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Stretching induced phase transformations in melt extruded poly(vinylidene fluoride) cast films: Effect of cast roll temperature and speed

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Title Stretching induced phase transformations in melt extruded poly(vinylidene fluoride) cast films: Effect of cast roll temperature and speed
 
Creator MHALGI, MV
KHAKHAR, DV
MISRA, A
 
Subject processing property interactions
polyvinylidene fluoride
crystalline phase
light-scattering
pvdf films
polymers
behavior
spectroscopy
morphology
history
 
Description Melt extruded poly(vinylidene fluoride) cast films were prepared at different cast roll temperatures and speeds to study the effect of casting temperature and preorientation of the melt on the alpha- to beta-phase transformation in these films after uniaxial stretching. X-ray and fourier transform infrared spectroscopy were used to identify the crystalline phases. The unstretched films were characterized using small angle light scattering (SALS). The films were stretched to a stretch ratio of 4.2 and at 80 degrees C. Birefringence of the films and the fraction of beta-phase [F(beta)] formed after uniaxial stretching increased with stretch ratio. The films showed increased crystallinity after stretching. For the films prepared at different cast roll temperatures, there was little change in F(beta) in the films having a cast roll temperature between 75 and 120 degrees C, but for the film with a cast roll temperature of 130 degrees C F(beta) decreased considerably. For the films prepared at different cast roll speeds, the F(beta) increased with stretch ratio as well as with cast roll speed for a fixed stretch ratio. The primary effect of changing both the parameters is a change in the average spherulitic radius (R), in the unstretched films measured using SALS. The F(beta) obtained correlated well with R and lower spherulitic radii resulted in the higher conversion to the beta-phase. POLYM. ENG. SCI., 47:1992-2004, 2007. (C) 2007 Society of Plastics Engineers.
 
Publisher JOHN WILEY & SONS INC
 
Date 2011-08-16T14:52:04Z
2011-12-26T12:54:59Z
2011-12-27T05:43:28Z
2011-08-16T14:52:04Z
2011-12-26T12:54:59Z
2011-12-27T05:43:28Z
2007
 
Type Article
 
Identifier POLYMER ENGINEERING AND SCIENCE, 47(12), 1992-2004
0032-3888
http://dx.doi.org/10.1002/pen.20885
http://dspace.library.iitb.ac.in/xmlui/handle/10054/9533
http://hdl.handle.net/10054/9533
 
Language en