Grafting of polytetrahydrofuran from neoprene W in the presence of perchlorate salts

Silver, mercury, and lead perchlorates can be used to prepare graft copolymers of polytetrahydrofuran from neoprene. Iron and aluminum perchlorates lead to graft copolymers but the conversion is low. The most efficient graft copolymerizations are obtained at high salt-to-neoprene ratios, long reaction times, and low monomer-to-neoprene concentration ratios. Very surprisingly, high initial monomer-to-neoprene concentration ratios lead to low graft copolymerization efficiencies.