Size exclusion chromatography characterization of thermoplastic starch composites 1. Influence of plasticizer and fibre content

• Published in: Polymer degradation and stability 2003, Vol.79 (1), p.133-138
• Main Authors: Carvalho, A.J.F., Zambon, M.D., Curvelo, A.A.S., Gandini, A.
• Format: Article
• Language: English
• Subjects: Applied sciences; Biodegradable materials; Composites; Degradation; Exact sciences and technology; Forms of application and semi-finished materials; Polymer industry, paints, wood; Pulp; Size exclusion chromatography; Technology of polymers; Thermoplastic starch
• ISSN: 0141-3910; 1873-2321
• DOI: 10.1016/S0141-3910(02)00265-3

Thermoplastic starch (TPS) compounds of conventional cornstarch and glycerol reinforced with cellulosic fibres were characterized by high performance size exclusion chromatography. The molecular weight and its distribution were analysed to verify the possible occurrence of chain degradation due to the thermoplasticization and mixing processes. The compounds and composites were prepared in an intensive batch mixer at 150–160 °C, with glycerol and fibre contents in the range of 30–50 and 5–15%, respectively. The results showed that an increase in glycerol content reduces starch degradation whereas an increase in fibre content leads to its increase. The changes in the chromatographic profiles were more pronounced in the high molecular weight fraction, corresponding to amylopectin. The polydispersity index of the matrix was lower than that of native starch due to selective breakage of large amylopectin molecules as a result of shear-induced fragmentation.