Side streams were collected from three locations in a flooring factory and their suitability in biocomposite formulations was assessed. The side stream (S3) that contained mainly residues from ...high-density fibreboards (HDF) was selected for further material testing. The effect of different fractions of S3, thermomechanical pulp (TMP) fibres and polylactic acid (PLA) were assessed in terms of their mechanical, melt flow and thermal properties. A biocomposite made from PLA, 20 wt% TMP fibres and 10 wt% S3 revealed a significant increase in modulus (5800 MPa), compared to the neat PLA (3598 MPa), and a similar melt-flow index (MFI = 4.5). The tensile strength was however somewhat reduced from 66 to 58 MPa. Importantly, numerical modelling and simulations were applied to demonstrate that building a model chair out of biocomposite can potentially reduce the material volume by 12% while maintaining similar load bearing capacity, compared to neat PLA.
In this research mechanical, thermal, and water uptake behaviour of silane-treated sea-urchin spike filler and kenaf fibre mat-reinforced neem oil blended epoxy resin composite has been studied. The ...principal aim of this research was fabrication of eco-friendly composite and explicit the importance of silane-treatment on reinforcement’s surface. Neem oil blended with epoxy resin to convert it as an eco-friendly one, whereas additions of kenaf fibre and sea urchin particles into neem-epoxy matrix made the composites tougher. Both filler and fibre was surface-treated by an amino silane (APTMS). The results revealed that, additions of surface-treated sea urchin particle and kenaf fibre increased the mechanical properties of composite. Similarly thermal results exposed that addition of sea urchin bio ceramic filler increased the thermal stability of neem-epoxy bio composite. SEM fractograph showed uniform dispersion of sea urchin filler and improved adhesion of kenaf fibre with epoxy matrix.
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•The initial discolouration for WPC is attributed to wood particle colour change.•Strong correlation between changes in polymer light transmittance and WPC fading.•WPC ...whitening/fading is mainly caused by polymer microcracking.•Reduced surface erosion observed for WPC with heat-treated wood.
In the present work weathering peculiarities for heat-treated wood plastic composites (HTWPC) were investigated mainly focusing on the effects caused by UV radiation. In addition, the discolouration mechanism for WPC was analysed in general. The results showed that the colour change during UV exposure for WPC with untreated wood particles (WPC(UT)) initially is caused by wood particle discolouration, which is followed by rapid increase in lightness that is due to polypropylene photodegradation. For HTWPC initial colour change caused by heat-treated wood particles was insignificant, however eventually the discolouration for the composite was several times larger than for WPC(UT) due to polypropylene photodegradation in combination with darker initial colour of the composite. Microcracking that reduce the light transmittance of the polypropylene matrix was the main reason for the large colour change. Despite the larger discolouration, the results regarding surface erosion and microcracking showed that HTWPC are more resistant against UV radiation.
•Fibers reinforced composite with sodium alginate binder were prepared for the first time•Wood fibers and reclycled cotton fibers where mixed in various proportion to manufacture composites with ...different softness.•Addition of crosslinkers in the sodium alginate matrix provides more rigid composites.•These new biocomposites have low thermal conductivity, high thermal capacity and medium bending and compressive strength.
Alginate derived from seaweed is a natural polysaccharide able to form stable gel through carbohydrate functional groups largely used in the food and pharmaceutical industry. This article deals with the use of sodium alginate as an adhesive binder for wood fibres/textile waste fibres biocomposites. Several aldehyde-based crosslinking agents (glyoxal, glutaraldehyde) were compared for various wood/textile waste ratios (100/0, 50/50, 60/40, 70/30 and 0/100 in weight). The fully biomass derived composites whose properties are herewith described satisfy most of the appropriate requirements for building materials. They are insulating with a thermal conductivity in the range 0.078–0.089 W/m/K for an average density in the range 308–333 kg/m3 according to the biocomposite considered. They are semi-rigid with a maximal mechanical strength of 0.84 MPa under bending and 0.44 MPa under compression for 60/40 w/w wood/textile waste biocomposites with a glutaraldehyde crosslinking agent.
Polypropylene (PP)/elastomer/wood flour composites were prepared from two PP reactor blends. The detailed analysis of the deformation and failure of the composites has shown that several local ...deformation processes take place during loading which differ considerably in terms of energy consumption. These processes may even interact with each other, sometimes resulting in an antagonistic effect on impact resistance. The shear yielding of the matrix consumes energy the most efficiently. The presence of wood decreases shear yielding by hindering overall deformation and initiating other local processes like debonding. The role of debonding is controversial; it may increase, but also decrease plastic deformation and impact resistance. The fracture of wood does not consume much energy and thus does not contribute to impact resistance. PP cannot be reinforced with wood flour, if impact resistance is an important aspect. Other methods are more suitable in such cases, like the addition of synthetic fibers.
•Measurements of polymer composites using capillary rheometer requires correction.•Entrance pressure losses correction is necessary for high shear rate values.•The wood flour content has a ...significant effect on the entrance effects.•The size of the wood flour has no significant effect on the entrance effects.•Special capillary injection moulding rheological device was used.
