RAFT polymerization of N-vinylcaprolactam and effects of the end group on the thermal response of poly(N-vinylcaprolactam)

• DOI: 10.1016/j.reactfunctpolym.2012.04.002
• Publication Date: 2012-04-12T12:50:44Z
• Authors: Lidong Shao; Minqi Hu; Lin Chen; Li Xu; Yunmei Bi
• Keywords: 01 natural sciences; 0104 chemical sciences

Abstract The reversible addition–fragmentation chain transfer (RAFT) radical polymerization of N -vinylcaprolactam (NVCL) was performed using either S -benzyl- S -(benzyl propionate) trithiocarbonate ( CTA 1 ) or N , N -diethyl- S -(α,α′- dimethyl-α″-acetic acid) dithiocarbamate ( CTA 2 ) as a chain transfer agent (CTA). The polymerizations were controlled processes that yielded polymers with high conversion (>60%), controlled molecular weights that were close to the theoretical values and a narrow molecular weight distribution (minimal value: 1.13). The cloud point temperatures of poly( N -vinylcaprolactam) (PNVCL) were measured by turbidimetry and shifted to lower temperature and concentrations as the hydrophobicity of the end groups and the molecular weights of the polymers increased.