Manufacture of polymeric materials

In the emulsion polymerization of vinyl acetate by the process of the parent Specification wherein the polymerization is effected in the presence of polyvinylacetate hydrolysed to the extent of 78-92%, a persulphate catalyst and an alkali, part of the partially hydrolysed polyvinylacetate is replaced by a watersoluble polysaccharide. The polysaccharide and the polyvinylacetate may each be present in amounts of 0.5-4% by weight of the charge. Suitable polysaccharides are the starches and starch dextrins, e.g. maize, wheat or sago starch or dextrins derived therefrom, starch ethers and esters, amyloses, cellulose ethers and carboxymethyl celluloses. In the examples the monomer and catalyst are added stepwise.