物理表面包覆MDA及聚氨酯弹性体的制备和性能研究

Preparation and Properties of Physical Surface Coated MDA and Polyurethane Elastomers

粒状4,4′ 二氨基二苯甲烷(MDA)与水按质量比为1∶1制得糊状MDA,再以不同比例的聚乙烯吡咯烷酮(PVP)采用包浆法对MDA颗粒表面进行包覆,制备出了4种物理钝化改性的扩链剂。按扩链系数0.8分别对用聚四氢呋喃二醇(PTMG2000)和2,4 甲苯二异氰酸酯(2,4 TDI)制备的预聚体进行扩链,制备了4种聚氨酯(PU)弹性体,并对扩链反应凝胶时间和PU弹性体的性能进行了研究。结果表明,钝化后的MDA为扩链剂制备的PU弹性体凝胶时间比钝化前的有大幅度延长,在MDA与PVP质量比为20∶(1~2.5)范围,凝胶时间随PVP用量的增加而延长,25℃时凝胶时间均能延长到60 min以上,改善了制备浇注型PU弹性体的可操作性,解决了扩链剂MDA与PU预聚体相容性差等问题。当MDA与PVP质量比为20∶1.5时,PU弹性体的力学性能最佳。

The 4,4′ diaminodiphenyl methane(MDA)pastes were firstly prepared with granulated MDA and water in a mass ratio of 1∶1.Then,four kinds of physical passivation modified chain extenders were prepared by coating MDA particle surface with different proportions of polyvinylpyrrolidone(PVP).Four kinds of polyurethane(PU)elastomers were prepared by chain extending the prepolymers which prepared from polytetrahydrofuran diol(PTMG2000)and 2,4 toluene diisocyanate(2,4 TDI)with modified MDA according to a chain extension coeffi cient of 0.8.The gelling time and the performance of the PU elastomer were investigated.The results showed that the gelling time of PU elastomer system based on passivation modified MDA was significantly prolonged compared with using pure MDA.In the range of MDA/PVP mass ratio at 20/(1~2.5),the gelling time was prolonged with the increasing of PVP dosage.The gelling time could be extended to more than 60 min at 25℃.It would increase the operability and solve the problems of poor compatibility between the chain extender MDA and the PU prepoly mer.When the mass ratio of the MDA/PVP was 20∶1.5,the mechanical properties of the PU elastomer were the best.