Abstract
This review focuses on synthesis methods of cellulose derivatives, in particular, those of cellulose ethers, from viewpoints of regiocontrolled introduction of protective and functional groups, published over roughly a quarter of a century. Influence of regioselective functional groups of cellulose on performance is discussed with particular focus on methylcellulose derivatives, 2-O-methyl, 3-O-methyl, 6-O-methyl, 2, 3-di-O-methyl, 2, 6-di-O-methyl, 3, 6-di-O-methyl, and 2, 3, 6-tri-O-methyl celluloses. Synthesis methods for tri-O-alkyl celluloses (carbon numbers of alkyl chain = 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14 and 18), and alternatingly 2-O- and 6-O-methylated celluloses are also summarized. In addition, regioselectively functionalized cellulose esters are described. Moreover, synthesis methods of cellulosic block copolymers with other polymer blocks and diblock cellulose ethers with regioselective functionalization patterns are summarized. New insights into structure-property relationships of methylcellulose with blocky structure to form thermoresponsive hydrogels are described in detail.
