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Challenge to fortyfold expansion of biodegradable polyester foams by using carbon dioxide as a blowing agent
Author(s) -
Park Chul B.,
Liu Yuejian,
Naguib Hani E.
Publication year - 2000
Publication title -
journal of vinyl and additive technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.295
H-Index - 35
eISSN - 1548-0585
pISSN - 1083-5601
DOI - 10.1002/vnl.10221
Subject(s) - blowing agent , materials science , polyester , supercritical carbon dioxide , expansion ratio , volume (thermodynamics) , composite material , carbon dioxide , biodegradable polymer , extrusion , chemical engineering , polymer , organic chemistry , chemistry , thermodynamics , polyurethane , physics , engineering
This paper presents a new foaming technology using supercritical carbon dioxide as a blowing agent to obtain large volume expansions of biodegradable polyester foams of over fortyfold. The basic approach for the promotion of a large volume expansion ratio with carbon dioxide was to prevent cell coalescence by using a branched material, to dissolve carbon dioxide completely in the melt by promoting convective diffusion under a high processing pressure, to reduce the diffusivity of gas by lowering the melt temperature, and to optimize the processing conditions in the die to maximize volume expansion. The desirable composition of the materials includes dehydrated branched biodegradable polyester (polybutylene succinate), CO 2 (blowing agent), and tale (nucleating agent). A single‐screw extrusion system was used for foam processing. A large volume expansion ratio of up to forty‐fivefold was achieved from the biodegradable polyester foams. The morphologies and volume expansion ratios of biodegradable polyester foams at various processing temperatures and pressures were studied.