Isotactic polyether-based thermoplastic polyurethane elastomer and preparation method thereof

Abstract

The invention belongs to the field of high polymer materials, and particularly relates to an isotactic polyether-based thermoplastic polyurethane elastomer and a preparation method thereof. The isotactic polyether with adjustable steric regularity is used as a soft segment, and the molecular structure of the isotactic polyether fuses the chain segment flexibility of traditional polypropylene glycol and the chain regularity and crystallization tendency of polytetrahydrofuran. The highly regular soft segment structure can promote formation of a more regular and more stable soft segment micro-area in the thermoplastic polyurethane elastomer, so that the micro-phase separation degree between the soft segment and the hard segment is remarkably improved, and finally the performance of the material is improved. Meanwhile, by introducing an isotactic polyether soft segment, the thermoplastic polyurethane elastomer is endowed with photodegradability. After the service life of the material is over, controllable chain segment breakage and degradation can occur under a specific illumination condition, high performance and environmental friendliness are unified, and the application potential of the material in emerging scenes such as green packaging, disposable medical equipment and environment-sensitive fields is expanded.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials, specifically relating to an isotactic polyether-based thermoplastic polyurethane elastomer and its preparation method. Background Technology

[0002] Thermoplastic polyurethane elastomers (TPEs) are polymeric materials that combine the elasticity of rubber with the processing properties of plastics. Their molecular structure is essentially a linear block copolymer, composed of alternating flexible segments made of long-chain diols and rigid segments made of diisocyanates and small-molecule chain extenders. This unique microscopic phase-separation structure gives TPEs a series of excellent macroscopic properties, including high elasticity, high strength, wear resistance, and oil resistance. More importantly, by precisely adjusting the types, molecular weights, and ratios of the chemical raw materials constituting the soft and hard segments, the physical and mechanical properties (such as hardness, modulus, tensile strength, and elastic recovery rate) and application characteristics (such as low-temperature resistance, transparency, and biocompatibility) of TPEs can be "customized" over a very wide range. Therefore, as an engineering material with adjustable performance and easy processing, TPEs are widely used in many fields, from industrial seals, drive belts, and cable sheaths to consumer electronics, medical catheters, and sports shoe materials. Among them, the long-chain diol structure, as a key component determining the flexibility and elasticity of materials, has a crucial impact on the final performance of thermoplastic polyurethane elastomers through its design and innovation. Currently, common soft segment materials mainly include polytetrahydrofuran (PTMEG), polypropylene glycol (PPG), and polycaprolactone (PCL), each imparting different characteristics such as hydrolysis resistance, low-temperature toughness, and biocompatibility. However, with the continuous expansion of material applications and increasingly stringent performance requirements, traditional soft segment structures still have certain limitations in terms of functional diversity and environmental adaptability. Therefore, through molecular design innovation of soft segment structures, the performance boundaries of thermoplastic polyurethane elastomers can be further expanded, endowing them with superior mechanical strength, photodegradability, and other novel functions, thereby meeting the urgent needs of cutting-edge fields such as high-end manufacturing, medical devices, and green materials for high-performance elastomers.

[0003] Invention patent CN103539917A uses conventional polyether polyols such as polyethylene glycol, polypropylene glycol, or polytetrahydrofuran as soft segments to prepare thermoplastic polyurethane elastomers through traditional formulations and processes. Its advantages lie in mature processes and low cost, but the performance of the resulting material is still limited by the intrinsic properties of the selected base polyol, making it difficult to achieve functional breakthroughs. Invention patent CN117430786A, to meet the requirements of charging pile cables for high strength and high flame retardancy, introduces hydroxybutyl-terminated polydimethylsiloxane into the polycaprolactone / polytetrahydrofuran soft segment through physical blending. This method aims to improve the compatibility and overall performance of flame retardants by utilizing the heat resistance of the organosilicon segments. However, physical blending may lead to inhomogeneous microphase separation structures in the soft segments, and the compatibility between the organosilicon segments and the main polyol is limited, thus restricting its performance improvement potential and stability. Invention patent CN110358065A addresses the demand for low-hardness, high-comfort thermoplastic polyurethane elastomers in wearable devices. This technology further develops polysiloxane-ester polyols as soft segments. This method connects polysiloxane segments with polyester segments through chemical bonds, forming block copolymers, which improves reactivity and material uniformity, thereby obtaining low-hardness thermoplastic polyurethane elastomers with superior overall performance. This marks a step forward in soft segment design from simple mixing to customized chemical structures. Summary of the Invention

[0004] Based on the analysis of existing technologies, this invention proposes using an isotactic polyether with precise stereoregularity as the soft segment. This isotactic polyether combines the flexibility of traditional polypropylene glycol with the regular crystallization tendency of polytetrahydrofuran, exhibiting an extremely low glass transition temperature of approximately -70°C and a melting point of approximately 60°C. This unique structure not only enhances the mechanical properties of the elastomer by increasing the micro-order of the soft segment microregions, but also improves compatibility with the hard segment due to the increased chain segment regularity, achieving a superior microphase separation structure. Furthermore, the material properties can be adjusted by regulating the stereoregularity of the polyether chains. Most importantly, this isotactic polyether structure endows the material with controllable photodegradability, enabling environmentally friendly degradation under specific conditions, thus overcoming the limitations of existing technologies that struggle to balance high performance and green degradability.

