| Abstract: | The scientific and technical history of polymerization can be divided into three periods, which will be illustratedfor emulsion polymerization. The first period was when emulsion polymers were originally produced, and was developed asan attempt to copy natural rubber latex. Indeed, the natural process is quite different from the synthetic process of emulsionpolymerization, which in fact does not even need an emulsion to be present: the term is a misnomer! The results werefunctional but limited. In the second period, the first theories appeared, and a huge range of products was madefor surface coatings, adhesives, commodity polymers such as SBR, neoprene, etc. The work of the outstanding pioneers wasbased on limited types of experimental data, and some suppositions are now seen to be incorrect. Nevertheless, manyexcellent products were made and have evolved to many materials currently in everyday use. The third period of emulsionpolymerization is now dawning. The scientific efforts of many teams over previous decades, aided by the advent of newphysical techniques for investigation, have resulted in better understanding of the fundamentals of emulsion polymerizations.Some examples from the author's group involve creating novel materials using controlled seeded emulsion polymerizationfrom natural rubber latex and other polyenes. Latex topology and controlled free-radical chemistry can be combined toproduce a) a comb polymer with hydrophobic backbone and hydrophilic "teeth", or b) with sufficient in situ compatibilizerbetween two otherwise incompatible polymers to yield a spatially uniform material down to the nanostructure level, and c) toproduce controlled nanostructures. |
