Isocyanate-terminated polydimethylsiloxane-modified epoxy resin: Preparation and curing, characterization and mechanical properties

Isocyanate-terminated polydimethylsiloxane (ITPDMS) was synthesized by the reaction of Hydroxyl-terminated polydimethylsiloxane (HTPDMS) with Toluene diisocyanate (TDI) and was used to modify epoxy resin (Diglycidyl ether of bisphenol A epoxy resin (DGEBA)). The chemical structure of ITPDMS and ITPDMS/ER was characterized by FTIR. The morphology of fracture surfaces of the ITPDMS/ER cured samples were studied by SEM and the thermal analysis was carried out via TGA. The modified epoxy resin shows biphasic toughness fracture morphology and 5~6°C improvement in thermal stability over unmodified epoxy resin with brittle fracture morphology. The mechanical properties were investigated by universal testing machine and DMA. The results show that the modified epoxy resin has better mechanical properties with tensile strength, bending strength and elongation increased by 6.76%, 5.05% and 11.84% respectively than unmodified epoxy resin.