Controllable radical copolymerization of styrene and methyl methacrylate using 1,1,2,2-tetraphenyl-1,2-bis(trimethylsilyloxy) ethane as initiator

Copolymerization of styrene (St) and methyl methacrylate (MMA) was carried out using 1,1,2,2-tetraphenyl-1,2-bis (trimethylsilyloxy) ethane (TPSE) as initiator; the copolymerization proceeded via a "living" radical mechanism and the polymer molecular weight (M-w) increased with the conversion and po lymerization time. The reactivity ratios for TPSE and azobisisobutyronitril e (AIBN) systems calculated by Finemann-Ross method were r(St) = 0.216 +/- 0.003, r(mmA)= 0.403 +/- 0.01 for the former and r(St) 0.52 +/- 0.01, r(MMA )= 0.46 +/- 0.01 for the latter, respectively, and the difference between t hem and the effect of polymerization conditions on copolymerization are dis cussed. Thermal analysis proved that the copolymers obtained by TPSE system showed higher sequence regularity than that obtained by the AIBN system, a nd the sequence regularity increased with the content of styrene in copolym er chain segment. (C) 2001 John Wiley & Sons, Inc.