Wood Polymer Composites Research Articles

Physical, Mechanical, and Flammability Properties of Wood-Plastic Composites (WPC) Containing Beech-Wood Flour and Flame-Retardant Additives.

This study aims to develop a recyclable, economical, and flame-retardant composite material using polypropylene, beech flour, tetrabromobisphenol A bis (TBBPA), and antimony trioxide (ATO). Flame-retardant additives (TBBPA and ATO) were initially added into polypropylene at different rates, and masterbatch (MB) samples were produced by the extrusion method. Subsequently, different percentages of wood flour (10%, 15%, 20%, 25%, and 30%) along with 60% MB were added to the polypropylene to create wood-polymer composites (WPC) using the injection method. The TBBPA, ATO, and wood flour were introduced through side-feeding hoppers during injection to ensure a homogeneous distribution within the WPC. Physical, thermal, and mechanical tests were conducted on the WPC samples. Additionally, TGA, FTIR, and SEM analyses were performed. The results indicated that the optimal ratios for TBBPA and ATO additives were 20% and 10%, respectively. It was observed that increasing the wood flour content in the WPC samples led to enhanced density, water absorption, hardness, impact, and abrasion resistance. Conversely, MFI, bending strength, and tensile strength decreased with higher wood flour content. It was observed that WPC samples exhibited flame resistance up to 725 °C. The produced WPC materials can be used in flooring applications, interior furniture, decorative wall panels, and aesthetic structural elements due to their fire behavior, good mechanical properties, low water-absorption rates, and aesthetic appearance.

Hot-Pressing Process of Flat-Pressed Wood-Polymer Composites: Theory and Experiment.

The objective of this research was to develop a mathematical model of the hot-pressing process for making flat-pressed wood-polymer composites (FPWPCs). This model was used to calculate and predict the temperature and time required for FPWPC pressing. The model's performance was analysed using the experimental results of hot pressing FPWPCs. It was found that an increase in the content of wood particles led to a rapid increase in the pressing time. The model and experiment showed that the core temperature of the wood-polymer mat remained nearly constant for the first 20-30 s of the hot-pressing process. After this period, this temperature increased rapidly until it reached 100 °C, after which the rate of increase began to decelerate sharply. This transition was more distinct in FPWPCs with a high wood-particle content, while in those with a high thermoplastic-polymer content, it was smoother. Increasing the pressing temperature contributed to a reduction in the time required to heat the FPWPC, as confirmed by both experimental data and the modelling of the hot-pressing process. A decrease in the predicted density of the FPWPC resulted in a directly proportional increase in the time required to heat the mat. Validation of the mathematical model revealed a mean absolute percentage error (MAPE) of only 2.5%, confirming its high precision and reliability. The developed mathematical model exhibited a high degree of accuracy and can be used for further calculations of the time required for FPWPC pressing, considering variable parameters such as pressing temperature, wood-polymer ratio, mat thickness, and density.

Wood fibers with natural blowing agents for extrusion and injection molding of polypropylene

ABSTRACT This paper presents a new two-step approach of foaming polypropylene (PP) containing wood fibers (WF) with tri-sodium citrate dihydrate as the low-temperature chemical blowing agent (CBA) and sucrose as the high-temperature CBA. The first CBA was intentionally selected to thermally degrade during extrusion (lower temperature range), whereas the second CBA during the injection molding (higher temperature range). The CBAs were dissolved in water, and WF were soaked in these solutions, afterward dried, ground, and then mixed with PP and extruded. The extruded granules were then injection molded to produce dumbbell-shaped samples. The porosity, thermal degradation, PP crystallization, mechanical and thermomechanical properties of the wood-polymer composites (WPCs), as well as their susceptibility to acoustic damping, were determined. It was shown that sucrose can be an effective CBA for injection-molded WPC samples. However, the effectiveness of this additive is improved by the addition of tri-sodium citrate dihydrate, which decomposed during extrusion.

Determination of Fire Resistance, Mechanical Property and Physical Stability of Boron Phosphate Containing Wood Polymer Composites

Determination of Fire Resistance, Mechanical Property and Physical Stability of Boron Phosphate Containing Wood Polymer Composites

Coniferous Bark as Filler for Polylactic Acid-Based Biocomposites.

This study explores the possibilities of utilisation of coniferous bark as a filler in wood-polymer composites (WPCs), its impact on properties such as the modulus of rupture (MOR), modulus of elasticity (MOE), thickness swelling (TS) and water absorption (WA) after 2 h and 24 h of immersion in water and the significance of this impact compared to other factors. Six variants of bark-polylactic acid (PLA) WPCs were manufactured, differentiated by their filler content and filler particle size. As a comparison, analogous composites filled with coniferous sawdust were also manufactured. Bark-filled composites were characterised by lower TS and WA after both 2 h and 24 h of immersion, as well as lower water contact angles and surface free energy. The bark filler decreased the composites' MORs and MOEs, while greater differences were noticed for variants filled with small particles. The type of filler was the second most important factor contributing to variance in this study, with the filler content being the most important one.

