A bio-based polyester elastomer-toughened CPVC power protection pipe material and its preparation method

Abstract

This invention belongs to the field of polymer materials technology, specifically relating to a bio-based polyester elastomer-toughened CPVC power protection pipe material and its preparation method. Addressing the current problem of poor compatibility between bio-based polyester elastomers and CPVC, this invention prepares an unsaturated bio-based polyester elastomer prepolymer via melt polycondensation reaction using 2,5-furandicarboxylic acid, 1,3-propanediol, and itaconic acid as raw materials under the catalysis of tetrabutyl titanate. This prepolymer is then mixed with epoxidized soybean oil and dicumyl peroxide for epoxy functionalization modification, yielding an epoxy-functionalized bio-based polyester elastomer. Finally, CPVC resin, the epoxy-functionalized bio-based polyester elastomer, an organotin heat stabilizer, and a lubricant are premixed and melt-extruded to obtain the bio-based polyester elastomer-toughened CPVC power protection pipe material.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, specifically relating to a bio-based polyester elastomer-toughened CPVC power protection pipe material and its preparation method. Background Technology

[0002] CPVC, or chlorinated polyvinyl chloride, is a thermoplastic resin obtained by chlorination modification of PVC. Compared with ordinary PVC, CPVC has higher heat resistance, flame retardancy, chemical corrosion resistance, and insulation, making it suitable for applications such as power cable protection pipes.

[0003] However, CPVC resin has a high molecular chain rigidity and a narrow melt processing window, making the products prone to low-temperature brittleness, construction impact cracking, and interface defects. Existing technologies often use CPE, ACR, MBS, EVA, inorganic fillers, or fibers for toughening and reinforcement. For example, CN105111649A discloses a CPVC cable protection pipe. Its background technology indicates that CPVC resin has a chlorine content of up to 61%–68%, exhibiting good heat resistance, flame retardancy, weather resistance, and chemical resistance. However, CPVC resin is brittle and requires toughening with CPE, EVA, ABS, etc. This patent uses PVC resin, CPVC resin, light calcium carbonate, stabilizers, ACR impact modifiers, CPE impact modifiers, MBS resin, and lubricating components to improve impact performance.

[0004] For example, CN105295272A discloses a chlorinated polyvinyl chloride (CPVC) plastic cable conduit and its processing technology. The components include CPVC resin, SAN resin, PVC resin, engineering plastics, fillers, compatibilizers, impact modifiers, stabilizers, thermal conductive agents, lubricants, plasticizing accelerators, and pigments. CN110760146A discloses a high-strength CPVC high-voltage power sheathing pipe, which uses CPVC resin, PVC resin, nano-calcium carbonate, carbon fiber, modified talc, and glass fiber to achieve increased rigidity and toughness. These solutions can improve some mechanical properties, but still mainly rely on petroleum-based impact modifiers, inorganic fillers, or fibers. They suffer from problems such as insufficient bonding between the toughening agent and CPVC interface, difficulty in balancing toughness and heat resistance, a decrease in Vicat softening temperature when toughness is increased, and insufficient processing thermal stability.

[0005] In summary, there is an urgent need for a technical solution to address the poor compatibility between bio-based polyester elastomers and CPVC. Summary of the Invention

[0006] This invention provides a bio-based polyester elastomer-toughened CPVC power protection pipe material and its preparation method.

[0007] The specific technical solution is as follows: A method for preparing a bio-based polyester elastomer-toughened CPVC power protection pipe material is as follows: S1: Preparation of bio-based polyester elastomer prepolymer: 2,5-furandicarboxylic acid and 1,3-propanediol are mixed, and then a portion of tetrabutyl titanate is added. The mixture is heated under nitrogen protection and reacted. The temperature is then lowered to 165°C, and itaconic acid, p-methoxyphenol and the remaining portion of tetrabutyl titanate are added. The mixture is heated under nitrogen protection and reacted under vacuum polycondensation. The mixture is then cooled to room temperature to obtain an unsaturated bio-based polyester elastomer prepolymer.

[0008] S2: Preparation of epoxy-functionalized bio-based polyester elastomer: The unsaturated bio-based polyester elastomer prepolymer prepared in S1, epoxidized soybean oil and dicumyl peroxide are mixed and reacted under nitrogen protection, and then cooled to room temperature to obtain epoxy-functionalized bio-based polyester elastomer.

