Effects of CTBN rubber on mechanical properties and morphology of bisphenol epoxy resins

In this research, the effect of CTBN rubber on epoxy resin had been investigated. Two types of resins (Epon 828 and Epon 862) and three kinds of hardeners are Jeffamine T-403, Imicure EMI-24 and DCA221 used for found optimum ratio between resin and hardener. From results, epoxy resin without CTBN rubber had the high mechanical properties. The best mechanical properties were obtained at 100 to 80 wt% for Epon 828/Jeffamine T-403 and 100 to 40 wt% for Epon 862/Jeffamine T-403. These formulae gave the high mechanical properties. After that, the various concentrations of the CTBN rubber that added to epoxy resin were prepared. Addition of small amount CTBN rubber led to the decrease of mechanical properties of the materials. This was due to the phase separation between epoxy resin phase and CTBN rubber phase. In contrast, when high amount of CTBN rubber was added to epoxy resin, the mechanical properties increased. This may be due to the increase of particle size of CTBN rubber in epoxy resin. Scanning Electron Microscope was used to study the phase separation between epoxy resin with hardener and CTBN rubber. The phase separation of CTBN rubber in epoxy resin with hardener matrix was observed. It can be concluded that CTBN rubber was less compatible with epoxy resin with hardener.

本研究考察了羧基丁腈橡胶（CTBN rubber）对环氧树脂的作用效果。选用两种环氧树脂（Epon 828与Epon 862）以及三种固化剂：Jeffamine T-403、Imicure EMI-24与DCA221，以确定树脂与固化剂间的最优配比。研究结果显示，未掺加羧基丁腈橡胶的环氧树脂基体具有较高的力学性能。对于Epon 828/Jeffamine T-403体系，当树脂与固化剂质量比为100:80时可获得最优力学性能；而Epon 862/Jeffamine T-403体系的最优配比则为100:40，上述配方体系均可获得较高的力学性能。随后，本研究制备了一系列掺加不同浓度羧基丁腈橡胶的环氧树脂复合材料。少量掺加羧基丁腈橡胶会导致复合材料的力学性能下降，该现象源于环氧树脂相与羧基丁腈橡胶相之间发生了相分离。与之相反，当掺加较高含量的羧基丁腈橡胶时，复合材料的力学性能反而有所提升，这可能是由于环氧树脂基体中羧基丁腈橡胶的颗粒粒径增大所致。本研究采用扫描电子显微镜（Scanning Electron Microscope）对固化环氧树脂基体与羧基丁腈橡胶之间的相分离行为进行了表征，观察到了固化环氧树脂基体中羧基丁腈橡胶的相分离现象。综上可得出结论：羧基丁腈橡胶与固化环氧树脂基体的相容性较差。