Impact of Processing Temperature and Composition on Foaming of Biodegradable Poly(hydroxyalkanoate) Blends

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• 作者：Amy Tsui ; Curtis W. Frank
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2014
• 出版时间：October 15, 2014
• 年：2014
• 卷：53
• 期：41
• 页码：15896-15908
• 全文大小：673K
• ISSN：1520-5045

文摘

Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) was melt-foamed using a single screw extrusion process and found to be susceptible to cell coalescence at the higher processing temperatures used for achieving low bulk density. The addition of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) allowed for the generation of a range of crystallization temperatures much broader than can be achieved through small molecular crystal nucleation agents. This broader range can induce solidification to occur earlier during cooling and so can be used to minimize cell coalescence. Several PHBHHx/PHBV blend compositions were produced and characterized; initial understanding of the crystallinity and impact of blending miscible crystallizable polymers was gained through thermal analysis. PHBHHx and PHBV appeared to be fully miscible across all compositions used in this study. The impacts of blend composition and extruder temperature profile on foam properties were investigated. It was found that just 2% PHBV consistently led to 30% improvement in cell density over pure PHBHHx when the highest extruder zone temperature was 170 掳C. As a result, PHBHHx/PHBV was able to achieve greater than twofold expansion with reduced cell coalescence, which has not been previously achievable by PHBV with the same blowing agent.