引入PNA、1, 2-PG对聚氨酯胶粘剂微相形态及性能的影响

引入PNA、1; 2-PG对聚氨酯胶粘剂微相形态及性能的影响;聚氨酯胶粘剂;结晶;微相分离;软段;硬段

Influence of PNA and 1,2-PG on the Microphase Structure and Properties of Polyurethane Adhesives

A series of polyurethane adhesives were prepared by using MDI-BDO as the hard-segment and PBA as the soft-segment.In order to control the crystallinity of the hard and soft segments,1,2-PG and PNA,which contain(dissymmetrical) and symmetrical side methyl groups respectively,were incorporated into the hard-segment and the soft-(segment) respectively.The influences of the changes of the soft-segment and the hard-segment structures and their contents on the crystallinity,(micro-)phase separation,mechanical properties and adhesive strength were studied by DSC,WAXD,and SEM.The results show that the introduction of PNA reduced the crystallinity of the soft-and the hard-segment simultaneously,and increased the micro-phase separation.The crystallinity and micro-phase separation of the hard-segments decreased upon the introduction of(1,2-PG),and the tensile strength decreased with the increased content of 1,2-PG;however,the adhesive strength increased from 16.8 N/cm to 18.1 N/cm.When the hard-segment content increased from 23% to 31%,the tensile strength of polyurethane adhesive was enhanced from 25.6 MPa to 37.1 MPa,but the(elasticity) declined.