Translated reproduction of Sakurada, I. Mixed Polymerization [Kongo Jugo]**. In: Polymer Chemistry Association [Kobunshi Kagaku Kyokai]*** (ed.) ‘High Polymerization Reaction [Koujugo Hannno]’, 35-41, 1946, Tokyo. (Selected Books on Polymers; Vol. 3) Translation by Yutaka Sakurada
Polymerization processes conducted with one kind of monomer are called ‘single polymerizations’ (or ‘homopolymerizations’). Alternatively, polymerizations conducted with two or more kinds of monomers are called ‘mixed polymerizations’ (or copolymerizations). As applications of synthetic resins become broader and as materials are refined for specific targets, resins with properties intermediate to those of two or more types of synthetic resins are often required. For this reason, polymer blends sometimes become necessary. However, combining different polymers is generally difficult, and finely mixed blends with long-term stability cannot be attained. To cope with this problem, two or more types of monomers have been mixed and polymerized, and several examples of successful industrial applications have been demonstrated. Such examples include mixed polymerizations of vinyl chloride with vinyl acetate, vinyl chloride with acrylic ester, and butadiene with acrylonitrile. When mixed polymerization is performed, we can expect not only properties intermediate to those of the two separately synthesized polymers but also entirely different, copolymer-specific properties. It is still questionable whether mixed polymerizations (copolymers) will take the place of alloys of metallic materials, but their importance will certainly increase in the near future.