[0009] S3: Composite material preparation, CPVC resin, epoxy-functionalized bio-based polyester elastomer prepared in S2, organotin heat stabilizer, lubricant are premixed, melt extruded, cooled, pelletized, and dried to obtain bio-based polyester elastomer toughened CPVC power protection pipe material granules.

[0010] Furthermore, the itaconic acid described in S1 has a molar ratio of 0.20:1 to 0.80:1 with 2,5-furandicarboxylic acid. The 1,3-propanediol described in S1 has a molar ratio of 1.02:1 to 1.12:1 with (2,5-furandicarboxylic acid + itaconic acid).

[0011] The tetrabutyl titanate described in S1 is added in an amount of 0.1% to 0.5% of the total mass of the reactants.

[0012] The amount of p-methoxyphenol described in S1 added is 0.01% to 0.04% of the total mass of the reactants.

[0013] The heating reaction described in S1 has the following parameters: temperature 160-200℃, duration 2-6h.

[0014] The vacuum polycondensation described in S1 has the following parameters: temperature 200-220℃, absolute pressure 50-100Pa, and duration 2-8h.

[0015] The unsaturated bio-based polyester elastomer prepolymer described in S1 has an acid value of 10-30 mgKOH / g and a hydroxyl value of 10-60 mgKOH / g.

[0016] Furthermore, the heating reaction described in S2 has the following parameter settings: temperature 140–160°C, duration 1–4 hours.

[0017] The epoxy-functionalized bio-based polyester elastomer described in S2 has an epoxy value of 0.2 to 0.6 mmol / g. Based on 100 parts of unsaturated bio-based polyester elastomer prepolymer, the composition of each raw material is as follows: 5 to 30 parts of epoxidized soybean oil and 0.8 to 2 parts of dicumyl peroxide.

[0018] Furthermore, the organotin heat stabilizer described in S3 is one or more of dibutyltin dilaurate, dibutyltin maleate, and methyltin mercaptan.

[0019] The lubricant described in S3 is one or more of stearic acid, calcium stearate, polyethylene wax, and oxidized polyethylene wax.

[0020] The premixing described in S3 has the following parameters: rotation speed 800-1500 rpm, duration 5-15 min.

[0021] The melt extrusion described in S3 has the following parameter settings: feeding section 150~170℃, compression section 170~190℃, metering section 180~200℃, die head temperature 180~195℃, and screw speed 50~300rpm.

[0022] The drying process described in S3 has the following parameters: temperature 80–100°C, duration 4–8 hours.

[0023] The bio-based polyester elastomer toughened CPVC power protection pipe material granules described in S3, based on 100 parts of CPVC resin, have the following raw material weight ratios: 5-25 parts of epoxy functionalized bio-based polyester elastomer, 1-5 parts of organotin heat stabilizer, and 0.5-3 parts of lubricant.

[0024] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention introduces epoxy groups into the molecular chain of bio-based polyester elastomers through chemical bonding, thereby improving the interfacial compatibility between the elastomer and CPVC.

[0025] 2. This invention modifies unsaturated polyester prepolymers with epoxidized soybean oil and dicumyl peroxide, giving the elastomers flexible aliphatic chains and epoxy groups, thereby improving processing stability. Attached Figure Description

[0026] Figure 1 The NMR spectra are those of the epoxy-functionalized bio-based polyester elastomer prepared in Example 1, the unsaturated bio-based polyester elastomer prepolymer prepared in Comparative Example 1, the elastomers prepared in Comparative Examples 2 and 3, and the original epoxy soybean oil. In the latter case, H1 is Example 1, and C1-C3 are Comparative Examples 1-3.

[0027] Figure 2These are SEM images of the bio-based polyester elastomer-toughened CPVC power protection pipe material granules prepared in Example 1 and Comparative Examples 1-2, where H1 is Example 1 and C1-C2 are Comparative Examples 1-2. Detailed Implementation

[0028] The following embodiments further explain and illustrate the technical solutions of the present invention. It should be specifically noted that each specific embodiment is a concretization and explanation of the technical solution and should not be considered as a limitation on the scope of protection of the present invention. Those skilled in the art still have the right to modify the technical solutions of these embodiments and make equivalent substitutions for some or all of the technical features, and these modifications or substitutions do not change the essence of the corresponding technical solutions, nor do they cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions described in the present invention.

