Abstract: Method of making a composite material by paste polymerization, by forming an emulsion of at least one polymerizable monomer in an aqueous material, polymerizing the emulsion to provide a latex containing particles of polymer, in which the polymer has a glass transition temperature above 65° C., adding nanoparticles to the latex, the nanoparticles having at least one dimension in the range 0.5 to 200 nm, and spray-drying the latex. The at least one polymerizable monomer contains vinyl chloride.

Abstract: This invention relates to composite materials and methods of their production. More especially the invention provides methods of making a composite material by paste polymerisation comprising the steps of a) forming an emulsion of at least one polymerisation monomer in an aqueous material b) polymerising the emulsion to provide a latex comprising particles of polymer, c) adding nanoparticles to the latex said nanoparticles having at least one dimension in the range 0.5 to 200 nm, and d) spray-drying the laytex.

Abstract: A procedure for the production of PVC particles with a narrow size distribution in the range 10-50 &mgr;m, preferably 10-30 &mgr;m, in which, in a first stage, a vinyl monomer or a mixture of monomers is polymerised to form a polymer/oligomer seed particle in the range 1-10 &mgr;m. In a second stage, another vinyl monomer or mixture of monomers is swelled into the polymer/oligomer seed particles and polymerisation takes place in such a way that they grow into polymer particles of the desired size. It is preferable to use aromatic vinyl monomers or acrylates as the monomer in the seed particles. The seed particles in the first stage can be produced in a two-stage swelling process or by dispersion polymerisation.