THE TENSILE BEHAVIOR AND TOUGHNESS OF POLY(VINYLIDENE CHLORIDE) POLY(BUTYL METHACRYLATE) COMPOSITES PREPARED BY THE CONCENTRATED EMULSION APPROACH

Procedures for the preparation of poly(vinylidene chloride)/poly(butyl methacrylate) (PVDC/PBMA) composites based on concentrated emulsions are described. In one of them, two partially polymerized paste-like concentrated emulsions in water of two different systems were blended and subjected to complete polymerization. One of the systems was butyl methacrylate monomer (BMA), while the other was either vinylidene chloride monomer (VDC) or a dilute solution of PBMA in VDC. In the other procedure, a partially polymerized concentrated emulsion of VDC in water was blended with BMA monomer, and the paste-like system obtained was further polymerized. The composites thus obtained contained PVDC, PBMA and also some copolymer. The glass transition temperatures and the melting points measured by differential scanning calorimetry allowed qualitative identification of the presence of the above compounds. VDC-co-BMA copolymers of various compositions were also prepared via the concentrated emulsion method for comparison purposes. The effects of the preparation procedure, of the molar ratio of the two monomers and of the concentration of surfactant in the continuous water phase on the tensile properties were investigated. The toughness of the composites is much better than that of the copolymers.