PVC & WPC FOAM BOARD

Wood-plastic composites (WPCs) are composite materials made of wood fiber/wood flour and thermoplastic(s) such as PE, PP, PVC, or PLA.

In addition to wood fiber and plastic, WPCs can also contain other ligno-cellulosic and/or inorganic filler materials. WPCs are a subset of a larger category of materials called natural fiber plastic composites (NFPCs), which may contain no cellulose-based fiber fillers such as pulp fibers, peanut hulls, bamboo, straw, digestate, etc.

Chemical additives seem practically “invisible” (except mineral fillers and pigments, if added) in the composite structure. They provide for integration of polymer and wood flour (powder) while facilitating optimal processing conditions.

In recent years, people in the flooring industry starts referring to WPC as a type of floor that has a basic structure of top vinyl veneer plus a rigid extruded core (the core can be made without any wood fiber). WPC is now an established product category within LVT. This type of WPC is different from WPC decking and is not intended for outdoor usage.

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, general-purpose 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.

A wood–plastic composite (WPC) is a common term referring to wood-based elements such as lumber, veneer, fibers, or particles that are combined with polymers to create a composite material. It is a broadly used term, and as such, wood elements can be combined with either thermosetting or thermoplastic polymers. The term wood–plastic composite is used interchangeably with wood–polymer composites, and the wood composites made from either thermoplastic or thermosetting polymers are often categorized as separate material types. Examples of wood–plastic composites made from different polymer types and wood elements are listed in Table 1.

Plastic and wood wastes have been a main environmental concern. Plastic is the biggest problem due to its high amount of waste generated, non biodegradability and the fastest depletion of natural resources regarding its short life cycle, therefore increased amount of material utilized in its production, and waste generated. The same applies to wood with lesser degree where it is depleting trees and forests and the wastes mainly are either burned or disposed; resulting in extra consumption, depletion, and pollution of nature. Several worldwide attempts have been adopted; especially in the developed countries, to take advantage of these types of waste especially with the raised need for alternatives to virgin materials. Wood plastic composite (WPC) is a product which could be obtained from plastic and wood. WPC is a composite with a rapid growing usage consisting of a mixture of wood waste and polymeric material . Many trials of obtaining a WPC product were basically built on the concept of a Cradle to Cradle approach where the material is recycled at the end of its life cycle to produce a Cradle (new) product and thus close the loop and imitate the natural ecosystem. As a consequence, this minimizes the solid waste content and conserve the natural resources. Therefore, costs, energy, and depletion of virgin materials are reduced. In addition, it assures the sustainability over the incoming years for future generations’ use.

WPC has become currently an important address of research that gained popularity over the last decade especially with its properties and advantages that attracted researchers such as: high durability, Low maintenance, acceptable relative strength and stiffness, fewer prices relative to other competing materials, and the fact that it is a natural resource . Other advantages have been strength points including : the resistance in opposition to biological deterioration especially for outdoor applications where untreated timber products are not suitable, the high availability of fine particles of wood waste is a main point of attraction which guarantees sustainability, improved thermal and creep performance relative to unfilled plastics where It can be produced to obtain structural building applications including: profiles, sheathings, decking, roof tiles, and window trims. On the other hand, WPCs are not nearly as stiff as solid wood; however, they are stiffer than unfilled plastics. In addition, they do not require special fasteners or design changes in application as they perform like conventional wood.

As mentioned, the reasons for using WPC are many; however, there are other causes that men forced many countries to tend for using alternative sources to virgin materials. In the United States, for example, the U.S. Environmental Protection Agency, by the beginning of 2004, has phased out the usage of wood treated with chemicals such as the chromate copper arsenate (CCA) to prevent environmental and microbial degradation. As this type of wood was used in the building products’ market concerned with residential applications such as decking, the need for the alternative survived the WPC market. In Europe, environmental concerns are focused on limiting the use of finite resources and the need to manage waste disposal; therefore, the tendency to recycle materials at the end of their useful life has increased tremendously. Recycling polymers in Europe was less preferred than other types of materials such as metal; however, illegality of land filling and waste management priority in many European countries were the motive to do so . In addition to the enforced environmental policies, the growth of environmental awareness led to a new orientation to use wasted natural materials for different applications and industries such as the automotive, packaging and construction industries.