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Cross‐linked Poly(Octadecyl Acrylate)/Polybutadiene Shape Memory Polymer Blends Prepared by Simultaneous Free Radical Cross‐linking, Grafting and Polymerization of Octadecyl Acrylate/Polybutadiene Blends
Author(s) -
Du Haiyan,
Marin Angel Juan,
Basak Sayan,
Lai TzuYu,
Cavicchi Kevin A.
Publication year - 2021
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.202100072
Subject(s) - polybutadiene , materials science , acrylate , elastomer , crystallinity , polymer chemistry , polymer , polymerization , monomer , thermoplastic elastomer , radical polymerization , grafting , composite material , copolymer
A semi‐crystalline, shape memory polymer (SMP) is fabricated by free radical cross‐linking, polymerization, and grafting in a blend of n‐ octadecyl acrylate and polybutadiene (PB). Poly( n‐ octadecyl acrylate) (PODA) is a side‐chain crystalline polymer, which serves as the structure‐fixing network counterbalancing the elastically deformed, cross‐linked polymer network. At a constant 50/50 ratio of monomer and polymer the amount of free radical initiator, dicumyl peroxide (DCP) is varied from 1% to 5% w/w PB. From swelling measurements and calculation of the cross‐link density it is determined that DCP produces greater than one cross‐link per DCP molecule. It is found that lower cross‐linking efficiency is favorable for higher shape fixity. This lower efficiency is found to produce a higher degree of crystallinity of the PODA in the 2–5% DCP samples, which is determined to be the main driver of higher shape fixity of the polymer. A SMP with >90% fixity and 100% recovery at uniaxial strains from 34–79% is achieved. This material should be useful for mold processing of shape memory articles. This approach provides a method to decouple the elastomeric and thermoplastic portions of a SMP to convert commodity elastomers into SMPs and tailor the shape memory response.