ABSTRACT
JEAN-PIERRE VAIRON and NICOLAS SPASSKY Laboratoire de Chimie Macromoleculaire, UR A 24, Uni ver site Pierre et Marie Curie, Paris, France
I. INTRODUCTION
Industrial polymers obtained by cationic polymerization are based either on alkenes or on heterocyclic monomers. More than three dozen of com mercial polymers and copolymers, with different grades and composi tions, are shared between these two main families, and their current pro duction is close to 3 million metric tons per year, which represents roughly 3% of the overall amount of synthetic polymers. It is in fact difficult to get a more precise picture of the market because, besides the well-known major products (polybutenes, butyl type elastomers, polyacetal resins) representing two-thirds of the production, a wide variety o f specialty poly mers are synthesized each of them in a much more limited amount (104-1 0 5 tons per year) and the companies are particularly sparing of information. For example, it is striking that the overall consumption of the so-called “hydrocarbon resins” involving alkenes, dienes, vinyl aromatic mono mers, and terpenes is comparable to that of butyl rubbers. Moreover it must be noticed that some of the considered polymers and copolymers are also, and sometimes mainly, obtained through other types of polymer ization, and the part related to cationic processes is indistinguishable. This is the case for silicones which are not considered in the above-mentioned world production estimate.
