Abstract: A method for improving the expandability of styrenic polymer particles is disclosed. The method comprises copolymerizing a styrenic monomer with an amount of an acrylate monomer effective to improve the expandability of the particles without adversely affecting their heat sensitivity. Polymer foams of low density can be prepared with reduced amounts of blowing agents.

Abstract: Fire-retardant expandable vinyl aromatic polymer beads are prepared by an aqueous suspension method whereby a bromophenyl allyl ether fire-retardant agent and a volatile aliphatic hydrocarbon foaming agents are incorporated into particles of a thermoplastic such as polystyrene. The beads are useful in the preparation of molded foam articles having excellent resistance to flame.

Abstract: A method of introducing flame retardants into expandable vinyl aromatic polymer beads made in a one-step process is disclosed. Flame retardants with good solubility in blowing agents are introduced after monomer conversion is substantially complete, resulting in vinyl aromatic polymer beads with low residual monomer content.

Abstract: Fire-retardant expandable vinyl aromatic polymer beads are prepared by an aqueous suspension method whereby micronized hexabromocyclododecane and a volatile aliphatic hydrocarbon foaming agent are incorporated into particles of a thermoplastic such as polystyrene. The beads are useful in the preparation of molded foam articles having excellent resistance to flame.

Abstract: Various rubber polymers and copolymers have been added as a coating to seed beads of vinyl aromatic polymers. Cups molded from these beads were coffee leak tested and generally exhibited enhanced retention of coffee.

Abstract: Various flame retardant agents have been added as a coating to seed beads of vinyl aromatic polymers. The resulting products have high resistance to burning and permit the use of lower concentrations of the retardant.

Abstract: Thermoplastic particles are suspended in water or other suspending fluids with a suspending aid(s) to prevent agglomeration of the beads, pellets or particles. To this suspension is added monomer(s) containing a multifunctional initiator(s). The monomer and initiator(s) are preemulsified in water or other fluid(s) before the addition in order to improve distribution of the monomer(s) and initiator(s) in or on the particles. After or during the addition(s), the suspension temperature is raised to cause polymerization. The procedures may be repeated to increase the coating or penetrated polymer content. New compositions of matter are made by this technique wherein the new compositions are plastic resins either coated or penetrated, or both, with a thermoplastic(s) of very high molecular weight not obtainable by present, commercial polymerization techniques. The compositions are superior to the feed resins because of the enhancement of physical properties brought about by the high molecular weights phase(s).

Abstract: Thermoplastic particles are suspended in water or other suspending fluids with a suspending aid(s) to prevent agglomeration of the beads, pellets or particles. To this suspension is added monomer(s) containing a multifunctional initiator(s). The monomer and initiator(s) are pre-emulsified in water or other fluid(s) before the addition in order to improve distribution of the monomer(s) and initiator(s) in or on the particles. After or during the addition(s), the suspension temperature is raised to cause polymerization. The procedures may be repeated to increase the coating or penetrated polymer content. New compositions of matter are made by this technique wherein the new compositions are plastic resins either coated or penetrated, or both, with a thermoplastic(s) of very high molecular weight not obtainable by present, commercial polymerization techniques. The compositions are superior to the feed resins because of the enhancement of physical properties brought about by the high molecular weights phase(s).