[0005] Technical solution of the present invention

[0006] An isotactic polyether-based thermoplastic polyurethane elastomer is obtained by polymerization of isotactic polyether, diisocyanate and chain extender, with the following general formula:

[0007] .

[0008] In the formula: x, n and m are all integers greater than 0, and p is an integer from 1 to 6.

[0009] A method for preparing an isotactic polyether-based thermoplastic polyurethane elastomer includes the following steps:

[0010] (1) Mix isotactic polyether and diisocyanate evenly, selectively add catalyst and organic solvent, heat and stir for a certain time to obtain prepolymer;

[0011] (2) Add chain extender to prepolymer, selectively add antioxidant, hydrolysis resistant agent and colorant, heat and stir for a certain time, transfer to vacuum drying oven for curing, and obtain isotactic polyether-based thermoplastic polyurethane elastomer.

[0012] Furthermore, in step (1), the reaction temperature is 60~90 ℃ and the reaction time is 0.5~3 h.

[0013] Furthermore, in step (2), the reaction temperature is 50~110 ℃ and the reaction time is 1 min~1 h. The aging temperature in the vacuum drying oven is 100~130 ℃ and the aging time is 8~24 h.

[0014] In the method for preparing isotactic polyether-based thermoplastic polyurethane elastomer:

[0015] The raw materials are in the following proportions by weight: 50-70 parts isotactic polyether, 10-120 parts diisocyanate, 2-47 parts chain extender, 0.1-0.3 parts antioxidant, 0.05-0.2 parts hydrolysis resistant agent, 0.05-0.2 parts colorant, 0.02-0.1 parts catalyst, and 20-150 parts organic solvent.

[0016] The stereoregularity of the isotactic polyether is 80%~100%.

[0017] The number-average molecular weight of the isotactic polyether is 500~5000 g / mol.

[0018] The diisocyanate is one or more selected from 4,4'-diphenylmethane diisocyanate (MDI), 2,4-toluene diisocyanate (TDI), isophenyl dimethyl isocyanate (XDI), 1,5-naphthalene diisocyanate (NDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), and 4,4'-dicyclohexylmethane diisocyanate (HMDI), with the following structural formula:

[0019] .

[0020] The chain extender is one or more of ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol, with the following structural formula:

[0021] .

[0022] The antioxidant is one or more of triphenyl phosphate, trimethyl phosphate, and tris(2,4-di-tert-butylphenyl) phosphite.

[0023] The hydrolysis-resistant agent is one or more of monohydroxyoxazolidine and polycarbodiimide.

[0024] The colorant is one or more of thiourea dioxide, cobalt phthalocyanine, and 1,4-bis(isopropylamino)anthraquinone.

[0025] The catalyst is one or more of stannous octoate, dibutyltin dilaurate, and bismuth caprylate.

[0026] The organic solvent is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide.

[0027] Any of the isotactic polyether-based thermoplastic polyurethane elastomers described herein has photodegradability.

[0028] Beneficial effects of the present invention

[0029] (1) This invention uses isotactic polyethers with adjustable stereoregularity as soft segments. Its molecular structure combines the segmental flexibility of traditional polypropylene glycol with the chain regularity and crystallization tendency of polytetrahydrofuran. This highly regular soft segment structure not only endows the material with excellent low-temperature toughness (glass transition temperature of about -70°C), but also promotes the formation of more regular and stable soft segment microregions in thermoplastic polyurethane elastomers, thereby significantly improving the degree of microphase separation between soft and hard segments and ultimately improving the material performance.

[0030] (2) This invention introduces isotactic polyether soft segments to endow thermoplastic polyurethane elastomers with photodegradability. This enables the material to undergo controllable chain segment breakage and degradation under specific light conditions after its service life, achieving a balance between high performance and environmental friendliness. It effectively solves the environmental burden problem of traditional high-performance elastomers being difficult to biodegrade or chemically recycle, and expands the application potential of the material in emerging scenarios such as green packaging, disposable medical devices, and environmentally sensitive fields. Attached Figure Description

[0031] Figure 1 The infrared spectrum of the thermoplastic polyurethane elastomer prepared in Example 1 is shown below.

[0032] Figure 2 The stress-strain curves of the thermoplastic polyurethane elastomers prepared in Examples 8-10 are shown.

[0033] Figure 3 The number-average molecular weight of the thermoplastic polyurethane elastomers prepared in Example 28, Comparative Example 2, and Comparative Example 3 changes with photodegradation time. Detailed Implementation

[0034] The technical solution of the present invention will be further described below through embodiments.

[0035] Unless otherwise specified, the terminology used in this invention generally has the meanings commonly understood by those skilled in the art. It should be particularly noted that isotactic polyethers can be further classified into R-isotactic polyethers and S-isotactic polyethers based on the absolute configuration of their chiral centers, and their structural formulas are shown below:

[0036] .

