Abstract: Polymerization of vinyl chloride in aqueous suspension using a polymerization reactor having adherently deposited on internal surfaces thereof a build-up suppressant coating comprising a product of build-up suppressant activity formable by (and preferably formed by) the condensation of an effective 1-naphthol (preferably 1-naphthol itself) and formaldehyde. The condensation is preferably effected in a base-catalyzed reaction; it may also (less preferably) be effected in an acid-catalyzed reaction. The coating product itself and a process for its production are also claimed.

Abstract: Aromatic polyethersulphones that are particularly useful as adhesives and coatings having end groups of formula --OCH.sub.2 COR, where R is alkyl or alkoxy. Preferred examples are --OCH.sub.2 COCH.sub.3 and --OCH.sub.2 COOC.sub.2 H.sub.5. Such polymers may be made by heating polyethersulphones made from halophenates or bisphenate/dihalide mixtures, in the presence of a reagent of formula XCH.sub.2 COR (X is halogen, preferably chlorine), such as chloroacetone or ethyl chloroacetate, for a short period of time. Such polymers of molecular weight (RV<0.25) are of particular use in coating compositions comprising a dispersion of a fluorocarbon polymer dispersed in a solution or dispersion of the polyethersulphone.