聚氨酯/环氧树脂互穿网络半硬泡沫压缩行为研究

采用同步法合成聚氨酯/环氧树脂互穿聚合物网络(PU/ER IPN)半硬泡沫。对IPN半硬泡沫进行了应变率在1.67×10-4～1.67×10-2 s-1范围内的静态压缩实验。研究表明,泡沫在平行发泡方向和垂直发泡方向上压缩应力-应变曲线没有明显区别。平行方向上的压缩应力-应变曲线表现出3个变形阶段:弹性阶段,"平台"阶段和"硬化"密实阶段。应力-应变曲线单调增加,平台阶段没有产生应变软化,整个压缩过程中试样变形是均匀分布的。IPN半硬泡沫材料在静态实验中存在明显的应变率效应。讨论IPN半硬泡沫的压缩力学本构关系。

Compression behavior of semirigid PU/ER interpenetrating polymer networks foams

A series of semirigid interpenetrating polymer networks foams,based on polyurethane and epoxy resin,were prepared by a simultaneous polymerization technique.The compression stress-strain behaviors of the simirigid polyurethane/epoxy interpenetrating polymer networks(PU/ER IPN)foams were tested at strain rate of 1.67×10~(-4)-1.67×10~(-2) s~(-1).The compression stress-strain responses of the IPN foam in the rising and transversal directions were almost identical.Compression in the two directions yields a three-stage stress-strain response-an initial linear elastic response,a protracted plateau and a final sharp rise in compressive stress,gives rise to a monotonously increasing stress-strain curve without strain-softening and always produces uniformly distributed deformation.Experimental results show that the compression behaviors of the IPN foams are sensitive to the strain-rates.The constitutive relation describing the compression behavior was discussed.