Nano-reinforced thermal conductive plastic based ice storage coil pipe and preparation method of nano-reinforced thermal conductive plastic based ice storage coil pipe

Abstract

The invention relates to the field of plastic ice storage coils, in particular to a nano-reinforced heat-conducting plastic ice storage coil and a preparation method thereof. The plastic ice storage coil pipe is used for solving the problems that an existing plastic ice storage coil pipe is poor in heat conduction efficiency and low in heat exchange efficiency in the icing and ice melting process. According to the plastic ice storage coil pipe, PBT and PEI react through an imide ring and an ester group to form a three-dimensional interpenetrating bicontinuous phase structure, the heat conductivity coefficient of the plastic ice storage coil pipe is increased, boron nitride is modified and added into PBT / PEI blended particles, the heat conduction efficiency is optimized, multi-walled carbon nanotube amination and carboxylated expanded graphite react, a continuous heat conduction network is formed, and the heat conduction efficiency of the plastic ice storage coil pipe is improved. The heat conduction performance of the plastic ice storage coil pipe is improved through cooperation with a plastic base body; the plastic ice storage coil pipe not only can improve the heat exchange efficiency, but also can improve the uniformity of ice block melting distribution, so that the overall energy efficiency of an ice storage system is improved, and the service life of the ice storage system is prolonged.

Description

TECHNICAL FIELD

[0001] The application relates to the field of plastic ice storage coils, in particular to a nano-enhanced heat-conducting plastic ice storage coil and a preparation method thereof. BACKGROUND

[0002] At present, the traditional plastic ice storage coil has ice or water with ice storage capacity, but there are certain limitations in heat exchange efficiency and heat preservation effect, especially in the environment with rapid temperature change, the existing plastic ice storage coil is difficult to efficiently transmit and store heat, which not only leads to low ice storage efficiency, but also causes uneven ice melting, high energy consumption and other problems.

[0003] The application provides a nano-enhanced heat-conducting plastic ice storage coil and a preparation method thereof, which effectively improves the heat conduction capacity of the plastic by adding nano materials in the plastic matrix, so that the application of the plastic in the energy-saving ice storage system becomes possible. SUMMARY

[0004] In order to overcome the above technical problems, the purpose of the application is to provide a nano-enhanced heat-conducting plastic ice storage coil and a preparation method thereof, which solves the problems of poor heat conduction efficiency of the existing plastic ice storage coil and low heat exchange efficiency in the ice melting and ice melting process.

[0005] The purpose of the application can be realized by the following technical solutions.

[0006] In a first aspect, the application provides a nano-enhanced heat-conducting plastic ice storage coil, which comprises the following components by weight: modified PBT / PEI composite particles 50-60 parts, multi-walled carbon nanotube-expanding graphite composite particles 20-30 parts, nano calcium carbonate 10-20 parts, antistatic agent PEG-6000 0.3-0.4 parts, antioxidant 1010 0.16-0.2 parts, and pentabromophenol 0.2-0.4 parts.

[0007] The modified PBT / PEI composite particles are prepared by the following steps:

[0008] Step A1: Put polybutylene terephthalate into a drying box and dry at 140-150 DEG C under vacuum for 4-6 hours to obtain dried polybutylene terephthalate, and put polyetherimide into a blast drying oven and dry at 110-120 DEG C under blast for 3-4 hours to obtain dried polyetherimide;

[0009] Step A2: polyetherimide, N-methylpyrrolidone was added to a three-necked flask equipped with a thermometer, a stirrer, stirred at 50-60℃ for 10-20min, maleic anhydride and dicumyl peroxide were added, nitrogen was introduced for protection, the temperature was raised to 110-120℃, and refluxed for 3-4h. After the reaction was completed, it was precipitated in ethanol, filtered and washed with ethanol for 3-5 times, and then placed in a drying oven at 50-60℃ for 8-10h to obtain maleic anhydride grafted polyetherimide. The dried polybutylene terephthalate, dried polyetherimide and maleic anhydride grafted polyetherimide were added to a high-speed mixer, and premixed at a speed of 450-500r / min for 5-10min. The premixed material was added to a twin-screw extruder and blended at a temperature of 280-300℃ and a speed of 200-300r / min. After blending, the extruded melt strip was cooled in a water bath at 20-30℃, and then cut into 3-5mm particles by a pelletizer to obtain PBT / PEI blended particles.

[0010] Step A3: boric acid, urea was added to a three-necked flask equipped with a stirrer, and then β-cyclodextrin was added and stirred for 42-46min. The solution was spray dried, the spray was collected and placed in a tube furnace for sintering at 500℃ for 4h and at 1100℃ for 2h under the protection of nitrogen to obtain boron nitride. The boron nitride and hydrogen peroxide were added to a three-necked flask equipped with a reflux condenser and a thermometer, ultrasonicated at 20-30℃ for 40-45min, and refluxed at 110-120℃ for 44-48h. The product was centrifuged for 15-20min, washed with distilled water for 3-5 times, and dried to obtain hydroxylated boron nitride.

[0011] Step A4: octamethylcyclotetrasiloxane, ethanol aqueous solution was added to a three-necked flask equipped with a stirrer and a thermometer, stirred at 50-100r / min for 5-10min, and then hydroxylated boron nitride was added and stirred at a water bath of 60-70℃ for 300min. The modified boron nitride was obtained by filtration and drying. The PBT / PEI blended particles and the modified boron nitride were added to a high-speed mixer and premixed at a speed of 450-500r / min for 5-10min. The premixed material was added to a twin-screw mixer and blended at a temperature of 250-300℃ and a speed of 200-300r / min. After blending, the extruded melt strip was cooled in a water bath at 20-30℃, and then cut into 3-4mm particles by a pelletizer, placed in a drying oven at 60-70℃ for 3-4h, and then modified PBT / PEI composite particles were obtained.

[0012] As a further scheme of the application, the amount of polybutylene terephthalate in step A1 is 20-30g.

[0013] As a further scheme of the present application: the amount of the polyetherimide in step A1 is 20-30g.

[0014] As a further scheme of the present application: the model of the polybutylene terephthalate in step A1 is PBT6131C NC010.

[0015] As a further scheme of the present application: the model of the polyetherimide in step A1 is PEI ULTEM 1010R.

[0016] As a further scheme of the present application: the amount ratio of the polyetherimide, N-methylpyrrolidone, maleic anhydride, dicumyl peroxide, dry polybutylene terephthalate and dry polyetherimide in step A2 is 5-10g: 50-100mL: 0.15-0.3g: 0.015-0.03g: 10-20g: 10-20g.

[0017] As a further scheme of the present application: the amount ratio of the boric acid, urea and β-cyclodextrin in step A3 is 1-2mol: 0.39-0.78mol: 10-20g.

[0018] As a further scheme of the present application: the amount ratio of the boron nitride, hydrogen peroxide in step A3 is 40-80mL.

