Study of effect of wood-flour content on mechanical, thermal, rheological properties and thermoformability of wood-polypropylene composites

Wood plastic composites (WPC) were made from polypropylene (PP), impact copolymer (ICP) and wood flour (WF) by varying the WF content from 10 to 40% with PP grafted maleic anhydride as a coupling agent. The effect of varying WF content was studied on rheological, thermal, mechanical properties and dynamic mechanical properties. Experimental small amplitude oscillatory shear (SAOS) data was compared with the Einstein–Batchelor and empirical Krieger–Dougherty relations. Significant dependence of mechanical and rheological properties on WF content was observed. Young’s modulus, flexural modulus and dynamic shear viscosity increased with WF content. Results of dynamic mechanical analysis (DMA) showed increase in storage modulus with WF content. Three millimeter thick compression molded composites sheets were thermoformed using axisymmetric molds with two draw depths. Sag observed visually during thermoforming decreased with increasing WF content. Components made from the composites showed close to uniform thickness distribution as compared to those from ICP.

Application of biowaste in rubber blend

Submitted paper deals with the incorporation of biological waste into the rubber blend and moreover, it is mainly connected with the determination of the influence of this biowaste on the basic properties of the blends and vulcanizate. Wood flour, which comes from the production of wood pellets, was used as the biowaste. Biowaste was used as a filler but also as a plasticizer. The effect of the mentioned biowaste (wood flour) in rubber blend was determined from the aspect of curing characteristics and physical-mechanical properties. In addition, Payne effect was also determined. Achieved results show the possibilities of partial use of biowaste in the rubber blend and provide other research possibilities.

Improvement of technological properties of wood plastic composites reinforced with glass and carbon fibre fabric

In this study, HDPE-based flat-pressed WPCs were reinforced with glass fibre and carbon fibre woven fabrics, which could be used where high strength and stiffness are required. The effect of reinforcement on some physical, mechanical, and thermal properties and fire performance was investigated. According to the results, the increase in woven fabric density resulted in holding much water in the microvoids in the fabric, which increased water absorption up to 32.96%. Reinforcement also resulted in increased hardness. In general, continuous filaments in the fabric significantly increased mechanical properties. The improvement exceeded over 400% for tensile strength compared to unreinforced control samples, while the increases were 129% and 115% for the flexural strength and MOE, respectively. The interlocking of matrix and woven fabrics is an important factor that affects load transfer. The strong interaction between wood-polymer and the wood-polymer-woven fabric was observed from the SEM investigation. The thermal stability of composites was also improved, possibly due to the homogeneous distribution of heat within fibres. Glass and carbon fibres presumably acted as a buffer against increasing heat, increasing the onset temperature. Moreover, according to the LOI test, the need for oxygen increased from 24.72 to 26.01 with the effect of wood flour and reinforcement.

Application of spruce wood flour as a cellulosic-based wood additive for recycled paper applications— A pilot paper machine study

This study gives a first insight into the use of wood flour as a plant-based and cellulosic-based alter-native additive for newsprint and paperboard production using 100% recycled fibers as a raw material. The study compares four varieties of a spruce wood flour product serving as cellulosic-based additives at addition rates of 2%, 4%, and 6% during operation of a 12-in. laboratory pilot paper machine. Strength properties of the produced newsprint and linerboard products were analyzed. Results suggested that spruce wood flour as a cellulosic-based additive represents a promising approach for improving physical properties of paper and linerboard products made from 100% recycled fiber content. This study shows that wood flour pretreated with a plant-based polysaccharide and untreated spruce wood flour product with a particle size range of 20 μm to 40 μm and 40 μm to 70 μm can increase the bulk and tensile properties in newsprint and linerboard applications.

STADY OF SURFACE TENSION OF MODIFIED WOOD

The study of the surface tension of wood of various tree species impregnated with used sunflower oil was carried out. Samples of birch, pine and linden wood were used for oil treatment. Impregnation of wood materials was carried out by the method of “hot-cold baths”. As an impregnating material, used refined fryer oil was used. In more detail, the paper examines the effect of an impregnating composition based on used fryer oil, with a filler and a desiccant on birch wood. Wood flour of coniferous wood species and a metal salt-based drier were used as a filler. The surface tension for all images was determined by the edge angle of wetting. For this purpose, the method of a liquid drop on the surface of a solid body was used. It was found that the impregnation of untreated wood with deep-frying oil leads to an increase in the surface tension on all samples, to a greater extent this is typical for pine wood. The introduction of a 1% siccative in the impregnating composition together with wood flour reduces the drying time and improves the water-repellent properties of birch wood.

Preparation and Characterisation of Sustainable Wood Plastic Composites Extracted from Municipal Solid Waste

Municipal solid waste (MSW) contains plastic waste that can be used as a sustainable green substitute to reduce oil footprints, CO2 emissions, and environmental pollution. This study aims to recycle plastic waste by manufacturing wood-plastic composites and to improve its mechanical properties by using additives, coupling agents, and lubricants. These composites are prepared by mixing 40–70% of wood flour with 20–25% of a polymer matrix. Wood was degraded at 220 °C, and then the composites were processed at 50 °C. The manufacturing process carried out in the study involved wood waste meshing, drying, shredding, drying, trimming, filling, blending, compounding, and extrusion moulding. The compounding of composites was accomplished in twin-screw extruders. Once the mixture was uniformly mixed, its final shape was given by a two-step extrusion moulding. Previously, researchers aimed at enhancing the mechanical properties of the composites, but our research focus was to improve their durability for different industrial applications. The results suggest that the impact strength is 17 MPa with 50% of wood powder ratio while the maximum value for the tensile strength is 32.5 MPa. About 50% of an increase in wood powder resulted in 8.1% bending strength increase from 26.1 to 32.8 MPa. Reducing the plastic matrix and the wood-particles water swelling ratio resulted in better mechanical properties. The wood species also affected the mechanical properties with their excellent dimensional stability and less variability. A high proportion of wood fibre tends to increase its steady-state torque and viscosity. The mechanical properties against different wood-flour proportions indicate that composite materials exhibit superior water swelling behaviour and extrusion quality.