Post polymerization cure shape memory polymers

• US 9,540,481 B2
• Filed: 05/13/2013
• Issued: 01/10/2017
• Est. Priority Date: 05/06/2010
• Status: Active Grant

• Current Assignee: Lawrence Livermore National Security LLC (Government of the United States of America)
• Original Assignee: Lawrence Livermore National Security LLC (Government of the United States of America)
• Inventors: Wilson, Thomas S., Hearon, Michael Keith II, Bearinger, Jane P.
• Primary Examiner(s): ZEMEL, IRINA SOPJIA
• Application Number:
  US13/892,719
• Publication Number:
  US 20130296503A1
• Time in Patent Office: 1,338 Days
• US Class Current: 1/1
• CPC Class Codes: B29C 45/0001 characterised by the choice of material
• CPC Class Codes: B29C 48/00 Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor extrusion blow-moulding B29C49/04
• CPC Class Codes: B29C 48/03 characterised by the shape of the extruded material at extrusion
• CPC Class Codes: B29C 51/00 Shaping by thermoforming , i.e. shaping sheets or sheet like preforms after heating, e.g. shaping sheets in matched moulds or by deep-drawing; Apparatus therefor blow moulding of tubular preforms B29C49/00, deforming of tubular or hollow preforms B29C67/0014
• CPC Class Codes: B29C 51/002 characterised by the choice of material
• CPC Class Codes: B29C 61/06 Making preforms having internal stresses, e.g. plastic memory
• CPC Class Codes: B29C 67/20 for porous or cellular articles, e.g. of foam plastics, coarse-pored chemical aspects of working up macro-molecular substances to porous or cellular articles C08J9/00
• CPC Class Codes: B29C 71/02 Thermal after-treatment B29C71/0063 and B29C71/0072 take precedence
• CPC Class Codes: B29C 71/04 by wave energy or particle radiation , e.g. for curing or vulcanising preformed articles during moulding, e.g. in a mould B29C35/08
• CPC Class Codes: B29K 2075/00 Use of PU, i.e. polyureas or polyurethanes or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2105/04 cellular or porous
• CPC Class Codes: C08G 18/3206 aliphatic
• CPC Class Codes: C08G 18/673 containing two or more acrylate or alkylacrylate ester groups
• CPC Class Codes: C08G 18/675 Low-molecular-weight compounds
• CPC Class Codes: C08G 18/722 Combination of two or more aliphatic and/or cycloaliphatic polyisocyanates
• CPC Class Codes: C08G 18/73 acyclic
• CPC Class Codes: C08G 18/758 containing two or more cycloaliphatic rings
• CPC Class Codes: C08G 18/83 Chemically modified polymers
• CPC Class Codes: C08G 2101/00 Manufacture of cellular products
• CPC Class Codes: C08G 2280/00 Compositions for creating shape memory
• CPC Class Codes: C08G 63/52 : Polycarboxylic acids or polyhydroxy compounds in which at least one of the two components contains aliphatic unsaturation

Abstract

This invention relates to chemical polymer compositions, methods of synthesis, and fabrication methods for devices regarding polymers capable of displaying shape memory behavior (SMPs) and which can first be polymerized to a linear or branched polymeric structure, having thermoplastic properties, subsequently processed into a device through processes typical of polymer melts, solutions, and dispersions and then crossed linked to a shape memory thermoset polymer retaining the processed shape.

Claims

1. A method comprising:

forming a polymer composition comprising a thermoplastic polymer;

(a) having shape memory properties and crosslinkable sites substantially regularly spaced from each other, (b) which comprises at least one of a back bone and a side chain having an electron withdrawing group with alpha and beta positions, a methyne carbon in the alpha position, and an unsaturated carbon-carbon double bond in the beta position;

forming the polymer composition into a shape;

crosslinking the shaped thermoplastic polymer to form a thermoset polymer having shape memory properties;

wherein the thermoplastic polymer is a polyurethane.

2. The method of claim 1, wherein the thermoplastic polymer includes crosslinkable sites that are double bonds.

3. The method of claim 1, wherein the crosslinking includes crosslinking by at least one of heat and electron beam radiation.

4. The method of claim 1, wherein the thermoplastic polymer has the side chain comprising the electron withdrawing group, the methyne carbon in the alpha position, and the unsaturated carbon-carbon double bond in the beta position.

5. The method of claim 1 comprising forming the thermoplastic polymer into a foam by at least one process selected from the group comprising freeze drying, high inverse phase emulsion foaming, physical blowing, pore templating, solution spinning, stereolithographic patterning, micro-extrusion, ink pen printing, 3D microdot based printing, and laser machining.

6. The method of claim 1, wherein crosslinking the thermoplastic polymer includes a curing mechanism selected from the group consisting of thermally or radiatively initiated radical crosslinking of vinyl groups, peroxide or sulfur based crosslinking of vinyl groups, thiol addition to vinyl, reaction of isocyanate containing curing agents with hydroxyl, carboxylic acid, amine, or other functionality on the polymer chains;

condensation of ester linkages, epoxy chemistry, silane and siloxane coupling reactions.

7. The method of claim 1, wherein the thermoplastic polymer is derived from alkene diol monomers and the crosslinking includes crosslinking by e-beam radiation.

8. The method of claim 1, wherein the thermoplastic polymer comprises at least one radiation sensitizer.

9. The method of claim 8, wherein the radiation sensitizer comprises at least one tris[2-(acryloyloxy)ethyl]isocyanurate (TAcIc) and pentaerithol triacrylate (PETA).

10. The method of claim 1 comprising forming the thermoplastic polymer into a foam, and subsequently crosslinking the thermoplastic polymer into the thermoset polymer.

11. The method of claim 10, wherein both of the thermoplastic and thermoset polymers are amorphous.

12. The method of claim 10, wherein both of the thermoplastic and thermoset polymers are aliphatic.

13. The method of claim 10, wherein the thermoplastic polymer is extruded.

14. The method of claim 10 comprising forming the thermoplastic polymer from trimethylhexamethylene diisocyanate.

15. An article of construction made by the method of claim 10.