[0019] As a further scheme of the present application: the mass fraction of the hydrogen peroxide in step A3 is 30%.

[0020] As a further scheme of the present application: the amount ratio of the octamethylcyclotetrasiloxane, aqueous ethanol solution, hydroxylated boron nitride and PBT / PEI blended particles in step A4 is 0.04-0.08g: 20-30mL: 2-4g: 20-40g.

[0021] As a further scheme of the present application: the mass fraction of the aqueous ethanol solution in step A4 is 67.8%.

[0022] As a further scheme of the present application: the multi-walled carbon nanotube-exfoliated graphite composite particles are prepared by the following steps:

[0023] Step B1: a mixture of multi-walled carbon nanotubes, concentrated nitric acid and concentrated sulfuric acid is added to a single-necked flask, ultrasonic treatment is performed for 1-2h, washed with deionized water for 3-5 times, placed in a drying box for vacuum drying at 50-60℃ for 10-12h, the obtained solid is added to a three-necked flask equipped with a thermometer and a reflux condenser, reflux reaction is performed at 70-80℃ for 8-10h, after the reaction is completed, centrifuged with anhydrous ethanol for 3 times, placed in a drying box for vacuum drying at 50-60℃ for 7-8h, to obtain aminated multi-walled carbon nanotubes;

[0024] Step B2: expandable graphite, concentrated nitric acid were added into a three-necked flask equipped with a thermometer and a stirrer, and stirred at 48-50℃ for 3-4h. After the reaction was completed, the mixture was washed with deionized water for 5-7 times, and then was placed in a drying oven for vacuum drying at 70-80℃ for 8-10h to obtain carboxylated expandable graphite.

[0025] Step B3: the amino-functionalized multi-walled carbon nanotubes, the carboxylated expandable graphite and N,N-dimethylformamide were added into a single-necked flask, and ultrasonically dispersed at a power of 300W for 28-30min. Then, 1-ethyl-(3-dimethylaminopropyl) carbodiimide was added, and the mixture was stirred magnetically for 5-10min. The mixture was transferred into a three-necked flask equipped with a reflux condenser, a thermometer and a stirrer, and was protected by nitrogen. The temperature was raised to 130-140℃, and the mixture was stirred at a rotation speed of 280-300r / min for 5-6h. After the reaction was completed, the mixture was cooled to 24-26℃, and was centrifuged twice with N,N-dimethylformamide, and then was washed with distilled water for 3-5 times. The mixture was vacuum dried at 50-60℃ for 10-12h to obtain multi-walled carbon nanotube-expandable graphite composite particles.

[0026] As a further scheme of the present application, the use amount ratio of the multi-walled carbon nanotubes, the mixed solution of concentrated nitric acid and concentrated sulfuric acid and ethylenediamine in step B1 is 1-2g:40-80mL:50-100mL.

[0027] As a further scheme of the present application, the average outer diameter of the multi-walled carbon nanotubes in step B1 is 13nm, and the average length is 20μm.

[0028] As a further scheme of the present application, the volume ratio of concentrated nitric acid to concentrated sulfuric acid in the mixed solution of concentrated nitric acid and concentrated sulfuric acid in step B1 is 1:3.

[0029] As a further scheme of the present application, the mass fraction of the concentrated nitric acid in step B1 is 65%.

[0030] As a further scheme of the present application, the mass fraction of the concentrated sulfuric acid in step B1 is 98.3%.

[0031] As a further scheme of the present application, the use amount ratio of the expandable graphite and concentrated nitric acid in step B2 is 2.5-5g:50-100mL.

[0032] As a further scheme of the present application, the mass fraction of the concentrated nitric acid in step B2 is 65%.

[0033] As a further scheme of the present application, the expansion volume of the expandable graphite in step B2 is 300mL / g.

[0034] As a further scheme of the present application: the amount ratio of the aminated multi-walled carbon nanotube, the carboxylated expanded graphite, the N,N-dimethylformamide and the 1-ethyl-(3-dimethylaminopropyl) carbodiimide in step B3 is 1.15-2.3g:1.35-2.7g:50-100mL:0.25-0.5g.

[0035] In a second aspect, the present application provides a preparation method of the nanometer-reinforced heat-conducting plastic ice-storage coil pipe, comprising the following steps:

[0036] Step one: according to the weight parts, the modified PBT / PEI composite particles 50-60 parts, the multi-walled carbon nanotube-expanded graphite composite particles 20-30 parts, the nano calcium carbonate 10-20 parts, the antistatic agent PEG-6000 0.3-0.4 parts, the antioxidant 1010 0.16-0.2 parts, and the pentabromophenol 0.2-0.4 parts are weighed;

[0037] Step two: the modified PBT / PEI composite particles, the multi-walled carbon nanotube-expanded graphite composite particles, the nano calcium carbonate, the antistatic agent, the antioxidant and the pentabromophenol are hot-melted, the composite pipe is extruded through a hot-melt extruder, the extruded composite pipe is passed through a cooling device to harden the composite pipe into a shape, the hardened composite pipe is continuously bent, and the bent pipe is shaped to obtain the nanometer-reinforced heat-conducting plastic ice-storage coil pipe.

[0038] The present application has the following advantages:

[0039] The nanometer-reinforced heat-conducting plastic ice-storage coil pipe and the preparation method thereof have the following advantages: the polybutylene terephthalate and the polyetherimide are blended and added into the modified boron nitride to improve the heat-conducting performance of the material; the aminated multi-walled carbon nanotube and the carboxylated expanded graphite are compounded through an amide reaction to obtain the multi-walled carbon nanotube-expanded graphite composite particles, and the thermal conductivity and the mechanical property are improved; the ice-storage coil pipe has high efficient heat conduction of the modified PBT / PEI composite particles and the multi-walled carbon nanotube-expanded graphite composite particles, realizes the heat exchange performance, can store and release the cold energy in a short time, and improves the working efficiency of the refrigeration system.

[0040] In the process of preparing the ice storage coil based on nano-enhanced thermal conductive plastic, first, the modified PBT / PEI composite particles are prepared. The imide ring of polyetherimide and the ester group on polybutylene terephthalate form a molecular level interaction through hydrogen bonding and π-π stacking to form a three-dimensional interpenetrating double continuous phase structure, thereby improving the thermal conductivity of the material. Boric acid and urea are used to prepare boron nitride. Hydroxyl groups are grafted on the surface of boron nitride by using hydrogen peroxide. The hydroxyl groups undergo ring-opening reaction with octamethylcyclotetrasiloxane to generate silanol groups. The silanol groups undergo dehydration condensation to form Si-O-B, thereby enhancing the interfacial bonding force and optimizing the thermal conduction efficiency. The surface of the multi-walled carbon nanotube is grafted with carboxyl groups by using a mixed solution of concentrated nitric acid and concentrated sulfuric acid. The amino groups are grafted on the surface of the multi-walled carbon nanotube by reacting the carboxyl groups with ethylenediamine. The carboxyl groups are grafted on the surface of the expanded graphite by using concentrated nitric acid. The amino groups in the amino-functionalized multi-walled carbon nanotube react with the carboxyl groups in the carboxyl-functionalized expanded graphite to form amide bonds, thereby forming a continuous thermal conduction network and improving the thermal conductivity of the material. The material has high thermal conductivity and can quickly transfer heat, so that the ice storage coil can realize efficient heat exchange during the ice formation and melting process, thereby improving the refrigeration and heating efficiency of the ice storage system. BRIEF DESCRIPTION OF DRAWINGS

[0041] In order to facilitate the understanding of those skilled in the art, the present application will be further described below with reference to the accompanying drawings.

