The emulsion polymerization of alkylbutadienes.

The polymerization of alkylbutadienes has a long history, dating from Grenville William's experiments with isoprene, obtained from the destructive distillation of natural rubber (l). However no large scale production of polymers of butadienes was attempted until World War I, when the Germans manufactured over 2300 tons of polydimethylbutadiene. Until then the natural sources of rubber yielded adequate supplies for world needs. Some research was continued in the field of synthetic rubber andby 1939 the Germans, and later the Western Allies, were able to produce large quantities of synthetic elastomers (the name given to high polymers that possess rubber-like properties). A copolymer of butadiene and styrene, called Buna-S or GR-S, wasconsidered to be the best general purpose synthetic elastomer and this copolymer is produced on a large scale on this continent. Much research has been done on this material but the pure polymers, such as polybutadiene and polyisoprene, have not been investigated as thoroughly since they have failed to show promising properties. As copolymers have the extra variable of compositional heterogeneity, it is thought that the study of pure polymers may lead to an easier and better understanding of the problems involved in obtaining elastomers of the desired properties.[...