混合扩链剂对聚氨酯弹性体宏观性能的影响

以4,4′-二苯基甲烷二异氰酸酯（MDI）和聚四氢呋喃均聚醚（PTMG）为原料合成聚氨酯（PU）预聚体（A组分），三羟基聚醚多元醇（330N）分别与1,4-丁二醇（BDO）或乙二醇（EGO）混合作为扩链剂（B组分），将A、B组分聚合制备PU弹性体。探讨330N/BDO与330N/EGO不同体系以及各体系不同质量比对PU弹性体热性能和机械性能的影响。结果表明，330N/BDO体系的软段玻璃化转变温度（T_gs）较低，硬段熔融热较高，随着330N/BDO质量比的下降，T_gs 上升，硬段熔融热增加；330N/EGO体系的拉伸强度、硬度稍高，而断裂伸长率和滞后损失（tan δ ）有较大落差，随着330N/EGO质量比的下降，弹性体的拉伸强度和硬度增加，断裂伸长率和滞后损失降低。

Effect of mixed chain extenders on the macroscopic properties of polyurethane elastomers

A series of polyurethane elastomers have been synthesized from prepolymers(component A) and chain extenders(component B).The prepolymers were prepared using 4,4′-diphenylmethane diisocyanate(MDI) and polytetrahydrofuran polyols(PTMG).The chain extenders were mixtures of trihydroxy polyether polyols(330N) with 1,4-butanediol(BDO) or ethylene glycol(EGO).The thermal and mechanical properties of polyurethane elastomers based on two different systems(330N/BDO and 330N/EGO) for a range of different mass ratios in each system were investigated.Differential scanning calorimetry(DSC) showed that the glass transition temperature of soft segments(Tgs) was lower in the 330N/BDO systems,whilst the melting heat of hard segments was higher in the 330N/BDO systems.The values of Tgs and the melting heat of hard segments increased with the decreasing 330N∶BDO and 330N∶EGO mass ratios.Measurements of mechanical properties and dynamic mechanical thermal analysis(DMTA) showed that tensile strength and the hardness were higher for the 330N/EGO system,while the elongation and hysteresis loss(tanδ) were lower.With decreasing 330N∶BDO and 330N∶EGO mass ratios,the tensile strength and hardness increased,but elongation and hysteresis loss(tanδ) decreased.