[0029] This invention proposes a bio-based polyester elastomer-toughened CPVC power protection pipe material and its preparation method, the detailed technical solution of which is as follows: 1. Preparation of bio-based polyester elastomer prepolymers 2,5-furandicarboxylic acid and 1,3-propanediol were mixed, and then a portion of tetrabutyl titanate was added. The mixture was heated under nitrogen protection and reacted. The temperature was then lowered to 165°C, and itaconic acid, p-methoxyphenol, and the remaining portion of tetrabutyl titanate were added. The mixture was heated under nitrogen protection and reacted under vacuum polycondensation. The mixture was then cooled to room temperature to obtain an unsaturated bio-based polyester elastomer prepolymer.

[0030] 2,5-furandicarboxylic acid, 1,3-propanediol, and itaconic acid undergo esterification under the catalysis of tetrabutyl titanate. The prepolymers with terminal hydroxyl and carboxyl groups generated by the esterification reaction further undergo polycondensation, with the molecular chains continuously growing to form high molecular weight polyesters. During the polycondensation process, small molecule byproduct water is continuously removed by vacuuming, which shifts the reaction equilibrium in the positive direction and promotes the continuous growth of polymer molecular weight, ultimately yielding unsaturated bio-based polyester elastomer prepolymers.

[0031] 2. Preparation of epoxy-functionalized bio-based polyester elastomers Unsaturated bio-based polyester elastomer prepolymer, epoxidized soybean oil and dicumyl peroxide (DCP) were mixed and reacted under nitrogen protection, and then cooled to room temperature to obtain epoxy-functionalized bio-based polyester elastomer.

[0032] Under heating conditions, DCP undergoes homolytic cleavage of the OO bonds, decomposing to generate two isopropylphenoxy free radicals. These isopropylphenoxy free radicals abstract hydrogen atoms from the allylic carbon atom of the unsaturated double bond in the epoxidized soybean oil molecule, forming a macromolecular free radical on the epoxidized soybean oil molecular chain. Similarly, these free radicals can also abstract hydrogen atoms from the allylic position of the itaconic acid unit double bond in the unsaturated bio-based polyester elastomer prepolymer molecular chain, forming polyester macromolecular free radicals. These macromolecular free radicals react with each other or with monomers: in the presence of dicumyl peroxide, unsaturated bio-based polyester reacts with epoxidized soybean oil to form a reaction-modified product containing grafted, branched, and / or partially cross-linked structures; epoxidized soybean oil macromolecular free radicals also undergo addition reactions with the double bonds in the polyester molecular chain, similarly achieving grafting. Through these reactions, epoxidized soybean oil is chemically bonded to the molecular chain of the unsaturated bio-based polyester elastomer prepolymer, forming an epoxy-functionalized bio-based polyester elastomer.

[0033] 3. Preparation of composite materials CPVC resin, epoxy-functionalized bio-based polyester elastomer, organotin heat stabilizer, and lubricant are premixed, melt-extruded, cooled, pelletized, and dried to obtain bio-based polyester elastomer-toughened CPVC power protection pipe material granules.

[0034] When CPVC resin is heated above its glass transition temperature, the molecular chain segments begin to move, and the resin gradually melts into a high-viscosity fluid. Under the strong shear force field provided by the twin-screw extruder, the epoxy-functionalized bio-based polyester elastomer is broken, stretched, and refined, uniformly dispersed in the continuous phase of CPVC at micron or submicron sizes. The epoxy-functionalized bio-based polyester elastomer molecular chains contain abundant epoxy groups. The polyester groups and epoxy groups in the reaction-modified toughening agent improve the polarity matching between the toughening agent and the CPVC matrix; the flexible aliphatic chains of the toughening agent help form a dispersed phase with suitable size; the epoxy groups may also react with acidic substances generated during processing. By controlling the glass transition temperature, epoxy value, gel content, and melt viscosity of the toughening agent, a stable dispersed phase is formed in CPVC, thereby inducing crazes and shear yielding and absorbing impact energy. When the material is subjected to external impact, stress can be effectively transferred from the CPVC matrix to the elastomer dispersion phase through the interface. The elastomer particles act as stress concentration points, inducing a large number of crazes and shear bands, absorbing a large amount of impact energy, thereby significantly improving the material's impact toughness. At the same time, due to the good interfacial bonding between the elastomer and the matrix, the elastomer particles are not likely to become stress defects and will not significantly reduce the material's tensile strength and heat resistance.