[0042] Figure 1 The thermal conductivity test results of Examples 1-3 and Comparative Examples 1-3 of the present application are shown in the following table. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present application will be described below in detail with reference to the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0044] Example 1

[0045] The present embodiment is a preparation method of an ice storage coil based on nano-enhanced thermal conductive plastic, comprising the following steps:

[0046] Step S1: 20g of polybutylene terephthalate is placed in a drying box and dried at 140℃ under vacuum for 4h to obtain dried polybutylene terephthalate. 20g of polyetherimide is placed in a forced air drying oven and dried at 110℃ for 3h to obtain dried polyetherimide.

[0047] Step S2: 5 g of polyetherimide, 50 mL of N-methylpyrrolidone were added to a three-necked flask equipped with a thermometer, a stirrer, stirred at 50°C for 10 min, 0.15 g of maleic anhydride and 0.015 g of dicumyl peroxide were added, protected by nitrogen, heated to 110°C, refluxed for 3 h, after the reaction was completed, precipitated into 100 mL of ethanol, filtered and washed with ethanol for 3 times, put into a drying box and vacuum dried at 50°C for 8 h to obtain maleic anhydride grafted polyetherimide, 10 g of dried polybutylene terephthalate, 10 g of dried polyetherimide and 0.8 g of maleic anhydride grafted polyetherimide were added to a high-speed mixer, pre-mixed at a speed of 450 r / min for 5 min, the pre-mixed material was added to a twin-screw extruder, mixed at a temperature of 280°C and a speed of 200 r / min, after the mixing was completed, the extruded melt strip was cooled in a water bath at 20°C, cut into 3 mm particles by a granulator, and PBT / PEI blended particles were obtained;

[0048] Step S3: 1 mol of boric acid, 0.39 mol of urea were added to a three-necked flask equipped with a stirrer, 10 g of β-cyclodextrin was added, stirred for 42 min, the solution was spray dried, the spray was collected, put into a tube furnace, sintered at 500°C for 4 h and at 1100°C for 2 h under the protection of nitrogen, and boron nitride was obtained, 2 g of boron nitride, 40 mL of hydrogen peroxide were added to a three-necked flask equipped with a reflux condenser and a thermometer, ultrasonic treated at 20°C for 40 min, refluxed at 110°C for 44 h, centrifuged for 15 min, washed with distilled water for 3 times, dried to obtain hydroxylated boron nitride;

[0049] Step S4: 0.04 g of octamethylcyclotetrasiloxane, 20 mL of ethanol aqueous solution were added to a three-necked flask equipped with a stirrer and a thermometer, stirred at 50 r / min for 5 min, 2 g of hydroxylated boron nitride was added, stirred in a water bath at 60°C for 300 min, filtered and dried to obtain modified boron nitride, 20 g of PBT / PEI blended particles, 5 g of modified boron nitride were added to a high-speed mixer, pre-mixed at a speed of 450 r / min for 5 min, the pre-mixed material was added to a twin-screw mixer, mixed at a temperature of 250°C and a speed of 200 r / min, after the mixing was completed, the extruded melt strip was cooled in a water bath at 20°C, cut into 3 mm particles by a granulator, put into a drying box and vacuum dried at 60°C for 3 h, and modified PBT / PEI composite particles were obtained;

[0050] Step S5: 1g of multi-walled carbon nanotubes, 40mL of a mixture of concentrated nitric acid and concentrated sulfuric acid were added to a single-necked flask, ultrasonic treatment for 1h, washed with deionized water for 3 times, put into a drying oven at 50℃ for vacuum drying for 10h, the obtained solid was added to a three-necked flask equipped with a thermometer and a reflux condenser with 50mL of ethylenediamine, refluxed at 70℃ for 8h, after the reaction was completed, centrifuged with anhydrous ethanol for 3 times, put into a drying oven at 50℃ for vacuum drying for 7h, to obtain amino-functionalized multi-walled carbon nanotubes;

[0051] Step S6: 2.5g of expanded graphite, 50mL of concentrated nitric acid were added to a three-necked flask equipped with a thermometer and a stirrer, stirred at 48℃ for 3h, after the reaction was completed, washed with deionized water for 5 times, put into a drying oven at 70℃ for vacuum drying for 8h, to obtain carboxylated expanded graphite;

[0052] Step S7: 1.15g of amino-functionalized multi-walled carbon nanotubes, 1.35g of carboxylated expanded graphite, 50mL of N,N-dimethylformamide were added to a single-necked flask, ultrasonic dispersion for 28min at a power of 300W, 0.25g of 1-ethyl-(3-dimethylaminopropyl) carbodiimide was added, magnetic stirring for 5min, the mixture was transferred to a three-necked flask equipped with a reflux condenser, a thermometer and a stirrer, protected by nitrogen, heated to 130℃, stirred at a speed of 280r / min for 5h, after the reaction was completed, cooled to 24℃, centrifuged with N,N-dimethylformamide for 2 times, washed with distilled water for 3 times, vacuum dried at 50℃ for 10h, to obtain multi-walled carbon nanotube-expanded graphite composite particles;

[0053] Step S8: the modified PBT / PEI composite particles 50 parts, the multi-walled carbon nanotube-expanded graphite composite particles 20 parts, the nano calcium carbonate 10 parts, the antistatic agent PEG-6000 0.3 parts, the antioxidant 1010 0.16 parts, the pentabromophenol 0.2 parts were weighed according to the weight parts;

[0054] Step S9: the modified PBT / PEI composite particles, the multi-walled carbon nanotube-expanded graphite composite particles, the nano calcium carbonate, the antistatic agent, the antioxidant and the pentabromophenol were hot-melted, the composite tube was extruded through a hot-melt extruder, the extruded composite tube was passed through a cooling device to harden the composite tube into a shape, the hardened composite tube was continuously bent, and the bent composite tube was shaped, to obtain a nano-reinforced heat-conductive plastic ice storage coil pipe.

