Carboxymethylated spruce galactoglucomannans: preparation, characterisation, dispersion stability, water-in-oil emulsion stability, and sorption on cellulose surface

Abstract

Natively acetylated galactoglucomannans (GGMs) is the main hemicellulose type in most softwood species and can be utilised as, for example, bioactive polymers, hydrocolloids, papermaking chemicals, or coating polymers. In this study, carboxymethylated GGMs (CM-GGMs) were prepared and characterised by GC-MS, H-1 and C-13 NMR and FTIR spectroscopy, and SEC-MALLS. The thermal stability of the products was investigated by DSC-TGA. The accessibility of different C-positions in mannose and glucose was investigated. The emulsion stability of CM-GGMs in resin dispersion was studied and it was shown that CM-GGMs can stabilise the resin dispersion also in presence of CaCl2. The possibility of using CM-GGMs as emulsifiers in water-in-oil emulsions was assessed. A CM-GGM with a DS value of 0.25 at a concentration higher than 3% performed the best. Finally, the study of sorption of CM-GGM onto cellulose surface exhibited a decrease in binding ability with an increase in the degree of substitution (DS).