[0035] Example 1 A method for preparing a bio-based polyester elastomer-toughened CPVC power protection pipe material is as follows: Table 1 Main Raw Materials ; S1: Preparation of bio-based polyester elastomer prepolymer: 159.28g of 2,5-furandicarboxylic acid and 121.74g of 1,3-propanediol were mixed in a polymerization reactor equipped with a mechanical stirrer, nitrogen inlet, temperature sensor, water separator, and vacuum interface. Then, 0.72g of tetrabutyl titanate was added, and the reactor was purged with nitrogen for 20min. The temperature was raised under nitrogen protection (first raised to 160℃ and held for 1h, then raised to 180℃ and reacted for 2h). The temperature was lowered to 165℃, and 65.71g of itaconic acid, 0.1g of p-methoxyphenol, and the remaining 0.32g of tetrabutyl titanate were added. Nitrogen gas was continued to be introduced, and the temperature was raised to 180℃ and reacted for 2h. Vacuum polycondensation was performed (temperature 210℃, absolute pressure 75Pa, duration 5h). The mixture was cooled to room temperature to obtain unsaturated bio-based polyester elastomer prepolymer.

[0036] S2: Preparation of epoxy-functionalized bio-based polyester elastomer: 100g of the unsaturated bio-based polyester elastomer prepolymer prepared in S1, 18g of epoxidized soybean oil and 1.8g of dicumyl peroxide were added to a reactor equipped with mechanical stirring and nitrogen protection and mixed. The mixture was heated under nitrogen protection (temperature 150℃, duration 2.5h) and cooled to room temperature to obtain epoxy-functionalized bio-based polyester elastomer (epoxy value 0.46mmol / g).

[0037] S3: Composite material preparation: 100g CPVC resin, 15g epoxy-functionalized bio-based polyester elastomer prepared in S2, 3g organotin heat stabilizer (dibutyltin dilaurate), and 1.8g lubricant (calcium stearate) were premixed at 1150rpm for 10min, melt-extruded (feeding section 160℃, compression section 180℃, metering section 190℃, die head temperature 188℃, screw speed 150rpm), cooled, pelletized, and dried at 90℃ for 6h to obtain bio-based polyester elastomer toughened CPVC power protection pipe material pellets.

[0038] Example 2 The composition and preparation process are the same as in Example 1, except that: In the preparation process S1, the molar ratio of itaconic acid to 2,5-furandicarboxylic acid is 0.20:1, the molar ratio of 1,3-propanediol to (2,5-furandicarboxylic acid + itaconic acid) is 1.02:1, the amount of tetrabutyl titanate added is 0.1% of the total mass of the reactants, the amount of p-methoxyphenol added is 0.01% of the total mass of the reactants, and other components are the same.

[0039] In step S1 of the preparation process, the heating reaction parameters are set as follows: temperature 160℃, duration 2h; the vacuum polycondensation parameters are set as follows: temperature 200℃, absolute pressure 50Pa, duration 2h; and other steps are the same.

[0040] In the preparation process S2, the epoxy-functionalized bio-based polyester elastomer is based on 100 parts of unsaturated bio-based polyester elastomer prepolymer, 5 parts of epoxidized soybean oil, 0.8 parts of dicumyl peroxide, and other components are the same.

[0041] The temperature rise reaction in step S2 of the preparation process is set with the following parameters: temperature 140℃, duration 1h, and other steps are the same.

[0042] Example 3 The composition and preparation process are the same as in Example 1, except that: In the preparation process S1, the molar ratio of itaconic acid to 2,5-furandicarboxylic acid is 0.80:1, the molar ratio of 1,3-propanediol to (2,5-furandicarboxylic acid + itaconic acid) is 1.12:1, the amount of tetrabutyl titanate added is 0.5% of the total mass of the reactants, the amount of p-methoxyphenol added is 0.04% of the total mass of the reactants, and other components are the same.

[0043] In the preparation process S1, the heating reaction parameters were set as follows: temperature 200℃, duration 6h; the vacuum polycondensation parameters were set as follows: temperature 220℃, absolute pressure 100Pa, duration 8h; and other steps were the same.

[0044] In the preparation process S2, the epoxy-functionalized bio-based polyester elastomer is based on 100 parts of unsaturated bio-based polyester elastomer prepolymer, 30 parts of epoxidized soybean oil, and 2 parts of dicumyl peroxide, with other components being the same.

[0045] The temperature rise reaction in step S2 of the preparation process is set as follows: temperature 160℃, duration 4h, and other steps are the same.

[0046] Example 4 The composition and preparation process are the same as in Example 1, except that: In the preparation process S3, the organotin heat stabilizer is dibutyltin maleate, the lubricant is stearic acid, and the other components are the same.

