Investigation of Thermal Degradation Kinetics of Pyrazabole Centered Two- Armed Poly(methyl methacrylate)
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Tarih
2016
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info:eu-repo/semantics/openAccess
Özet
Abstract: Atom transfer radikal polimerizasyon (ATRP) metoduyla 2,6-dibromo pirazabol başlatıcısı varlığında CuBr/2,2'-bipiridin katalizör sistemi ile katalizlenen metil metakrilatın 100 oC'de farklı sürelerde sonlandırılan bir seri iki kollu polimeri (PMMA) sentezlendi. Polimerlerin ortalama molekül ağırlıkları ve molekül ağırlık dağılımları GPC tekniği ile belirlenerek polimerizasyon kinetiği araştırıldı. 240 dakikalık sürede polimerleştirilen iki kollu PMMA'ın termal davranışı detaylıca test edildi. TGA metodu kullanılarak 5, 10, 15, 20 ve 25 oC/dak ısıtma hızlarında termal bozunma kinetiği araştırıldı. TGA sonuçlarından, ısıtma hızı ile polimerin termal kararlılığı arasında doğrusal bir ilişki tespit edildi. Polimerin termal bozunma aktivasyon enerjisi FlynnWall-Ozawa ve Kissinger metotlarından sırasıyla 120,98 kJ/mol ve 112,53 kJ/mol olarak hesaplandı. Polimerin termal bozunma mekanizmasını belirlemek amacıyla Coats-Redfern, Tang ve Madhusudanan gibi kinetik metotlar kullanıldı. Elde edilen kinetik veriler ışığında pirazabol merkezli iki kollu PMMA'ın termal bozunma mekanizmasının D2 tipi yavaşlama mekanizması üzerinden 5 °C/dak optimum ısıtma hızında ilerlediği gözlemlendi
Abstract: A series of two armed polymers of methyl methacrylate (PMMA) was synthesized by atom transfer radical polymerization (ATRP) method using 2,6dibromopyrazabole as initiator and CuBr/2,2’-bipyridine as catalyst system at 100 °C ended different times. Average number molecular weights and molecular weight distributions of polymer series were recorded with GPC technique and thus, polymerization kinetic was determined. Thermal behavior of two-armed PMMA polymerized at 240 minutes was investigated detailed by TGA method at the heating rates of 5, 10, 15, 20 and 25 oC/min. From TGA results, a linear correlation was determined between the heating rate and the thermal stability of the polymer. Decomposition activation energies of polymer were found to be 120,98 kJ/mol and 112,53 kJ/mol by the Flynn-Wall-Ozawa and Kissinger methods, respectively. Some kinetic methods such as Coats-Redfern, Tang and Madhusudanan were used to investigate the thermal degradation mechanisms of polymer. In the light of obtained kinetic data, it was observed that the thermal decomposition mechanism of the pyrazabole centered two-armed PMMA was followed by D2 type deceleration mechanism at 5 °C/min optimum heating rate
Abstract: A series of two armed polymers of methyl methacrylate (PMMA) was synthesized by atom transfer radical polymerization (ATRP) method using 2,6dibromopyrazabole as initiator and CuBr/2,2’-bipyridine as catalyst system at 100 °C ended different times. Average number molecular weights and molecular weight distributions of polymer series were recorded with GPC technique and thus, polymerization kinetic was determined. Thermal behavior of two-armed PMMA polymerized at 240 minutes was investigated detailed by TGA method at the heating rates of 5, 10, 15, 20 and 25 oC/min. From TGA results, a linear correlation was determined between the heating rate and the thermal stability of the polymer. Decomposition activation energies of polymer were found to be 120,98 kJ/mol and 112,53 kJ/mol by the Flynn-Wall-Ozawa and Kissinger methods, respectively. Some kinetic methods such as Coats-Redfern, Tang and Madhusudanan were used to investigate the thermal degradation mechanisms of polymer. In the light of obtained kinetic data, it was observed that the thermal decomposition mechanism of the pyrazabole centered two-armed PMMA was followed by D2 type deceleration mechanism at 5 °C/min optimum heating rate
Açıklama
Anahtar Kelimeler
Kaynak
Adıyaman Üniversitesi Fen Bilimleri Dergisi
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Scopus Q Değeri
Cilt
6
Sayı
2
Künye
AYAZ H,GÜLTEK A,KURT A (2016). Investigation of Thermal Degradation Kinetics of Pyrazabole Centered Two- Armed Poly(methyl methacrylate). Adıyaman Üniversitesi Fen Bilimleri Dergisi, 6(2), 233 - 251.