Surface modification of cellulose membranes

Abstract

This short review is intended to give a concise overview of methods used in the modification of polymeric cellobiose fibres, with a focus on the surface functionalisation of commercially available cellulose membranes in particular. Reliable and readily available methods will be highlighted, as well as a green approach to grafting-from cellulose membrane composites.

Wood Surface Modification—Classic and Modern Approaches in Wood Chemical Treatment by Esterification Reactions

“…In the past decades, they have been used as highly efficient green solvents for ligno-cellulosic materials: fractionation and biorefinery, dissolution of polysaccharides, processing cellulosic fibers, and, particularly, as reaction medium for the synthesis of substituted polysaccharide derivatives [117,118]. ILs have proven great potential for large scale application due to their structural diversity, recyclability, high dissolution power, their high viscosity and hydrophilicity, and ability to be co-solvents in various systems [117,[119][120][121]. Still, the information on wood surface modification in ILs is scarce, despite the high interest in cellulose functionalization in such medium.…”

“…1-Butyl-and 1-benzylimidazole have been employed for homogeneous tosylation of cellulose when mixtures of IL and another co-solvent were used [123]. As both ILs have basicity comparable to imidazole and 1-methylimidazole but lower hydrophilic character, they can be easily extracted and recycled due to their high partition coefficient in the non-polar phase [117].…”

“…Special attention must be paid to the influence of the cation as it may affect the viscosity of the reaction mass. Thus, liquid imidazolium dialkyl phosphates cannot be used for the homogeneous tosylation at room temperature due to the rapid gelation of the reaction mixture upon the addition of the reagent, but the reaction is successful when tetraalkylammonium dialkyl phosphates were used under the same conditions [117,127].…”

Advances in Surface Modification and Treatment of Wood

“…Cellulose tosylation in ILs is usually performed in the presence of 1-allyl-3-methylimidazolium chloride (AMIMCl) or 1-butyl-3-methylimidazolium chloride (BMIMCl), at room temperature or below in order to avoid the tosyl reaction with chloride ions yielding in chlorodeoxycellulose as by-product, or the formation of insoluble cellulose derivatives by the cross-linking reaction between different hydroxyl groups [2,122]. However, cellulose tosylation in ILs at 10 • C yielded in a mixture of tosylated derivative (65%) and unmodified cellulose (45%) as result of the ineffective stirring of the reaction medium [117].…”

“…In addition, some studies evidenced that ILs are solvents not really as "green" as initially asserted, their reduced toxicity strongly depending on the structure, cation type, application, recovery and recycling, disposal etc. [117,[128][129][130][131][132].…”