Abstract: Process for the preparation of polyvinylarene polymer particles by suspension polymerization, wherein (a) vinylarene monomers are suspended in an aqueous medium to yield a suspension; (b) the temperature of the suspension is adjusted to a temperature above 50° C., at which temperature an initiator is added; (c) subsequently, the reaction temperature is increased by 5 to 30° C. per hour until a temperature of at least 120° C. has been reached; and (d) the temperature is retained at a temperature of at least 120° C. until the polymerization is complete.

Abstract: Particles of a copolymer of a vinyl arene and a copolymerizable compound containing a polar moiety and a vinyl moiety containing water may be prepared by forming a mixture of monomers and small amounts of water and polymerizing under agitation to 20 to 70% conversion and then suspending the mass in water and finishing the polymerization. The resulting polymer beads contain finely dispersed water which is useful as an environmentally acceptable blowing agent.

Abstract: It is desirable to reduce the amount of volatile organic blowing agent in expandable polystyrene. This may be accomplished by partially polymerizing a mass of styrene and incorporating therein water together with an emulsifier. The partially polymerized mass is then polymerized to a high conversion using conventional suspension techniques. The polymer beads containing water which acts as a blowing agent are recovered.

Abstract: The present invention provides a process for preparing an expandable polymer of a vinyl aromatic monomer and a polar water adsorbing monomer. The monomers are partially polymerized and then suspended in water so that the resulting beads contain from 3 to 40 weight % water which act as the sole or a predominant blowing agent.