Examples Wood-Plastic Composites

Examples Wood-Plastic Composites A few results of such a testing can be found in actual specifications/descriptions, available in the literature  

Notes of the author Most of the composite deck board materials show good fungus resistance when tested in accord with the ASTM D 1413 procedure, against standard white- and brown-rot fungi. In fact, I have never seen any ASTM D 1413 test data that would have shown a problem with any tested commercial composite deck board. 

One desperate composite deck user wrote from Kentucky in February 2005 I am writing to make sure as many people know about the problems I and others are having with (that composite material—AK). I built a deck in 2003 that gets full sun all day long. This past summer it developed mold spots all over it.. .. When I contacted the manufacturer they said that mold was an act of god and that they weren t responsible.  

In conclusion, though ASTM D 1413 is generally useful for a comparison of WPC materials with standard wood samples, it does not predict actual resistance of composite materials with respect to microbial degradation in the real world. 

blocks. Calculations of weight-loss are the same as in ASTM D 1413. 

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Figure 14.22 Example of a line for the manufacturing wood-plastic composites...

These materials are from renewable sources and are often made from plant materials that can be grown year after year and should come from agricultural nonfood crops. Biodegradable polymers are broken down into CO 2 and water by microorganisms. Although biopolymers may be able to help solve the disposal problems of current plastic packaging, it is not clear if they can really deliver on this promise and whether there is possible competition with the food chain. Cellulose is the most common biopolymer and organic compound on Earth. Other examples are starch, PHB (polyhydroxybutyrate), natural fibers, silk, and wood plastic composites (WPC). 

D. Plastic Composites. Many different woods have been treated with organic monomers and the monomers catalytically polymerized within the wood structure. The subject of treating wood to form plastic composites is covered by Dr. John Meyer in another section of this publication. For the most part, these composites have been prepared and studied for their use in dimensional-stabilized products (for example, see 13-17). 

UV absorbers generally decrease the oxidative degradation of plastics and plastic-based composites. However, they do not always significantly change the fading of WPC materials. For example, wood flour (50% w/w, 40 mesh)-fllled HDPE (MFI 0.72) after an accelerating weathering in a box for 3000 h increased its L value by 115% after... 

Composites from natural fibres have not yet been fully established in high-tech industry because a sufficient quality for engineering applications is not adequately offered (e.g. by Natural Fiber Composites Inc. and North Wood Plastics). Fibres are available from many plants (highlighted of high quality) for example, wood, abaca, coir, cotton, flax, hemp, henequen, istle, jute, kenaf, ramie, sisal or sunn. 

Composites can occur naturally or may be synthetically produced. For example, wood is a naturally occurring, water-plasticized composite consisting of oriented cellulose fibers in a continuous, cross-linked matrix of lignin. With synthetically produced composites, the matrix may, for example, be a metal (an example of which is steel-reinforced concrete). Here, the discussion will be limited to composites with synthetic polymers as the matrix material. 

There are a variety of WPC products in the market These commerdal products could originate from virgin or recycled polymers and virgin or reclaimed wood. For instance, Andersen Windows Company utilizes waste PVC from their manufacturing plant in producing WPC window components. Certain Teed Company uses recycled fibers in their Boardwalk plastic composites. Some examples of WPC products and their major components are listed in Table 13.4, with a focus on the United States, which has the biggest WPC market for building applications. 

The primary nutrient in flexible PVC is the plasticizer. Epoxidized natural oils arc easily metabolized by a variety of bacteria and fungi. In some cases, hquid epoxy resins can be substituted for, for example, ESO, improving microbial resistance. Since epoxy resins usually add tack, revision of the lubricant system may be required. In filled or pigmented compounds, it would be preferable to use an acid absorber such as hydrotalcite or zeolite in place of ESO, or a stabilizer system based on such ingredients. This is also possible in translucent compounds such as shower crrrtains. Polyol components of stabilizers, such as pentaerythritol, are also nutrients. As with rigid PVC/wood fiber composites, the ideal stabilizer would be a combination of organotin carboxylate and hydrotalcite or zeolite, hr many cases, the required material cost... 

Laminates aie materials made up of plies or laminae stacked up like a deck of cards and bonded together. Plywood is a common example of a laminate. It is made up of thin pHes of wood veneer bonded together with various glues. Laminates ate a form of composite material, ie, they ate constmcted from a continuous matrix and a reinforcing material (1) (see also Reinforced plastics). 

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