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Natural fibres have remained increasingly applied as reinforcement filler in polymer matrix for fabrication of composites for a long time. Environmentally friendly and sustainable fibres offer the possibility of a feasible substitute and alternative materials to synthetic fibres for a diverse range of products from composite materials. In this research, a new bio-composite has been produced by using date palm fibre (DP) and eggshell (ES) wastes into bio matrix. The current work focuses on how ES particles affect the physical, mechanical, and morphological aspects of DP/bio-epoxy composites. Bio-composites was manufactured by using a fibre loading of 40 wt% DP and filler concentrations of 5, 10, 15, and 20 wt% ES by closed mold hot press. A DP/bio-epoxy composite without ES filler was also prepared as control. Characterization of bio-composites was carried out as per ASTM standard. The obtained results indicate that ES can be used as a filler in bio-epoxy with this novel material composition. Mechanical properties results show that 15 wt% by weight of the ES particles filler loading displays good tensile and flexural properties with better impact strength at 5 wt%. The incorporation of ES above 15 wt% in DP/bio-epoxy composite is not remarkable, so 15 wt% filler matrix replacement is recommended. Furthermore, scanning electron microscopy (SEM) reveals fracture in matrix, implying that the bio-epoxy polymer structures are altered by the fillers. We concluded from findings that ES particles can utilize as potential source of green raw material for strengthening in polymer composites and ultimately help to establish its potential in structural applications. [ABSTRACT FROM AUTHOR]

The present study involved valorisation of rice straw (RS) in the form of rice straw flour (RSF) for the fabrication of poly (butylene succinate) (PBS) based bio-composites through a melt extrusion method, using dicumyl peroxide (DCP) as the cross-networking agent, and study of the morphological, thermal, mechanical and rheological behaviours of the extruded bio-composites. A layered like morphology with good dispersion of RSF in the PBS matrix was observed from X-ray diffraction and field emission scanning electron microscopic analysis. Thermo gravimetric analysis showed that the incorporation of RSF improved the thermal stability of PBS, whereas the value of the different thermal properties i.e. glass transition temperature (Tg), melting temperature (Tm) remained almost identical. Addition of DCP (2 wt%) into the PBS-RSF systems increased both the tensile strength and elongation at break (EB) (%) values. Rheological investigation of the bio-composites showed that the storage modulus (G') was less than the loss modulus (G") over the angular frequency (ω) range until crossover, corroborating the viscous behaviour of the samples. The complex viscosity, η' was constant when ω was less than 1 rad/s for all the samples, showing Newtonian characteristics. Shear thinning behaviour was observed when ω was greater than 1 rad/s. Furthermore, no phase separation was observed from the Han plot and good compatibility was noticed from the Cole–Cole plot, which signifies good rheological properties of the fabricated bio-composites. [ABSTRACT FROM AUTHOR]

The focus of this work was to analyze the influence of leaf treatments on mechanical, physical and chemical properties and thermal stability of the gelatin/lotus leaf composites. Lotus leaves were treated with drinking water at 95 °C for 5 min. The gelatin/untreated lotus leaf (referred to as GUL) and the gelatin/hot water treated lotus leaf (referred to as GHL) composites have been prepared by the compression molding technique. The composites have been investigated by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TAG), Scanning electron microscopy (SEM). Effect of the lotus leaf hand lay-up fiber orientation was studied for longitudinal, transverse and random orientation of the fibers. The tensile strength of gelatin/lotus leaf composites were influenced by the orientation of the fibers. It was found that longitudinal orientation delivered higher mechanical properties than that of the transverse and random orientation whether untreated or treated. The hot water modification of the lotus leaf was employed to improve the interfacial adhesion of the composites in order to improve the tensile properties. By using TGA analysis data and Ozawa-Flynn-Wall (OFW) method, the thermal stability and degradation temperature of the lotus leaves treated with hot water were higher than those of untreated leaves. In addition, the properties of the novel bio-composites were potential in further development of biodegradable packaging materials. [ABSTRACT FROM AUTHOR]

