Effect of Alkaline treatment on the characteristics of pineapple leaves fibre and PALF/PP biocomposite

Abstract

Pineapple leaves fibre (PALF) is one of the natural fibre that has high potential to substitute non-renewable synthetic fibre in thermoplastic products. The PALF were alkali treated with different concentrations of NaOH. Untreated and alkali treated PALF were characterized using Thermal Gravimetric Analysis (TGA) and Scanning Electron Microscopy (SEM) to determine the thermal stability and surface morphology of the fibres respectively. Biocomposites were prepared by reinforced alkali treated and untreated PALF with polypropylene (PP) matrix. Tensile properties and water absorption analysis of PALF/PP biocomposites were studied. Biocomposite with 8 wt.% of alkali treated PALF express excellent thermal stability, with maximum degradation temperature at 270 ℃ which is a 7.17% improvement compared to untreated PALF. This biocomposite also had increased tensile strength (116 MPa) with 43% improvement compared to untreated PALF/PP (66 MPa) biocomposite and had lower water absorption at 6% compared to untreated biocomposite which at 21%. Hence, alkali treated PALF is able to improve the characteristic of PALF and increase the compatibility between fibre and polymer by reducing hemicellulose and lignin components.

Studies on interfacial shear strength of pineapple leaf fibre from agro-waste reinforced polypropylene composites: Influence of fibre length and carding parameters

“…Then the sun-dried, sticky PALF is chemically degummed to remove the non-cellulosic elements. [5][6][7] Alkalization is the most common chemical treatment used for removing the hemicellulose and lignin as well as other non-cellulosic constituents, which are the most hydrophilic parts of ligno-cellulosic fibres. 7,8 Alkali and acid treatments are simple and cost-effective, but not eco-friendly.…”

“…Higher concentrations of chemicals may effectively eliminate lignin and hemicellulose along with some degradation of cellulose. 6,8 As an alternative, physical treatments can be used to modify the ligno-cellulosic PALF. The wettability and affinity of the fibres with the polymer matrix in composites will be improved by physically changing the surface properties.…”

“…Higher concentrations of chemicals may effectively eliminate lignin and hemicellulose along with some degradation of cellulose. 6,8…”

A novel physical method for processing agro-waste derived pineapple leaf fibre for fabricating polypropylene matrix composites with higher mechanical performance

“…These treatments are easier and more economical, but they are not eco-friendly. Additionally, if the procedure is not carried out under optimised conditions, cellulosic materials in PALF may also be degraded deteriorating the physico-mechanical properties of bres (Gnanasekaran et al 2022;Gnanasekaran et al 2021;Asim et al 2016;Dittenber et al 2012).…”