Thermal properties and enthalpy relaxation of tyrosine-derived polyarylates

Varawut Tangpasuthadol, Adi Shefer, Chun Yu, Jing Zhou, Joachim Kohn

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

Sixteen degradable, tyrosine-derived polyarylates with well-defined chemical structures were used to study the effect of polymer structure on the glass transition temperature and enthalpy relaxation kinetics (physical aging). These polyarylates compose a model system where the number of methylene groups present in either the pendent chain or the polymer backbone can be altered independently and in a systematic fashion. Quantitative differential scanning calorimetry was employed to measure the glass transition temperature and the enthalpy relaxation kinetics. Correlations between these material properties and the polymer structure were established. The glass transition temperature of this family of polymers ranged from 13 to 78°C. The addition of methylene groups to either the pendent chain or the polymer backbone made a fairly constant contribution to lowering the glass transition temperature. The rate of enthalpy relaxation increased with an increasing number of methylene groups in the polymer backbone, but was independent of the number of methylene groups in the pendent chain. This observation indicated that the rate of enthalpy relaxation in these polymers was limited by the mobility of the polymer backbone. The enthalpy relaxation data was fitted to the Cowie-Ferguson model and the relaxation times obtained ranged from 44 min to about 100 min. Although these structure-property correlations facilitate the design of new materials with predictable thermal properties, they are rarely investigated for biomedical polymers.

Original languageEnglish (US)
Pages (from-to)1441-1448
Number of pages8
JournalJournal of Applied Polymer Science
Volume63
Issue number11
DOIs
StatePublished - Mar 14 1997

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Surfaces, Coatings and Films
  • Polymers and Plastics
  • Materials Chemistry

Keywords

  • Biomaterial
  • Biopolymer
  • Differential scanning calorimetry
  • Enthalpy relaxation
  • Glass transition temperature
  • Physical aging
  • Structure-property correlation
  • Tyrosine

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