In present research report four types of biocomposites were synthesized and characterized by surface area analysis (SEM–EDX); porosity (BET), X-Ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). These synthesized bio-composites were further examined for Zn(II) removal and recovery in batch reactors followed by column experiments using industrial effluent. The Aspergillus flavus NA9 immobilized glutaraldehyde cross-linked calcium alginate beads (FGCAB) proved as a novel biosorbent with maximum uptake capacity of (324 ± 2.1) mg Zn(II)/g in the studied concentration range (100–600 mg of Zn(II)/L). The chemistry of Zn and FGCAB interaction was studied using SEM–EDX and XRD analysis. Isotherm models used to analyze the data generated in batch bioreactors showed a best fit to Freundlich isotherm. Column studies depicted maximum 89.6% Zn(II) recovery with FGCAB using 0.01 M HCl. The column containing 1.5 g dry weight of FGCAB purified 5.25 L of paint industry effluent (9.58 mg Zn(II) /L before breakthrough occurred and became saturated after 11 L of influent, which revived upto three sorption–desorption cycles. Thus, A. flavus NA9 immobilized glutaraldehyde cross-linked alginate beads could be promising sorbent for treatment of Zn(II) contaminated industrial waste stream. [ABSTRACT FROM AUTHOR]

In this work poly(lactic acid) (PLA) composites containing modified natural fillers obtained from physically and chemically treated mallow and eucalyptus fibers were prepared and characterized. The fibers were submitted to different alkaline and acid hydrolysis methods. The results showed that chemical treatment improved the thermal stability of the mallow fibers and reduced that of the eucalyptus fibers; however, there was a significant increase in the degree of crystallinity in both fibers. After the thermal and morphological analysis, the treated fibers were added to a commercial PLA matrix at 5 wt% content in a twin-screw Haake Minilab mini-extruder. First, the neat PLA was processed at 180 °C at 60, 120 and 180 rpm for 5 min to adapt the parameters to the material’s rheological characteristics. According to the results, the best conditions were obtained when processing at 120 rpm; subsequently, all of the composites were prepared using this speed. Then, the composites were characterized showing that the addition of fibers to the polymer matrix improved stiffness, which was more significant in the case of the PLA/eucalyptus fiber composites, where the treatment applied to the fibers decreased the fiber diameter and improved the surface adhesion. [ABSTRACT FROM AUTHOR]

Natural fibers are limited in their use as reinforcement to commodity polymers. They cannot be used to reinforce engineering polymers due to their low thermal stability at high processing temperatures. This study presents an approach to successfully reinforce polyamides using a derivative of natural fibers as reinforcement without the effects of thermal degradation during melt processing. Biocarbon from miscanthus fibers was used to reinforce polyamide 6 up to 40 wt%. At 40 wt% filler content, the tensile and flexural strengths increased by 19.6 and 47% respectively in comparison to the neat polyamide. The moduli were also increased by 31.5 and 63.7% respectively. A maximum increase in impact strength of 43.7% was achieved at 20 wt% biocarbon loading. The morphology of the tensile fractured samples showed stretched polyamide ligaments attached to the biocarbon particles, indicating the presence of interaction between filler and matrix. Interestingly, more bonded interfaces were observed between the polyamide and biocarbon particles with increasing biocarbon content possibly stemming from increased biocarbon surfaces with functional groups. These composites show great potential to substitute in part or whole, some particulate filled polyamides currently used in the automotive industry. [ABSTRACT FROM AUTHOR]

The south and center-west of Brazil are agribusiness and rice production centers. Hence, after the rice processing, approximately 20% of the rice husk is residue that is discarded by the industry. In this sense, the aim of this research is to evaluate the influence of hot water treatment in the rice husk (RH) and then use it as reinforcement in polyhydroxybutyrate (PHB) matrix. PHB/RH composites with ratio of 90/10 and 80/20 were obtained by melt blending. Two groups of fibers were used, in nature rice hull (RHi) and treated (RHt). The FTIR results of the effluent showed the presence of C=O, C=C, CO, CH, OH groups and silicon. Additionally, indicating a low molecular weight compounds on the natural fiber that are soluble in water. The matrix and composites were characterized by their physical, chemical, mechanical and morphological properties. Tensile and impact tests results showed that all the composites had better performance in terms of mechanical properties related to the unreinforced matrix. There was good interfacial adhesion between fiber and matrix for all the composites, which was verified by SEM images, especially for reinforced composites with untreated rice husk. [ABSTRACT FROM AUTHOR]

