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The influence of polyols on the molecular organization in starch‐based plastics
Author(s) -
Smits Angela L. M.,
Hulleman Stephan H. D.,
Van Soest Jeroen J. G.,
Feil Herman,
Vliegenthart Johannes F. G.
Publication year - 1999
Publication title -
polymers for advanced technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.61
H-Index - 90
eISSN - 1099-1581
pISSN - 1042-7147
DOI - 10.1002/(sici)1099-1581(199910)10:10<570::aid-pat909>3.0.co;2-m
Subject(s) - crystallinity , amylopectin , amylose , starch , materials science , recrystallization (geology) , crystallization , differential scanning calorimetry , chemical engineering , glycerol , plasticizer , amorphous solid , polysaccharide , polymer chemistry , composite material , crystallography , organic chemistry , chemistry , thermodynamics , engineering , paleontology , physics , biology
The effect of processing temperature and time on the B‐type crystallinity of thermoplastic starch was studied by recording X‐ray diffractograms of conditioned, compression molded starch systems containing glycerol and water as plasticizers at a ratio of 100 : 30 : 56 (w/w/w). Initial recrystallization, developed during molding, was investigated further on similar amorphous potato starch and potato amylopectin systems. The crystallinity prior to processing does not influence the recrystallization, though residual (granular) crystallinity, present due to incomplete melting, increases the total crystallinity. After molding at high temperatures (>160 °C), amylose is mainly responsible for initial recrystallization in the B‐type lattice. The observed degree of recrystallization, however, cannot be due to amylose crystallization alone. Amylose seems to serve as a nucleus for crystallization of amylopectin or amylose–amylopectin co‐crystallization takes place. Thermally induced starch polysaccharide–glycerol interactions were investigated on mixtures of dried starch and glycerol using differential scanning calorimetry and solid‐state nuclear magnetic resonance spectroscopy. An exothermal transition was observed after which the mobility of glycerol was decreased significantly. This indicated the development of a strong polysaccharide–glycerol interaction in the absence of water. Copyright © 1999 John Wiley & Sons, Ltd.