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Hassan Ismaiel Sawalha (Manasra)
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Polylactide films formed by immersion precipitation: Effects of additives, nonsolvent, and temperature
Thu, 2013-02-14 14:34 —
Hassan Ismaiel Sawalha (Manasra)
Journal Title, Volume, Page:
Journal of applied polymer science, 104(2): p. 959-971.
Year of Publication:
2007
Link:
http://onlinelibrary.wiley.com/doi/10.1002/app.25808/full
Authors:
Hassan Sawalha
Food and Bioprocess Engineering Group, Wageningen University, Wageningen, The Netherlands Publication History
Current Affiliation:
Chemical Engineering Department, An-Najah National University, Nablus, Palestine
[email protected]
Karin Schroën
Food and Bioprocess Engineering Group, Wageningen University, Wageningen, The Netherlands Publication History
Remko Boom
Food and Bioprocess Engineering Group, Wageningen University, Wageningen, The Netherlands Publication History
Preferred Abstract (Original):
The influence of nonsolvent, crystallinity of the polymer film, and addition of dodecane (a poor solvent for the polymer and for the nonsolvent) on the morphology of polylactides films has been investigated and was related to phase separation behavior. Both amorphous poly-DL-lactide (PDLLA) and crystalline poly-L-lactide (PLLA) were dissolved in dichloromethane, and subsequently films were made by immersion in nonsolvent baths. PDLLA gave dense films without any internal structure, since the structure was not solidified by crystallization or glassification. PLLA films show varying structure depending on the nonsolvent. With methanol, asymmetric morphologies were observed as a result from combined liquid-liquid demixing and crystallization, while with water symmetric spherulitic structures were formed. As a next step, dodecane was added, which is not miscible with the nonsolvent, and we found it to have a strong influence on the morphology of the films. The PDLLA films with dodecane did not collapse: a closed cell structure was obtained. In PLLA films, dodecane speeds up phase separation and induces faster crystallization in the films, and the porosity, size of the pores, and interconnectivity increased. When the PLLA solutions were subjected to a heat pretreatment, crystallization could be postponed, which yielded a cellular structure around dodecane, which did not contain spherulites anymore. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 959–971, 2007
(quaternary) phase diagram
immiscible additives
morphology
phase separation
Polylactide
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