[0055] Example 2:

[0056] The embodiment is a preparation method of a nano-reinforced heat-conductive plastic ice storage coil pipe, which comprises the following steps:

[0057] Step S1: 25 g of polybutylene terephthalate was placed in a drying oven and dried at 145 °C under vacuum for 5 h to obtain dried polybutylene terephthalate, and 25 g of polyetherimide was placed in a blast drying oven and dried at 115 °C under blast for 3.5 h to obtain dried polyetherimide;

[0058] Step S2: 7.5 g of polyetherimide, 75 mL of N-methylpyrrolidone was added to a three-necked flask equipped with a thermometer and a stirrer, stirred at 55 °C for 15 min, 0.225 g of maleic anhydride and 0.0225 g of dicumyl peroxide were added, protected by nitrogen, heated to 115 °C, and refluxed for 3.5 h. After the reaction was completed, it was added to 150 mL of ethanol to precipitate, filtered and washed with ethanol 4 times, and placed in a drying oven and dried at 55 °C under vacuum for 9 h to obtain maleic anhydride grafted polyetherimide. 15 g of dried polybutylene terephthalate, 15 g of dried polyetherimide and 1.2 g of maleic anhydride grafted polyetherimide were added to a high-speed mixer and premixed at a speed of 475 r / min for 7 min. The premixed material was added to a twin-screw extruder and blended at a temperature of 290 °C and a speed of 250 r / min. After blending, the extruded melt strip was cooled in a water bath at 25 °C, cut into 4 mm particles by a granulator, and PBT / PEI blended particles were obtained.

[0059] Step S3: 1.5 mol of boric acid, 0.585 mol of urea was added to a three-necked flask equipped with a stirrer, 15 g of β-cyclodextrin was added, stirred for 44 min, the solution was spray dried, the spray was collected, placed in a tube furnace under the protection of nitrogen, sintered at 500 °C for 4 h and at 1100 °C for 2 h to obtain boron nitride. 3 g of boron nitride, 60 mL of hydrogen peroxide was added to a three-necked flask equipped with a reflux condenser and a thermometer, ultrasonic treated at 25 °C for 43 min, refluxed at 115 °C for 46 h, centrifuged for 17 min, washed with distilled water 4 times, and dried to obtain hydroxylated boron nitride.

[0060] Step S4: 0.06 g of octamethylcyclotetrasiloxane, 25 mL of aqueous ethanol solution was added to a three-necked flask equipped with a stirrer and a thermometer, stirred at 75 r / min for 7 min, 3 g of hydroxylated boron nitride was added, stirred in a water bath at 65 °C for 300 min, filtered and dried to obtain modified boron nitride. 30 g of PBT / PEI blended particles, 7.5 g of modified boron nitride was added to a high-speed mixer and premixed at a speed of 475 r / min for 7 min. The premixed material was added to a twin-screw mixer and blended at a temperature of 275 °C and a speed of 250 r / min. After blending, the extruded melt strip was cooled in a water bath at 25 °C, cut into 4 mm particles by a granulator, and placed in a drying oven and dried at 65 °C under vacuum for 3.5 h to obtain modified PBT / PEI composite particles.

[0061] Step S5: 1.5 g of multi-walled carbon nanotubes, 60 mL of a mixture of concentrated nitric acid and concentrated sulfuric acid were added to a single-necked flask, ultrasonic treatment for 1.5 h, washed with deionized water for 4 times, put into a drying oven at 55℃ for vacuum drying for 11 h, the obtained solid was added to a three-necked flask equipped with a thermometer and a reflux condenser with 75 mL of ethylenediamine, refluxed at 75℃ for 9 h, after the reaction was completed, centrifuged with anhydrous ethanol for 3 times, put into a drying oven at 55℃ for vacuum drying for 7.5 h, to obtain amino-functionalized multi-walled carbon nanotubes;

[0062] Step S6: 3.75 g of expanded graphite, 75 mL of concentrated nitric acid were added to a three-necked flask equipped with a thermometer and a stirrer, stirred at 49℃ for 3.5 h, after the reaction was completed, washed with deionized water for 6 times, put into a drying oven at 75℃ for vacuum drying for 9 h, to obtain carboxylated expanded graphite;

[0063] Step S7: 1.725 g of amino-functionalized multi-walled carbon nanotubes, 2.025 g of carboxylated expanded graphite, 75 mL of N,N-dimethylformamide were added to a single-necked flask, ultrasonic dispersion for 29 min at a power of 300 W, 0.375 g of 1-ethyl-(3-dimethylaminopropyl) carbodiimide was added, magnetic stirring for 7 min, the mixture was transferred to a three-necked flask equipped with a reflux condenser, a thermometer and a stirrer, protected by nitrogen, heated to 135℃, stirred at a speed of 290 r / min for 5.5 h, after the reaction was completed, cooled to 25℃, centrifuged with N,N-dimethylformamide for 2 times, washed with distilled water for 4 times, vacuum dried at 55℃ for 11 h, to obtain multi-walled carbon nanotube-expanded graphite composite particles;

[0064] Step S8: the modified PBT / PEI composite particles 55 parts, the multi-walled carbon nanotube-expanded graphite composite particles 25 parts, the nano calcium carbonate 15 parts, the antistatic agent PEG-6000 0.35 parts, the antioxidant 1010 0.18 parts, the pentabromophenol 0.3 parts were weighed according to the weight parts;

[0065] Step S9: the modified PBT / PEI composite particles, the multi-walled carbon nanotube-expanded graphite composite particles, the nano calcium carbonate, the antistatic agent, the antioxidant and the pentabromophenol were hot-melted, the composite tube was extruded through a hot-melt extruder, the extruded composite tube was passed through a cooling device to harden the composite tube into a shape, the hardened composite tube was continuously bent, and the bent composite tube was shaped, to obtain a nano-reinforced heat-conductive plastic ice storage coil pipe.

[0066] Example 3:

[0067] The embodiment is a preparation method of a nano-reinforced heat-conductive plastic ice storage coil pipe, which comprises the following steps:

[0068] Step S1: 30 g of polybutylene terephthalate was placed in a drying oven and vacuum dried at 150 °C for 6 h to obtain dried polybutylene terephthalate, 30 g of polyetherimide was placed in a blast drying oven and blast dried at 120 °C for 4 h to obtain dried polyetherimide;

[0069] Step S2: 10 g of polyetherimide, 100 mL of N-methylpyrrolidone was added to a three-necked flask equipped with a thermometer and a stirrer, stirred at 60 °C for 20 min, 0.3 g of maleic anhydride and 0.03 g of dicumyl peroxide were added, protected by nitrogen, heated to 120 °C, refluxed for 4 h, after the reaction was completed, precipitated in 200 mL of ethanol, filtered and washed with ethanol for 5 times, placed in a drying oven and vacuum dried at 60 °C for 10 h to obtain maleic anhydride grafted polyetherimide, 20 g of dried polybutylene terephthalate, 20 g of dried polyetherimide and 1.6 g of maleic anhydride grafted polyetherimide were added to a high-speed mixer, pre-mixed at a speed of 500 r / min for 10 min, the pre-mixed material was added to a twin-screw extruder, blended at a temperature of 300 °C and a speed of 300 r / min, after blending, the extruded melt strip was cooled in a water bath at 30 °C, cut into 5 mm particles by a granulator, and PBT / PEI blended particles were obtained;

