| abstract |
A method of making a foamed article comprises the steps of (a) milling a block or sheet of a thermoplastic polymer to form a precursor; (b) crosslinking the thermoplastic polymer; (c) heating the precursor to a first temperature to soften the thermoplastic polymer; (d) injecting at least one inert gas into the thermoplastic polymer at a first pressure sufficient to permeate the at least one inert gas into the softened thermoplastic polymer; and (e) while the thermoplastic polymer softens, reducing the pressure to a second pressure less than the first pressure to at least partially foam the precursor in the foamed article, wherein the foamed article is in substantially the same shape as the precursor. has |