Polymer foams have low density, good heat insulation, good sound insulation effects, high specific strength, and high corrosion resistance, and are widely used in civil and industrial applications. In this paper, the classification of polymer foams, principles of the foaming process, types of blowing agents, and raw materials of polymer foams are reviewed. The research progress of various foaming methods and the current problems and possible solutions are discussed in detail.

https://www.mdpi.com/2073-4360/11/6/953/pdf

Recent Trends of Foaming in Polymer Processing: A Review.

Utilizing Malaysian bamboo for use in thermoplastic composites

Due to its abundance, wood is the pre-eminent lignocellulosic raw material for a sustainable bioeconomy based society. Wood is widely used as fuel, construction material, and raw material in cellulose and lignocellulose based products. Besides the established uses of wood powder, like co-firing with coal and biofuel production, there are also novel uses and process applications, e.g., advanced wood-plastic composites and biochemical production are emerging for which the pulverization or fine grinding of wood is an essential pre-treatment step. Due to the tenacious nature of the wood matrix, size reduction is an energy intensive process and thermal or chemical pre-treatment may be needed to improve economy. This paper provides a broad overview of the fine grinding of wood. First, wood breakage mechanisms and the mechanisms of size reduction are presented, followed by fine grinding techniques and wood pre-treatment methods. A comparison of the specific energy consumption of wood fine grinding in both a gaseous and liquid environment is illustrated. Additionally, examples are given of the role played by pre-treatment methods in decreasing energy consumption. The particle aspect ratio is discussed briefly. Finally, the use and requirements of wood powders in various applications are discussed.

/pdf/fine-grinding-of-wood-overview-from-wood-breakage-to-4ebw62zvps.pdf

Fine grinding of wood – Overview from wood breakage to applications

A comparison between bio- and mineral calcium carbonate on the properties of polypropylene composites

The Babool, Sheesham, Mango, and Mahogany trees are commonly found in India. The wood-plastic composites (WPCs) were prepared by injection molding using wood dust of the selected Indian trees as the reinforcements in the polypropylene matrix. The mechanical, wear, and morphological characterizations of WPCs were performed. Different wood dust proportions were utilized to observe the comparative variation in Young's modulus, wear rate, and morphology of the WPCs. The resistance to natural weathering and biodegradability of WPCs were evaluated following ASTM D1435–99 and ASTM D5338-11 respectively. The degradation of the WPCs due to Ultraviolet-B (UVB) radiation is also examined. The structure-property relation was established and the usability of different WPCs for different applications was highlighted.

Experimental study on mechanical behavior, biodegradability, and resistance to natural weathering and ultraviolet radiation of wood-plastic composites

Rheological properties of wood polymer composites at high shear rates

Wood-polyvinyl chloride (PVC) composites were prepared using industrial wood particles used for manufacturing three-layer particleboards. The effect of particle size (0.25–0.5, 0.5–1, 1–2, and 2–4 mm) on the mechanical properties of the composites was investigated. The effect of cross-section size (4×10, 6×15 and 8×20 mm2) of composite pieces made by an injection moulding method was also studied. Both the particle size and specimen cross-section area significantly influenced these properties. The tensile and flexural properties as well as the impact strength in general increased with increasing particle size, and decreased with increasing cross-section size.

/pdf/effect-of-industrial-wood-particle-size-on-mechanical-5021su1y7q.pdf

Effect of industrial wood particle size on mechanical properties of wood-polyvinyl chloride composites

Summary — Industrial wood particles used for manufacturing three-layers particleboards were employed to prepare wood/PE-LD composites by an injection molding process. The effect of particle size (sieve analysis 0.25—0.5, 0.5—1, 1—2, and 2—4 mm) and of specimen cross-section size (40, 90 and 160 mm 2 ) on the mechanical properties was studied. Both these factors significantly influenced studied properties. The tensile, flexural and impact strengths properties in general increased with increasing particle size while with increasing of specimen cross-section the tensile and flexural moduli increased, and the tensile, flexural and impact strengths decreased.

Effect of wood particle size on mechanical properties of industrial wood particle-polyethylene composites

This study examined, the effect of chemically extracted raspberry pomace on the thermal stability, mechanical properties, flammability, chemical structure and processing of poly(vinyl chloride). It was observed that the pomace in this study was used to extract naphtha, thereby permitting the removal of bio-oil as a factor preventing the obtaining of homogeneous composites. Furthermore, adding 20% raspberry pomace filler after extraction extended the thermal stability time for the composites by about 30%. It was observed that composite density, impact strength, and tensile strength values decreased significantly with increasing concentrations of filler in the PVC matrix. At the same time, their modulus of elasticity and Shore hardness increased. All tested composites were characterized by a good burning resistance with a flammability rating of V0 according to the UL94 test. Adding 20 to 40% of a natural filler to the PVC matrix made it possible to obtain composites for the production of flame resistant elements that emitted less hydrogen chloride under fire conditions while ensuring good rigidity.

https://www.mdpi.com/2073-4360/13/7/1079/pdf

Poly(vinyl chloride) Composites with Raspberry Pomace Filler.

Porous product with reduced apparent density keeps good mechanical properties. Extruded composites of poly(vinyl chloride) blown under microwave irradiation

Jacek Mirowski

Papers

Rheological properties of wood polymer composites at high shear rates

Effect of industrial wood particle size on mechanical properties of wood-polyvinyl chloride composites

Effect of wood particle size on mechanical properties of industrial wood particle-polyethylene composites

Poly(vinyl chloride) Composites with Raspberry Pomace Filler.

Porous product with reduced apparent density keeps good mechanical properties. Extruded composites of poly(vinyl chloride) blown under microwave irradiation