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Expansion moulding of shape memory polymers

  • US 9,815,240 B2
  • Filed: 04/16/2008
  • Issued: 11/14/2017
  • Est. Priority Date: 04/18/2007
  • Status: Expired due to Fees
First Claim
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1. A pre-relaxed three-dimensional shape memory polymer material having a molded configuration made by the method comprising:

  • consolidating a material including an amorphous shape memory polymer material to form an isotropic cylinder in a first configuration;

    orientating the amorphous shape memory polymer material in the isotropic cylinder having the first configuration thereby forming an orientated shape memory polymer material having a second configuration;

    forming a mold about the orientated shape memory polymer material having the second configuration, such that the mold constrains the first portion of the oriented shape memory polymer material and the mold does not constrain a second portion of the oriented shape memory polymer material;

    applying a source of energy to, and/or exposing to at least one plastizer the orientated shape memory polymer material having the second configuration while the first portion is within the mold, thereby at least partially relaxing the orientated shape memory polymer material into a third configuration in which only the first portion conforms to the configuration of the mold and in which the first portion retains more shape memory potential than the second portion;

    ceasing the application of the source of energy to the shape memory polymer material when the shape memory polymer material is formed into the third configuration; and

    removing the mold when the shape memory polymer material is formed into the third configuration and the application of the source of energy, and/or exposure to at least one plastizer has ceased, wherein the shape memory polymer material having the third configuration retains its configuration unless a source of energy is applied to, and/or at least one plastizer is exposed to the shape memory polymer material in the third configuration, the retention of the shape memory polymer material in the third configuration after ceasing the application of the source of energy to, and/or the exposure to at least one plasticer, and the removal of the mold being greater than the retention of a configuration formed of the same shape memory polymer material treated by the same method except for not being in a mold when at least partially relaxed, and wherein the first, second, and third configurations are different to each other, and molecular motion of the third pre-relaxed configuration is stimulated to trigger further relaxation, wherein the shape memory polymer comprises an amorphous polymer.

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