The study presents the results of rheological tests of wood polymer composites (WPC) on a polypropylene matrix. The influence of the filler on the additional pressure losses as a result of entrance effects has been analysed. The tests were carried out with the use of a capillary rheometer and a rheological head at the values of apparent share rate up to 101 860 s−1.
The influence of the Bagley corrections on the apparent viscosity curve defined for the tested composites was determined. In the case of rheological tests at low shear rates, omit the additional pressure losses does not significantly affect the determined rheological properties. It was observed that with the increase of the filler content and shearing rate, the value of pressure losses significantly increases. It is necessary to consider the values of pressure losses in rheological measurements of rheological properties of WPC with the use of capillary rheometers.
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Thermoplastic starch (TPS) composites were manufactured from potato starch, wood fibers (WF) with content up to 41.5 wt% and deep eutectic solvents (DES) based on choline chloride ...with urea or glycerol (Gl) as well as imidazole (Im) with Gl. Processing method: mechanical mixing of the components followed by thermocompression with simultaneous WF modification. DES can play a triple role of starch plasticizer, WF surface modifier, and the composite components interfacial adhesion improver. The biocomposites mechanical, thermomechanical, moisture sorption and surface wetting properties were dependent on DES type. The highest TPS/WF performance exhibited composites with Im/Gl: tensile strength up to 11 MPa, Young’s modulus to 590 MPa, moisture sorption to 4 wt% and water contact angle about 100°. Clear correlation between DES activity towards WF and its surface modification on the one side, and mechanical and thermomechanical features of TPS/WF composites manufactured in sustainable process on the other, was found.
Mixing lignocellulosic fibres with a mineral binder to produce fibreboards is a challenging process due to their large volume per unit mass and their susceptibility to agglomeration (balling effect). ...The main objective in the dry mixing-spraying process presented in our study is the uniform distribution of the geopolymer binder in the lignocellulosic material. In this work, we compare the properties of two types of composites processed by implementing the abovementioned technique. Geopolymer-bonded fibreboards were produced using up to 50 wt% seagrass or wood fibres. Microscopy and X-ray micro-tomography investigations of the geopolymer composites indicated that their mechanical and physical properties depend on the size of incorporated fibres. Large seagrass fibres were appropriately mixed with the mineral binder matrix forming solid fibreboards that were able to reach the standard requirements for cement boards. More specifically, seagrass-based fibreboards exhibit up to 42% higher bending strength (up to 9.4 MPa) compared to fibreboards composed of wood fibres. In addition, their low thickness swelling and low mean heat release rate in a cone calorimeter (varying from 21.5 to 26.6 kW m−2) indicated a high resistance to water and fire. Considering the resulting properties of the produced fibreboards, the dry-mixing spraying process can be an appropriate technique for producing geopolymer composites containing large amounts of relatively long fibres.
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•The dry mixing-spraying process was utilized for the production of fibreboards.•Seagrass and wood fibreboards were investigated, and their properties were compared.•The adequate coverage of fibres with the geopolymer binder affects the properties of the produced composites.•The dry mixing-spraying can be applied to a wide variety of lignocellulosic materials.
This paper presents a comprehensive characterisation of wood flour geometry for polylactic acid (PLA) wood plastic composites (bioWPCs), and hence explores how the wood flour may influence the ...microstructure and performance of bioWPCs. The results show that current characterisation of wood flour from the literature can be misleading as they mostly rely on sieve analysis. Image analysis was used to critically study the fibres retained at various mesh sizes to investigate and examine the length and width distributions of the fibres prior to and after processing into bioWPCs. There were clear relationships between the reduction in both fibre size and aspect ratio and compounding processes depending on the original fibre geometry. It was also determined that by sieving out only the fibres retained at 500 µm much stronger bioWPCs can be produced than that using a single size fibre, achieving tensile and flexural stress of 15.3 and 13.2 MPa, respectively.
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•Nanoscale fibril composite was compared with microscale wood fiber (WF) composite.•Differences in mechanical properties and deformation mechanisms were studied.•Oriented WF had ...superior eco-indicators but properties comparable to random MFLC.•FEM updating predicted 4 independent elastic constants from a single orthotropic WF composite.
Hot-pressed, binder-free wood fiber (WF) composites can serve as load-bearing and eco-friendly materials, and the comparison of nanoscale fibril reinforcement with microscale wood fibers is of interest. We investigated property differences and interpreted deformation mechanisms with strain field measurements using digital image correlation combined with orthotropic, elastic–plastic finite element model updating predictions. Random-in-plane microfibrillated lignocellulose (MFLC) composites showed better mechanical properties than WF composites due to stronger strain-hardening from lower porosity and better interfibrillar adhesion, provided by the intrinsic lignin-hemicellulose binder. Axially oriented wood fiber composites (O-WF) achieved comparable mechanical properties to random MFLC, with lower values for eco-indicators. The FEM updating method could successfully determine all 4 independent elastic constants from one 45° off-axis experiment, although the plasticity model required two more experiments.
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