料温对RIM交联型聚氨酯脲结构与性能的影响

EFFECT OF REACTANT TEMPERATURE ON STRUCTURE AND PROPERTIES OF RIM POLYURETHANE-URSA ELASTOMERS

采用便携式微型反应注射成型机制备了一组料温分别为３０，４０，５０，６０℃的交联型聚氨酯脲。用ＤＳＣ和力学性能对试样进行表征的结果表明：料温提高有利于软、硬微相的混合，而硬链段微区的有序性变差。反映在宏观力学性能上则表现为：试样的拉伸强度提高，伸长率在５０℃料温时出现极大值，弯曲强度和弯曲模量则出现最小值。料温为３０℃时，物料混合不充分，随着料温升高，混合逐渐均匀，试样透明度提高。

A series of polyurethane -urea elastomers were prepared at the reactant temperatures of30, 40,50 and 60℃, by a reaction injection moulding (RIM) mini-machine. It was found that the mixing quality of reactants and the transparency of the final product were strongly dependent on the temperature of reactants. The specimens were charaterized by DSC, tensile and flexure tests. It was found that the difference between the formation rate of urethane network and urea reduced,and microphase mixing improved with increasing reactant temperature. As observed on mechanital properties, the tensile strength increased with increasing reactant temperature, while the toughness reached its maximum at 50℃.