Use of Recycled Additive Materials to Promote Efficient Use of Resources While Acting as an Effective Toughness Modifier of Wood-Polymer Composites.

Wood-polymer composites (WPCs) with polypropylene (PP) matrix suffer from low toughness, and fossil-based impact modifiers are used to improve their performance. Material substitution of virgin fossil-based materials and material recycling are key aspects of sustainable development and therefore recycled denim fabric, and elastomer were evaluated to replace the virgin elastomer modifier commonly used in commercial WPCs. Microtomography images showed that the extrusion process fibrillated the denim fabric into long, thin fibers that were well dispersed within the WPC, while the recycled elastomer was found close to the wood fibers, acting as a soft interphase between the wood fibers and PP. The fracture toughness (KIC) of the WPC with recycled denim fabric matched the commercial WPC which was 1.4 MPa m1/2 and improved the composite tensile strength by 18% and E-modulus by 54%. Recycled elastomer resulted in slightly lower KIC, 1.1 MPa m1/2, as well as strength and modulus while increasing elongation and contributing to toughness. The results of this study showed that recycled materials can potentially be used to replace virgin fossil-based elastomeric modifiers in commercial WPCs, thereby reducing the CO2 footprint by 23% and contributing to more efficient use of resources.

Research of the Performance Characteristics of Wood-polymer Composites Based on the Recycled Linear Polyethylene

The results of a comparative study of the performance characteristics of wood-polymer composites based on recycled linear polyethylene (LLDPE) manufactured according to TU 38.32.33-001-44971101-2017 and high-density polyethylene (LDPE) grade 15303-003 produced by PJSC Kazanorgsintez are presented. It has been found that it is promising to use LLDPE to produce the wood-polymer composites, since its performance properties are comparable to LDPE, but at the same time it is significantly cheaper.

Predicting orientation in extruded wood polymer composites

Predicting orientation in extruded wood polymer composites

Mechanical and Processing Properties of Plasticised PVC/Wood Composites.

The paper presents the results of testing the properties of wood-polymer composites (WPC) based on plasticised poly(vinyl chloride) (PVC-P). Materials with variable contents of wood filler (Arbocel C 320) or plasticiser (di-isononyl phthalate) were produced and then analysed. The share of wood flour in the material was up to 50 phr, and the plasticiser content was up to 40 phr. Functional properties, such as tensile properties, mechanical properties at variable temperature (DMTA), and water absorption, as well as processing properties such as rheological properties and analysis of the fusion process, were analysed. The influences of wood flour and plasticiser on the composites' properties in the solid and melted state were found. For example, with 40 phr of plasticiser, increasing the filler share from 0 phr to 50 phr resulted in an increased tensile modulus from 18 MPa to 274 MPa and viscosity at a share rate of 20 s-1, from 721 Pa·s to 1581 Pa·s. However, increasing the share of plasticiser from 20 phr to 40 phr with 30 phr of filler reduces the value of these properties from 1760 MPa to 112 MPa and from 2768 Pa·s to 1151 Pa·s, respectively. It was also found that increasing the share of wood flour in the composite noticeably reduces the effectiveness of the plasticiser.

The effect of two-stage filler processing on the properties of a wood-polymer composite

The effect of two-stage filler processing on the properties of a wood-polymer composite

Influence of fly ash on the properties of wood-polymer composites

This study reports the influence of fly ash on the operational, technological, and physical-mechanical properties of composites based on secondary high-density polyethylene filled with wood flour. It is shown that when calcite is replaced by fly ash in the composite, the operational and technological properties of the material are improved: water absorption, coefficient of linear thermal expansion and technological shrinkage are reduced. When using fly ash as a filler, there is also an increase in the flexural strength of the composite by 9% (from 51.3 MPa in the absence of fly ash to 55.8 MPa in the absence of calcite), but the Charpy impact toughness of samples with cut is decreased by more than 2 times (from 11.9 kJ/m2 to 5.1 kJ/m2, respectively).

