Thermal, Mechanical, Morphological and Aesthetical Properties of Rotational Molding PE/Pine Wood Sawdust Composites

This research addresses the importance of pine wood sawdust granulometry on the processing of medium-density polyethylene (MDPE)/wood composites by rotational molding and its effects on the morphological, mechanical and aesthetical properties of parts, aiming to contribute for the development of sustainable wood polymer composites (WPC) for rotational molding applications. Pine wood sawdust was sieved (<150, 150, 300, 500, 710, >1000 µm) and analyzed for its physical, morphological and thermal characteristics. Rotational molded parts were produced with matrix/wood ratios from 90/10 to 70/30 wt% considering different wood granulometries. As a natural material, wood changed its color during processing. Granulometries below 500 µm presented better sintering, homogeneity and less part defects. Furthermore, 300–500 µm favored the impact resistance (1316 N), as irregular brick-shaped wood was able to anchor to PE despite the weak interfacial adhesion observed. The increase of wood content from 10 to 30% reduced the impact properties by 40%, as a result of a highly porous structure formed, revealing sintering difficulties during processing. WPC parts of differentiated aesthetics and functionalities were achieved by rotational molding. A clear relationship between wood granulometry and WPC processing, structure and properties was identified.

Effect of incorporating different types of Sentang tree waste particle on the thermal stability of Wood Polymer Composite (WPC)

This article presents the potential use of tree waste materials such as the leaves (L), branches (B) and trunks (T) of Azadirachta excelsa (Sentang) tree in the production of wood polymer composite (WPC). The WPC was fabricated from high-density polyethylene (HDPE) as bonding matrix, maleic anhydride (MA) as coupling agent, and Sentang tree waste particles (L, B and T) as filler, prepared using twin-screw extruder followed by injection moulding machine. The effects of incorporating these types of Sentang tree waste particle (at 35% and 45% particles loading by weight) on the thermal stability of WPC were reported. The chemical compositions of L, B and T were also determined and their influences on the thermal stability of WPC were discussed. The thermal behaviour was determined by using thermogravimetric analysis (TGA), whereas the chemical analysis using Technical Association of the Pulp and Paper Industry (TAPPI) methods. The addition of these tree waste particles as filler has increased the thermal stability of WPC compared to virgin HDPE (without any particle incorporation). The highest mass loss was experienced by virgin HDPE. It was also observed that chemical compositions of the particles played vital role in influencing the thermal stability of WPC.

Fatigue Characteristic and Weibull Analysis of Sustainable Rubberwood Flour/Recycled Polypropylene Composites

Although there is a perpetual interest in natural fibre composite, the fatigue data and their durability behaviour is still lacking, thus limiting their potential use in high-end applications. In this study, wood polymer composite made from rubberwood flour and recycled polypropylene was subjected to a tension-tension fatigue test in order to investigate their fatigue characteristic. Hysteresis loop was captured in order to establish their stress to number of failure (S-N) curve. The fatigue strength of the composite strongly depends on the stress amplitude. At the lowest stress level, the fatigue life of the composite exceeds the 1.5 million cycles limit, suggesting that the endurance limit for composite materials to be 11.06 MPa. The residual modulus and energy dissipated are plotted as a function of number of fatigue cycles. As the cycles progress, the residual modulus fall and dissipated energy increase indicated the cyclic damage in the composite structure. Two parameters Weibull probability were used to statically analyse the fatigue life and reliability of the rubberwood/recycled polypropylene composite. The S-N curve was plotted at different reliability index (RI = 0.1, 0.368, 0.5, 0.9, 0.99) using Weibull data. This data is used to identify the first failure time and design limits of the materials.

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.

RESISTANCE TO VIBRATION OF WOOD TEMPERATURE POLYMER COMPOSITE MATERIAL

In this work, a wood composite material is considered, which incorporates all the best properties of the known wood polymer composites: water resistance, moisture resistance, high bending strength. It was concluded that according to the criterion of resistance to temperature fluctuations, it is possible to give more complete recommendations on the optimal composition of the wood polymer composite material based on a two-factor study. To ensure comparability of optimization results for a number of other properties, a series of computer experiments was carried out according to the same plan as for the study of compression resistance, that is, the concentration of wood and at the same time the concentration of sand was changed from 10 to 50 % with a step of 10 %, respectively. The material has acquired new advantages, which do not have known analogues – the possibility of using any wood waste, higher strength due to the content of sand in the composition, cheaper production due to the fact that most of the components of the material are household and wood waste, namely waste from the woodworking and forestry industries in the form of chips, sawdust, chips, lump waste, as well as sand, which is a publicly available and inexpensive material.

ANALYSIS OF EFFECT OF TEMPERATURE CHANGE ON WOOD POLYMER COMPOSITE MATERIAL

In this work the research of new wood polymeric composite material as which filler timber industry waste in the form of sawdust, shaving, spill, lumpy waste and polyethyleneterephthalate, a research of its frost resistance by means of a method of a computer experiment is used is considered. A computer program has been developed to simulate the structure and physical properties of building blocks made of wood polymer composite material. The program allows you to set geometric and physical parameters of the building block and material components in the windows of the interface form in program code, as well as test conditions for cyclic heating and cooling to temperatures maximum possible during operation, and investigate the influence of parameters on the internal and surface destruction of the building block. The program is applicable for a wide range of concentrations of composite components, geometric parameters of the building block, various mechanical and thermocyclic tests. Influence of composition of wood polymer composite material on structure in thermocyclic tests is investigated. Dependencies of broken bonds on concentration of wood, cartogram of breaking bonds of wood polymer composite material with concentration of wood from 20 to 80% are obtained.