Studies On Preparation And Performance Of The Blend Of Bisphenol A Epoxy/Branched Polyether Epoxy Resin

In this paper, utilizing TP200, PP150 and PP50 as precursors, three novel branched polyether epoxy resins (TP200EP, PP150EP and PP50EP) were synthesized by terminal groups modification method. Then, they were characterized by FTIR, 13C-NMR, 1H-NMR, and GPC. The obtained epoxy resins were employed as modifiers of commercial bisphenol A epoxy(DGEBA)and blend systems were obtained. Their influences on the mechanical performances, dynamic mechanical performances, thermal properties and fracture characters of the systems were investigated by impact test, tensile test, bend test, dynamic mechanical test, TG and SEM. Besides, the toughening mechanism was also investigated. The main results are as follows: 1. One "Y"type and two "+"type branched polyether epoxy resins are synthesized successfully and comprehensive characterizations are carried through. 2. The blend systems containing these branched polyether epoxy resin and bisphenol A epoxies (DGEBA) are obtained. Research results show that TP200EP and PP150EP can greatly improve the impact strengths of the blend systems,but PP50EP can only obviously improve impact strength of blends of containing E-44 epoxy resin. When the amount of TP200EP or PP150EP is 50% of bisphenol A epoxy,the impact strengths of the blend systems are increased by 200% to 300%. There is no phase separation in all blend systems and there are no dramatic changes in the dynamic mechanical behaviors of blend systems at lower temperature. The glass transition temperatures of blend systems descend with increasing amount of TP200EP and PP150EP. But they have little influence on thermal decomposition temperatures. 3. The mechanism of branched polyether epoxy resin (TP200EP and PP150EP) toughening bisphenol A epoxy is that they can facility plastic deformation of cross-linking network and induced yield of systems under stress. And during this process, a lot of impact energy is dissipated and impact strengths of the blend systems are greatly improved. Meanwhile, their branched flexible macular chains can lessen stress concentration and disperse impact energy. These should have some contributions to improvement of the impact strengths of the systems in a certain extent.