Department of Food Engineering, School of Food Engineering, University of Campinas, Campinas, SP CEP 13083-862, Brazil.
Department of Food Engineering, School of Food Engineering, University of Campinas, Campinas, SP CEP 13083-862, Brazil.
Carbohydr Polym. 2020 Nov 15;248:116744. doi: 10.1016/j.carbpol.2020.116744. Epub 2020 Jul 13.
This work aimed to produce and characterize cellulose nanofibers obtained from cassava peel with a combination of pre-treatments with acid hydrolysis or TEMPO-mediated oxidation and ultrasonic disintegration. All nanofibers presented nanometric diameter (5-16 nm) and high negative zeta potential values (around -30 mV). Oscillatory rheology showed a gel-like behavior of the aqueous suspensions of nanofibers (1.0-1.8 % w/w), indicating their use as reinforcement for nanocomposite or as a thickening agent. Additionally aqueous suspensions of nanofibers obtained by acid hydrolysis presented higher gel strength than those produced by TEMPO-mediated oxidation. However, ultrasound application increased even more viscoelastic properties. Flow curves showed that suspensions of nanofibers obtained by acid hydrolysis presented a thixotropy behavior and viscosity profile with three regions. Therefore our results showed that it is possible to tune mechanical properties of cellulose nanofibers choosing and modifying chemical and physical process conditions in order to allow a number of applications.
本工作旨在通过酸水解或 TEMPO 介导的氧化与超声分散相结合的方法，从木薯皮中制备并表征纤维素纳米纤维。所有纳米纤维均表现出纳米级直径（5-16nm）和高负 Zeta 电位值（约-30mV）。振荡流变学表明纳米纤维水悬浮液（1.0-1.8%w/w）具有凝胶状行为，表明其可用作纳米复合材料的增强剂或增稠剂。此外，通过酸水解得到的纳米纤维水悬浮液的凝胶强度高于通过 TEMPO 介导的氧化得到的纳米纤维水悬浮液。然而，超声应用甚至提高了粘弹性。流动曲线表明，通过酸水解得到的纳米纤维悬浮液表现出触变性行为和具有三个区域的粘度曲线。因此，我们的结果表明，可以通过选择和修改化学和物理过程条件来调节纤维素纳米纤维的机械性能，从而允许多种应用。
