Poly(Hydroxyl Ether Of Bisphenol A)-block-Polydimethylsiloxane Alternative Block Copolymer: Synthesis, Characterization And Its Nanostructured Blends Of Epoxy Thermosets

Epoxy resin has many excellent properties such as good chemical and thermal stabilities, high intension and modulus, and good adhesive property and processing properties etc.. These excellent properties make epoxy resin widely used in different kinds of industries. However the biggest disadvantage of epoxy resin is that it is fragile after curing, easy to crack and has bad resistance to impulsion. This disadvantage largely restricts the application of epoxy resin. Nevertheless, Polydimethyl siloxane (PDMS) has good thermal stability, anti-oxidation, weatherability, excellent properties under low temperature and low surface energy etc., so PDMS modifying epoxy resin is becoming popular these years. PDMS can reduce the internal stress of epoxy resin as well as keep the original characteristics of epoxy resin and increase its thermal stability and heat resistance. So, choosing PDMS as modifier of epoxy resin becomes the interesting task for many researchers.Because PDMS is not miscible with epoxy resin, compatibilization of PDMS before applying it on epoxy resin is necessary. In this study, the compatibilizing method is to extend the chain of bisphenol A first, and then react Poly(hydroxy ether of bisphenol A), the product after chain extending, with Paraformaldehyde and amino-capped PDMS to synthesize PDMS multi-segment copolymer containing Benzoxazine. Fourier transform infrared(FTIR), differential ccanning caliorimetric(DSC) and thermal gravity analysis(TGA) were used to characterize and investigate the physical properties. Blend this copolymer with epoxy resin precursor and transparent and uniform solution was obtained. 4,4'-Diaminobiphenylmethane (DDM) was used as curing agent to get transparent modified epoxy resin. Atomic force microscope(AFM) ,differential ccanning caliorimetric(DSC) and three-point bending methods were used to investigate the morphology of epoxy resin after curing. The results showed that fracture toughness of epoxy resin after modification was largely increased and had the nanostructure of micro-phase separation via self-assembly.