Determination of pre-gelation and post-gelation activation energies during free radical crosslinking copolymerization

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Küçük Resim

Tarih

2005

Dergi Başlığı

Dergi ISSN

Cilt Başlığı

Yayıncı

Taylor & Francis Ltd

Erişim Hakkı

info:eu-repo/semantics/closedAccess

Araştırma projeleri

Organizasyon Birimleri

Dergi sayısı

Özet

Steady-state fluorescence (SSF) and dilatoraetric techniques were used to study the free-radical crosslinking copolymerization (FCC) of styrene (S) and divinylbenzene (DVB) in bulk. The gel points (t g) were recorded by dilatometry at various DVB contents and temperatures in pre-gelation regime during FCC process. Pyrene (Py) was used as a fluorescence probe for the in situ polymerization experiments. The time required for a sudden increase in the fluorescence intensity of Py was recorded for the samples at various DVB contents and temperatures. Py fluorescence intensity during FCC exhibits a sudden increase corresponding to the reaction time at which the rate of polymerization becomes maximum due to the gel effect in post-gelation regime. The onset of gel effect point (t ge) was determined for various DVB contents and temperatures. The results show that alhough the dilatometric technique recorded the gel point, the fluorescence technique can be used to monitor the onset of the gel effect during S–DVB copolymerization. Pre-gelation and post-gelation actuation energies. ?E pre and ?E post were measured and it is observed that pre-gelation regime needs smaller energies than post-gelation regime during FCC.

Açıklama

Anahtar Kelimeler

Activation energy, Free-radical crosslinking copolymerization, Gel effect, Gel point, Steady-state fluorescence, Fast transient fluorescence, Methyl-methacrylate, High conversions, Polymerization, Styrene, Temperatures

Kaynak

Composite Interfaces

WoS Q Değeri

Q3

Scopus Q Değeri

Q2

Cilt

12

Sayı

5

Künye

Kaya Aktaş, D. & Pekcan, M. Ö. (2005). Determination of pre-gelation and post-gelation activation energies during free radical crosslinking copolymerization. Composite Interfaces, 12(5), 395-410. doi:10.1163/1568554054275742