Abstract:

Poly(tert-butyl acrylate)(PtBA)telomer with tribromomethyl end group was synthesized by radical telomerization of tert-butyl acrylate(tBA)with CBr₄ as telogen and 2,2′-azobisisobutyronitrile(AIBN)as initiator. The number-average molecular weight(M_n)of PtBA-Br telomers was determined by GPC and ¹H NMR，and PtBA-Br telomers with M_n of 2730—9200 were obtained. The M_n calculated from ¹H NMR spectrum matched well with the M_n,GPC results. In order to accurately control the molecular weight of PtBA-Br telomers，the chain transfer constant(C_s)of CBr₄ was determined by using the Mayo equation and simulation，and the value was 1.11 at 60℃. When the ratio of telogen and monomer concentration was 0. 02，the M_n of PtBA-Br telomers at 60℃ was between 5940 and 6450 at increased conversion from 25% to 73%. The M_n values were consistent with simulation results and the molecular weight distributions were all under 1.70.