[0037] In the following embodiments, various processes and methods not described in detail are conventional methods known in the art. Furthermore, due to the diverse proportions of polymer structures, not all preparation methods are described in detail; instead, typical examples are used to illustrate the specific process steps of the present invention.

[0038] The hard segment content (Ch) in the final isotactic polyether-based thermoplastic polyurethane elastomer can be calculated based on the mass of the isotactic polyether (Wg), the mass of the diisocyanate (Wi), and the mass of the chain extender (Wd). The calculation formula is as follows:

[0039] The isotactic polyether-based thermoplastic polyurethane elastomers obtained in the examples were subjected to longitudinal tensile and thermal property tests. The longitudinal tensile property test was conducted in accordance with GB / T 1040.1-2018, and the thermal property test was conducted in accordance with GB / T 19466.3-2004.

[0040] Example 1

[0041] Under nitrogen protection, 50 g of R-isotactic polyether with stereoregularity >99.5% and number-average molecular weight of 500 g / mol was added to a reactor, along with 0.1 g of triphenyl phosphate, 0.05 g of cobalt phthalocyanine, and 36 g of MDI. The reaction was carried out at 60 °C for 3 h to obtain a prepolymer. 3.9 g of 1,4-butanediol was added to the prepolymer, and the reaction was carried out at 50 °C for 1 h. The reaction solution was then poured into a dumbbell-shaped PTFE mold and transferred to a vacuum drying oven for curing at 130 °C for 8 h to obtain an isotactic polyether-based thermoplastic polyurethane elastomer with a hard segment content of 45%, designated TPU-1.

[0042] Example 2

[0043] Under nitrogen protection, 53 g of R-isotactic polyether with stereoregularity >99.5% and number-average molecular weight of 1000 g / mol was added to a reactor, along with 0.2 g of triphenyl phosphate, 0.1 g of cobalt phthalocyanine, and 15 g of TDI. The reaction was carried out at 65 °C for 2.8 h to obtain a prepolymer. 4.0 g of 1,4-butanediol was added to the prepolymer, and the reaction was carried out at 60 °C for 0.8 h. The reaction solution was then poured into a dumbbell-shaped PTFE mold and transferred to a vacuum drying oven for curing at 125 °C for 10 h to obtain an isotactic polyether-based thermoplastic polyurethane elastomer with a hard segment content of 25%, designated as TPU-2.

[0044] Example 3

[0045] Under nitrogen protection, 56 g of R-isotactic polyether with stereoregularity >99.5% and number-average molecular weight of 2000 g / mol was added to a reactor, along with 0.02 g of dibutyltin dilaurate and 70 g of HMDI. The reaction was carried out at 70 °C for 2.5 h to obtain a prepolymer. 20 g of 1,4-butanediol was added to the prepolymer, and the reaction was carried out at 70 °C for 0.5 h. The reaction solution was then poured into a dumbbell-shaped PTFE mold and transferred to a vacuum drying oven for curing at 120 °C for 14 h to obtain an isotactic polyether-based thermoplastic polyurethane elastomer with a hard segment content of 60%, designated TPU-3.

[0046] Example 4

[0047] Under nitrogen protection, 59 g of R-isotactic polyether with a stereoregularity >99.5% and a number-average molecular weight of 2500 g / mol was added to a reactor, along with 0.05 g of stannous octoate and 103 g of HDI. The reaction was carried out at 75 °C for 2.0 h to obtain a prepolymer. 35 g of ethylene glycol was added to the prepolymer, and the reaction was carried out at 80 °C for 0.3 h. The reaction solution was then poured into a dumbbell-shaped PTFE mold and transferred to a vacuum drying oven at 115 °C for 16 h to obtain an isotactic polyether-based thermoplastic polyurethane elastomer with a hard segment content of 70%, designated TPU-4.

[0048] Example 5

[0049] Under nitrogen protection, 63 g of S-isotactic polyether with stereoregularity >99.5% and number-average molecular weight of 3000 g / mol was added to a reactor, along with 0.08 g of bismuth caprylate and 50 g of IPDI. The reaction was carried out at 80 °C for 1.5 h to obtain a prepolymer. 24 g of 1,6-hexanediol was added to the prepolymer, and the reaction was carried out at 90 °C for 0.2 h. The reaction solution was then poured into a dumbbell-shaped PTFE mold and transferred to a vacuum drying oven for curing at 110 °C for 20 h to obtain an isotactic polyether-based thermoplastic polyurethane elastomer with a hard segment content of 55%, designated TPU-5.

[0050] Example 6

[0051] Under nitrogen protection, 67 g of S-isotactic polyether with a stereoregularity >99.5% and a number-average molecular weight of 4000 g / mol was added to a reactor, along with 0.1 g of bismuth caprylate and 33 g of XDI. The reaction was carried out at 85 °C for 1.0 h to obtain a prepolymer. 12 g of 1,3-propanediol was added to the prepolymer, and the reaction was carried out at 100 °C for 0.1 h. The reaction solution was then poured into a dumbbell-shaped PTFE mold and transferred to a vacuum drying oven for curing at 105 °C for 22 h to obtain an isotactic polyether-based thermoplastic polyurethane elastomer with a hard segment content of 40%, designated as TPU-6.

