No 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.

Pineapple leaf fibres (PALF) is one of the abundant residues generated from pineapple plantation. The residues are left on the plantation for nutrient cycling or burning, and this circumstance leads to environmental issues. PALF has high cellulose content among other natural fibres. Cellulose is a reinforcing element that exists as whisker-like microfibrils and has a long-chain structure. In this study, cellulose produced from PALF was treated by steam and chemical treatment. The fibre was treated with steam at 121°C, a pressure of 21 psi for 30 or 60 min. Next, the steam-treated fibre was treated with 5 wt% sodium chlorite (NaClO2) solution with pH adjusted between 4 and 5 for 90 min. The condition was varied with three different temperatures, which were room temperature, 50, and 70°C. Then, the bleached fibre was treated with 5 wt% sodium hydroxide (NaOH) at room temperature for 3 h. After the treatments, the fibre was analysed for its thermal stability, morphology, and chemical composition. Cellulose obtained from the treatment condition of steam for 60 min, bleaching at 70°C, and alkali treatment at room temperature expressed the highest degradation temperature of 276°C at 20% weight loss, percentage of cellulose of 86% and lowest moisture content (8%) compared to others sample. It also had an excellent surface morphology with finest fibril disintegration. It showed longer steam treatment (60 min) degrading more hemicellulose; and bleaching treatment at high temperature (70°C), increasing the rate of oxidative delignification. In conclusion, the suggested treatment provides a simple but efficient method to isolate cellulose that can be used for various types of applications.

Pineapple leaf fibre (PALF) is major waste from pineapple cultivation with high cellulose content that exhibits superior mechanical properties. In this study, chemical-mechanical treatments were conducted to produce cellulose and microcellulose. For alkali and steam treatment, PALF treated with 5 wt% sodium hydroxide solution and steamed in an autoclave at temperature of 121 °C and pressure of 21 psi. Next, the PALF was bleached with 5 wt% sodium chlorite. Continued with acid hydrolysis with 3.5 M and 7.5 M hydrochloric acid to produce cellulose. For, the mechanical treatment which involved homogenization and ultrasonication to produce the microcellulose, the ultrasonication was varied for 30 and 60 min. The samples were analysed by Scanning Electron Microscopy, Thermal Gravimetric Analysis and Fourier Transform Infrared Spectroscopy (FTIR) to study surface morphology, thermal stability and functional group respectively. The results showed that ABAHU60 with alkali treatment, bleaching, acid hydrolysis, homogenization and ultrasonication of 60 min exhibits excellent thermal stability and surface morphology, where the maximum degradation temperature occurs at 349 °C, which is a 5% improvement compare to untreated fibre. Its surface is smoother without impurities, with a loose structure and reduce diameter of fibre.