Chemical Modification of Cellulose Using a Green Route by Reactive Extrusion with Citric and Succinic Acids

Jéssica Fernanda Pereira,Beatriz Marjorie Marim,Suzana Mali

doi:10.3390/polysaccharides3010017

Jéssica Fernanda Pereira, Beatriz Marjorie Marim + Show 1 more

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https://doi.org/10.3390/polysaccharides3010017

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Journal: Polysaccharides	Publication Date: Mar 13, 2022
Citations: 12	License type: CC BY 4.0

Affiliation: Universidade Estadual de Londrina

Abstract

Cellulose is a natural, unbranched, and fibrous homopolymer that is a major component in several agroindustrial residues. The aim of this study was to extract cellulose from oat hulls and then to modify it using a green route to obtain esterified cellulose through reaction with organic acids employing the reactive extrusion process, which is a process that presents some advantages, including low effluent generation, short reaction times, and it is scalable for large scale use. Citric (CA) and succinic (SA) acids were employed as esterifying agents in different concentrations (0, 5, 12.5, and 20%). Modified cellulose samples were characterized by their degree of substitution (DS), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (DRX), scanning electron microscopy (SEM), wettability, oil and water absorption capacities, and thermal stability. DS of modified samples ranged from 2.28 to 3.00, and FTIR results showed that the esterification occurred in all samples for both acids by observation of important bands at 1720 and 1737 cm−1 for samples modified with CA and SA, respectively. All modified samples presented increased hydrophobicity. The modification did not have an influence on the morphological structure or crystallinity pattern of all samples. This study proved to be possible to modify cellulose using a simple and ecofriendly process based on reactive extrusion with organic acids.

Highlights

Cellulose is one of the most abundant natural, renewable, and biodegradable polymers; it is an unbranched and fibrous homopolymer that can be obtained from plants or synthesized by bacteria
After bleaching with peracetic acid, the obtained sample presented a composition of 78% cellulose, 8% hemicellulose, and 3% lignin, and this sample was labeled as cellulose
Ratanakamnuan et al [31] reported similar Degree of Substitution (DS) values to those obtained in this study, their values ranged from 2.41 and 2.69 for cotton cellulose esterified with several fatty acids (C4 to C12) under microwave heating, and they stressed that shorter reaction times are required to obtain samples with higher DS when the microwave power increases

Summary

Introduction

Cellulose is one of the most abundant natural, renewable, and biodegradable polymers; it is an unbranched and fibrous homopolymer that can be obtained from plants or synthesized by bacteria. Agroindustrial residues can be considered interesting sources for cellulose extraction, and in the last few years, an increased interest in the obtainment of cellulose from these materials using different approaches was seen, which can be considered a promising alternative for the production of sustainable products at affordable prices to reduce the dependency on petroleum-based products [8]. The use of agroindustrial residues to obtain new products is inserted into the concept of biorefineries, meeting the vision of a sustainable economy using biological resources, maximizing benefits and profits through strategies to add value to the plant biomass chain [9,10].

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