Processing, Structure and Properties of PVDF Films · · 2009-02-04Processing, Structure and...
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RSS 2009, Dept. of Chemical Engg, IIT Bombay Processing, Structure and Properties of PVDF Films Vijayakumar R.P 1 , Devang V. Khakhar 1 * and Ashok Misra 2 1 Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India 2 Intellectual Ventures, No.701, Raheja Paramount, 138, Residency road, Bangalore – 560 025, India [email protected] Abstract The β crystal phase of PVDF has good piezoelectric and pyroelectric properties because of its dipolar conformation. PVDF cast films were drawn at different temperatures to different draw ratios using a constant draw rate for understanding the mechanism of α to β phase transformation during mechanical deformation. WAXD and FTIR studies were carried out to determine the formation and content of β phase in the drawn films. It was found that lower stretch temperatures gave higher fraction of β phase. The cast PVDF films were also drawn at suitable temperature below the PVDF ambient melting point to a draw ratio of 6.4. The highest fraction of β phase obtained in these ultra drawn films was 0.98. SALS studies carried out for films at different stretch ratios show the change in spherulitic structure with the stretching parameters and gave information for the understanding of phase transformation during stretching of PVDF films. It is reported that the addition of nanoclay results in the formation of the β phase. We have carried out a study of the effect of onium salts on the formation of the β phase during crystallization from a melt. Benzyl triphenyl phosphonium chloride as well as Tetrabutyl ammonium perchlorate was mixed in PVDF using a micro compounder. WAXD and FTIR studies were carried to determine the formation of β phase in compression molded films. In the present work it is observed that by the addition of ca 0.5 wt % of onium salts directly induces β phase in the compression molded PVDF films. TGA studies show that the onset of decomposition temperature is higher than the PVDF processing temperature. Keywords: PVDF, Phase transformation, FTIR, SALS and TGA. 6 Oral Presentations
Transcript of Processing, Structure and Properties of PVDF Films · · 2009-02-04Processing, Structure and...
RSS 2009, Dept. of Chemical Engg, IIT Bombay
Processing, Structure and Properties of PVDF Films
Vijayakumar R.P1, Devang V.
Khakhar1* and Ashok Misra2
1Department of Chemical Engineering,
Indian Institute of Technology Bombay,
Powai, Mumbai 400 076, India 2Intellectual Ventures, No.701, Raheja
Paramount, 138, Residency road,
Bangalore – 560 025, India
Abstract
The β crystal phase of PVDF has good piezoelectric and pyroelectric properties because of its dipolar conformation. PVDF cast films were drawn at different temperatures to different draw ratios using a constant draw rate for understanding the mechanism of α to β phase transformation during mechanical deformation. WAXD and FTIR studies were carried out to determine the formation and content of β phase in the drawn films. It was found that lower stretch temperatures gave higher fraction of β phase. The cast PVDF films were also drawn at suitable temperature below the PVDF ambient melting point to a draw ratio of 6.4. The highest fraction of β phase obtained in these ultra drawn films was 0.98. SALS studies carried out for films at different stretch ratios show the change in spherulitic structure with the stretching parameters and gave information for the understanding of phase transformation during stretching of PVDF films.
It is reported that the addition of nanoclay results in the formation of the β phase. We have carried out a study of the effect of onium salts on the formation of the β phase during crystallization from a melt. Benzyl triphenyl phosphonium chloride as well as Tetrabutyl ammonium perchlorate was mixed in PVDF using a micro compounder. WAXD and FTIR studies were carried to determine the formation of β phase in compression molded films. In the present work it is observed that by the addition of ca 0.5 wt % of onium salts directly induces β phase in the compression molded PVDF films. TGA studies show that the onset of decomposition temperature is higher than the PVDF processing temperature. Keywords: PVDF, Phase transformation, FTIR, SALS and TGA.
6 Oral Presentations