[0070] Step S3: 2 mol of boric acid, 0.78 mol of urea was added to a three-necked flask equipped with a stirrer, 20 g of β-cyclodextrin was added, stirred for 46 min, the solution was spray dried, the spray was collected, placed in a tube furnace and sintered at 500 °C for 4 h and at 1100 °C for 2 h under the protection of nitrogen to obtain boron nitride, 4 g of boron nitride, 80 mL of hydrogen peroxide was added to a three-necked flask equipped with a reflux condenser and a thermometer, ultrasonic treated at 30 °C for 45 min, refluxed at 120 °C for 48 h, centrifuged for 20 min, washed with distilled water for 5 times, and dried to obtain hydroxylated boron nitride;

[0071] Step S4: 0.08 g of octamethylcyclotetrasiloxane, 30 mL of ethanol aqueous solution was added to a three-necked flask equipped with a stirrer and a thermometer, stirred at 100 r / min for 10 min, 4 g of hydroxylated boron nitride was added, stirred in a water bath at 70 °C for 300 min, filtered and dried to obtain modified boron nitride, 40 g of PBT / PEI blended particles, 10 g of modified boron nitride was added to a high-speed mixer, pre-mixed at a speed of 500 r / min for 10 min, the pre-mixed material was added to a twin-screw mixer, blended at a temperature of 300 °C and a speed of 300 r / min, after blending, the extruded melt strip was cooled in a water bath at 30 °C, cut into 4 mm particles by a granulator, placed in a drying oven and vacuum dried at 70 °C for 4 h to obtain modified PBT / PEI composite particles;

[0072] Step S5: 2g of multi-walled carbon nanotubes, 80mL of a mixture of concentrated nitric acid and concentrated sulfuric acid were added to a single-necked flask, ultrasonic treatment for 2h, washed with deionized water for 5 times, put into a drying oven at 60℃ for vacuum drying for 12h, the obtained solid was added to a three-necked flask equipped with a thermometer and a reflux condenser with 100mL of ethylenediamine, refluxed at 80℃ for 10h, after the reaction was completed, centrifuged with anhydrous ethanol for 3 times, put into a drying oven at 60℃ for vacuum drying for 8h, to obtain amino-functionalized multi-walled carbon nanotubes;

[0073] Step S6: 5g of expanded graphite, 100mL of concentrated nitric acid were added to a three-necked flask equipped with a thermometer and a stirrer, stirred at 50℃ for 4h, after the reaction was completed, washed with deionized water for 7 times, put into a drying oven at 80℃ for vacuum drying for 10h, to obtain carboxylated expanded graphite;

[0074] Step S7: 2.3g of amino-functionalized multi-walled carbon nanotubes, 2.7g of carboxylated expanded graphite, 100mL of N,N-dimethylformamide were added to a single-necked flask, ultrasonic dispersion for 30min at a power of 300W, 0.5g of 1-ethyl-(3-dimethylaminopropyl) carbodiimide was added, magnetic stirring for 10min, the mixture was transferred to a three-necked flask equipped with a reflux condenser, a thermometer and a stirrer, protected by nitrogen, heated to 140℃, stirred at a speed of 300r / min for 6h, after the reaction was completed, cooled to 26℃, centrifuged with N,N-dimethylformamide for 2 times, washed with distilled water for 5 times, vacuum dried at 60℃ for 12h, to obtain multi-walled carbon nanotube-expanded graphite composite particles;

[0075] Step S8: the modified PBT / PEI composite particles 60 parts, the multi-walled carbon nanotube-expanded graphite composite particles 30 parts, the nano calcium carbonate 20 parts, the antistatic agent PEG-6000 0.4 parts, the antioxidant 1010 0.2 parts, the pentabromophenol 0.4 parts were weighed according to the weight parts;

[0076] Step S9: the modified PBT / PEI composite particles, the multi-walled carbon nanotube-expanded graphite composite particles, the nano calcium carbonate, the antistatic agent, the antioxidant and the pentabromophenol were hot-melted, the composite tube was extruded through a hot-melt extruder, the extruded composite tube was passed through a cooling device to harden the composite tube into a shape, the hardened composite tube was continuously bent, and the bent composite tube was shaped, to obtain a nano-reinforced heat-conductive plastic ice storage coil pipe.

[0077] Comparative Example 1

[0078] The present comparative example is a preparation method of a nano-reinforced heat-conductive plastic ice storage coil pipe, comprising the following steps:

[0079] Step S1: 30 g of polybutylene terephthalate was placed in a drying oven and vacuum dried at 150°C for 6h to obtain dried polybutylene terephthalate;

[0080] Step S2: 2 mol of boric acid, 0.78 mol of urea were added to a three-necked flask equipped with a stirrer, 20 g of β-cyclodextrin was added, stirred for 46 min, the solution was spray dried, the spray was collected and placed in a tube furnace, sintered at 500°C for 4h under the protection of nitrogen, sintered at 1100°C for 2h to obtain boron nitride, 4 g of boron nitride, 80 mL of hydrogen peroxide were added to a three-necked flask equipped with a reflux condenser and a thermometer, ultrasonic treatment was carried out at 30°C for 45 min, refluxed at 120°C for 48h, the product was centrifuged for 20 min, washed with distilled water for 5 times, dried to obtain hydroxylated boron nitride;

[0081] Step S3: 0.08 g of octamethylcyclotetrasiloxane, 30 mL of aqueous ethanol solution were added to a three-necked flask equipped with a stirrer and a thermometer, stirred at 100 r / min for 10 min, 4 g of hydroxylated boron nitride was added, stirred in a water bath at 70°C for 300 min, filtered and dried to obtain modified boron nitride, 30 g of dried polybutylene terephthalate, 10 g of modified boron nitride were added to a high-speed mixer, pre-mixed at a speed of 500 r / min for 10 min, the pre-mixed material was added to a twin-screw mixer, blended at a temperature of 300°C and a speed of 300 r / min, after blending, the extruded melt strip was cooled in a water bath at 30°C, cut into 4 mm particles by a pelletizer, placed in a drying oven and vacuum dried at 70°C for 4h to obtain modified polybutylene terephthalate composite particles;

[0082] Step S4: 2 g of multi-walled carbon nanotubes, 80 mL of a mixture of concentrated nitric acid and concentrated sulfuric acid were added to a single-necked flask, ultrasonic treatment was carried out for 2h, washed with deionized water for 5 times, placed in a drying oven and vacuum dried at 60°C for 12h, the obtained solid was added to a three-necked flask equipped with a thermometer and a reflux condenser, 80°C reflux reaction for 10h, after the reaction was completed, centrifuged with anhydrous ethanol for 3 times, placed in a drying oven and vacuum dried at 60°C for 8h to obtain aminated multi-walled carbon nanotubes;

