Crystallization kinetics and morphology of poly(lactic acid) with polysaccharide as nucleating agent
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An ever-increasing concern about environmental pollution has spearheaded research into alternative biodegradable polymers. Currently, poly(lactic acid) (PLA) is one of the most notable biodegradable polymers due to its superior properties and low production cost. Nucleating agents have been used to overcome slow PLA crystallization. The present work aims at investigating cashew gum (CG) as nucleating agent in PLA produced by casting process. The effect of the CG (1–10 mass%) on the PLA crystallization process was evaluated by thermal analysis and hot-stage optical microscopy. The relative degree of crystallinity, crystallization kinetic parameters under isothermal conditions, and crystallite morphology of pure PLA and PLACG samples were also investigated. The PLA crystallization rate increased with the CG content at a temperature ranging from 130 °C to 140 °C. An increase in the degree of crystallinity and a reduction in the crystallite size of the PLA were observed in the samples which contained 5 and 10 mass% of CG. Cashew gum proved to be an effective nucleating agent for PLA. Results show that cashew gum can be used as a natural nucleating agent for PLA when faster crystallization rate, better crystallite size control or higher degree of crystallinity are required.
KeywordsPoly(lactic acid) Cashew gum Nucleating agent Crystallization rate DSC
The authors gratefully acknowledge the financial support from the Brazilian National Council for Scientific and Technological Development (CNPq) and the Brazilian Agricultural Research Corporation (EMBRAPA) for supplying the cashew gum.
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