Observation of critical opalescence in free radical crosslinking copolymerization of styrene and divinylbenzene by fluorescence method

PEKCAN O., Kaya D., Okay O.

EUROPEAN POLYMER JOURNAL, cilt.35, sa.11, ss.2025-2029, 1999 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 35 Sayı: 11
  • Basım Tarihi: 1999
  • Doi Numarası: 10.1016/s0014-3057(99)00007-5
  • Dergi Adı: EUROPEAN POLYMER JOURNAL
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.2025-2029
  • İstanbul Teknik Üniversitesi Adresli: Evet

Özet

In situ fluorescence technique was used to study the free-radical crosslinking copolymerization of styrene and divinylbenzene in bulk. Pyrene (Py) was used as a fluorescence probe for the real time gelation experiments. The critical times, t(r) required for a dramatic increase in Py intensity, I-p, corresponding to the onset of the gel effect were determined. The spikes in I,curves were also observed at high crosslinker densities. These spikes were attributed to the existence of "critical opalescence" during the gel formation process where two different gel phases having two different concentrations coexist. to values at which the critical opalescence is occurred are recorded in the close vicinity of the t(r) points. (C) 1999 Elsevier Science Ltd. All rights reserved.