Investigate Technical Viability to Fabricate Wood Polymer Composites Made of Waste Wood Powder and Epoxy Resin

Investigate Technical Viability to Fabricate Wood Polymer Composites Made of Waste Wood Powder and Epoxy Resin

The application of chromatography and complementary techniques for wood identification — State of the art and future directions

Summary Wood identification, whether it involves distinguishing between known species or identifying unfamiliar wood samples, is a scientific field increasingly valuable across various disciplines ranging from biology to criminology, structural engineering, and art conservation. It carries a growing economic, commercial, social, and ecological significance. Numerous scientific methods have been employed for wood identification. Visual analysis techniques, such as macroscopy, optical microscopy, scanning electron microscopy, X-ray tomography, and computer-assisted wood identification, play a pivotal role. Analytical approaches like mass spectrometry, near-infrared spectroscopy, thermogravimetry, and DNA barcoding have also been utilised. However, chromatography stands out due to its exceptional precision in providing quantitative and qualitative results, prompting its development and widespread use. This paper offers a critical review of the role of chromatography in wood identification. Advantages are highlighted, including the capability to identify specific components unique to each wood species, thus achieving remarkable differentiation at the species level. Additionally, potential drawbacks are discussed, such as the time-intensive sample preparation procedures, mainly when dealing with materials like wood-polymer composites (WPC), and the absence of an open-source database. This comprehensive analysis aims to provide a broader perspective on the possibilities and limitations of this technique.

Wood Polymer Composite Based on Poly-3-hydroxybutyrate-3-hydroxyvalerate (PHBV) and Wood Flour-The Process Optimization of the Products.

This study involved the optimization of the molded pieces manufacturing process from a poly-3-hydroxybutyrate-co-3-hydroxyvalerate biocomposite containing 30% wood flour by mass. The amount of wood flour and preliminary processing parameters were determined on the basis of preliminary tests. The aim of the optimization was to find the configuration of important parameters of the injection process to obtain molded pieces of good quality, in terms of aesthetics, dimensions, and mechanical properties. The products tested for quality were dog bone specimens. The biocomposite was produced using a single-screw extruder, whereas molded pieces were made using an injection molding process. The Taguchi method was applied to optimize the injection molding parameters, which determine the products quality. Control factors were selected at three levels. The L27 orthogonal plan was used. For each set of input parameters from this plan, four processing tests were performed. The sample weight, shrinkage, elongation at break, tensile strength, and Young's modulus were selected to assess the quality of the molded parts. As a result of the research, the processing parameters of the tested biocomposite were determined, enabling the production of good-quality molded pieces. No common parameter configuration was found for different optimization criteria. Further research should focus on finding a different range of technological parameters. At the same time, it was found that the range of processing parameters of the produced biocomposite, especially processing temperature, made it possible to use it in the Wood Polymer Composites segment.

Modeling of mechanical properties of wood-polymer composites with Artificial Neural Networks

Mechanical properties (tensile strength (TS), modulus of elasticity in tensile (MET), flexural strength (FS), modulus of elasticity (MOE)) of the material to be obtained depending on the production parameters in the production of high-density polyethylene (HDPE) wood-polymer composites with Scots pine wood flour additive were predicted using Artificial Neural Networks (ANN) model and without destructive testing. In the first stage of the study, an ANN model was developed using data from 56 different studies in the literature on the mechanical properties of wood polymer composites. In the second stage, in order to determine the reliability of the model, output values were estimated using input parameters that had not been used in training and testing of the model. Based on the same input parameters, test specimens were produced and mechanical tests were performed. The results obtained from the experiments and ANN model were compared by considering the mean absolute percentage error (MAPE) value. The coefficient of determination (R2) values obtained in the training and testing phase of the ANN models were all higher than 0.90. In this way, the mechanical properties of the wood polymer composite were successfully predicted by the ANN model. Because most of the MAPE values obtained from the mechanical tests were below 10%, the model was considered a reliable model.

A review on natural fiber composites: Polymer matrices, fiber surface treatments, fabrication methods, properties, and applications

AbstractHigh performance and durability are essential for goods to satisfy the needs of the expanding worldwide market. Wood plastic composites (WPCs) are materials made from a combination of wood, polymers, and additives. WPCs can be extruded, injected, compressed, or thermoformed. Presently, WPCs are manufactured using sophisticated processes including as laser sintering, fused layer modeling, and additive manufacturing. Properly managing the melt temperature and pressure is crucial in the manufacturing process of WPCs to ensure effective polymer incorporation. Natural fibers have distinct benefits for polymer composites, but they also have some serious drawbacks, like lower strength properties—especially lower impact strength than synthetic fibers—poor compatibility with hydrophobic polymers, poorer dimensional stability and moisture absorption due to hydroxly groups, a maximum processing temperature that is limited, thermal degradation above 200–220°C, and lower biological durability. The modification of the surface of the fibers improves the mentioned disadvantages of the natural fibers. High‐quality WPCs require the application of chemical or physical treatment to the wood fibers. This extensive review focused on the modification techniques applied to the surface of wood, manufacturing processes, and properties and applications of WPCs.Highlights Modification methods used in surface treatment of natural fibers was explained. Properties and recent applications of wood polymer composites were given. Optimum requirements of natural fibers and polymer matrices are given. Fabrication methods of natural fiber composites are extensively given.

