Method and apparatus to produce auxetic foam

An apparatus to compress polymer foam in preparation to impart auxetic properties to the polymer foam by at least one of a chemical and thermal treatment, the apparatus comprising:

• a first pair of opposing compression surfaces, one of the first pair of opposing compression surfaces being movable in relation to a second compression surface of the first pair along a first axis between a first expanded position and a first compressed position;
• a mold having a pair of opposing first mold segments, each of the first mold segments having a mold surface, one of the first mold segments being movable in relation to a second mold segment of the first pair of mold segments along the first axis between a first open position in which the first mold surfaces are distant from one another and a first closed position in which the first mold surfaces are proximal to one another, wherein when the first pair of compression surfaces is in the first expanded position the first compression surfaces are spaced apart sufficiently to accommodate between the first pair of compression surfaces the first mold segments in the first open position, and the first pair of compression surfaces in moving from the first expanded position to the first compressed position apply a first compressive force to move the first mold segments into the first closed position, the first mold segments enclosing a mold cavity bounded by the first opposing mold surfaces;
• and
• a second pair of opposing compression surfaces, one of the second pair of opposing compression surfaces being movable in relation to a second compression surface of the second pair along a second axis between a second expanded position and a second compressed position,
• the mold having a pair of second opposing mold segments, each of the second mold segments having a mold surface, one of the second mold segments being movable in relation to a second mold segment of the pair of second mold segments along the second axis between a second open position in which the second mold surfaces are distant from one another and a second closed position in which the second mold surfaces are proximal to one another, wherein when the second pair of compression surfaces is in the second expanded position the second compression surfaces are spaced apart sufficiently to accommodate between the second compression surfaces the second mold segments in the second open position, and the second compression surfaces in moving from the second expanded position to the second compressed position apply a second compressive force to move the second mold segments into the second closed position, the mold cavity being bounded by the second opposing mold surfaces,
• a third pair of opposing compression surfaces, one of the third pair of opposing compression surfaces being movable in relation to a second compression surface of the third pair of opposing compression surfaces along a third axis between a third expanded position and a third compressed position,
• the mold having a pair of third opposing mold segments, each of the third mold segments having a mold surface, one of the third mold segments being movable in relation to a second mold segment of the third pair of mold segments along the third axis between a third open position in which the third mold surfaces are distant from one another and a third closed position in which the third mold surfaces are proximal to one another, wherein when the third pair of compression surfaces is in the third expanded position the third compression surfaces are spaced apart sufficiently to accommodate between the third pair of opposing compression surfaces the third mold segments in the third open position, and the third compression surfaces in moving from the third expanded position to the third compressed position apply a third compressive force to move the third mold segments into the third closed position, the mold cavity being bounded by the third opposing mold surfaces;
• and
• at least one fastener, wherein the at least one fastener holds the first mold segments in the first closed position separately from the first pair of opposing compression surfaces such that the mold remains in the first closed position when the first compressive force on the first mold segments is removed,
• wherein the at least one fastener holds the second mold segments in the second closed position such that the mold remains in the second closed position when the second compressive force on the second mold segments is removed,
• wherein the at least one fastener holds the third mold segments in the third closed position such that the mold remains in the third closed position when the third compressive force on the third mold segments is removed, and
• wherein the at least one fastener includes an elongate member that extends parallel to the first axis to restrain the second mold segments in the second axis and the third mold segments in the third axis.