Thermal degradation kinetics of thermoresponsive poly(N-isopropylacrylamide-co-N,N-dimethylacrylamide) copolymers prepared via RAFT polymerization

Bauri, Kamal and Roy, Saswati Ghosh and Arora, Simran and Dey, Rajib Kumar and Goswami, Ankur and Madras, Giridhar and De, Priyadarsi (2013) Thermal degradation kinetics of thermoresponsive poly(N-isopropylacrylamide-co-N,N-dimethylacrylamide) copolymers prepared via RAFT polymerization. In: JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY, 111 (1). pp. 753-761.

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Abstract

Reversible addition-fragmentation chain transfer polymerization at 70 A degrees C in N,N-dimethylformamide was used to prepare poly(N-isopropylacrylamide-co-N,N-dimethylacrylamide) copolymers in various compositions to afford well-defined polymers with pre-determined molecular weight, narrow molecular weight distribution, and precise chain end structure. The copolymer compositions were determined by H-1 NMR spectroscopy. The reactivity ratios of N-isopropylacrylamide (NIPAM) and N,N-dimethylacrylamide (DMA) were calculated as r (NIPAM) = 0.838 and r (DMA) = 1.105, respectively, by the extended Kelen-Tudos method at high conversions. The lower critical solution temperature of PNIPAM can be altered by changing the DMA content in the copolymer chain. Differential scanning calorimetry and thermogravimetric analysis at different heating rates were carried out on these copolymers to understand the nature of thermal degradation and to determine its kinetics. Different kinetic models were applied to estimate various parameters like the activation energy, the order, and the frequency factor. These studies are important to understand the solid state polymer degradation of N-alkyl substituted polymers, which show great potential in the preparation of miscible polymer blends due to their ability to interact through hydrogen bonding.

Item Type:	Journal Article
Publication:	JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
Publisher:	SPRINGER
Additional Information:	Copyright for this article belongs to SPRINGER, NETHERLANDS
Keywords:	Copolymerization;Reactivity ratio;Lower critical solution temperature;Activation energy of degradation
Department/Centre:	Division of Mechanical Sciences > Chemical Engineering
Date Deposited:	18 Feb 2013 08:56
Last Modified:	18 Feb 2013 08:56
URI:	http://eprints.iisc.ac.in/id/eprint/45776

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