Optimizing cellulose microfibrillation with NaOH pretreatments for unbleached Eucalyptus pulp

Caio Cesar Nemer Martins,Gustavo Henrique Denzin Tonoli,Jefferson Resende Félix,Renato Augusto Pereira Damásio,Matheus Cordazzo Dias,Luiz Eduardo Silva,Alisson Farley Soares Durães,Maressa Carvalho Mendonça

doi:10.1007/s10570-021-04221-x

Caio Cesar Nemer Martins, Gustavo Henrique Denzin Tonoli + Show 6 more

Open Access

https://doi.org/10.1007/s10570-021-04221-x

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Journal: Cellulose	Publication Date: Oct 13, 2021
Citations: 15	License type: cc-by

Affiliation: Universidade Federal de Lavras

Abstract

Microfibrillated cellulose (MFC) is a form of biopolymer that stands out because of its versatile use. However, the process of obtaining MFC requires adjustments to provide the increase of microfibrillation in industrial scale. Thus, this study aimed to apply pretreatments with NaOH in unbleached Eucalyptus sp. fibers to optimize the microfibrilation process, in order to evaluate the effect of drying and not drying the fibers after pretreatments for reduction of energy consumption. Treatments of MFC with NaOH at 5% with 2 h of reaction and by 10 wt% were evaluated for the resulting morphology, chemical composition, and energy consumption. The length and width of the pulp fibers pretreated with NaOH decreased significantly, mainly with hasher pretreatments. Pretreating fibers with 5 wt% NaOH for 2 h increased the water retention value (WRV), in addition to presenting the lowest energy consumption for fibrillation, promoting energy savings of up to 48%. Pulps that were non-dried after the NaOH pretreatments resulted in easier microfibrillation and lower energy consumption when compared to dried pulp, which shows the negative impact of drying on the fibers to obtain MFC.

Highlights

Cellulose is a biopolymer that stands out for several reasons, such as its abundance, renewability, and nontoxicity to the environment and biodegradability after disposal
Nanostructured cellulose can be obtained from several sources, such as bacterial cellulose (Gatenholm and Klemm 2010), or from lignocellulosic materials spread into cellulose nanofibrils (CNFs) (Osong et al 2016), cellulose nanocrystals (CNCs)
This study sought to evaluate the effect of chemical pretreatments to optimize the process of obtaining microfibrillated cellulose (MFC)

Summary

Introduction

Cellulose is a biopolymer that stands out for several reasons, such as its abundance, renewability, and nontoxicity to the environment and biodegradability after disposal. (Sehaqui et al 2011), and microfibrillated cellulose (MFC) (Guimarães Junior et al.2018). Microfibrillated cellulose (MFC) is a fibrillated material with fibrils with average diameter of less than 100 nm and a length that can reach more than 10 μm (Abdul Khalil et al 2012). This material has a high specific surface area due to the large amount of individual micro/nanofibrils, which increases bonding with each other or with other matrices, forming high-strength films (Guimarães Junior et al 2018). Several industrial sectors and researchers are developing applications for MFC, such as those reported elsewhere for pharmaceutical (Mohd Amin et al 2012), food, paint and cosmetics (Nikolajski et al 2012), films and coating (Matos et al 2019), and fibercement composite (Fonseca et al 2019) fields, as well as bacterial nanocellulose for medical uses (Klemm et al 2011)

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