Proparation of a structured acrylic copolymer and its application in rigid PVC foam products

PMMA/Poly(MMA-co-St-co-AN), PMSN, with core-shell structured copolymer was prepared by seeded emulsion polymerization. The monomer conversion is high and the particle diameter distribution monitored by dynamic light scattering is narrow. This results show that the particles grow without significantly secondary nucleation occurring and the latex particle size can be designed. Meanwhile, the intrinsic viscosity [η] for the soluble polymer of PMSN in butanone increases with the addition of allyl methacrylate (AMA). When PMSN is blended with low molecular weight poly(vinyl chloride)(PVC) resin, the melt equilibrium torque is increased with the increase of intrinsic viscosity of PMSN. Extrusion of rigid foam is the most demanding PVC process in terms of melt strength. Since the final targeted density can typically be a third of that of compact PVC, high melt strength is essential to retain gas bubbles in the melt and to avoid a collapse of the cells. Finally, the PMSN process aid synthesized meets the industrial requirements of rigid PVC foam.