Critical extent of reaction of a polydimethylsiloxane polymer network

Sundar K. Venkataraman, Larry Coyne, Francois Chambon, Moshe Gottlieb, H. Henning Winter

Research output: Contribution to journalArticlepeer-review

41 Scopus citations


A direct rheological technique was used to measure the critical time for gelation, tc, of a well characterized polydimethylsiloxane (PDMS) polymer network. This technique is based on the observation that the gel point of crosslinking systems occurs at the instant at which the viscoelastic behaviour reduces to power-law relaxation (critical state described by the gel equation). The extent of reaction, p(t), was measured by a Fourier-transform infra-red method. The measured value of the critical extent of reaction, pc = p(tc) = 0.57 ± 0.01, agrees extremely well with the value predicted by mean-field theory. This agreement is an independent confirmation of the observation that power-law relaxation is a property of the polymer at the gel point.

Original languageEnglish
Pages (from-to)2222-2226
Number of pages5
Issue number12
StatePublished - 1 Jan 1989
Externally publishedYes


  • crosslinking polymer
  • gel equation
  • gel point
  • polydimethyl siloxane

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics
  • Materials Chemistry


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