Microscale thermomechanical characterization of environmentally conditioned shape memory polymers

Y. C. Lu, J. T. Fulcher, G. P. Tandon, D. C. Foster, J. W. Baur

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

Shape memory polymers (SMPs) are an emerging class of active polymers that have dual-shape capability and are, therefore, candidate materials for reconfigurable structures. However, the durability of SMPs has not been fully investigated to ensure they function properly in relevant environments. In this study, epoxy-based SMPs were conditioned separately in simulated service environments designed to be reflective of anticipated performance requirements, namely, (1) exposure to UV radiation for 125 cycles, (2) immersion in lube oil at ambient temperature, (3) immersion in water at 49 °C. A novel high-temperature indentation method was used to evaluate the shape recovery ability and mechanical properties of the conditioned SMPs. Results show that environmentally conditioned SMPs generally exhibit decreased glass transition temperatures and higher moduli and strain rate sensitivities in comparison to an unconditioned one. Environmental conditioning affects the shape recovery abilities of the SMPs if the recovery temperatures are set low. In particular, the UV exposed and water immersed SMPs exhibit noticeable lower shape recovery ratios compared to the unconditioned material. When the recovery temperature is above Tg, the material's ability to regain shape remains relatively unchanged with conditioning.

Original languageEnglish
Pages (from-to)563-570
Number of pages8
JournalPolymer Testing
Volume30
Issue number5
DOIs
StatePublished - Aug 2011

Bibliographical note

Funding Information:
This work was supported by the grants made by the NASA EPSCoR Research Infrastructure Development Program (RID), the Kentucky Space Grant Consortium (KSGC), and the Universal Technology Co .

Keywords

  • Durability
  • Environmental conditioning
  • High temperature nanoindentation
  • Shape memory polymer

ASJC Scopus subject areas

  • Polymers and Plastics
  • Organic Chemistry

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