[0083] Step S5: 5 g of expanded graphite, 100 mL of concentrated nitric acid were added to a three-necked flask equipped with a thermometer and a stirrer, stirred at 50°C for 4h, after the reaction was completed, washed with deionized water for 7 times, placed in a drying oven and vacuum dried at 80°C for 10h to obtain carboxylated expanded graphite;

[0084] Step S6: 2.3 g of amino-functionalized multi-walled carbon nanotubes, 2.7 g of carboxyl-functionalized expanded graphite, and 100 mL of N,N-dimethylformamide were added to a single-necked flask, and ultrasonic dispersion was performed for 30 min at a power of 300 W. 0.5 g of 1-ethyl-(3-dimethylaminopropyl) carbodiimide was added, and magnetic stirring was performed for 10 min. The mixture was transferred to a three-necked flask equipped with a reflux condenser, a thermometer, and a stirrer, and was protected by nitrogen. The temperature was raised to 140 DEG C, and stirring was performed at a rotation speed of 300 r / min for 6 h. After the reaction was completed, the temperature was lowered to 26 DEG C, and the mixture was centrifuged twice with N,N-dimethylformamide and then washed five times with distilled water. Vacuum drying was performed at 60 DEG C for 12 h to obtain multi-walled carbon nanotube-expanded graphite composite particles.

[0085] Step S7: The modified polybutylene terephthalate composite particles, the multi-walled carbon nanotube-expanded graphite composite particles, the nano calcium carbonate, the antistatic agent PEG-6000, the antioxidant 1010, and the pentabromophenol were weighed according to the proportions of 60 parts, 30 parts, 20 parts, 0.4 parts, 0.2 parts, and 0.4 parts, respectively.

[0086] Step S8: The modified polybutylene terephthalate composite particles, the multi-walled carbon nanotube-expanded graphite composite particles, the nano calcium carbonate, the antistatic agent, the antioxidant, and the pentabromophenol were subjected to hot melting. The composite tube was extruded through a hot melt extruder, and the extruded composite tube was hardened into a shape by passing through a cooling device. The hardened composite tube was subjected to continuous bending treatment, and the bent tube was shaped to obtain a nano-reinforced heat-conductive plastic ice storage coil.

[0087] Comparative Example 2

[0088] This comparative example is a method for preparing a nano-reinforced heat-conductive plastic ice storage coil, which comprises the following steps:

[0089] Step S1: 30 g of polybutylene terephthalate was placed in a drying oven and vacuum dried at 150 DEG C for 6 h to obtain dried polybutylene terephthalate. 30 g of polyetherimide was placed in a forced air drying oven and forced air dried at 120 DEG C for 4 h to obtain dried polyetherimide.

[0090] Step S2: 10 g of polyetherimide, 100 mL of N-methylpyrrolidone were added to a three-necked flask equipped with a thermometer, a stirrer, stirred at 60°C for 20 min, 0.3 g of maleic anhydride and 0.03 g of dicumyl peroxide were added, nitrogen was introduced for protection, the temperature was raised to 120°C, and refluxed for 4 h. After the reaction was completed, it was precipitated into 200 mL of ethanol, filtered and washed with ethanol for 5 times, and then placed in a drying box and dried at 60°C for 10 h under vacuum to obtain maleic anhydride grafted polyetherimide. 20 g of dried polybutylene terephthalate, 20 g of dried polyetherimide and 1.6 g of maleic anhydride grafted polyetherimide were added to a high-speed mixer and premixed at a speed of 500 r / min for 10 min. The premixed material was added to a twin-screw extruder and blended at a temperature of 300°C and a speed of 300 r / min. After blending, the extruded melt strip was cooled in a water bath at 30°C, cut into 5 mm particles by a granulator, and PBT / PEI blended particles were obtained.

[0091] Step S3: 40 g of PBT / PEI blended particles, 10 g of boron nitride were added to a high-speed mixer and premixed at a speed of 500 r / min for 10 min. The premixed material was added to a twin-screw mixer and blended at a temperature of 300°C and a speed of 300 r / min. After blending, the extruded melt strip was cooled in a water bath at 30°C, cut into 4 mm particles by a granulator, and placed in a drying box and dried at 70°C for 4 h under vacuum to obtain PBT / PEI composite particles.

[0092] Step S4: 2 g of multi-walled carbon nanotubes, 80 mL of a mixture of concentrated nitric acid and concentrated sulfuric acid were added to a single-necked flask, ultrasonically treated for 2 h, washed with deionized water for 5 times, and placed in a drying box and dried at 60°C for 12 h under vacuum. The obtained solid was added to a three-necked flask equipped with a thermometer and a reflux condenser, and 100 mL of ethylenediamine was added. The mixture was refluxed at 80°C for 10 h. After the reaction was completed, it was centrifuged with anhydrous ethanol for 3 times, and placed in a drying box and dried at 60°C for 8 h under vacuum to obtain amino-functionalized multi-walled carbon nanotubes.

[0093] Step S5: 5 g of expanded graphite, 100 mL of concentrated nitric acid were added to a three-necked flask equipped with a thermometer and a stirrer, and stirred at 50°C for 4 h. After the reaction was completed, it was washed with deionized water for 7 times, and placed in a drying box and dried at 80°C for 10 h under vacuum to obtain carboxylated expanded graphite.

[0094] Step S6: 2.3 g of amino-functionalized multi-walled carbon nanotubes, 2.7 g of carboxyl-functionalized expanded graphite, and 100 mL of N,N-dimethylformamide were added into a single-necked flask, and ultrasonic dispersion was performed for 30 min at a power of 300 W. 0.5 g of 1-ethyl-(3-dimethylaminopropyl) carbodiimide was added, and magnetic stirring was performed for 10 min. The mixture was transferred into a three-necked flask equipped with a reflux condenser, a thermometer, and a stirrer, and was protected by nitrogen. The temperature was raised to 140 DEG C, and stirring was performed at a rotation speed of 300 r / min for 6 h. After the reaction was completed, the temperature was cooled to 26 DEG C, and centrifugation was performed twice with N,N-dimethylformamide and then washed with distilled water for 5 times. Vacuum drying was performed at 60 DEG C for 12 h to obtain multi-walled carbon nanotube-expanded graphite composite particles.

[0095] Step S7: PBT / PEI composite particles 60 parts, multi-walled carbon nanotube-expanded graphite composite particles 30 parts, nano calcium carbonate 20 parts, antistatic agent PEG-6000 0.4 parts, antioxidant 1010 0.2 parts, and pentabromophenol 0.4 parts were weighed according to the weight parts.

