Dynamic mechanical analysis of amorphous-phase organization in acrylic polymers

M. T. Jeppesen, Henry R Rawls

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Factors affecting polymer network organization were studied in highly crosslinked acrylics of the type used in dental adhesive resins. The variables tested were comonomer content and processing conditions. Bis EMA (2,2,-bis[4-(2-methacryloyloxyethoxy)-phenyl]propane) and Bis EMA + TEGDMA (triethyleneglycol dimethacrylate) were cured with and without 25% comonomer. Comanomers had characteristics that are expected to influence intrachain organization in amorphous phases: TEGDMA, crosslinking; methyl methacrylate (MMA), monomer conversion; isobornyl methacrylate (IBM), low cure shrinkage; tetrahydrofurfuryl methacrylate (THFM), antiplasticization. Dynamic mechanical analysis temperature scans were run at 0.1 Hz 2h or 24h after ambient cure, or 24h postcure after heating at 75° or 125°C. After 24h, tan δ maxima occurred in ranges centering on approximately -30°, 75° and 150°C (Tg). Heating at 125°C nearly eliminated all peaks except Tg, reduced tan 8 peaks and increased Tg by 0-14°. Tg increased in the order: TEGDMA> 1250 C>IBM>MMA>75°C>2h>24h>THFM. The ability to crosslink, and postcure heating at 125°C, were the more important factors found to increase intrachain organization in amine-promoted, unfilled BisEMA resins of the type used in dental sealants, luting cements and bulk-filling resin composite materials.

Original languageEnglish (US)
Pages (from-to)191-199
Number of pages9
JournalThe Journal of Adhesion
Volume47
Issue number1-3
DOIs
StatePublished - Sep 1 1994

Keywords

  • acrylics
  • adhesion
  • crosslinking
  • dynamic mechanical analysis
  • glass transition
  • heat
  • interphase
  • intrachain organization
  • polymer
  • treatment

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Chemistry
  • Mechanics of Materials
  • Surfaces, Coatings and Films
  • Surfaces and Interfaces

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