The Role of Chitosan in Improving the Ageing Resistance of Rosin Sized Paper

Popis
Abstrakt:	SUMARRIES. A new technique for improving the durability of rosin-alum sized paper is described, i.e. using chitosan as a polymer for surface treatment. Samples of such paper were dipped in 0.2% and 0.4% chitosan 1% acetic acid, using sodium hydroxide or sodium silicate as precipitators. After accelerated ageing for different periods mechanical and optical qualities of the samples were measured. IR-spectroscopy was used to determine the mean strength of hydrogen bonds (MSHB) and the relative absorbance of carbonyl groups (Eo-o) of both unaged and aged samples. In a second test series the samples were first aged and then submitted to chitosan treatment. The results show that the type of alkali for precipitation of chitosan is of crucial importance. Generally it can be stated that chitosan-treatment in the higher concentration (0.4%) and precipitated with sodium silicate can improve the durability of alum-rosin sized paper made from short fibre and that it can also improve the durability of such paper that has already suffered some decay from ageing.
ISSN:	ISSN 0034-5806

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