[0052] Example 7

[0053] Under nitrogen protection, 70 g of S-isotactic polyether with stereoregularity >99.5% and a number-average molecular weight of 5000 g / mol was added to a reactor, along with 0.05 g of 1,4-bis(isopropylamino)anthraquinone and 43 g of NDI. The reaction was carried out at 90 °C for 0.5 h to obtain a prepolymer. 14 g of 1,3-propanediol was added to the prepolymer, and the reaction was carried out at 110 °C for 1 min. The reaction solution was then poured into a dumbbell-shaped PTFE mold and transferred to a vacuum drying oven for curing at 100 °C for 24 h to obtain an isotactic polyether-based thermoplastic polyurethane elastomer with a hard segment content of 45%, designated TPU-7.

[0054] The isotactic polyether-based thermoplastic polyurethane elastomers obtained in Examples 1-7 were subjected to longitudinal tensile and thermal property tests. The maximum longitudinal tensile strength, elongation at break and 5% decomposition temperature are shown in Table 1.

[0055] Table 1. Isotactic polyether-based thermoplastic polyurethane elastomers obtained from different formulations and their performance characterization.

[0056]

[0057] Based on the results of the above embodiments, it can be seen that by controlling the polyether configuration, number-average molecular weight, type and ratio of diisocyanate and chain extender, high-quality synthesis of isotactic polyether-based thermoplastic polyurethane elastomers with good mechanical and thermal properties can be achieved.

[0058] Example 8

[0059] Under nitrogen protection, 50 g of R-isotactic polyether with stereoregularity >99.5% and number-average molecular weight of 1000 g / mol was added to a reactor, along with 23 g of MDI. The reaction was carried out at 80 °C for 3 h to obtain a prepolymer. 3.5 g of BDO was added to the prepolymer, and the reaction was carried out at 80 °C for 0.5 h. The reaction solution was then poured into a dumbbell-shaped PTFE mold and transferred to a vacuum drying oven for curing at 110 °C for 18 h to obtain an isotactic polyether-based thermoplastic polyurethane elastomer with a hard segment content of 35%, designated TPU-8.

[0060] Example 9

[0061] Under nitrogen protection, 50 g of R-isotactic polyether with stereoregularity >99.5% and number-average molecular weight of 2000 g / mol was added to a reactor, along with 21.7 g of MDI. The reaction was carried out at 80 °C for 3 h to obtain a prepolymer. 5.2 g of BDO was added to the prepolymer, and the reaction was carried out at 80 °C for 0.5 h. The reaction solution was then poured into a dumbbell-shaped PTFE mold and transferred to a vacuum drying oven for curing at 110 °C for 18 h to obtain an isotactic polyether-based thermoplastic polyurethane elastomer with a hard segment content of 35%, designated TPU-9.

[0062] Example 10

[0063] Under nitrogen protection, 50 g of R-isotactic polyether with stereoregularity >99.5% and number-average molecular weight of 3000 g / mol was added to a reactor, along with 21.0 g of MDI. The reaction was carried out at 80 °C for 3 h to obtain a prepolymer. 6.0 g of BDO was added to the prepolymer, and the reaction was carried out at 80 °C for 0.5 h. The reaction solution was then poured into a dumbbell-shaped PTFE mold and transferred to a vacuum drying oven for curing at 110 °C for 18 h to obtain an isotactic polyether-based thermoplastic polyurethane elastomer with a hard segment content of 35%, designated TPU-10.

[0064] Example 11

[0065] Under nitrogen protection, 50 g of R-isotactic polyether with stereoregularity >99.5% and number-average molecular weight of 4000 g / mol was added to a reactor, along with 21.2 g of MDI. The reaction was carried out at 80 °C for 3 h to obtain a prepolymer. 6.2 g of BDO was added to the prepolymer, and the reaction was carried out at 80 °C for 0.5 h. The reaction solution was then poured into a dumbbell-shaped PTFE mold and transferred to a vacuum drying oven for curing at 110 °C for 18 h to obtain an isotactic polyether-based thermoplastic polyurethane elastomer with a hard segment content of 35%, designated TPU-11.

[0066] Example 12

[0067] Under nitrogen protection, 50 g of R-isotactic polyether with stereoregularity >99.5% and number-average molecular weight of 5000 g / mol was added to a reactor, along with 20.8 g of MDI. The reaction was carried out at 80 °C for 3 h to obtain a prepolymer. 6.2 g of BDO was added to the prepolymer, and the reaction was carried out at 80 °C for 0.5 h. The reaction solution was then poured into a dumbbell-shaped PTFE mold and transferred to a vacuum drying oven for curing at 110 °C for 18 h to obtain an isotactic polyether-based thermoplastic polyurethane elastomer with a hard segment content of 35%, designated TPU-12.

[0068] The isotactic polyether-based thermoplastic polyurethane elastomers obtained in Examples 8-12 were subjected to longitudinal tensile and thermal property tests. The maximum longitudinal tensile strength, elongation at break, and 5% decomposition temperature are shown in Table 2.

