CPC B29C 33/3821 (2013.01) [B29C 35/0227 (2013.01); B29C 35/045 (2013.01); B29C 2035/046 (2013.01); B29L 2031/3076 (2013.01)] | 20 Claims |
1. A material system, comprising:
a plurality of expandable pellets, comprising:
a polymer matrix configured to hold an expandable core; and
a flexible skin configured to encapsulate the polymer matrix; and
wherein the flexible skin is at least partially permeable with respect to the expandable core or a gas released by the expandable core.
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