Abstract
For the complex films composed of various molar (repeat unit) ratios of chitosan and carboxymethyl chitin (CM chitin) moisture sorptions were measured at 20°C, 65%RH and 20°C, 90%RH and water sorptions were measured in 5, 000-fold as much water as complex film after 24h at 30°C. Hygroscopicities of complex films became higher as the increase of the content of CM chitin irrespective of relative humidity and they did higher independent of the composition of complex film at 90%RH compared with those at 65%RH. Water sorptions of complex films were lower as molar (repeat unit) ratios of chitosan and CM chitin were in the range of 0.4/0.6 to 0.3/0.7. Except this range water sorptions of complex films were higher. The lowest value in water sorption was seen in approximately 1.0 of -NH2/-COOH ratio, because it is then easy for chitosan and CM chitin to form polyion complex.
