Surface modification of cellulose nanocrystals

Cellulose nanocrystal surface modification is an expanding area in cellulose research and this thesis aims to add knowledge to this growing field. Two esterification techniques new to cellulose nanocrystal research were applied successfully to the formation of esters of (methylthio)acetic add, two pyridinum substituted benzoic acids and rnethacrylic acid. The efficacy of the two methods was compared with each other and with those used in the literature. Two click chemistry reactions were also applied to cellulose nanocrystals. Azidation of chlorinated cellulose nanocrystals allowed application of copper(I) catalysed azidealkyne cydoaddition to the grafting of two irnidazoliurn salts and ferrocene to cellulose nanocrystals. Attachment of a disulfide to cellulose nanocrystais lead to a one-pot disulfide reduction and thiol Michael addition to graft cellulose nanocrystals with pentabromobenzyl acrylate. These different surface modification strategies were used to prepare a variety of surface active nanopartides for further application. Cationic cellulose nanocrystals were produced with higher surface charge density than previously reported in the literature. The cationic nature of the nanocrystals was probed using an anionic dye adsorption methodology. The variation in anion affinity for imidazolium grafted cellulose nanocrystals was determined using a batch mixing methodology with ion chromatography. Cellulose (methylthio)acetate nanocrystals were tested as a potential supported sulfur ylid in the rhodiurn(II) acetate and sulfide co-catalysed conversion of aldehydes to epoxides. This proved unsuccessful with by-products suggesting fa ilure to form supported ylids. Finally, cellulose nanocrystals were modified with a multidentate amine ligand using a diisocyanate and the resulting nanocrystals used to bind palladiurn(II) acetate. These nanocrystals were tested in Sonogashlra reactions for recydability of the palladium catalyst. Significant leaching of the palladium catalyst occurred without the use of a copper co-catalyst and the exact nature of the palladium species present on the surface of the nanocrystals remains unknownEThOS - Electronic Theses Online ServiceGBUnited Kingdo