Chain transfer constants of polyethylene glycol and its dodecyl ether in radical polymerization

Chain transfer constants of the end groups (CE) and of the middle portions (CM) of the polymer chain of polyethylene glycol and its dodecyl ether were determined at 60°C. in vinyl acetate polymerization. In the case of polyethylene glycol, CE and CM represent the chain transfer constants of (HOC2H4) and that of (CH2CH2O) which were estimated as 0.004 and 0.0017 respectively, and were compared with the chain transfer constants of propanol and ethanol. The chain transfer constant of the dodecyl radical in polyethylene glycol dodecyl ether is estimated as 0.001, which is in fairly good agreement with that obtained theoretically from the chain transfer constant of the methylene group in acetic esters, but not from that in alcohols. This situation may be attributed to the inhibition of resonance energy transfer by the etherlike oxygen atom.