[0069] Table 2. Thermoplastic polyurethane elastomers prepared with isotactic polyethers of different number-average molecular weights and their performance characterization.

[0070]

[0071] Based on the results of the above embodiments, it can be seen that by fixing the types of diisocyanate and chain extender, as well as the content of hard segments, and adjusting the number-average molecular weight of isotactic polyether, the tensile strength of thermoplastic elastomer increases, the elongation at break decreases, and the thermal decomposition temperature increases slightly but does not change much with the increase of the number-average molecular weight.

[0072] Example 13

[0073] Under nitrogen protection, 50 g of R-isotactic polyether with 95% stereoregularity and a number-average molecular weight of 2000 g / mol was added to a reactor, along with 21.7 g of MDI. The reaction was carried out at 80 °C for 3 h to obtain a prepolymer. 5.2 g of BDO was added to the prepolymer, and the reaction was carried out at 80 °C for 0.5 h. The reaction solution was then poured into a dumbbell-shaped PTFE mold and transferred to a vacuum drying oven for curing at 110 °C for 18 h to obtain an isotactic polyether-based thermoplastic polyurethane elastomer with a hard segment content of 35%, designated TPU-13.

[0074] Example 14

[0075] Under nitrogen protection, 50 g of R-isotactic polyether with a stereoregularity of 90% and a number-average molecular weight of 2000 g / mol was added to a reactor, along with 21.7 g of MDI. The reaction was carried out at 80 °C for 3 h to obtain a prepolymer. 5.2 g of BDO was added to the prepolymer, and the reaction was carried out at 80 °C for 0.5 h. The reaction solution was then poured into a dumbbell-shaped PTFE mold and transferred to a vacuum drying oven for curing at 110 °C for 18 h to obtain an isotactic polyether-based thermoplastic polyurethane elastomer with a hard segment content of 35%, designated TPU-14.

[0076] Example 15

[0077] Under nitrogen protection, 50 g of R-isotactic polyether with 85% stereoregularity and a number-average molecular weight of 2000 g / mol was added to a reactor, along with 21.7 g of MDI. The reaction was carried out at 80 °C for 3 h to obtain a prepolymer. 5.2 g of BDO was added to the prepolymer, and the reaction was carried out at 80 °C for 0.5 h. The reaction solution was then poured into a dumbbell-shaped PTFE mold and transferred to a vacuum drying oven for curing at 110 °C for 18 h to obtain an isotactic polyether-based thermoplastic polyurethane elastomer with a hard segment content of 35%, designated TPU-15.

[0078] Example 16

[0079] Under nitrogen protection, 50 g of R-isotactic polyether with 80% stereoregularity and a number-average molecular weight of 2000 g / mol was added to a reactor, along with 21.7 g of MDI. The reaction was carried out at 80 °C for 3 h to obtain a prepolymer. 5.2 g of BDO was added to the prepolymer, and the reaction was carried out at 80 °C for 0.5 h. The reaction solution was then poured into a dumbbell-shaped PTFE mold and transferred to a vacuum drying oven for curing at 110 °C for 18 h to obtain an isotactic polyether-based thermoplastic polyurethane elastomer with a hard segment content of 35%, designated TPU-16.

[0080] Comparative Example 1

[0081] Under nitrogen protection, 50 g of R-isotactic polyether with a stereoregularity of 70% and a number-average molecular weight of 2000 g / mol was added to a reactor, along with 21.7 g of MDI. The reaction was carried out at 80 °C for 3 h to obtain a prepolymer. 5.2 g of BDO was added to the prepolymer, and the reaction was carried out at 80 °C for 0.5 h. The reaction solution was then poured into a dumbbell-shaped PTFE mold and transferred to a vacuum drying oven for curing at 110 °C for 18 h to obtain an isotactic polyether-based thermoplastic polyurethane elastomer with a hard segment content of 35%, designated CTPU-1.

[0082] The isotactic polyether-based thermoplastic polyurethane elastomers obtained in Examples 9, 13-16 and the comparative examples were subjected to longitudinal tensile and thermal property tests. The maximum longitudinal tensile strength, elongation at break and 5% decomposition temperature are shown in Table 3.

[0083] Table 3. Thermoplastic polyurethane elastomers prepared from polyethers with different stereoregularities and their performance characterization.

[0084]

[0085] Based on the results of the above embodiments, it can be seen that by fixing the type of diisocyanate, chain extender, and number-average molecular weight of isotactic polyether, and controlling the stereoregularity of the number-average molecular weight, the tensile strength, elongation at break, and thermal decomposition temperature of the synthesized thermoplastic polyurethane elastomer all decrease as the stereoregularity decreases, and this is particularly evident below 80% stereoregularity.

[0086] Example 17

[0087] Under nitrogen protection, 50 g of R-isotactic polyether with stereoregularity >99.5% and number-average molecular weight of 2000 g / mol was added to a reactor, along with 14.0 g of MDI. The reaction was carried out at 80 °C for 3 h to obtain a prepolymer. 2.7 g of BDO was added to the prepolymer, and the reaction was carried out at 80 °C for 0.5 h. The reaction solution was then poured into a dumbbell-shaped PTFE mold and transferred to a vacuum drying oven for curing at 110 °C for 18 h to obtain an isotactic polyether-based thermoplastic polyurethane elastomer with a hard segment content of 25%, designated TPU-17.

