Wood–Plastic Composite Technology

Abstract

Wood-plastic composites (WPCs) are a form of composite combining wood-based elements with polymers. The processes for manufacturing WPCs include extrusion, injection molding, and compression molding or thermoforming (pressing). Newer manufacturing processes for WPCs include additive manufacturing via fused layer modeling and laser sintering. An important constraint for polymers used in WPCs is requiring process conditions (melt temperature, pressure) that will not thermally degrade the wood filler. Wood degrades around 220°C; thus, generalpurpose polymers like polyethylene and poly vinyl chloride are typically used for manufacturing WPCs. Wood fibers are inherently hydrophilic because of the hydroxyl groups contained in the cellulose and hemicellulose molecular chains. Thus, modification of the wood fiber via chemical or physical treatments is very critical to making improved WPCs. The most abundant profiles made from wood-plastic composites are boards or lumber used in outdoor decking applications. Although early WPC products were mainly extruded for profiled sections, nowadays, many injected parts made of WPC are being introduced for various industries, including electrical casings, packaging, daily living supplies, and civil engineering applications. Mold and mildew and color fading of WPCs tend to be the durability issues of prime importance for WPCs. Most recent research on WPC durability focuses on studies to better understand the mechanisms contributing to various degradation issues as well as methods to improve durability. Most WPC products in the USA are utilized in building materials with few exceptions for residential and commercial building applications, which means that building codes are the most important national rules for the WPC manufacturers. New developments are being made especially in the area of nano additives for WPCs including nanocellulose. Recently, the trend of patent registrations for WPCs has shifted to new products or applications instead of the materials itself.

Bamboo Particles-Polyvinyl Chloride Composites: Analysis of Particles Size Distribution and Composites Performance

“…In a different report by Stark and Gardner (2008), increasing the wood particles size increased the equilibrium moisture content of the composites. Nevertheless, it was specified that the materials with larger aspect ratio are the best candidate for composite's reinforcement (Gardner, Han, & Wang, 2015). In accordance to Stark and Rowlands (2003), it was confirmed that increase in mechanical properties was found to correspond with increase in aspect ratio of particles.…”

“…About 99% of particles from B. vulgaris/75-µm group had an aspect ratio of less than 4.2. According to Gardner et al (2015), the large-sized particles with high aspect ratio provided better mechanical properties than the small-sized particles. Transfer efficiency of load from matrix to wood fiber could be possibly increased with increasing fiber length/diameter ratio (Migneault, Koubaa, Erchiqui, Chaala, Englund, Krause, & Wolcott, 2008).…”

Análisis de Juntas Adhesivas Elaboradas con (Lámina de Madera Plástica) / (Adhesivo Ecológico) / (Lámina de Madera Plástica)

“…De otro lado, los aditivos que hacen parte del compuesto como lubricantes, ceras con el tiempo migran hacia la superficie ayudando a incrementar la complejidad del mecanismo de adhesión (Gardner et al, 2015). En esta investigación se elaboraran juntas adhesivas a partir de substratos tipo WPC elaborados con polietileno de baja densidad y 32% en peso de harina de madera del arbusto Telinne monspessulana.…”

“…Estos materiales ofrecen ventajas sobre los compuestos tradicionales (polímero/carga mineral), tales como alta resistencia y módulo, baja densidad, menor desgaste abrasivo en la maquinaria de proceso (Gardner et al, 2015;Gupta et al, 2007;Kim y Pal, 2010;Oporto et al, 2007). Con respecto a la madera, WPC tienen mejor estabilidad dimensional en condiciones de humedad, mayor resistencia térmica y al ataque microbiano.…”

The Influence of Chemically Pre-treated Chestnut Waste and Pinecone Filler Content on the Properties of Polyester Composites

“…In addition to increasing fuel prices, there is much pressure from environmental groups and government agencies to find other means of creating composites with more environmentally friendly processing methods and materials [1,2]. Today, rapid technological change and increased competition in many industries necessitate lighter and stronger materials for use in high-performance products [3,4]. Composite structures that can provide the desired properties are created when polymers that do not meet some of the necessary physical and/or chemical characteristics in the application fields are supported by fibers of various types and proportions [5,6].…”