Composite Dispersant Prepar Of PVC Suspension Polymerization Course

Polyvinyl Chloride resin is a thermoplastic polymer derived by polymerization from vinyl chloride.The main polymerization methods in industrial production are suspension, emulsion, bulk-Polymerizatiion, solution and microsuspension. It is an amorphous white powder, with density 1.35-1.45g/cm3, apparent density 0.45～0.65 g/cm3. Different sizes of resin particles are obtained under different polymerization methods of production, generally, size 60-150μm of resin particles are produed by suspension,30～80μm by bulk-Polymerizatiion, 1～50μm by emulsion and 1～50μm by microsuspension.This paper takes the dispersant in PVC of suspension polymerization as an example, aming at the characteristics of PVC resin particles, to make a research on forming Process of PVC Particles. Start with the characteristics of dispersant, summarize reasonable proportion of it and improve the characteristics of resin particles.Dispersant own reducing Interfacial Tension Between solution and VCM, and colloid-protection ability. A great deal of experiments have be done, to research the Characteristic Parameters, amount, mixed variety and proportion, etc, influnce on Interfacial Tension and colloid-protection ability.The interfacial tention of the single dispersant depends on the parameters,the interfacial tention of the PVA increases linearly with the increasing degree of alcoholysis,the greater the hydroxypropyl substitution degree,the smaller the interfacial tention; the interfacial tention of the binary complex dispersant is relation to the compound ratio of the dispersant and the compound species.The interfacial tention of composite system is between the two single dispersants, the agent of the interfacial tention and the composite ratio of dispersing is linear.With the increase of the content of the dispersant,the interfacial tention of the ternary complex dispersant decreases,and as the increase of the dispersing with high interfacial tention in the main dispersing agent,the interfacial tention of the composites system increases.The adhesive ability of single dispersant is relating to the dispersing specifications. The adhesive ability of PVA is relating to the degree of alcoholysis, polymerization degree and other relevant parameters.And the affection of the polymerization degree is relatively larger, the adhesive ability increased when the polymerization degree increased,while it decreased when the degree of alcoholysis increased;the adhesive ability of the binary composite dispersion is between the two single dispersing agent,it is relating to the composite types, it also increased when the the dispersant with strong adhesive ability increased in the dispersing system, in ternary complex dispersing system, when the total dispersant increased, the adhesive ability of the dispersing agent to protect plastic increased.PVC resin were produced in 110m3 polymerisation reactor using different kinds of dispersant. The influnce of dispersant on apparent density and plasticizer absorption were studied, which offer the basis of commercial production.