不同硫酸浓度水解制备纤维素纳米晶及其稳定Pickering乳液研究

Preparation of cellulose nanocrystals by hydrolysis with different sulfuric acid concentrations and their stabilized Pickering emulsions

以菠萝皮渣纤维素为原料,采用传统硫酸水解法提取纤维素纳米晶(cellulose nanocrystals,CNCs),考察不同硫酸质量分数(58%、61%和64%)对制备的CNCs(CNCs-58%、CNCs-61%和CNCs-64%)的形貌粒径、电位、热稳定性和稳定Pickering乳液性能的影响。研究表明,随着硫酸溶液质量分数的增加,CNCs的直径、长度逐渐减小且均一性增加,电位绝对值逐渐增加(-33.5、-43.6和-45.7 mV),但热稳定性降低。与CNCs-58%相比,CNCs-61%和CNCs-64%表现出更好的稳定Pickering乳液性能,具有更小的液滴尺寸和更好的贮藏稳定性,乳液电位绝对值也相对较大;但在低CNCs质量分数(0.2%),CNCs-64%稳定乳液的析水程度相对较高,这主要与CNCs的形貌结构有关;随着CNCs质量分数的增加,乳液析水程度明显降低。该研究为硫酸水解果蔬皮渣纤维素制备CNCs及其在Pickering乳液中的应用提供参考。

Cellulose nanocrystals(CNCs)were extracted from pineapple peel cellulose by traditional sulfuric acid hydrolysis method.The effects of sulfuric acid solution concentration(58%,61%,and 64%,mass fraction)on particle size,morphology,potential,thermal stability,and stable Pickering emulsion properties of the prepared CNCs(CNCs-58%,CNCs-61%,and CNCs-64%)were investigated.Results showed that with the increase of sulfuric acid solution concentration,the diameter and length of CNCs decreased gradually with increased uniformity,and the absolute potential increased gradually(-33.5 mV,-43.6 mV,and-45.7 mV),but the thermal stability decreased.Compared with CNCs-58%,CNCs-61%and CNCs-64%showed better stable Pickering emulsion properties,showing a smaller droplet size,better storage stability,and a relatively larger absolute value of potential.However,at low CNCs concentration(0.2%,mass fraction),the degree of water evolution of CNCs-64%stabilized emulsion was relatively high,which was related to the morphology of CNCs.With the increase in CNCs concentration,the water evolution degree of emulsion decreased significantly.This study provides a reference for the preparation of CNCs from fruit and vegetable peel cellulose hydrolyzed by sulfuric acid and its application in Pickering emulsions.