Homogenous Synthesis of New C6 Regioselective Cellulose Acetate Butyl hexane-1,6-Diyldicarbamate Based on Esparto cellulose of Morocco Oriental

Abstract

In this paper, we exploited the strong relation between the degree of substitution (DS) of the cellulosic derivatives and their physicochemical behavior, in particular the solubility. Thus, it is smart to change the problem of finding new and complex solvent system by an understanding the effect of cellulose acetate DS on the solubility process and to take it as a base for grafting new functionalities on the main chain of polymer to improve its physicochemical properties. In this context, we used cellulose acetate having a DS equal to 1.7 (DS 1.7 ) as a base polymer. The value of 1.7 of the CA shows a good solubility in THF. The CA 1.7 was synthesized from cellulose stemming from Esparto Stipa tenacissima of eastern Morocco by acetylation deacetylation process. This method proved the deacetylation of 50% of the C6-OH groups, which increases the reactivity of the hydroxyls liberated and consequently the ease of C6-regioselective grafting of the new functionalities in homogenous and organic medium (THF). C6 Regioselective Cellulose Acetate Butyl hexane-1,6-Diyldicarbamate was synthesized by grafting of urethane segments (Butyl 1,6-Diyldicarbamate) on cellulose acetate CA 1.7 and the resulted cellulose derivatives was characterized using different spectroscopic techniques (FTIR, 1 H NMR, 13 C NMR, DEPT...). The influence of grafting behavior (DS value) on TGA/DTG thermograms and RXD diffractogramms was deeply investigated. NMR was used to study scarcely the regioselective grafting on CA in homogenous medium. The results of the structural analyzes showed that the grafting is regioselective on the hydroxyl groups of C6 position (OH-C6) and the DS of urethane groups was found around 0.7.