Molecular alignment during gel formation from methyl methacrylate: An excimer fluorescence study
Yükleniyor...
Dosyalar
Tarih
2005-05
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Taylor & Francis Ltd
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
Glass transition during bulk polymerization was studied in free-radical cross-linking copolymerization (FCC) of methyl methacrylate (MMA) using the steady-state fluorescence (SSF) technique. Naphthalene (N) was used as a monomer and excimer forming probe. Changes in the viscosity of the pregel solutions due to gel formation dramatically enhance both monomer and excimer fluorescent yield of N molecules. The reaction time at which the monomer and excimer intensities exhibit a sudden increase corresponds to the reaction time at which the rate of polymerization becomes maximum resulting from the gel effect. This effect was used to study the gelation of MMA, as a function of time, in various N concentrations. The results were interpreted in the view of percolation theory. The gel fraction, beta, and weight average degree of polymerization, gamma, exponents beta=0.40 +/- 0.02 and gamma=1.70 +/- 0.07 were found in agreement with percolation results for both monomer and excimer measurements, respectively.
Açıklama
Anahtar Kelimeler
Free-radical polymerization, Glass-transition, Rate constants, Bulk, Copolymerization, Liquids, Probe, Excimer lasers, Fluorescence, Free radical polymerization, Gels, Glass transition, Molecular orientation, Naphthalene, Gelation
Kaynak
Phase Transitions
WoS Q Değeri
Q3
Scopus Q Değeri
Q3
Cilt
78
Sayı
5
Künye
Kaya Aktaş, D., Erdoğan, M. & Pekcan, M. Ö. (2005). Molecular alignment during gel formation from methyl methacrylate: An excimer fluorescence study. Phase Transitions, 78(5), 387-400. doi:10.1080/01411590500114799
