GB723947A - Heat stabilized moulding compositions of vinyl aromatic polymers and method of making the same - Google Patents

Abstract

Polymers of one or more monovinyl aromatic compounds having the vinyl radical directly attached to a carbon atom of a benzene nucleus, e.g. polystyrene and p-methyl, m-methyl, o- and p-dimethyl or diethyl styrenes are heat stabilized prior to moulding by incorporating therein 0.04 to 3 per cent of a saturated acyclic aliphatic mono- or dihydric secondary alcohol or a glycol or an acyclic, aliphatic mono- or di-hydric ether-alcohol, composed of carbon, hydrogen and oxygen atoms, and which glycol or ether-alcohol contains an hydroxyl group attached to a secondary carbon atom in the molecule and having a molecular weight of 60 to 300. Isopropyl alcohol, 2-pentanol, 2-octanol, 1,2-propylene, dipropylene, tripropylene and tetrapropylene glycols, mono-isobutyl ether of propylene glycol, mono-propyl ether of dipropylene glycol, monomethyl ether of tripropylene and tetrapropylene glycols, and 3-ethoxy, 1,2-propane diol or mixtures thereof and the reaction products of 1,2-propylene oxides with methanol, ethanol, isopropanol, butanol, octanol, cyclohexanol or benzyl alcohol in the presence of an alkaline catalyst, e.g. sodium or potassium hydroxide are specified. They may be incorporated with the monomer, e.g. styrene, alone or with other polymerizable monovinyl aromatic compounds before bulk polymerizing with or without a catalyst, or they may be admixed with granular polymer with agitation at a plastifying temperature and cooled, or admixed just prior to moulding.