Starch thermal degradation

High shear forces and stagnation zones should be avoided when processing biodegradable polyesters such as starch compounds because they are sensitive to thermal degradation [12]. 

Zhang, L. M., Hu, Z. H. (2002). Synthesis and thermal degradation of a novel starch graft copolymer incorporating a sulpfobetaine zwitterionic monomer. Starch, 54, 290-295. 

A powdered extract is made by replacing the moisture in a soft extract with an equal amount of a substrate such as calcium phosphate, starch or maltodextrin. The moisture is normally removed using a vacuum oven to avoid excessive thermal degradation of the extract. 

Bryce, D. J., and Greenwood, C. T. (1966). The thermal degradation of starch. Part 6. The pyrolysis of amylomaize starch in the presence of inorganic salts. In Thermoanalysis of Fibers and Fiber-Forming Polymers, Applied Polymer Symposium, Vol. 2, pp. 159-173. Interscience, New York. 

Greenwood, C. T., Aspects of the Physical Chemistry of Starch, 11, 335-385 Greenwood, C. T., The Size and Shape of Some Polysaccharide Molecules, 7, 289-332 11, 385-393 Greenwood, C. T., The Thermal Degradation of Starch, 22,483-515 Greenwood, C. T., and Milne, E. A., Starch Degrading and Synthesizing Enzymes A Discussion of Their Properties and Action Pattern, 23, 281-366... 

Greenwood CT. The thermal degradation of starch. Adv Carbohydr Chem Biochem 1967 22 483-515. 

Ohkita T, Lee S-H (2006) Thermal degradation and biodegradability of poly (lactic acid)/ com starch biocomposites. J Appl Polym Sci 100(4) 3009-3017 Thyman JHP (1979) Chem Soc Rev 8 499... 

Pyrolysis is always accompanied by the evolution of volatile, decomposition products. The proportions and chemical complexity of these depend on the severity of the experimental conditions. However, under diminished pr ure, even at temperatures below 100°, water is liberated, and a major problem in this area of starch chemistry is to distinguish between the processes of dehydration and decomposition. At higher temperatures, the problem of thermal degradation may be complicated by the occurrence of intramolecular rearrangements and second-order interactions. It is also becoming increasingly apparent that the course of pyrolysis is markedly altered by the presence of small proportions of inorganic materials. 

Th e thermoanalytical techniques have been used with great success in the field of synthetic fibers, and have been applied to studies of cellulose. For the latter, pyrolysis Avas found to be best conducted in a nitrogen atmosphere, to avoid the poor curves caused by overlapping reactions that occur in an oxidizing atmosphere. The effect of various potential fire-retardants on the thermal degradation of cellulose has also been studied successfully in this way. However, in the starch field, unfortunately, these valuable techniques have not yet been applied with sufficient care and attention paid to those complicating factors already outlined. 

---