Abstract: A foamed sheet containing a polymer composition including a polymer formed by polymerizing a mixture including 40% to 90% of styrenic monomers; 5% to 45% of maleate-type monomers; 0.1% to 25% by weight of elastomeric polymers with Mn greater than 6,000; and 0.1% to 10% by weight of low molecular weight polymers that include one or more monomers according to the formula CH2?CR3R2, where R3 is H or a C1-C3 alkyl group and R2 is a C1-C22 linear, branched or cyclic alkyl or alkenyl groups. The low molecular weight polymer has Mn of from 400 to 6,000 and can optionally include functional groups. The foamed sheet is made by injecting blowing agents into the polymer melt composition; mixing the blowing agent with the polymer composition; and extruding the mixture to provide a foamed sheet. The foamed sheets can be thermoformed into containers suitable for use in microwave heating of food.

Abstract: A styrenic copolymer composition comprising 55% to 94% by weight of one or more styrenic monomers; 2% to 25% by weight of one or more maleate-type monomers; and 4% to 20% by weight of an elastomer composition comprising one or more partially hydrogenated elastomeric polymers comprising repeat units from one or more monomers according to the formula 63% 1,4 cis/trans butadiene, 1% 1,2 vinyl butadiene, 26% tetramethylene, and 10% butylene. The styrenic copolymer composition may also comprise one or more high molecular weight elastomeric polymers having a number average molecular weight of greater than 12,000 and optionally, polybutene. The styrenic copolymer composition is formed via polymerizing methods. A thermoplastic sheet is made by extruding the polymer melt composition to provide a thermoplastic sheet. The thermoplastic sheets can be thermoformed into containers suitable for use in microwave heating of food.

Abstract: A foamed sheet containing a polymer composition including a polymer formed by polymerizing a mixture including 40% to 90% of styrenic monomers; 5% to 45% of maleate-type monomers; 0.1% to 25% by weight of elastomeric polymers with Mn greater than 6,000; and 0.1% to 10% by weight of low molecular weight polymers that include one or more monomers according to the formula CH2?CR3R2, where R3 is H or a C1-C3 alkyl group and R2 is a C1-C22 linear, branched or cyclic alkyl or alkenyl groups. The low molecular weight polymer has Mn of from 400 to 6,000 and can optionally include functional groups. The foamed sheet is made by injecting blowing agents into the polymer melt composition; mixing the blowing agent with the polymer composition; and extruding the mixture to provide a foamed sheet. The foamed sheets can be thermoformed into containers suitable for use in microwave heating of food.

Abstract: A thermoplastic sheet containing a polymer composition including a polymer formed by polymerizing a mixture including 40% to 90% of styrenic monomers; 5% to 45% of maleate-type monomers; 0.1% to 25% by weight of elastomeric polymers with Mn greater than 12,000; and 0.1% to 10% by weight of low molecular weight polymers that include one or more monomers according to the formula CH2?CR3R2, where R3 is H or a C1-C3 alkyl group and R2 is a C1-C22 linear, branched or cyclic alkyl or alkenyl groups. The low molecular weight polymer has Mn of from 400 to 12,000 and can optionally include functional groups. The thermoplastic sheet is made by extruding the polymer melt composition to provide a thermoplastic sheet. The thermoplastic sheets can be thermoformed into containers suitable for use in microwave heating of food.