scholarly journals Dielectric relaxation study of the crystalline chain motion of poly(vinylidene fluoride) under carbon dioxide

2010 ◽  
Vol 42 (5) ◽  
pp. 419-422 ◽  
Author(s):  
Yoshiko Yamamura ◽  
Kazuo Yoshida ◽  
Kiyu Kawate ◽  
Noboru Osaka ◽  
Hiromu Saito
Keyword(s):  
Carbon Dioxide ◽  
Dielectric Relaxation ◽  
Vinylidene Fluoride ◽  
Relaxation Study ◽  
Poly Vinylidene Fluoride

Microcellular Polymeric Foams (MPFs) Generated Continuously in Supercritical Carbon Dioxide

2000 ◽  
Vol 629 ◽  
Author(s):  
Srinivas Siripurapu ◽  
Yvon J. Gay ◽  
Joseph R. Royer ◽  
Joseph M. DeSimone ◽  
Saad A. Khan ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Vinylidene Fluoride ◽  
Amorphous Polymer ◽  
Extrusion Process ◽  
Operating Conditions ◽  
Polymeric Foams ◽  
Poly Vinylidene Fluoride ◽  
Cell Densities ◽  
Supercritical Carbon

ABSTRACTMicrocellular polymeric foams (MPFs) hold tremendous promise for engineering applications as substitutes to their solid analogs in light of reduced manufacturing/materials costs and improved properties. We present a two-part study addressing the generation of such materials in the presence of supercritical carbon dioxide (scCO2). The first part describes the production of polystyrene MPFs in a continuous extrusion process, as well as the effect of operating conditions such as temperature and CO2 concentration on foam morphology. The second part discusses microcellular foaming of poly (vinylidene fluoride) (PVDF), a semicrystalline polymer, via blending with the amorphous polymer poly (methyl methacrylate) PMMA. Foams of pure PVDF possess ill-defined morphologies, whereas those of PVDF-PMMA blends show an improvement with cell sizes on the order of 10 mm or less and cell densities in excess of 109 cells/cm3.

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