[0047] In the preparation process S3, the premixing parameters are set as follows: rotation speed 800 rpm, duration 5 min; melt extrusion parameters are set as follows: feeding section 150℃, compression section 170℃, metering section 180℃, die head temperature 180℃, screw speed 50 rpm; drying parameters are set as follows: temperature 80℃, duration 4 h. Other steps are the same.

[0048] Example 5 The composition and preparation process are the same as in Example 1, except that: In process S3, the organotin heat stabilizer is methyl tin mercaptan, the lubricant is polyethylene wax, and the other components are the same.

[0049] In the preparation process S3, the premixing parameters are set as follows: rotation speed 1500 rpm, duration 15 min; melt extrusion parameters are set as follows: feeding section 170℃, compression section 190℃, metering section 200℃, die head temperature 195℃, screw speed 300 rpm; drying parameters are set as follows: temperature 100℃, duration 8 h. Other steps are the same.

[0050] Example 6 The composition and preparation process are the same as in Example 1, except that: In process S3, the lubricant is oxidized polyethylene wax, and the bio-based polyester elastomer toughened CPVC power protection pipe material granules are based on 100 parts of CPVC resin, 5 parts of epoxy functionalized bio-based polyester elastomer, 1 part of organotin heat stabilizer, and 0.5 parts of lubricant, with other components being the same.

[0051] Example 7 The composition and preparation process are the same as in Example 1, except that: In process S3, the organotin heat stabilizer is dibutyltin dilaurate and dibutyltin maleate in a mass ratio of 1:1. The lubricant is stearic acid and calcium stearate in a mass ratio of 1:1. The bio-based polyester elastomer toughened CPVC power protection pipe material granules are based on 100 parts of CPVC resin, with 25 parts of epoxy functionalized bio-based polyester elastomer, 5 parts of organotin heat stabilizer, and 3 parts of lubricant. Other components are the same.

[0052] Comparative Example 1 The composition and preparation process are the same as in Example 1, except that: In step S2 of the preparation process, epoxy functionalization is not performed. In step S3, the unsaturated bio-based polyester elastomer prepolymer prepared in step S1 is directly added. The other steps are the same.

[0053] Comparative Example 2 The composition and preparation process are the same as in Example 1, except that: In step S3 of the preparation process, no elastomer toughening agent is added; the other steps are the same.

[0054] Comparative Example 3 The composition and preparation process are the same as in Example 1, except that: In step S3 of the preparation process, the epoxy-functionalized bio-based polyester elastomer is replaced with traditional chlorinated polyethylene (CPE) as the toughening agent, while the other steps remain the same.

[0055] Samples were taken from the epoxy-functionalized bio-based polyester elastomer prepared in Example 1, the unsaturated bio-based polyester elastomer prepolymer prepared in Comparative Example 1, the elastomers prepared in Comparative Examples 2 and 3, and the original epoxidized soybean oil (ESO, with ESO raw material used directly as a reference and no extraction). The samples were cut into slices of approximately 1–2 mm, and 1.5000 g (initial mass m0) was weighed and dried in a vacuum oven at 40°C for 24 h. After removal, the samples were cooled to room temperature in a desiccator and weighed again. If the mass change between two weighings over a 2-hour interval was greater than 0.2%, drying was continued, followed by Soxhlet extraction (150 mL n-hexane). After cooling, the residue was washed twice with a small amount of fresh n-hexane, and then dried under vacuum at 40°C to constant weight, yielding the residue after n-hexane extraction (m2). The n-hexane extracts were combined, and the solvent was removed by rotary evaporation in a water bath at a temperature not exceeding 40°C. The residue was then dried under vacuum to constant weight, and the extract mass (m2) was obtained. e Weigh 25 mg from the residue after hexane extraction; first attempt to dissolve it with CDCl3; if the dissolution is incomplete, use THF-d8; if still insufficient, use DMSO-d6 and gently shake at 45℃, add 0.7 mL of deuterated solvent, seal and shake for 8 min, let stand, control the sample height at 4.0 cm, and perform testing using a liquid nuclear magnetic resonance spectrometer (NMR). Figure 1 As shown, H1 is Example 1, and C1 to C3 are Comparative Examples 1-3. The furan peak of H1 is retained, the itaconic acid double bond integral decreases, and there are still epoxide, aliphatic chain and CH3 peaks after extraction. The furan, itaconic acid double bond and OCH2 peaks of C1 are obvious, and there are basically no ESO aliphatic chain and epoxide peaks. After full extraction, the epoxide and aliphatic chain peaks of C2 decrease significantly. There are no ESO epoxide and aliphatic chain peaks in C3.

