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High-fiber loading green composites were prepared from recycled high-density polyethylene (rHDPE)/recycled polyethylene terephthalate (rPET) blend matrix and rice husk (RH) as filler (from 40 wt% up to 80 wt%) via corotating twin-screw extruder and compression molding. The water absorption (WA) upon immersion in sea water, mechanical behavior, and combustion enthalpy of green composites were examined. The WA mechanisms obeyed the Fickian diffusion. The computed diffusion coefficient (D), thermodynamic solubility (S), permeability (P), and orthotropic swelling were generally increased as a function of RH filler. The increment of tensile strength and modulus of composites were maximized up to 16% and 121%, respectively, which was achieved at 70 wt% RH filler. The theoretical prediction of tensile strength and Young's modulus from micromechanical models for random oriented RH fiber/blend composites were compared with the experimental results. As the RH weight fraction increased, the combustion enthalpy decreased (by approximately 30–48%) and thereby the enhancing the fire retardancy of green composite. [ABSTRACT FROM AUTHOR]

As the most consumed edible oil worldwide, palm oil consumption boosting results in more planting and more oil palm by-products (5 times more than palm oil production). In order to meet environmental sustainability, various oil palm by-products in the form of residual lignocellulosic biomass are available for exploitation from palm oil mills. Although their disposal might pose some undesirable environmental impacts, economical applications of these untapped by-products, oil palm fiber in particular, into useful alternatives have been progressively developed over the past decades: pulp and paper, animal feed, renewable energy, automobile, agricultural and architectural substitutes, water treatment media, polymer and composite, to name a few. This review addresses various innovative valorization of oil palm fiber, their versatile application status and potential projection as a sustainable alternative. A proposed scheme to fill in the knowledge gaps identified and provide future direction is put forth for consideration. • Examines progress and rate of oil palm fiber utilisation under improper disposal issue. • Various innovative valorization and potential projection as a sustainable alternative. • The top three sectors in 2022 is revealed via bibliometric analysis of the literature. • The research findings of dominant sectors can serve as a guide for future study. [ABSTRACT FROM AUTHOR]

Green composite materials were made from agricultural and plastic wastes which were rice husk (RH), recycled high‐density polyethylene (rHDPE), and recycled polyethylene terephthalate (rPET), by twin‐screw extrusion and hot/cold pressing molding. The dimensional stability, orthotropic swelling, and mechanical performance of the green composites were determined as a function of bio‐filler concentration for neat (uncompatibilized) and compatbilized rHDPE/rPET blend based composites. Water absorption and swelling results showed a linear increase with the RH concentration. The highest swelling occurred in the thickness of the composites, followed by the width and length, respectively. Water absorption and dimensional instability of compatibilized recycled polymer blend (rPB)‐based composites were lower than those of neat rPB‐based composites. As RH concentration increased, the flexural properties increased significantly. The optimum tensile strength and modulus were achieved at 70 wt% RH. It is interesting to note that compatibilization of polymer blend matrix had further increased the strength and elongation properties of composites. POLYM. COMPOS., 39:2695–2704, 2018. © 2016 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Cellulose hydrogel was produced from pretreated oil palm empty fruit bunch fiber (EFB) that went through acid hydrolysis and thermal hydrolysis. The pretreated EFB was dissolved in LiOH/urea aqueous solution using the rapid dissolution method and was subjected to a crosslinking process with the aid of epichlorohydrin to form hydrogel. The effects of both hydrolyses' time on average molecular weight (Mŋ), solubility, and properties of EFB hydrogels were evaluated. Both hydrolyses led to lower Mŋ, lower crystallinity index (CrI) and hence, resulted in higher cellulose solubility. X-ray diffraction (XRD) characterization revealed the CrI and transition of crystalline structure of EFB from cellulose I to II. The effects of hydrolysis time on the transparency, degree of swelling (DS), and morphology of the regenerated cellulose hydrogel were also investigated using an ultraviolet-visible (UV-Vis) spectrophotometer and a Field emission scanning electron microscope (FESEM), respectively. These findings provide an efficient method to improve the solubility and properties of regenerated cellulose products. [ABSTRACT FROM AUTHOR]

In this study, activated carbon (AC) from coconut shell, as a widely available agricultural waste, was synthesised in a simple one-step procedure and used to produce a magnetic Fe3O4/AC/TiO2 nano-catalyst for the degradation of methylene blue (MB) dye under UV light. Scanning electron microscopy revealed that TiO2 nanoparticles, with an average particle size of 45 to 62 nm, covered the surface of the AC porous structure without a reunion of its structure, which according to the TGA results enhanced the stability of the photocatalyst at high temperatures. The photocatalytic activities of synthesised AC, commercial TiO2, Fe3O4/AC, and Fe3O4/AC/TiO2 were compared, with Fe3O4/AC/TiO2 (1:2) exhibiting the highest catalytic activity (98%). Furthermore, evaluation of the recovery and reusability of the photocatalysts after treatment revealed that seven treatment cycles were possible without a significant reduction in the removal efficiency. [ABSTRACT FROM AUTHOR]

Dissolved oil palm empty fruit bunch cellulose (EFBC) and sodium carboxymethylcellulose (NaCMC) were chemically crosslinked with epichlorohydrin (ECH) to generate designated hydrogel. After swelling process in distilled water, the swollen hydrogel was frozen and freeze-dried to form cryogel. The swelling phenomenon of hydrogel during the absorption process gave substantial effects on thinning of crosslinked network wall, pore size and volume, steadiness of cryogel skeletal structure, and re-swelling of cryogel. The swelling effects on hydrogel were confirmed via microscopic study using variable pressure scanning electron microscope (VPSEM). From the retrieved VPSEM images, nano-thin crosslinked network wall of 24.31 ± 1.97 nm and interconnected pores were observed. As a result, the amount of water, the swelling degree, and the freeze-drying process indirectly affected the VPSEM images that indicated pore size and volume, formation of interconnected pores, and re-swelling of cryogel. This study determined the intertwined factors that affected both hydrogel and cryogel properties by investigating the swelling phenomenon and its ensuing effects. Unlabelled Image • Cryogel was regenerated from dissolved EFB cellulose and NaCMC. • Swelling degree of hydrogel influenced thinning of crosslinked network wall of cryogel. • Cryogel exhibit nano-thin crosslinked network wall attained higher pore volume and water absorption. [ABSTRACT FROM AUTHOR]