[0088] Example 18

[0089] Under nitrogen protection, 50 g of R-isotactic polyether with stereoregularity >99.5% and number-average molecular weight of 2000 g / mol was added to a reactor, along with 32.0 g of MDI. The reaction was carried out at 80 °C for 3 h to obtain a prepolymer. 9.0 g of BDO was added to the prepolymer, and the reaction was carried out at 80 °C for 0.5 h. The reaction solution was then poured into a dumbbell-shaped PTFE mold and transferred to a vacuum drying oven at 110 °C for 18 h to obtain an isotactic polyether-based thermoplastic polyurethane elastomer with a hard segment content of 45%, designated TPU-18.

[0090] Example 19

[0091] Under nitrogen protection, 50 g of R-isotactic polyether with stereoregularity >99.5% and number-average molecular weight of 2000 g / mol was added to a reactor, along with 47.0 g of MDI. The reaction was carried out at 80 °C for 3 h to obtain a prepolymer. 14.0 g of BDO was added to the prepolymer, and the reaction was carried out at 80 °C for 0.5 h. The reaction solution was then poured into a dumbbell-shaped PTFE mold and transferred to a vacuum drying oven for curing at 110 °C for 18 h to obtain an isotactic polyether-based thermoplastic polyurethane elastomer with a hard segment content of 55%, designated TPU-19.

[0092] Example 20

[0093] Under nitrogen protection, 50 g of R-isotactic polyether with stereoregularity >99.5% and number-average molecular weight of 2000 g / mol was added to a reactor, along with 70.0 g of MDI. The reaction was carried out at 80 °C for 3 h to obtain a prepolymer. 23.0 g of BDO was added to the prepolymer, and the reaction was carried out at 80 °C for 0.5 h. The reaction solution was then poured into a dumbbell-shaped PTFE mold and transferred to a vacuum drying oven for curing at 110 °C for 18 h to obtain an isotactic polyether-based thermoplastic polyurethane elastomer with a hard segment content of 65%, designated TPU-20.

[0094] The isotactic polyether-based thermoplastic polyurethane elastomers obtained in Examples 9 and 17-20 were subjected to longitudinal tensile and thermal property tests. The maximum longitudinal tensile strength, elongation at break, and 5% decomposition temperature are shown in Table 4.

[0095] Table 4. Isotactic polyether-based thermoplastic polyurethane elastomers with different hard segment contents and their performance characterization

[0096]

[0097] Based on the results of the above embodiments, it can be seen that, with fixed diisocyanate, chain extender type, isotactic polyether number-average molecular weight and stereoregularity, as the hard segment content increases, the tensile strength and 5% decomposition temperature of the synthesized thermoplastic polyurethane elastomer increase, while the elongation at break decreases.

[0098] Example 21

[0099] Under nitrogen protection, 50 g of R-isotactic polyether with stereoregularity >99.5% and number-average molecular weight of 2000 g / mol was added to a reactor, along with 18.1 g of TDI. The reaction was carried out at 80 °C for 3 h to obtain a prepolymer. 8.9 g of BDO was added to the prepolymer, and the reaction was carried out at 80 °C for 0.5 h. The reaction solution was then poured into a dumbbell-shaped PTFE mold and transferred to a vacuum drying oven for curing at 110 °C for 18 h to obtain an isotactic polyether-based thermoplastic polyurethane elastomer with a hard segment content of 35%, designated TPU-21.

[0100] Example 22

[0101] Under nitrogen protection, 50 g of R-isotactic polyether with stereoregularity >99.5% and number-average molecular weight of 2000 g / mol was added to a reactor, along with 19.0 g of HDI. The reaction was carried out at 80 °C for 3 h to obtain a prepolymer. 8.0 g of BDO was added to the prepolymer, and the reaction was carried out at 80 °C for 0.5 h. The reaction solution was then poured into a dumbbell-shaped PTFE mold and transferred to a vacuum drying oven for curing at 110 °C for 18 h to obtain an isotactic polyether-based thermoplastic polyurethane elastomer with a hard segment content of 35%, designated TPU-22.

[0102] Example 23

[0103] Under nitrogen protection, 50 g of R-isotactic polyether with stereoregularity >99.5% and number-average molecular weight of 2000 g / mol was added to a reactor, along with 22.0 g of HMDI. The reaction was carried out at 80 °C for 3 h to obtain a prepolymer. 4.9 g of BDO was added to the prepolymer, and the reaction was carried out at 80 °C for 0.5 h. The reaction solution was then poured into a dumbbell-shaped PTFE mold and transferred to a vacuum drying oven for curing at 110 °C for 18 h to obtain an isotactic polyether-based thermoplastic polyurethane elastomer with a hard segment content of 35%, designated TPU-23.

