Obtención de nanocelulosa a partir de celulosa de puntas de abacá.

Abstract

Abaca tips, currently considered waste, contain percentages of cellulose greater than 70 %, which is why they are ideal for obtaining cellulose nanocrystals (CNCs). The objective of this work was to obtain CNCs from cellulose pulp of abaca tips, by acid hydrolysis. The first step was to obtain cellulose by pulping process with NaOH, to remove lignin and other unwanted components. Subsequently, the crystalline zones of the cellulose were isolated and purified by acid hydrolysis with H2SO4 64 % (w/w) at temperature of 45 °C, using a 4x3 factorial design, whose study variables were the hydrolysis time (15, 30, 45 and 60 min) and the acid/cellulose ratio (10, 11,5 and 13 mL/g). For the purification of nanocrystals, two washing methods were used (by centrifugation and dialysis). The output variables were the size of the nanocrystals and its yield. The best time conditions and acid/cellulose ratio for obtaining CNCs were 45 min and 10 mL/g, purified through washing by dialysis, which produced type Iβ nanocrystals with dimensions of: 4,69 nm of thickness and 300,90 nm of length, with a yield of 7,94 % and a crystallinity of 82,26 %. Shorter hydrolysis times (15 and 30 min) failed to obtain nanocrystals; while longer times (60 min), its managed to obtain CNCs, but with low yields (4.23%).