GB755661A - Process for the production of polymers and copolymers - Google Patents

Abstract

In the production of polymers and copolymers from polymerizable olefinic compounds, lactones having a four-, six- or more than six-membered ring are added prior to or during the polymerization, or the final polymers are subjected to heat treatment in the presence of the lactones, the proportion of lactone molecules being less than 1 mol., preferably between 0.05 and 0.5 mol. per mol. of the olefinic structural units. The olefinic monomer may be styrene, acrylonitrile, isobutylene, isoprene, butadiene, acrylic acid, maleic acid, fumaric acid, vinyl acetate or methyl methacrylate, preferred monomers being those containing carboxyl, ester or hydroxyl groups. The lactone may be propiolactone, d-valerolactone, e-caprolactone, lactide, glycolide, trimethylene carbonate or ethylene oxalate. Polymerization may be effected in bulk or in solution in a solvent such as xylene. The polymerization catalyst may be benzoyl peroxide or, when polymerizing butadiene, metallic sodium. The reaction may take place in the presence of a substance which assists the opening of the lactone ring such as zinc, lead oxide or cadmium acetate. Mixtures of lactones may be used and there may also be employed mixtures of lactones with their polymeric transformation products, such as the mixture obtained by allowing 1,5-pentanediol to trickle over a copper catalyst heated to 160 DEG C., which mixture contains about 75 per cent d-valerolactone and 25 per cent polymeric d-valerolactone.