扩链剂对基于聚酯/MDI聚氨酯弹性体力学性能的影响

用聚酯多元醇(PBA、PEA、PEPA、PCL)、4,4'-二苯基甲烷二异氰酸酯(MDI)和混合扩链剂等原料合成了浇注型聚氨酯弹性体(PUE)。考察了聚酯多元醇种类、预聚体-NCO质量分数、扩链剂和扩链系数(R)等对PUE力学性能的影响,并比较了MDI/混醇体系与2,4-甲苯二异氰酸酯(TDI)/MOCA体系的性能。结果表明,PUE的硬度、模量和撕裂强度随预聚体-NCO含量增加而增加,随交联密度提高,撕裂强度和扯断伸长率下降,R>1.05时,PUE的力学性能急剧变化,MDI/混醇体系比TDI/MOCA体系的冲击弹性好。

Influence of Chain Extenders on Mechanical Properties of Polyurethane Elastomers Based on Polyester/MDI

A series of casting polyurethane elastomers(PUE) were synthesized by using polyester polyols(PBA,PEA,PEPA,PCL),4,4'-diphenylmethane diisocyanate(MDI),and chain extender mixture of 1,4-butanediol(BDO) with trimethylolpropane(TMP).The influence of the types of polyester polyols,mass fraction of-NCO in prepolymer,chain extenders and chain extension coefficient(R) on the mechanical properties of the PUE was investigated.The results show that hardness,modulus and tear strength of PUE increase with the increase of the content of-NCO in prepolymer,the tear strength and elongation at break decrease with the increase of the crosslinking density.When R>1.05,the mechanical properties of PUE change sharply.The impact resilience of MDI-polyol mixture PUE is better than that of TDI-MOCA PUE.