基于含亚胺键香草醛二醇的生物基可降解热塑性聚氨酯的制备及性能

Preparation and properties of bio-based degradable thermoplastic polyurethanes based on imine-bonded vanillin aldehyde diol

由于资源稀缺和环境保护要求,依赖于石化来源的传统热塑性聚氨酯(TPU)在工业生产可持续性和使用后的废物的回收方面都面临着重大挑战。开发由可再生生物质资源合成的生物基TPU正变得日益迫切。以可再生的生物质资源香草醛(VAN)与间苯二甲胺反应合成了分子结构中带亚胺键的生物基扩链剂VAN衍生二醇(VAN-OH),并与1,4-丁二醇(BDO)组成不同比例的扩链剂组分,通过两步法与聚己内酯二醇(PCL),4,4′-二苯基甲烷二异氰酸酯(MDI)加成聚合制备了一种高性能、可降解的生物基热塑性聚氨酯(BTPUs)。对BTPUs的结构、热性能、力学性能及化学降解性能进行了测试与表征。结果表明,适量生物基扩链剂VAN-OH的加入增强了BTPUs分子链结构中氢键作用、结晶性能和微相分离程度,从而提高了BTPUs的热稳定性、力学性能及降解性能。当VAN-OH在扩链剂中的物质的量分数为25%时,BTPUs的力学性能表现最佳,拉伸强度为33.32 MPa,断裂伸长率为823.62%,降解时间相较于未加VAN-OH的缩短了37.5%。当VAN-OH在扩链剂中的物质的量分数超过50%时,BTPUs的力学性能下降明显,但降解时间进一步缩短。上述研究结果验证了含动态亚胺键生物基扩链剂的存在能改善TPU的热学、力学与降解性能,可为开发新型BTPUs提供借鉴。

Traditional thermoplastic polyurethane(TPU)relying on petrochemical sources is facing significant challenges in both industrial production sustainability and the recycling of waste after use due to resource scarcity and environmental protection requirements.Developing bio-based TPU synthesized from renewable biomass resources is becoming more urgent.A renewable biomass resource,vanillin aldehyde(VAN),was reacted with m-xylylenediamine to synthesize a bio-based chain extender VAN derived diol(VAN-OH)with an imine bond in its molecular structure,which was then blended with 1,4-butanediol(BDO)to form chain extender components with different proportions of VAN-OH and BDO.A degradable bio-based TPU(BTPUs)with high performances were prepared by a two-step addition polymerization with the chain extender components,polycaprolactone diol(PCL)and 4,4′-diphenylmethane diisocyanate(MDI).The structure,thermal properties,mechanical properties and chemical degra-dation performance of BTPUs were tested and characterized.The results show that the moderate addition of the bio-based chain extender VAN-OH enhances the hydrogen bonding in the molecular chain structure of BTPUs,the crystallization properties,and the degree of microphase separation,which increases the thermal stability,mechanical and degradable properties of BTPUs.When the mass fraction of VAN-OH in the chain extender components is 25%,the mechanical properties of BTPUs are the best,with tensile strength of 33.32 MPa and elongation at break of 823.62%,and the degradation time is 37.5%shorter compared to that of the BTPUs without VAN-OH.When the mass fraction of VAN-OH in the chain extender components is more than 50%,the mechanical properties of BTPUs decrease significantly,but the degradation time is further shortened.The above results verify that the presence of a dynamic imine-bonded biobased chain extender can improve the thermal,mechanical and degradation properties of TPU,and providing valuable reference for developing and research of BTPUs.