[0096] Step S8: The PBT / PEI composite particles, multi-walled carbon nanotube-expanded graphite composite particles, nano calcium carbonate, antistatic agent, antioxidant, and pentabromophenol were hot-melted, and the composite tube was extruded through a hot-melt extruder. The extruded composite tube was passed through a cooling device to harden the composite tube into a shape. The hardened composite tube was subjected to continuous bending treatment, and the bent tube was shaped to obtain a nano-reinforced heat-conductive plastic ice-storage coil pipe.

[0097] Comparative Example 3

[0098] The present comparative example is a preparation method of a nano-reinforced heat-conductive plastic ice-storage coil pipe, which comprises the following steps:

[0099] Step S1: 30 g of polybutylene terephthalate was placed into a drying box and vacuum dried at 150 DEG C for 6 h to obtain dried polybutylene terephthalate. 30 g of polyetherimide was placed into a forced air drying box and forced air dried at 120 DEG C for 4 h to obtain dried polyetherimide.

[0100] Step S2: 10 g of polyetherimide, 100 mL of N-methylpyrrolidone were added to a three-necked flask equipped with a thermometer, a stirrer, stirred at 60°C for 20 min, 0.3 g of maleic anhydride and 0.03 g of dicumyl peroxide were added, nitrogen was introduced for protection, the temperature was raised to 120°C, and refluxed for 4 h. After the reaction was completed, it was added to 200 mL of ethanol for precipitation, filtered and washed with ethanol for 5 times, and then placed in a drying box for vacuum drying at 60°C for 10 h to obtain maleic anhydride grafted polyetherimide. 20 g of dried polybutylene terephthalate, 20 g of dried polyetherimide and 1.6 g of maleic anhydride grafted polyetherimide were added to a high-speed mixer and premixed at a speed of 500 r / min for 10 min. The premixed material was added to a twin-screw extruder and blended at a temperature of 300°C and a speed of 300 r / min. After blending, the extruded melt strip was cooled in a water bath at 30°C, cut into 5 mm particles by a granulator, and PBT / PEI blended particles were obtained.

[0101] Step S3: 2 mol of boric acid and 0.78 mol of urea were added to a three-necked flask equipped with a stirrer, 20 g of β-cyclodextrin was added, stirred for 46 min, and the solution was spray dried. The spray was collected and placed in a tube furnace under the protection of nitrogen, sintered at 500°C for 4 h and at 1100°C for 2 h to obtain boron nitride. 4 g of boron nitride and 80 mL of hydrogen peroxide were added to a three-necked flask equipped with a reflux condenser and a thermometer, ultrasonicated at 30°C for 45 min, and refluxed at 120°C for 48 h. The product was centrifuged for 20 min, washed with distilled water for 5 times, and dried to obtain hydroxylated boron nitride.

[0102] Step S4: 0.08 g of octamethylcyclotetrasiloxane and 30 mL of ethanol solution were added to a three-necked flask equipped with a stirrer and a thermometer, stirred at 100 r / min for 10 min, 4 g of hydroxylated boron nitride was added, stirred in a water bath at 70°C for 300 min, filtered and dried to obtain modified boron nitride. 40 g of PBT / PEI blended particles and 10 g of modified boron nitride were added to a high-speed mixer and premixed at a speed of 500 r / min for 10 min. The premixed material was added to a twin-screw mixer and blended at a temperature of 300°C and a speed of 300 r / min. After blending, the extruded melt strip was cooled in a water bath at 30°C, cut into 4 mm particles by a granulator, placed in a drying box and vacuum dried at 70°C for 4 h to obtain modified PBT / PEI composite particles.

[0103] Step S5: The modified PBT / PEI composite particles, multi-walled carbon nanotubes, nano calcium carbonate, antistatic agent PEG-6000, antioxidant 1010, and pentabromophenol were weighed according to the weight parts.

[0104] Step S6: melt the modified PBT / PEI composite particles, multi-walled carbon nanotubes, nano calcium carbonate, antistatic agent, antioxidant, pentabromophenol, and extrude the composite tube through a hot melt extruder, pass the extruded composite tube through a cooling device to harden the composite tube into a shape, perform continuous bending treatment on the hardened composite tube, and set the bent tube to obtain a nanometer-reinforced heat-conductive plastic ice storage coil pipe.

[0105] Referring to Figure 1 The plastic ice storage coil pipes of Examples 1-3 and Comparative Examples were selected to have a length of 5 cm, a width of 1 cm, and a thickness of 0.1 cm, and the thermal conductivity was measured using a TC3000E thermal conductivity meter.

[0106] Referring to Figure 1 As shown in the table, according to the comparison between Examples 1-3 and Comparative Examples 1-3, it can be seen that the thermal conductivity of the material obtained by blending the modified PBT / PEI composite material and the multi-walled carbon nanotube-exfoliated graphite composite particles is improved.

[0107] According to the comparison between Example 3 and Comparative Example 1, it can be seen that the thermal conductivity of the material obtained by blending the modified PBT / PEI composite material and the multi-walled carbon nanotube-exfoliated graphite composite particles is better than that of the material obtained by blending the modified polybutylene terephthalate composite particles and the multi-walled carbon nanotube-exfoliated graphite composite particles, which indicates that the material obtained by blending the modified PBT / PEI composite material and the multi-walled carbon nanotube-exfoliated graphite composite particles has excellent heat conduction efficiency.

[0108] According to the comparison between Example 3 and Comparative Example 2, it can be seen that the thermal conductivity of the material obtained by blending the modified PBT / PEI composite material and the multi-walled carbon nanotube-exfoliated graphite composite particles is better than that of the material obtained by blending the PBT / PEI composite material and the multi-walled carbon nanotube-exfoliated graphite composite particles, which indicates that the material obtained by blending the modified PBT / PEI composite material and the multi-walled carbon nanotube-exfoliated graphite composite particles has excellent heat conduction efficiency.

[0109] According to the comparison between Example 3 and Comparative Example 3, it can be seen that the thermal conductivity of the material obtained by blending the modified PBT / PEI composite material and the multi-walled carbon nanotube-exfoliated graphite composite particles is better than that of the material obtained by blending the modified PBT / PEI composite material and the multi-walled carbon nanotube, which indicates that the material obtained by blending the modified PBT / PEI composite material and the multi-walled carbon nanotube-exfoliated graphite composite particles has excellent heat conduction efficiency.

[0110] In the description of the specification, reference to terms "one embodiment", "an example", "a specific example" and so on is intended to indicate that a particular feature, structure, material or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. Descriptive expressions of the above terms in the specification do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0111] The above is only an example and illustration of the application, and those skilled in the art can make various modifications or supplements to the described specific embodiments or replace them with similar ways, as long as they do not deviate from the application or exceed the scope defined in the application.