[0056] Samples of the bio-based polyester elastomer-toughened CPVC power protection pipe material granules prepared in Examples 1 and 1-2 were taken and prepared into standard strips of 80mm × 10mm × 4mm. After standing for 24 hours, an A-type notch (root radius 0.25mm) was machined. The strips were then placed in an environment of 23℃ and 50% relative humidity for 96 hours and tested using a pendulum impact testing machine. The sample was placed horizontally on the two supports of the testing machine, with the back of the notch facing the direction of the pendulum impact. Ten sets of measurements were taken, and three strips with impact energies close to the median of the set were selected for gold sputtering treatment and then used for SEM testing. Figure 2As shown, H1 represents Example 1, and C1-C2 represent Comparative Examples 1-2. The low-magnification image of H1 shows a rough, undulating fracture surface with a curved crack path and a wide area of ​​plastic deformation, indicating that crack propagation requires more energy and macroscopic toughness is improved. The high-magnification image of H1 shows numerous torn ligaments, fibrosis, and shear yielding traces, indicating that particle cavitation and matrix shear yielding are synergistic. The low-magnification image of C1 shows a relatively smooth fracture surface with obvious mirror / river-like patterns or cleavage-like steps, indicating that the brittle fracture of untoughened CPVC is rapid. Crack propagation: The high-magnification C1 image shows sharp brittle steps and parallel river patterns, with almost no fiber stretching and micropore loss, indicating that the matrix lacks an effective plastic energy dissipation mechanism. The low-magnification C2 image shows an uneven cross-section with large pores, phase aggregation, and cracks propagating along the interface, indicating poor compatibility between unmodified polyester and CPVC. The high-magnification C2 image shows large and smooth particle pull-out holes, interface gaps, smooth pore walls, and a small number of ligaments, indicating that cracks preferentially propagate along weak interfaces, and large pores become defect sources.

[0057] The glass transition temperature (Tg) of the epoxy-functionalized bio-based polyester elastomers prepared in Examples 1-3, the unsaturated bio-based polyester elastomer prepolymer prepared in Comparative Example 1, and the chlorinated polyethylene used in Comparative Example 3 were tested: 10 mg of sample was placed in a sealed aluminum crucible and heated from -80 °C to 120 °C at a rate of 10 °C / min under nitrogen protection, and held at that temperature for 3 min; then the temperature was lowered to -80 °C at a rate of 10 °C / min and held at that temperature for 3 min; then the temperature was raised to 120 °C a second time, and the midpoint of the glass transition step of the second heating curve was taken as Tg. Three sets of measurements were taken, and the average value was taken. Dynamic Tg tests were conducted on the epoxy-functionalized bio-based polyester elastomers prepared in Examples 1-3, the unsaturated bio-based polyester elastomer prepolymer prepared in Comparative Example 1, and the chlorinated polyethylene used in Comparative Example 3. The samples were prepared into long strips of 30 mm × 5 mm × 1 mm. Strain scanning was first performed at 23 °C, and then a non-resonant tensile vibration mode was used (frequency 1 Hz; temperature range -60 to 100 °C; heating rate 3 °C / min). The loss factor tanδ was recorded, and the peak temperature of tanδ was taken as the dynamic Tg. Three sets of measurements were taken, and the average value was taken.

[0058] Samples were taken from the epoxy-functionalized bio-based polyester elastomers prepared in Examples 1-3, the unsaturated bio-based polyester elastomer prepolymer prepared in Comparative Example 1, and the chlorinated polyethylene used in Comparative Example 3, and constant elongation tensile resilience tests were performed: The samples were prepared into dumbbell-shaped specimens with an initial gauge length (L0) of 25 mm. 100% elongation was used, i.e., L1 = 50 mm. The specimens were stretched to the target elongation at 100 mm / min, held for 10 min, and then the load was released and the specimens were removed within 10 s. The specimens were then allowed to recover at room temperature for 30 min. The gauge length (L2) after recovery was measured, and the tensile resilience was calculated. Five sets of measurements were taken, and the average value was taken.

