Epoxy-based triblock, diblock, gradient and statistical copolymers of glycidyl methacrylate and alkyl methacrylates by nitroxide mediated polymerization

摘要

A series of triblock, diblock, gradient and statistical copolymers of glycidyl methacrylate (GMA) and C13 methacrylates (C13MA, alkyl methacrylates with the average side-chain length of 13.0) were synthesized by nitroxide mediated polymerization (NMP) using Dispolreg 007 in 50 wt% dioxane at 90 degrees C. The polymers had the number average molecular weights (M-n) in the range of 23-46 kg mol(-1) and dispersities (D) of 1.5-1.9. For the GMA/C13MA statistical copolymerization, reactivity ratios r(GMA) = 1.17 +/- 0.09 and r(C13MA) = 0.65 +/- 0.09 were determined. For statistical copolymers with GMA ratio (F-GMA) of 0.5-0.8, the appearance of a melting point (T-m) at -43 to -19 degrees C and two glass transition temperatures (T-g) in the range of -53 to 11 degrees C indicated the possibility of micro-phase separation and a weak gradient polymerization. TGA showed ash content up to 13 wt% for GMA/C13MA copolymers at 600 degrees C, suggesting the possibility of high flame retardancy. Furthermore, a transition from elastic solid to viscous liquid behavior was detected by an oscillatory frequency sweep at 30 degrees C for triblock copolymers of GMA/C13MA (F-GMA = 0.6-0.7, crossovers at 100-200 rad s(-1)) and gradient polymers with high GMA content (F-GMA = 0.88, crossover at 10 rad s(-1)).