[0104] Example 24

[0105] Under nitrogen protection, 50 g of R-isotactic polyether with stereoregularity >99.5% and number-average molecular weight of 2000 g / mol was added to a reactor, along with 21.0 g of IPDI. The reaction was carried out at 80 °C for 3 h to obtain a prepolymer. 6.0 g of BDO was added to the prepolymer, and the reaction was carried out at 80 °C for 0.5 h. The reaction solution was then poured into a dumbbell-shaped PTFE mold and transferred to a vacuum drying oven for curing at 110 °C for 18 h to obtain an isotactic polyether-based thermoplastic polyurethane elastomer with a hard segment content of 35%, designated TPU-24.

[0106] The isotactic polyether-based thermoplastic polyurethane elastomers obtained in Examples 21-24 were subjected to longitudinal tensile and thermal property tests. The maximum longitudinal tensile strength, elongation at break, and 5% decomposition temperature are shown in Table 5.

[0107] Table 5. Thermoplastic polyurethane elastomers prepared with different diisocyanates and their performance characterization.

[0108]

[0109] Based on the results of the above embodiments, it can be seen that by fixing the type of chain extender, the content of hard segments, and the number-average molecular weight and stereoregularity of isotactic polyether, changing the type of isocyanate can also achieve the control of material properties.

[0110] Example 25

[0111] Under nitrogen protection, 50 g of R-isotactic polyether with stereoregularity >99.5% and number-average molecular weight of 2000 g / mol was added to a reactor, along with 23.0 g of MDI. The reaction was carried out at 80 °C for 3 h to obtain a prepolymer. 4.0 g of ethylene glycol was added to the prepolymer, and the reaction was carried out at 80 °C for 0.5 h. The reaction solution was then poured into a dumbbell-shaped PTFE mold and transferred to a vacuum drying oven for curing at 110 °C for 18 h to obtain an isotactic polyether-based thermoplastic polyurethane elastomer with a hard segment content of 35%, designated TPU-25.

[0112] Example 26

[0113] Under nitrogen protection, 50 g of R-isotactic polyether with stereoregularity >99.5% and number-average molecular weight of 2000 g / mol was added to a reactor, along with 22.5 g of MDI. The reaction was carried out at 80 °C for 3 h to obtain a prepolymer. 4.7 g of 1,3-propanediol was added to the prepolymer, and the reaction was carried out at 80 °C for 0.5 h. The reaction solution was then poured into a dumbbell-shaped PTFE mold and transferred to a vacuum drying oven for curing at 110 °C for 18 h to obtain an isotactic polyether-based thermoplastic polyurethane elastomer with a hard segment content of 35%, designated TPU-26.

[0114] Example 27

[0115] Under nitrogen protection, 50 g of R-isotactic polyether with stereoregularity >99.5% and number-average molecular weight of 2000 g / mol was added to a reactor, along with 20.0 g of MDI. The reaction was carried out at 80 °C for 3 h to obtain a prepolymer. 6.1 g of 1,6-hexanediol was added to the prepolymer, and the reaction was carried out at 80 °C for 0.5 h. The reaction solution was then poured into a dumbbell-shaped PTFE mold and transferred to a vacuum drying oven for curing at 110 °C for 18 h to obtain an isotactic polyether-based thermoplastic polyurethane elastomer with a hard segment content of 35%, designated TPU-27.

[0116] The isotactic polyether-based thermoplastic polyurethane elastomers obtained in Examples 9 and 25-27 were subjected to longitudinal tensile and thermal property tests. The maximum longitudinal tensile strength, elongation at break, and 5% decomposition temperature are shown in Table 6.

[0117] Table 6. Thermoplastic polyurethane elastomers prepared with different chain extenders and their performance characterization

[0118]

[0119] Based on the results of the above embodiments, it can be seen that by fixing the type of isocyanate, the content of hard segments, and the number-average molecular weight and stereoregularity of isotactic polyethers, and changing the type of chain extender, the elongation at break of the synthesized thermoplastic polyurethane increases with the increase of the number of carbon atoms in the chain extender, and the tensile strength is greater for even-numbered carbon atoms than for odd-numbered carbon atoms. The 5% decomposition temperature increases with the increase of the chain extender's structural symmetry and the number of carbon atoms.

[0120] To further demonstrate the characteristics of the isotactic polyether described in this invention, polypropylene glycol (random) and polytetramethylene glycol were selected as comparative examples. These comparative examples were identical to Example 9 under the same conditions, except that the isotactic polyether (stereoregularity > 99.5%) was replaced with polypropylene glycol (random) and polytetramethylene glycol, respectively, forming Comparative Examples 2 and 3. The polymers obtained from Example 9, Comparative Examples 2 and 3 were subjected to photodegradation tests to form Example 28.

[0121] Comparative Example 2

[0122] Under nitrogen protection, 50 g of polypropylene glycol with a number average molecular weight of 2000 g / mol was added to a reactor, followed by 21.7 g of MDI. The reaction was carried out at 80 °C for 3 h to obtain a prepolymer. 5.2 g of BDO was added to the prepolymer, and the reaction was carried out at 80 °C for 0.5 h. The reaction solution was then poured into a dumbbell-shaped PTFE mold and transferred to a vacuum drying oven at 110 °C for 18 h to obtain a polyether-based thermoplastic polyurethane elastomer with a hard segment content of 35%, designated CTPU-2.

