Abstract: An improved process is disclosed for forming polymeric materials by a multistep, emulsion/suspension polymerization procedure. The improvement comprises using homogenization to disperse the monomeric reactants during the initial emulsion polymerization portion or portions of the multistep polymerization reaction to thereby reduce the amount of emulsifier that would be present for potential emulsifier-suspending agent interference during the later suspension polymerization portion or portions of the process. This improvement yields a cleaner reaction.

Abstract: A method for separating vinyl chloride monomer from an aqueous polyvinyl chloride resin mixture which comprises passing the aqueous resin mixture at an elevated temperature and sub-atmospheric pressure over a vibrating surface.

Abstract: The free radical copolymerization of vinyl chloride, vinyl acetate, and bis(hydrocarbyl)vinyl phosphonate in emulsion is moderated by the addition at the beginning of the reaction of an electronically resonating additive such as alphamethylstyrene. The use of such an additive limits the increase in viscosity of the system without retarding the rate of polymerization.

Abstract: Vinyl chloride monomer is suspension polymerized in an aqueous suspension polymerization medium in the presence of an effective amount of an organotin mercaptide and an expoxidized vegetable oil to lessen the amount of polymer scale formation from the reaction.

Abstract: Impact modified polyvinyl chloride is prepared by suspension polymerizing vinyl chloride in the presence of a dual catalyst system of a monomer soluble catalyst and a water soluble catalyst to form suspension polymer particles having irregular and porous surfaces, and then polymerizing, in the presence of the porous particles, monomers for forming gelled rubber-containing interpolymer particles having a Tg of less than 25.degree. C. No emulsification system is required for the rubber interpolymerization. Rubber-containing interpolymer particles in the order of 1 micron or less are formed on the surface of the suspension polyvinyl chloride particle. The process can be conducted in one reaction vessel and product contamination is reduced. The product can be used alone or blended with other thermoplastic polymers, such as polyvinyl chloride, to increase the impact strength thereof.

Abstract: A polyvinyl chloride extender resin having an average particle size of between about 5 microns and about 50 microns can be formed by using conventional suspension polymerization procedures if a prehomogenized solution comprising an effective amount of polyallyl compound and a low molecular weight propylene polymer are incorporated in the suspension polymerization medium to control the rheological properties of the resin.