[0059] Samples of the epoxy-functionalized bio-based polyester elastomers prepared in Examples 1-3, the unsaturated bio-based polyester elastomer prepolymers prepared in Comparative Example 1, and the chlorinated polyethylene used in Comparative Example 3 were taken and subjected to Shore hardness tests: the samples were prepared into square specimens (8mm×8mm×8mm), placed in an environment of 23°C and 50% relative humidity for 24h, and tested using a type A or type D hardness tester (15s). Five groups of tests were performed, and the average value was taken.

[0060] Based on Examples 1-7 and Comparative Examples 1-3, samples of the final prepared bio-based polyester elastomer toughened CPVC power protection pipe material granules were taken for notched impact strength testing: the granules were prepared into long strip-shaped specimens (80mm×10mm×4mm), and an A-type notch (root radius 0.25mm) was machined on them. Then, they were placed in an environment of 23℃ and 50% relative humidity for 96 hours and tested using a pendulum impact testing machine. The specimens were placed horizontally on the two supports of the testing machine, with the back of the notch facing the direction of the pendulum impact. The impact energy of each specimen was recorded, calculated, and 10 sets of measurements were taken, and the average value was taken.

[0061] Based on Examples 1-7 and Comparative Examples 1-3, samples of the final prepared bio-based polyester elastomer toughened CPVC power protection pipe material granules were taken for tensile strength and elongation at break tests: The granules were prepared into dumbbell-shaped specimens, and the initial gauge length (50 mm) was precisely marked on the narrow parallel section of the specimen. Then, the specimens were placed in an environment of 23°C and 50% relative humidity for 48 hours. The specimens were tested using a universal testing machine (tensile speed 50 mm / min). The specimens were centered and installed in the upper and lower clamps, ensuring that the longitudinal axis was consistent with the tensile direction and that the clamping force was uniform. An extensometer was installed, and the maximum force value during the test and the difference between the gauge length at break and the original gauge length were recorded. Five sets of measurements were taken, and the average value was taken.

[0062] Based on Examples 1-7 and Comparative Examples 1-3, samples of the final prepared bio-based polyester elastomer toughened CPVC power protection pipe material granules were taken and the average particle size of the dispersed phase was tested: small pieces of sample were cut from the strip after tensile testing, immersed in liquid nitrogen for low-temperature brittle fracture, then soaked in toluene for ultrasonic treatment, removed, dried, sputter-coated with gold, observed using a field emission scanning electron microscope, and analyzed to obtain the number-average particle size.

[0063] The specific test results are shown in Tables 2 and 3. Figure 1 , Figure 2 As shown: Table 2. Performance Comparison of Elastomers Prepared in Examples 1-3 and Comparative Examples 1 and 3 ; Table 3 Comparison of core performance between Examples 1-7 and Comparative Examples 1-3 ; The comparison results above show that Example 1 exhibits the best overall performance in terms of notched impact strength, elongation at break, and dispersed phase particle size among all examples and comparative examples. This indicates that under this formulation and process condition, the interfacial compatibility between the epoxy-functionalized bio-based polyester elastomer and CPVC is most significantly improved, resulting in the best toughening effect. This also demonstrates that Example 1 successfully addresses the issue of poor compatibility between bio-based polyester elastomer and CPVC. The notched impact strength of Examples 2-7 is significantly higher than that of Comparative Examples 1-3, while the dispersed phase particle size is smaller in all examples. This indicates that epoxy functionalization treatment can effectively improve the interfacial compatibility between the bio-based polyester elastomer and CPVC. The compatibility of C-based elastomers effectively toughens the material. Overall, the comprehensive performance of Examples 2 to 7 is slightly lower than that of Example 1, but still maintains a high level. Comparative Example 1, because it does not undergo epoxy functionalization treatment and directly adds unsaturated bio-based polyester elastomer prepolymer, results in poor compatibility between the elastomer and CPVC. Comparative Example 2 does not add elastomer toughening agent, and the material is brittle with low impact strength. Comparative Example 3 uses traditional chlorinated polyethylene (CPE) as toughening agent. Although it has a certain toughening effect, it fails to solve the compatibility problem between bio-based polyester elastomer and CPVC, and its impact strength and elongation at break are lower than all examples.

[0064] In summary, it can be clearly seen from the above embodiments and comparative examples that the bio-based polyester elastomer-toughened CPVC power protection pipe material provided by the present invention has significantly better notched impact strength and elongation at break than traditional solutions. This is attributed to the modification of the bio-based polyester elastomer, thereby solving the compatibility problem between the bio-based polyester elastomer and CPVC.

