Suspension polymerisation of vinyl chloride in presence of ultra fine filler particles

Polymer composites, filled with ultra fine particulate fillers, are alternatives to the conventional filled polymers. The reinforcement of the mechanical properties occurs to a greater extent when ultra fine particulate fillers are used in comparison with the conventional microdimensional fillers. To achieve all the benefits that the ultra fine fillers can provide, optimal dispersion as primary particles is essential. To achieve better dispersion of the inorganic particles in a polymer matrix, the ultra fine particles (UFP) are added to the polymerisation reactor so that they are dispersed in the monomer before polymerisation. Hence, the monomer is polymerised in the presence of the UFP (in situ). In this paper the effects of the UFP on the initial monomer dispersion are examined. The presence of the inorganic UFP in the polymerisation reactor influences the properties of the monomer phase and affects the drop size distribution. This in turn influences the grain sizes as well as their distribution, which influence the processability of the resin.