A thermoformed article that is formed from a polymeric sheet having a thickness of from about 0.1 to about 100 millimeters is provided. The polymeric sheet contains a thermoplastic composition that includes a continuous phase that includes a matrix polymer. A microinclusion additive and nanoinclusion additive are dispersed within the continuous phase in the form of discrete domains, and a porous network is defined in the composition that includes a plurality of nanopores having an average cross-sectional dimension of about 800 nanometers or less.

A thermoformed article that is formed from a polymeric sheet having a thickness of from about 0.1 to about 100 millimeters is provided. The polymeric sheet contains a thermoplastic composition that includes a continuous phase that includes a matrix polymer. A microinclusion additive and nanoinclusion additive are dispersed within the continuous phase in the form of discrete domains, and a porous network is defined in the composition that includes a plurality of nanopores having an average cross-sectional dimension of about 800 nanometers or less.

Provided is a method for producing hollow articles in a blow molding process with reduced cycle time and using a nucleation agent to foam a thermoplastic plastic with gas bubbles prior to blow forming. A nucleation agent is provided, which has substances that emit gas bubbles when a decomposition temperature is exceeded. When a mixture of thermoplastic plastic and the nucleation agent are heated, the decomposition temperature is exceeded. A supercritical fluid state of the gas bubbles emitted from the substances is maintained by having supercritical pressure values elevated relative to ambient pressure while continuously heating the mixture. Blow molding of a hollow article is carried out in a blow molding apparatus at the supercritical pressure values of the thermoplastic plastic pre-foamed with homogeneously distributed gas bubbles, at a softening or melting temperature of the thermoplastic plastic below a plastic-specific softening or melting temperature of the thermoplastic plastic.