Claims

1. A bio-based polyester elastomer toughened CPVC power protection pipe material, characterized in that: the bio-based polyester elastomer toughened CPVC power protection pipe material granules, with 100 parts of CPVC resin as a basis, the mass ratio of each raw material is as follows: 5-25 parts of epoxy functionalized bio-based polyester elastomer, 1-5 parts of organic tin heat stabilizer, 0.5-3 parts of lubricant. 2.The bio-based polyester elastomer toughened CPVC power protection pipe material according to claim 1, characterized in that: the epoxy functionalized bio-based polyester elastomer, with 100 parts of unsaturated bio-based polyester elastomer prepolymer as a basis, the composition ratio of each raw material is as follows: 5-30 parts of epoxy soybean oil, 0.8-2 parts of dicumyl peroxide. 3.The bio-based polyester elastomer toughened CPVC power protection pipe material according to claim 2, characterized in that: the unsaturated bio-based polyester elastomer prepolymer is prepared from 2,5-furandicarboxylic acid, 1,3-propanediol, itaconic acid, tetrabutyl titanate, and p-methoxyphenol, wherein the molar ratio of itaconic acid to 2,5-furandicarboxylic acid is 0.20:1-0.80:1, and the molar ratio of 1,3-propanediol to (2,5-furandicarboxylic acid + itaconic acid) is 1.02:1-1.12:1, the addition amount of tetrabutyl titanate is 0.1%-0.5% of the total mass of the reaction monomers, and the addition amount of p-methoxyphenol is 0.01%-0.04% of the total mass of the reaction monomers. 4.The bio-based polyester elastomer toughened CPVC power protection pipe material according to claim 1, characterized in that: the organic tin heat stabilizer is one or more of dibutyltin dilaurate, dibutyltin maleate, and methyltin mercaptide. 5.The bio-based polyester elastomer toughened CPVC power protection pipe material according to claim 1, characterized in that: the lubricant is one or more of stearic acid, calcium stearate, polyethylene wax, and oxidized polyethylene wax. including the following steps: S1: preparation of a bio-based polyester elastomer prepolymer, mixing 2,5-furandicarboxylic acid, 1,3-propanediol, and itaconic acid, then adding tetrabutyl titanate, and reacting under the protection of nitrogen gas, vacuum polycondensation, and cooling to room temperature to obtain an unsaturated bio-based polyester elastomer prepolymer; S2: preparation of an epoxy functionalized bio-based polyester elastomer, mixing the unsaturated bio-based polyester elastomer prepolymer prepared in S1, epoxy soybean oil, and dicumyl peroxide, and reacting under the protection of nitrogen gas, and cooling to room temperature to obtain an epoxy functionalized bio-based polyester elastomer; S3: preparation of a composite material, pre-mixing CPVC resin, the epoxy functionalized bio-based polyester elastomer prepared in S2, an organic tin heat stabilizer, and a lubricant, melt extruding, cooling, granulating, drying, and obtaining bio-based polyester elastomer toughened CPVC power protection pipe material granules. 7.A preparation method of the bio-based polyester elastomer toughened CPVC power protection pipe material according to claim 6, characterized in that: the temperature of the reaction in S1 is set to 160-200℃, and the time is set to 2-6h.

6. The process for the preparation of a bio-based polyester elastomer toughened CPVC electrical power protection pipe material according to any one of claims 1 to 5, characterized in that, ​ ​ ​ ​ ​ ​ The vacuum polycondensation of S1 has the parameter setting: temperature 200-220 ℃, absolute pressure 50-100 Pa, time length 2-8 h.

8. The method according to claim 6, wherein the preparation method of the bio-based polyester elastomer toughened CPVC power protection pipe material is characterized in that: The temperature rising reaction of S2 has the parameter setting: temperature 140-160 ℃, time length 1-4 h.

9. The method according to claim 6, wherein the preparation method of the bio-based polyester elastomer toughened CPVC power protection pipe material is characterized in that: The premixing of S3 has the parameter setting: rotating speed 800-1500 rpm, time length 5-15 min.

10. The method according to claim 6, wherein the preparation method of the bio-based polyester elastomer toughened CPVC power protection pipe material is characterized in that: The melt extrusion of S3 has the parameter setting: feeding section 150-170 ℃, compression section 170-190 ℃, metering section 180-200 ℃, die head temperature 180-195 ℃, screw rotating speed 50-300 rpm; The drying of S3 has the parameter setting: temperature 80-100 ℃, time length 4-8 h.

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