Claims

1. A nano-enhanced thermally conductive plastic ice storage coil, characterized in that: It comprises the following components in parts by weight: 50-60 parts of modified PBT / PEI composite particles, 20-30 parts of multi-walled carbon nanotube-expanded graphite composite particles, 10-20 parts of nano-calcium carbonate, 0.3-0.4 parts of antistatic agent PEG-6000, 0.16-0.2 parts of antioxidant 1010, and 0.2-0.4 parts of pentabromophenol; The modified PBT / PEI composite particles are prepared by the following steps: Step A1: vacuum drying polybutylene terephthalate to obtain dry polybutylene terephthalate, and air-drying polyetherimide to obtain dry polyetherimide; Step A2: polyetherimide and N-methylpyrrolidone are stirred, maleic anhydride and dicumyl peroxide are added, nitrogen protection is introduced, the temperature is raised to reflux, and after the reaction is completed, the mixture is added to ethanol for precipitation, filtered, washed with ethanol, and vacuum dried to obtain maleic anhydride-grafted polyetherimide, dried polybutylene terephthalate, dried polyetherimide, and maleic anhydride-grafted polyetherimide are added to a high-speed mixer for premixing, and the premix is ​​added to a twin-screw extruder for blending. After the blending is completed, the extruded melt strand is cooled in a water bath and cut into pellets by a pelletizer to obtain PBT / PEI blended pellets; Step A3: Boric acid and urea are added to a three-necked flask, β-cyclodextrin is added and stirred, the solution is spray-dried, the sprayed product is collected, and placed in a tube furnace under nitrogen protection, sintered at 500°C and 1100°C to obtain boron nitride, the boron nitride and hydrogen peroxide are sonicated and refluxed, the product is centrifuged, washed with distilled water, and dried to obtain hydroxylated boron nitride; Step A4: Stir octamethylcyclotetrasiloxane and ethanol aqueous solution, add hydroxylated boron nitride, stir in a water bath, filter and dry to obtain modified boron nitride, add PBT / PEI blend particles and modified boron nitride to a high-speed mixer for premixing, add the premix to a twin-screw mixer for blending, cool the extruded melt strands in a water bath after blending, cut into particles by a pelletizer, and vacuum dry to obtain modified PBT / PEI composite particles.

2. The nano-enhanced thermally conductive plastic ice storage coil according to claim 1, characterized in that: In step A1, the amount of polybutylene terephthalate used is 20-30 g; the amount of polyetherimide used is 20-30 g; the model of the polybutylene terephthalate is PBT 6131C NC010; the model of the polyetherimide is PEI ULTEM 1010R.

3. The nano-enhanced thermally conductive plastic ice storage coil according to claim 1, characterized in that: The usage ratio of the polyetherimide, N-methylpyrrolidone, maleic anhydride, dicumyl peroxide, dry polybutylene terephthalate and dry polyetherimide in step A2 is 5-10 g: 50-100 mL: 0.15-0.3 g: 0.015-0.03 g: 10-20 g: 10-20 g.

4. The nano-enhanced thermally conductive plastic ice storage coil according to claim 1, characterized in that: In step A3, the usage ratio of boric acid, urea and β-cyclodextrin is 1-2 mol: 0.39-0.78 mol: 10-20 g; the usage ratio of boron nitride and hydrogen peroxide is 40-80 mL.

5. The nano-enhanced thermally conductive plastic ice storage coil according to claim 1, characterized in that: The usage ratio of octamethylcyclotetrasiloxane, ethanol aqueous solution, hydroxylated boron nitride and PBT / PEI blended particles in step A4 is 0.04-0.08 g: 20-30 mL: 2-4 g: 20-40 g.

6. The nano-enhanced thermally conductive plastic ice storage coil according to claim 1, characterized in that: The multi-walled carbon nanotube-expanded graphite composite particles are prepared by the following steps: Step B1: ultrasonically treat a mixture of multi-walled carbon nanotubes, concentrated nitric acid, and concentrated sulfuric acid, wash with deionized water, and vacuum dry. Add the resulting solid and ethylenediamine to a three-necked flask and reflux. After the reaction, centrifuge with anhydrous ethanol and vacuum dry to obtain amino-modified multi-walled carbon nanotubes. Step B2: stirring the expanded graphite and concentrated nitric acid to react, washing with deionized water after the reaction, and vacuum drying to obtain carboxylated expanded graphite; Step B3: Ultrasonic dispersion of amino-modified multi-walled carbon nanotubes, carboxylated expanded graphite, and N,N-dimethylformamide was performed, and 1-ethyl-(3-dimethylaminopropyl)carbodiimide was added and magnetic stirring was performed. The mixture was transferred to a three-necked flask, nitrogen was introduced, and the temperature was increased with stirring. After the reaction, the mixture was cooled, centrifuged with N,N-dimethylformamide, washed with distilled water, and vacuum dried to obtain multi-walled carbon nanotube-expanded graphite composite particles.

7. The nano-enhanced thermally conductive plastic ice storage coil according to claim 6, characterized in that: In step B1, the ratio of the multi-walled carbon nanotubes, the mixed solution of concentrated nitric acid and concentrated sulfuric acid, and ethylenediamine is 1-2 g: 40-80 mL: 50-100 mL; the outer diameter of the multi-walled carbon nanotubes is 13 nm and the length is 20 μm; the volume ratio of concentrated nitric acid to concentrated sulfuric acid in the mixed solution of concentrated nitric acid and concentrated sulfuric acid is 1:3; the mass fraction of the concentrated nitric acid is 65%; and the mass fraction of the concentrated sulfuric acid is 98.3%.

8. The nano-enhanced thermally conductive plastic ice storage coil according to claim 6, characterized in that: In step B2, the usage ratio of the expanded graphite and concentrated nitric acid is 2.5-5 g:50-100 mL; the mass fraction of the concentrated nitric acid is 65%; and the expansion volume of the expanded graphite is 300 mL / g.

9. The nano-enhanced thermally conductive plastic ice storage coil according to claim 6, characterized in that: In step B3, the usage ratio of the amino-modified multi-walled carbon nanotubes, carboxylated expanded graphite, N,N-dimethylformamide, and 1-ethyl-(3-dimethylaminopropyl)carbodiimide is 1.15-2.3 g: 1.35-2.7 g: 50-100 mL: 0.25-0.5 g.

10. A method for preparing nano-enhanced thermally conductive plastic ice storage coil, characterized in that: The following steps are involved: Step 1: Weigh 50-60 parts of modified PBT / PEI composite particles, 20-30 parts of multi-walled carbon nanotube-expanded graphite composite particles, 10-20 parts of nano-calcium carbonate, 0.3-0.4 parts of antistatic agent PEG-6000, 0.16-0.2 parts of antioxidant 1010, and 0.2-0.4 parts of pentabromophenol according to weight; Step 2: hot-melt the modified PBT / PEI composite particles, multi-walled carbon nanotube-expanded graphite composite particles, nano-calcium carbonate, antistatic agent, antioxidant, and pentabromophenol, extrude the composite tube through a hot-melt extruder, pass the extruded composite tube through a cooling device to harden and shape the composite tube, continuously bend the hardened composite tube, and shape it after bending to obtain a nano-enhanced thermal conductive plastic ice storage coil.

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