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Title: The interaction of chitosan with cellulose and its use in paper
Author: Domszy, Julian Gregory
ISNI:       0000 0001 3428 1291
Awarding Body: Nottingham Trent University
Current Institution: Nottingham Trent University
Date of Award: 1983
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The aims of this study were to investigate the adsorption of chitosan onto cellulose and to apply the knowledge obtained to the application of chitosan to paper. The molecular weight and structure of chitosan are important in its adsorption. The viscometric constants of the modified Staudlnger equation were therefore determined in 0.1M acetic acid/0.2M sodium chloride solution and found to be a = 0.93 and K = 1.81 x 10⁻³ cm³ g⁻¹. Novel methods for determining the extent of residual N-acetylation have been developed based on the reaction between salicylaldehyde and chitosan, together with spectroscopic determination of the N-salicylidene chitosan produced or of the residual salicylaldehyde for homogeneous and heterogeneous reaction respectively. The results obtained agree well with those obtained by infrared spectroscopy and by alkalimetric titrations of chitosan hydrobromide. Measurement of the N-salicylidene chitosan chromophore has been extended to determining the concentration of chitosan in solution and, through use of reflectance spectroscopy, to measurement of chitosan adsorbed on paper handsheets. The adsorption of chitosan on cellulose was found to be an equilibrium process dependant on polymer-adsorbent, polymer-solvent and solvent-adsorbent interactions. Factors that decrease the effective volume of the chitosan molecule in solution, such as increasing degree of N-acetylation and addition of electrolyte, tend to increase the equilibrium uptake. Neutral electrolyte has a second effect, namely suppression of the surface charge, that predominates at higher concentrations and reduces the uptake. Although increasing the surface charge of the cellulose increases the extent of adsorption, the experimental evidence suggests that very few ionic links are formed between chitosan and cellulose. The proposed mechanism involves initial electrostatic attraction of the chitosan to the vicinity of the cellulose surface where it is adsorbed predominately through van der Waals forces and hydrophobic interaction. The influence of molecular weight of the chitosan indicates that the cellulose is acting as a porous substrate.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Organic chemistry