A fundamental knowledge of the solubility of biopolymers in solutions is essential to understand their interactions at different solid/liquid interfaces, and further to improve the properties of the products made of these biopolymers. Xyloglucans from Tamarind seeds are a group of natural biopolymers that can be used as additives in papermaking, thickening agents in food industry, and also shown big promises for making composite films with nano-cellulose. In order to clarify the interaction between these biopolymers at cellulose-water interfaces, it was crucial to initially study the solubility behavior of a range of xyloglucan fractions with different molar masses. The solubility was investigated by determining the size and molar mass of the different fractions at different concentrations using Dynamic Light Scattering (DLS), and Size Exclusion Chromatography (SEC), respectively. A detailed analysis of both molecular size and molar mass distributions shows that the solubility is considerably influenced by the molar mass and concentration. The solubility of xyloglucans decreases by an increase in concentration and molar mass. As the concentration increases the xyloglucan polymers are associated into larger structure with different conformations which best could be described as a phase separation. The morphology and size of these associates have been further investigated using Atomic Force Microscopy (AFM), and Size Exclusion Chromatography (SEC). The phase separation was also studied experimentally by viscometer, and theoretically by using the Flory Huggins theory. Following these associations and phase separation analysis, the adsorption behavior of the selected xyloglucan fractions onto model cellulose surfaces was investigated using quartz crystal microbalance (QCM) and stagnation point adsorption reflectometer (SPAR). The results obtained from the solubility and the adsorption studies show that the solubility of xyloglucan indeed affects their adsorption behavior at the cellulose/water interfaces.<br/>

Influence of solubility on the adsorption of different Xyloglucan fractions to cellulose model surfaces

2019 Spring National Meeting

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