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Effect of degree of deacetylation of chitin on the properties of chitin crystallites
Author(s) -
Li J.,
Revol J.F.,
Marchessault R.H.
Publication year - 1997
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/(sici)1097-4628(19970711)65:2<373::aid-app18>3.0.co;2-0
Subject(s) - crystallinity , crystallite , hydrolysis , titration , saponification , polymer chemistry , chitin , acid hydrolysis , materials science , ionic strength , charge density , chemical engineering , chemistry , chitosan , organic chemistry , composite material , aqueous solution , crystallography , engineering , physics , quantum mechanics
In the present article, chitin from crab shell was systematically deacetylated using a NaOH treatment with control of the reaction time. The degree of deacetylation, monitored using solid‐state NMR, revealed that the reaction was pseudo‐first order. Based on this, swollen and NaOH‐saturated particles are proposed as the reaction system. The weight loss of the partially saponified and neutralized samples after HCl hydrolysis increased linearly with the degree of deacetylation. The crystallinity of the samples was found to increase after acid hydrolysis. According to conductimetric titration, the surface charge density of the crystallites, after acid hydrolysis, was found to increase with base treatment time. The effect of surface charge on the formation of a chiral nematic phase, due to the rodlike nature of the crystallites, was explored. These results show that because the contribution of charged particles to the ionic strength was significant the double layer compression was affected, especially since the surface charge density was close to the Manning limit. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:373–380, 1997