[0123] Comparative Example 3

[0124] Under nitrogen protection, 50 g of polytetramethylene glycol with a number average molecular weight of 2000 g / mol was added to a reactor, along with 21.7 g of MDI. The reaction was carried out at 80 °C for 3 h to obtain a prepolymer. 5.2 g of BDO was added to the prepolymer, and the reaction was carried out at 80 °C for 0.5 h. The reaction solution was then poured into a dumbbell-shaped PTFE mold and transferred to a vacuum drying oven at 110 °C for 18 h to obtain a polytetrahydrofuran glycol-based thermoplastic polyurethane elastomer with a hard segment content of 35%, designated CTPU-3.

[0125] Example 28

[0126] TPU-9, CTPU-2, and CTPU-3 were prepared into uniformly sized samples and subjected to photodegradation experiments under 365 nm ultraviolet light at room temperature. Starting from the initial ultraviolet irradiation, samples were taken at 3, 6, 9, 12, 15, and 30 days after irradiation for gel permeation chromatography. The changes in molecular weight of the samples are shown in Table 7.

[0127] Gel permeation chromatography (Agilent 1260, differential detector); DMF as mobile phase, 30 ℃, flow rate 1.0 mL / min, sample concentration approximately 2 mg / mL, injection volume 50 μL, polystyrene as standard.

[0128] Table 7. Changes in molecular weight of thermoplastic polyurethane elastomer over time under 365nm UV light.

[0129]

Claims

1. An isotactic polyether-based thermoplastic polyurethane elastomer, characterized in that, The elastomer is obtained by polymerization of isotactic polyether, diisocyanate and chain extender, and has the following general formula: ； In the formula: x, n and m are all integers greater than 0, and p is an integer from 1 to 6.

2. The isotactic polyether-based thermoplastic polyurethane elastomer according to claim 1, characterized in that, The diisocyanate is one or a mixture of two or more of the following: 4,4'-diphenylmethane diisocyanate, 2,4-toluene diisocyanate, isophthalic dimethyl isocyanate, 1,5-naphthalene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate, with the following structural formula: 。 3. The isotactic polyether-based thermoplastic polyurethane elastomer according to claim 1, characterized in that, The chain extender is one or a mixture of two or more of ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol, with the following structural formula: 。 4. An isotactic polyether-based thermoplastic polyurethane elastomer according to any one of claims 1-3, characterized in that, It has photodegradability.

5. A method for preparing an isotactic polyether-based thermoplastic polyurethane elastomer according to any one of claims 1-4, characterized in that, Includes the following steps: (1) Mix isotactic polyether and diisocyanate evenly, selectively add catalyst and organic solvent, heat and stir to react, and obtain prepolymer; (2) Add chain extender to prepolymer, selectively add antioxidant, hydrolysis resistant agent and colorant, heat and stir to react, transfer to vacuum drying oven for aging, and obtain isotactic polyether-based thermoplastic polyurethane elastomer.

6. The method for preparing an isotactic polyether-based thermoplastic polyurethane elastomer according to claim 5, characterized in that, In step (1), the reaction temperature is 60~90 ℃ and the reaction time is 0.5~3 h.

7. The method for preparing an isotactic polyether-based thermoplastic polyurethane elastomer according to claim 5, characterized in that, In step (2), the reaction temperature is 50~110 ℃ and the reaction time is 1 min~1 h; the aging temperature in the vacuum drying oven is 100~130 ℃ and the aging time is 8~24 h.

8. The isotactic polyether-based thermoplastic polyurethane elastomer according to claim 5 and the preparation method according to claims 2-4, characterized in that, The raw materials are in the following proportions by weight: 50-70 parts isotactic polyether, 10-120 parts diisocyanate, 2-47 parts chain extender, 0.1-0.3 parts antioxidant, 0.05-0.2 parts hydrolysis resistant agent, 0.05-0.2 parts colorant, 0.02-0.1 parts catalyst, and 20-150 parts organic solvent.

9. The isotactic polyether-based thermoplastic polyurethane elastomer according to claim 5 and the preparation method shown in claims 2-5, characterized in that, The stereoregularity of the isotactic polyether is 80%~100%, and the number average molecular weight of the isotactic polyether is 500~5000 g / mol.

10. The method for preparing an isotactic polyether-based thermoplastic polyurethane elastomer according to claim 5, characterized in that, The antioxidant is one or a mixture of two or more of triphenyl phosphate, trimethyl phosphate, and tris(2,4-di-tert-butylphenyl) phosphite; the hydrolysis resistant agent is one or a mixture of one or more of monohydroxyoxazolidine and polycarbodiimide; the colorant is one or a mixture of one or more of thiourea dioxide, cobalt phthalocyanine, and 1,4-bis(isopropylamino)anthraquinone; the catalyst is one or a mixture of one or more of stannous octoate, dibutyltin dilaurate, and bismuth caprylate; and the organic solvent is one or a mixture of two or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide.

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