Mechanism of the polymerization ofn-butyl acrylate initiated byN,N-diethyldithiocarbamate derivatives. Part 2. Investigation of the reaction mechanism

Abstract

The polymerization of n-butyl acrylate (BuAc) initiated with a model compound (butyl-2-(N,N-diethyldithiocarbamyl)propionate, RTC) has been investigated. The living character of this polymerization has been assessed and compared with those of styrene and methyl methacrylate. The small variation of Mn with yield is explained by the faster propagation than for styrene and methyl methacrylate, which leads to slow initiation and extensive transfer to the initiator. Predominant reversible termination (or deactivation) of the growing chains by the dithiocarbamyl radicals gives, however, polymers of functionality near to unity, which are photoinitiated at the same rate as RTC and reinitiate the polymerization of BuAc with a linear growth of the Mn up to 40% yield. This is better than was obtained with methyl methacrylate. Side reactions also take place leading to a decrease of functionality, to the formation of tetraethylthiuram disulphide and of carbon disulphide. Possible mechanisms are proposed for the secondary reactions. © 1998 SCI.