Clear and consistent relationships between the properties of natural fibers and their corresponding performance in the bio-composites are not fully understood yet. This in order makes it practically difficult to predict the performance deterioration of such fibers in composites and makes proper selections of natural constituents to maximize the composites desirable performance very costly with discarding plenty of available natural resources. In this work, systematic investigations about the relationships between the inherent characteristics of natural fibers and their performance in composites are developed and carried out for the first time to enhance the understanding of such interactions. Here, investigating the relationships between the tensile strengths of natural fibers with their respective performance deteriorations in polypropylene composites are carried out. In addition, systematic comparative studies of the interactions of the fibers and polymers mechanical properties--like fibers' Young's moduli, tensile strengths and polymer flexural strengths-on their corresponding performance deteriorations in bio-composites are performed considering various performance characteristics. Several promising conclusions have been drawn here such as the possibility of using fibers with low moduli of elasticities to produce composites with much better tensile strengths comparable to costly fibers with high inherent tensile properties. Moreover, findings of this study stress upon compromising as well as the better utilization of the available natural resources and wastes to achieve desired composite characteristics considering economic viability of the available natural resources for proper resource-efficiency optimization. [ABSTRACT FROM AUTHOR]

Nanosized calcium carbonate (nano-CaCO) filled poly- l-lactide (PLLA)/polycaprolactone (PCL) bio-composites were prepared by using a twin-screw extruder. The melt flow behavior of the composites, including the entry pressure drop, melt shear flow curves and melt shear viscosity were measured through a capillary rheometer operated at a temperature range of 170-200 °C and shear rates varying from 50 to 10 s. The melt shear flow roughly followed the power law, while the effect of temperature on the melt shear viscosity might be estimated by using the Arrhenius equation. Moreover, the relationship between the PCL weight fraction and the melt shear viscosity for the PLLA/PCL/nano-CaCO composite was described by a quadratic equation. [ABSTRACT FROM AUTHOR]

Disk refining and ultrasonication treated sugarcane bagasse residues reclaimed from the waste stream of a simplified bioethanol process after fermentation were used to fabricate biobased composites with poly(vinyl alcohol) (PVA) by film casting. The morphologies and the size distributions of residue particles were characterized by scanning electronic microscopy and various particle size analyzers. The results showed that the residue particle sizes were about hundreds nanometers to tens microns after disk refining treatment. After further treatment by ultrasonication, the particle sizes ranged from about tens of nanometers to several microns. The treated residues were expected to have a large surface area to reinforce PVA. The results indicated that the addition of treated fermentation residues significantly increased the tensile modulus of neat PVA with minimal impact on tensile strength. Furthermore, the PVA composites had higher thermal degradation temperature compared to neat PVA. [ABSTRACT FROM AUTHOR]

The mechanical-thermal properties and volatile organic compound (VOC) emissions of natural-flour-filled, biodegradable polymer bio-composites were investigated according to variation in porous inorganic filler types. At a porous inorganic filler content of 3%, the tensile and flexural strengths of the hybrid bio-composites were not significant changed. However, the coefficient of thermal expansion and thermal expansion of the bio-composites were slightly decreased. Furthermore, the incorporation of the porous inorganic materials into bio-composites slightly increased the E' values of the hybrid bio-composites over the entire temperature range, although the tan δ temperature ( T) of the hybrid bio-composites was not significantly changed. At a porous inorganic filler content of 3%, the various odor and VOC emissions of the hybrid bio-composites were significantly decreased because the various oxidation and thermal degradation gases of the natural flour and matrix were absorbed in the pore structures of the porous inorganic fillers and thereby prevented the migration into the final products. [ABSTRACT FROM AUTHOR]