Effect of Alkali Treatment on the Properties of Acacia Caesia Bark Fibres

Palanisamy Sivasubramanian,Mayandi Kalimuthu,Carlo Santulli,Nagarajan Rajini,Azeez Alavudeen,Murugesan Palaniappan

doi:10.3390/fib9080049

Palanisamy Sivasubramanian, Mayandi Kalimuthu + Show 4 more

Open Access

https://doi.org/10.3390/fib9080049

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Abstract

As possible substitutes for non-biodegradable synthetic fibre, ligno-cellulosic fibres have attracted much interest for their eco-friendliness; a large number of them are already used for the production of green polymer composites. The search for further green candidates brings into focus other fibres not previously considered, yet part of other production systems, therefore available as by-products or refuse. The purpose of this study is to explore the potential of alkali treatment with 5% sodium hydroxide (NaOH) to enhance the properties of bark-extracted Acacia Caesia Bark (ACB) fibres. The microscopic structure of the treated fibres was elucidated using scanning electron microscopy (SEM). Moreover, the fibres were characterised in terms of chemical composition and density and subjected to single-fibre tensile tests (SFTT). Following their physico-chemical characterisation, fibre samples underwent thermal characterisation by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), and their crystallinity was assessed using X-ray diffraction (XRD). This level of alkali treatment only marginally modified the structure of the fibres and offered some improvement in their tensile strength. This suggested that they compare well with other bark fibres and that their thermal profile showed some increase of degradation onset temperature with respect to untreated ACB fibres. Their crystallinity would allow their application in the form of fibres with an average length of approximately 150 mm, even in thermoplastic biocomposites.

Highlights

As possible substitutes for non-biodegradable synthetic fibre, ligno-cellulosic fibres have attracted much interest for their eco-friendliness; a large number of them are already used for the production of green polymer composites
The objective of this work is to assess the suitability of alkali-treated Acacia Caesia bark (ACB) fibres and their use as the fillers in polymer composites, through the acquisition of physico-chemical data
Preliminary studies on alkali-treated Acacia Caesia bark (ACB) fibres offered some evidence regarding the possibility of extracting fibres, with diameters not exceeding 150 microns, from the bark, fibres which may offer some potential for application as the reinforcement of polymer composites

Summary

Introduction

As possible substitutes for non-biodegradable synthetic fibre, ligno-cellulosic fibres have attracted much interest for their eco-friendliness; a large number of them are already used for the production of green polymer composites. Following their physico-chemical characterisation, fibre samples underwent thermal characterisation by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), and their crystallinity was assessed using X-ray diffraction (XRD) This level of alkali treatment only marginally modified the structure of the fibres and offered some improvement in their tensile strength. The growth of worldwide environmental awareness is more significant than ever before in the development of recyclable and environmentally sustainable composites, such as those based on natural fibres [1,2] These fibres can be extracted, according to the single species, from different parts of the plant, such as stem or bast (e.g., hemp, flax, etc.), leaves (e.g., pineapple), fruit hair (e.g., coir fibres) or seed hair (e.g., cotton). This option is necessary in cases such as the introduction of rubber composites, which have been investigated on isora fibres [13]

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