non-covalent interactions formed by the molecules of additive A in the mixture of step (a) begin to break down, and The final dissociation temperature T dis(f) is the temperature at which the intermolecular non-covalent interactions formed by the molecules of Additive A in the mixture of step (c) are completely destroyed.

2. 2. The method of claim 1, wherein each molecule of Additive A contains two identical boronic ester functional groups.

3. The molecules of additive A are identical and have the formula (IA): 【Chemistry 2】 is a molecule of During the ceremony, Ar 1 is an aromatic group, F 1 and F 2 are the same or different and are selected from the group consisting of -NH-C(O)-, -C(O)-NH-, -NH-C(O)-NH-, -OC(O)-NH-, and -NH-C(O)-O-; a, b, i, and j are the same or different and are natural numbers equal to 0 or 1; When a is 1, - R 2 is C 1 ~C 4 Alkanediyl or C 1 ~C 4 alkenediyl, said alkanediyl or alkenediyl being optionally substituted with one or more halogens; R 3 is H, or - R 2 is assumed to be i=0. 3 together to form an aromatic group, said aromatic group being optionally substituted with one or more halogens; When a is 0, F 1 The group is attached directly to a carbon atom of the boronic ester, R 3 is H, When b is 1, - R 4 is C 1 ~C 4 Alkanediyl or C 1 ~C 4 alkenediyl, said alkanediyl or alkenediyl being optionally substituted with one or more halogens; R 5 is H, or - R 4 is assumed that j=0. 5 together to form an aromatic group, said aromatic group being optionally substituted with one or more halogens; When b is 0, F 2 The group is attached directly to a carbon atom of the boronic ester, R 5 is H, R 1 and R 6 The method according to claim 1 or 2, wherein are the same or different and each is a carbon-containing group.

4. The additive A molecules are identical and have the formula (IB): 【Chemistry 3】 is a molecule of During the ceremony, Ar 2 and Ar 3 are the same or different and are aromatic groups, F' 1 and F' 2 are the same or different and are selected from the group consisting of -NH-C(O)-, -C(O)-NH-, -NH-C(O)-NH-, -OC(O)-NH-, and -NH-C(O)-O-; a, b, i, and j are the same or different and are natural numbers equal to 0 or 1; When a is 1, - R' 2 is C 1 ~C 4 Alkanediyl or C 1 ~C 4 alkenediyl, wherein the alkanediyl or alkenediyl is optionally substituted with one or more halogens; R' 3 is H, or - R' 2 is R' assuming that i=0. 3 together to form an aromatic group, said aromatic group being optionally substituted with one or more halogens; When a is 0, F' 1 The R' group is attached directly to a carbon atom of the boronic ester. 3 is H, When b is 1, - R' 4 is C 1 ~C 4 Alkanediyl or C 1 ~C 4 alkenediyl, said alkanediyl or alkenediyl being optionally substituted with one or more halogens; R' 5 is H, or - R' 4 is R' assuming j=0. 5 together to form an aromatic group, said aromatic group being optionally substituted with one or more halogens; When b is 0, F' 2 The R' group is attached directly to a carbon atom of the boronic ester. 5 is H; R 7 The method of claim 1 or 2, wherein is a group containing carbon.

5. 5. The method of any of claims 1 to 4, wherein step (b) comprises shaping the non-crosslinked polymer composition, for example by extrusion, injection, compression, molding, or thermoforming.

6. 6. The method according to claim 1, wherein steps (a) and (b) are achieved simultaneously by extrusion.

7. 7. The method according to any one of claims 1 to 6, wherein step (c) is carried out for a time ranging from 1 minute to 1 hour, preferably from 2 minutes to 30 minutes, even more preferably from 5 minutes to 20 minutes.

8. 8. The method according to claim 1, wherein the mixture of step (a) comprises from 0.05 to 10% by weight, preferably from 0.1 to 3.5% by weight, more preferably from 0.5 to 1.5% by weight of additive A, relative to the weight of the thermoplastic polymer or blend thereof.

9. 9. The method according to any one of claims 1 to 8, wherein step (c) is carried out by compression molding, injection molding, or oven curing.

10. 10. The method according to claim 1, wherein a thermoplastic polymer not carrying any pendant boronic ester groups is further added during step a).

11. Step (a) comprises the following substeps: (a1) providing a thermoplastic polymer comprising pendant boronic ester groups and optionally a thermoplastic polymer not carrying any pendant boronic ester groups, or a blend thereof, as defined in any one of claims 1 to 9; (a2) providing an additive A as defined in any one of claims 1 to 9; (a3) The thermoplastic polymer of step (a1) and the additive A of step (a2) are processed at a processing temperature T mix The step of mixing Including, Here, T mix is higher than the glass transition temperature or melting temperature of the thermoplastic polymer provided in step (a1) and the initial dissociation temperature T of the crosslinker in the mixture in step (a3). dis(i) 11. The method of claim 1, wherein the .alpha.-amino acid is equal to or lower than .alpha.-amino acid.

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