Cork consolidated by hot compression as a viable bio-based alternative to polyolefines in decking boards: A preliminary study

Currently, three classes of materials are used in deck boards production, i.e., wood, plastics and wood polymer composites. Wood is the best choice being bio-based, biodegradable and displaying better mechanical performance, but the environmental concerns deriving from forest depletion make the identification of a new bio-based solution necessary. In this sense, agglomerated cork is promising, being derived from the bark of the oak, but in its native form is not suitable for decking boards production due to low bending properties. The present work proposes a solution to use agglomerated cork in decking board manufacturing by converting its cellular structure in a consolidated one by hot compression. Design of Experiment was used to optimize consolidated cork mechanical properties as a function of the main manufacturing parameters, i.e., time and temperature. The exposure to high temperatures allows cork cell walls welding by developing adhesive properties, but it also induces a strong degradation of polysaccharides. It was discovered that the manufacturing parameters which maximize both flexural and tensile properties are a 180 °C operating temperature and a 31.5 min holding time. These conditions ensure a bending stiffness 40.9% and a bending strength 107.1% higher than the ASTM D6662 minimum requirements.

Reducing the Environmental Impacts of Plastic Cosmetic Packaging: A Multi-Attribute Life Cycle Assessment

The global packaging industry has been growing significantly, resulting in an increase in waste and emissions. Social responsibilities, regulations and targets are shifting companies’ priorities to various sustainable practices. This study comprised a life cycle assessment (LCA) to quantify and compare key initiatives influencing the sustainability of plastic cosmetic packaging. The life cycle environmental effects of dematerialisation, recycled content, energy-saving initiatives and renewable energy powering the manufacturing processes, and the end-of-life (EoL) recycling rates of various scenarios, were evaluated. Moreover, a variety of fossil-based and bio-based polymers, such as acrylonitrile butadiene styrene (ABS), polypropylene (PP), polyethylene terephthalate (PET), wood–polymer composite (WPC) and polylactic acid (PLA), were considered. The study determined that dematerialisation and recycled content had the most beneficial impacts on packaging sustainability. When 100% recycled materials were used, an overall impact reduction of 42–60% was noted for all the materials considered. Using 100% renewable energy and applying measures to reduce the energy consumption in the manufacturing stage by 50% reduced the total impact by approximately 9–17% and 7–13%, respectively. Furthermore, it was concluded that PP had the lowest environmental impacts in the majority of the case scenarios considered, by an average of 46%.

Surface analysis of different wood polymer composites exposed to artificial weathering

This study presents a superficial analysis of different wood polymer composites (WPC) comprising polystyrene (WPSC), poly(furfuryl alcohol) (WPFAC), and pine resin (WPRC) when exposed to artificial weathering. The study investigates the influence of resin type on the composites, focusing on their chemical, colorimetric, morphological, and thermal properties. The main findings indicate WPSC exhibits poor resistance to weathering, allowing ultraviolet radiation damage on the lignocellulosic component of the composite, leading to oxidized groups formation. Conversely, WPFAC and WPRC demonstrate good wood protection capabilities by preventing significant deterioration of holocellulose and acting as filters for radiation and moisture. Moreover, WPFAC exhibits the lowest decrease in carbonyl index and O/C ratio, with reductions of 2.6 and 11.6%, respectively. These findings are significant as they demonstrate that poly(furfuryl alcohol) and pine resin can be used to produce WPCs that delay and mitigate wood degradation by weathering, contributing to the increased potential utilization of bioresins.

Investigate on the physical and mechanical properties of wood-polymer composition materials made on the premise of neighborhood wood flours

This study aims to demonstrate the feasibility of obtaining wood-polymer composites, which focus on materials that are difficult to recycle. For this purpose, local poplar and pavloniya wood samples, the density of which corresponds to this process, were impregnated with polyvinyl chloride and CaCO3, which form free radicals. Samples were taken using a hot press. Physico-mechanical parameters of the samples were analyzed. Due to the low permeability of the poplar wood showed only increasing values of stiffness parallel and perpendicular to the grain. Undebarked ponderosa pine chips were treated by hot water extraction to modify the chemical composition. In the treated pine (TP), the mass was reduced by approximately 20%, and the extract was composed mainly of degradation products of hemicelluloses. Wood flour produced from TP and unextracted chips (untreated pine, UP) was blended with high-density polyethylene (HDPE) and polypropylene (PP) and was extruded into wood plastic composites (WPCs).