Thermal degradation behaviors of poly (dimethylsiloxane)-urethane-graft-poly (methyl methacrylate) copolymers based on various diisocyanates

The thermal decomposition behaviors of slightly crosslinked poly(dimethylsiloxane)-urethane-graft-poly(methyl methacrylate) (PDMS-urethane-g-PMMA) copolymers based on two diisocyanates: 2,4-toluene diisocyanate (2,4-TDI) and m-xylene diisocyanate (m-XDI) are discussed. By analyzing the residues of the decomposed copolymers and thermal degradation behaviors of copolymers, it was proposed that poly(dimethylsiloxane) (PDMS) in the copolymers traps free radicals generated from the thermal decomposition of the copolymer and reduces the rate of thermal decomposition. In addition, the crosslinking structure of PDMS can also reduce the evaporation of volatiles from the thermal decomposition process.