COLLOIDAL STABILITY OF PVC PRIMARY PARTICLES IN VINYL-CHLORIDE

The electrostatic contribution to the colloidal stability of PVC primary particles dispersed in vinyl chloride, was calculated. The calculations showed that particle stability would decrease with particle size (experimentally-observed behavior), only if the particle charge increased with size at a lower rate than in proportion to particle radius. The calculations also suggest that particle growth may be governed by a competitive growth mechanism of electrostatic origin. Particle growth is assumed to occur by absorption of many small, weakly charged basic particles from the monomer phase. According to the calculations, the electrostatic interaction between primary and basic particles may be such that the growth of the smaller primary particles is favored over that of the larger ones.