Functionally graded shape memory polymer

Patent metadata

Field	Value
Publication number	US-10471648-B2
Application number	US-201715446487-A
Country	US
Kind code	B2
Filing date	Mar 1, 2017
Priority date	Feb 18, 2011
Publication date	Nov 12, 2019
Grant date	Nov 12, 2019

Abstract

A functionally graded shape memory polymer (SMP) that has a range of transition temperatures that are spatially distributed in a gradient fashion within one single article. The SMP is formed by post-curing a pre-cured glassy SMP in a linear temperature gradient that imposes different vitrification temperature limits at different positions along the gradient. Utilizing indentation-based surface shape memory coupled with optical measurements of photoelastic response, the capability of this material to respond over a wide range of thermal triggers is correlated with the graded glass transition behavior. This new class of SMP offers great potential for such applications as passive temperature sensing and precise control of shape evolution during a thermally triggered shape recovery.

First claim

What is claimed is:

1. A method of preparing a functionally graded shape memory polymer, said method comprising the steps of:
providing a shape memory polymer comprising a first end and a second end;
applying an increasing temperature gradient to said shape memory polymer from said first end to said second end, wherein said application produces a corresponding increasing gradient in crosslink density and glass transition temperatures (T g 's) to said shape memory polymer from said first end to said second end.

2. The method of claim 1 , further comprising the step of photocuring said shape memory polymer by use of a radiation source.

3. The method of claim 1 , wherein said shape memory polymer is a curable thermoset.

4. The method of claim 1 , wherein said curable thermoset is selected from the group consisting of polyacrylates, polymethacrylates, thermosets formed by thiol-ene reactions, polyurethanes, and epoxy resins.

5. A method of preparing a functionally graded shape memory polymer, said method comprising the steps of:
providing a shape memory polymer comprising a first end and a second end;
photocuring said shape memory polymer by use of a radiation source through a gradient photomask, wherein said gradient photomask allows an increasing amount of radiation to reach said shape memory polymer from said first end to said second end, wherein said photocuring produces a corresponding increasing gradient in crosslink density and glass transition temperatures (T g 's) to said shape memory polymer from said first end to said second end, wherein said photocuring is performed when said shape memory polymer is at a temperature greater than a maximum glass transition temperature (T g ) allowable by said shape memory polymer.

6. The method of claim 5 , wherein said shape memory polymer is a radiation-curable theremoset.

7. The method of claim 5 , wherein said radiation is ultra-violet radiation.

Assignees

• Mather Patrick
• Luo Xiaofan
• Diorio Andrew M
• Lee Kyung Min
• Univ Syracuse

Inventors

• Mather Patrick
• Luo Xiaofan
• Diorio Andrew M
• Lee Kyung-Min

Classifications

• C08L63/00

  Compositions of epoxy resins; Compositions of derivatives of epoxy resins · CPC title

• C08L71/02

  Polyalkylene oxides · CPC title

• C08L75/04

  Polyurethanes · CPC title

• C08F220/12

  of monohydric alcohols or phenols · CPC title

• C08F220/14

  Methyl esters {, e.g. methyl (meth)acrylate} · CPC title