Abdullah A. Mamun

Polyester-Kenaf Composites: Effects of Alkali Fiber Treatment and Toughening of Matrix Using Liquid Natural Rubber

In this study, polyester-kenaf fiber composites were prepared by adding various percentages of kenaf fiber in unsaturated polyester resin and subsequently cross-linked using methyl ethyl ketone peroxide and the accelerator cobalt octanoate. Liquid natural rubber (LNR) (3%) was added as a toughening agent. Kenaf fibers were treated with sodium hydroxide solution to improve the interfacial bonding between the fiber and the matrix. The mechanical properties of the composites were evaluated by impact and flexural testing. Environmental stress cracking resistance (ESCR) of composites in acid and base medium was also studied. Bonding mechanisms were assessed by scanning electron microscope and Fourier transform infrared analysis. It was found that the addition of LNR increased the impact strength and fracture toughness. Alkali fiber treatment was found to provide better impact and flexural strengths to the composites. Measurement of ESCR shows that the composite with acid medium has the fastest diffusion rate, followed by that with base medium, and then without medium.

Thermo-mechanical and morphological properties of short natural fiber reinforced poly (lactic acid) biocomposite: Effect of fiber treatment

Untreated oil palm empty fruit bunch (REFB), alkali treated EFB (AEFB), ultrasound treated EFB (UEFB) and simultaneous ultrasound-alkali treated EFB (UAEFB) short fibers were incorporated in poly(lactic acid) (PLA) for fabricating bio-composites. The REFB fiber-PLA (REPC) and treated EFB (TEFB) fiber-PLA (TEPC) composites were prepared and characterized. Glass transition temperature, crystal melting temperature, decomposition temperature, melt flow index, density and mechanical properties (tensile strength, tensile modulus and impact strength) of TEPC are found to be higher than those of REPC. The observed crystallization temperature of TEPC is lower than that of REPC. Among all samples, TEPC prepared from UAEFB fiber shows better performances than other samples fabricated by REFB and AEFB fibers. Scanning electron microscopy, Fourier transform infrared spectroscopy and XRD analyses well support all the observed results.

Preparation and Characterization of Poly(lactic acid)-Based Composites Reinforced with Poly Dimethyl Siloxane/Ultrasound-Treated Oil Palm Empty Fruit Bunch

Oil palm empty fruit bunch fiber and polylactic acid were used to produce composites by melting cast method. Fiber loading was considered up to 40 wt%. Oil palm empty fruit bunch fibers were treated using ultrasound and polydimethylsiloxane to improve the interfacial adhesion. The structure and surface properties of the fibers were analyzed by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and contact angle measurement. Moreover, Fourier transform infrared spectroscopy, tensile, flexural, X-ray diffraction, contact angle, differential scanning calorimetry, and thermogravimetric analysis were used to investigate composites’ properties. The analysis revealed that polydimethylsiloxane treatment composites show reduced wettability with increased crystallinity. GRAPHICAL ABSTRACT

Mechanical properties of hybrid glass/kenaf fibre-reinforced epoxy composite with matrix modification using liquid epoxidised natural rubber

The hybridisation of natural fibre with glass fibre provides a method to improve the mechanical properties instead of using the natural fibres alone. This research is focused on the hybridisation of glass/kenaf fibre with the addition of liquid epoxidised natural rubber to enhance the desired mechanical properties of the composite by reducing the synthetic fibre usage and encourage the natural fibre consumption. Liquid epoxidised natural rubber was added to the epoxy matrix in order to improve its mechanical properties whilst E-glass fibre and kenaf bast fibre were used as the reinforcement in the composite. Liquid epoxidised natural rubber (3%) was added as a toughening agent. Two types of kenaf fibre were prepared – untreated and treated with 6% NaOH – whilst the glass fibre was treated using a silane coupling agent. The flexural test, Izod impact test, environmental stress cracking resistance analysis and scanning electron microscopy analysis were performed to determine the effect of fibre treatment and liquid epoxidised natural rubber addition on the mechanical properties of the hybrid fibre-reinforced composite. It was found that the treatment and the addition of liquid epoxidised natural rubber contribute to the increment of the impact strength by 40% whilst the flexural properties recorded a 13% and 15% increment for both flexural strength and flexural modulus, respectively. The environmental stress cracking resistance analysis showed that the composites are more affected in acid medium followed by base medium and then with the control medium (air). The addition of liquid epoxidised natural rubber seems to improve the stability of the samples in the medium initially but tends to decrease rapidly over time due to debonding of the rubber particles.

Degradation And Stability Of Green Composites Fabricated From Oil Palm Empty Fruit Bunch Fiber And Polylactic Acid: Effect Of Fiber Length

In this work, polylactic acid and oil palm empty fruit bunch fiber-reinforced green composites have been fabricated by using random and fixed-length fibers through extrusion followed by injection molding. The prepared composites have been characterized by mechanical tests, thermal analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray diffractometry. Among all fabricated composites having various sizes and contents of fibers, 30-mm long and 40 wt% empty fruit bunch fiber-incorporated composites show the optimum tensile strength and modulus. As compared to raw empty fruit bunch fiber-loaded composites, simultaneous ultrasound and alkali-treated empty fruit bunch-reinforced composites have revealed improved mechanical performances, enhanced crystallinity, and thermal stability. In case of soil burial degradation studies, treated empty fruit bunch fiber-reinforced composite has been found to be more stable than untreated fiber-reinforced composite.

15 – The use of maize, oat, barley and rye fibres as reinforcements in composites

: Lignocellulosic residues are waste materials that are abundant and comparatively cheap. The quality, fibre contents and chemical composition of lignocellulosic residues depend on the process of grain collection and on food processing. In this study, an investigation is conducted on the morphology, composition, surface chemistry and thermal degradation characteristics of maize, oat, barley and rye plant residues. The aim is to explore the viability of processing and producing composites. In addition, investigations are carried out to examine the potential of lignocellulosic residues as a possible reinforcement for polymeric materials.

8 – The use of banana and abaca fibres as reinforcements in composites

: The fibre extracted from banana trees is a by-product of banana plants, which can be found in all tropical countries. Unlike bananas, abaca is inedible and cultivated solely for fibre extraction purposes. Fibre properties depend on botanical type, growing condition and extraction methods. The abaca fibre is considered to be one of the strongest natural fibres and shows excellent mechanical and chemical properties. It is currently used for pulping, cordage and yarns and fabrics. Several suface modifications can minimize the drawbacks of these fibres with the aim of increasing the applications of these fibres in the automobile and packaging industries. This chapter will describe the processing and performance of composites and the latest economic and technical developments.