Post-Polymerization Crosslinked Polyurethane Shape-Memory Polymers.
Journal Article (Journal Article)
Novel urethane shape-memory polymers (SMPs) of significant industrial relevance have been synthesized and characterized. Chemically crosslinked SMPs have traditionally been made in a one-step polymerization of monomers and crosslinking agents. However, these new post-polymerization crosslinked SMPs can be processed into complex shapes by thermoplastic manufacturing methods and later crosslinked by heat exposure or by electron beam irradiation. Several series of linear, olefinic urethane polymers were made from 2-butene-1,4-diol, other saturated diols, and various aliphatic diisocyanates. These thermoplastics were melt-processed into desired geometries and thermally crosslinked at 200°C or radiation crosslinked at 50 kGy. The SMPs were characterized by solvent swelling and extraction, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), tensile testing, and qualitative shape-recovery analysis. Swelling and DMA results provided concrete evidence of chemical crosslinking, and further characterization revealed that the urethanes had outstanding mechanical properties. Key properties include tailorable transitions between 25 and 80°C, tailorable rubbery moduli between 0.2 and 4.2 MPa, recoverable strains approaching 100%, failure strains of over 500% at T(g), and qualitative shape-recovery times of less than 12 seconds at body temperature (37°C). Because of its outstanding thermo-mechanical properties, one polyurethane was selected for implementation in the design of a complex medical device. These post-polymerization crosslinked urethane SMPs are an industrially relevant class of highly processable shape-memory materials.
Full Text
Duke Authors
Cited Authors
- Hearon, K; Gall, K; Ware, T; Maitland, DJ; Bearinger, JP; Wilson, TS
Published Date
- July 2011
Published In
Volume / Issue
- 121 / 1
Start / End Page
- 144 - 153
PubMed ID
- 21572577
Pubmed Central ID
- PMC3092441
Electronic International Standard Serial Number (EISSN)
- 1097-4628
International Standard Serial Number (ISSN)
- 0021-8995
Digital Object Identifier (DOI)
- 10.1002/app.33428
Language
- eng