Thermal Property and Microstructures of Poly(VAc-b-MA) and PVAc-b-Poly(MA-co-MMA) Block Copolymers and
The microstructure and thermal properties of the synthesized block copolymers and terpolymers via atom transfer radical polymerization (ATRP) were studied. The mole fraction of the blocks and chain length of the PVAc-b-PMA block copolymers were estimated with 1H NMR spectroscopy. Differential scanning calorimety measurement shows two different transitions at 36°C and 8°C assigned to PVAc and PMA blocks. Thermogravimetric analysis demonstrated the similar thermal degradation behavior of the block copolymers and a three-step degradation around 238, 295 and 345°C were attributed to dechlorination step and decomposition of the PVAc and PMA blocks. Study of thermal properties of PVAc-b-Poly(MA-co-MMA) copolymers indicated that glass transition temperature of second block increased from 49°C to 91°C with increase in MMA mole fraction from 0.358 to 0.733. The losses in the thermal degradation of block terpolymers were similar, and the higher thermal degredation temperature of MA unit has delayed the thermal degredation temperature of MMA in copolymer.
کلیدواژه ها [English]
atom transfer radical polymerization, microstructure, differential scanning calorimeter, block copolymer, block terpolymer