Effect of crystallinity on microcellular foaming in crystalline polymer
Hisao KOIKE, Toshio IMAUCHI
ASAHIKASEI CORPORATION
JAPAN

Keywords: microcellular-foam, crystalline morphology, bubble nucleation

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In microcellular technology it is very important to control the bubble nucleation density. In this work we invesitigated the
mechanism of bubble nucleation in microcellular batch processing using Polyvinylidenefluoride -hexafluoroplopylene
(PVDF-HFP) copolymer.

We prepared the film of PVDF-HFP copolymer by extrusion casting process with various casting temperature, and produced
the microcellular foams using HFC-134a as a blowing agent. We observed the significant change of bubble nucleation density
by the difference of casting temperature of the film. We found that the density of spherite of the film effect to the bubble nucleation
density by the measurement of crystalline morphology of the film using laser scattering method and differential scanning
calorimetry(DSC).

We also observed that the bubble nucleation density increased by adding H20 to HFC-134a as a blowing agent.