Solubility and degradation of polyhydroxyalkanoate biopolymers in propylene carbonate

• Published in: AIChE journal Vol. 56; no. 6; pp. 1616 - 1625
• Main Authors: McChalicher, Christopher W.J, Srienc, Friedrich, Rouse, Daniel P
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.06.2010; Wiley; American Institute of Chemical Engineers
• Subjects: Applied sciences; Biomass; Biopolymers; Block copolymers; Chemical engineering; Crystal structure; Degradation; degradation biopolymers; Dissolution; Exact sciences and technology; Extraction; PHAs; polymer processing; Polymer solubility; propylene carbonate; Solubility; Solvents; propylene carbonate; Extraction process; Solubility; Extract; degradation; Biomass; extraction; Dissolution; Petroleum; Gel permeation chromatography; PHAs; polymer processing; degradation biopolymers; Kinetics
• ISSN: 0001-1541; 1547-5905
• DOI: 10.1002/aic.12087

New biobased materials and chemicals require different processing strategies than petroleum-derived commodities. The extraction and recovery of polyhydroxyalkanoate (PHA) biopolymers from the residual cellular biomass is particularly difficult because the polymer is accumulated within the cell. PHAs have low solubility in many classical polymer solvents and are most often dissolved using undesirable chlorinated solvents. The solubility kinetics is greatly diminished when these polymers are highly crystalline. Here, 1,2-propylene carbonate is used to dissolve highly crystalline polyhydroxybutyrate at ambient pressures and moderate temperatures. We have used kinetic studies of the dissolution of the crystalline material to determine the energy barrier for dissolution of the system. Further, the degradation of polyhydroxybutyrate and similarly prepared PHA block copolymers were studied during this extraction process using molecular weight characterization by gel permeation chromatography. Finally, we have used these findings to extract PHA block copolymers from dried biomass at the bench scale. © 2009 American Institute of Chemical Engineers AIChE J, 2010