Wood-plastic composite processing

M. Bengtsson, and K. Oksman, Silane crosslinked wood plastic composites Processing and properties. Comp. Sci. Tech. 66 (13), 2177-86 (2006). 

Fifteen years ago, when wood-plastic composites were first introduced many people predicted that this process would solve the problem of wood dimensional stability and great claims were made for its future use. Now that the physical properties of wood-polymer composites are better understood, specific commercial products are being produced which take advantage of the desirable aesthetic appearance, the high compression strength, increased hardness and abrasion resistance and improved dimensional stability. Future use of wood-polymer composites will depend upon the imagination of the producer and the market place. 

CZVTKOVSKY, TIBOR. Radiation Processing of Wood Plastic Composites. Radiation Processing of Polymers. Hanser Publishers, New York (1992) 121-148. 

CZVIKOVSZKY T., Radiation processing of wood-plastic composites, in Radiation Processing of Polymers, (eds A. SINGH, J. SILVERMAN), Hanser - Oxford Univ.Press, Munich, NewYork, 1992. 

S.-K. Yeh, S. Agarval, and R.K. Gupta. Process development for ABS-based wood-plastic composites. In Progress in Wood-Fibre Plastic Composites 2006 International Conference, Toronto, Canada, May 1-2, 2006. 

The term wood-plastic composites (WPCs) refers to wood as a proxy for fibrous materials of plant origin. It can be wood flour or sawdust, or agricultural plant residues, typically cut, milled, or ground, or other types of natural fiber, such as hemp, jute, and kenaf, commonly as a by-product of the respective industrial process. 

C. Clemons. Use of invasive wood species in wood plastic composites compositional differences and their effects on processing and performance. In Progress in Wood and BioFibre Plastic Composites 2006, Toronto, Canada, May 2006. 

J. Markarian. Wood-plastic composites current trends in materials and processing. In Plastics Additives Compounding, September-October 2005, pp. 20-26. 

IMPREGNATION OF SOFT SOUND WOOD WITH MONOMERS, which are then polymerized in situ by 7 radiation, was a method used in many laboratories during the 1960s in an effort to obtain wood-plastic composites. The process was attractive in two respects there was a large choice of consolidants, and radiation-induced polymerization had many advantages. Various vinyl monomers are cured by 7 rays. By proper selection of the polymer or copolymer, materials can be tailor made for specific applications. The radiation process presents several advantages over the chemically catalyzed polymerization of monomers in wood. 

Gardner, D. J. 2002. Wood Plastic Composite Extrusion-Processing Systems, www.umaine. edu/adhesion/gardner/5502002/wpc%20ext%20pro%203-11-02.pdf. 

After the introduction of processing facilities for wood-plastic composites (WPC) by extrusion and later by injection moulding techniques, WPC production and its use increased almost exponentially. 

Rothlin O. Processing wood-plastic composites place new demands on feeders. Plastics Addit Compound [trade journal—Elsevier Ltd.[ luly/August 2007. 

The mechanical properties of Wood-Plastic-Composites substantially depend on the quality of the raw material, the composite and the manufacturing process. The density of WPC lies between 0.9 and 1.4 g cm and is higher than that of one of the two components, plastic and wood, alone. The porous wood structure is densified during the production process and plastics and additives partly penetrate into the cavities. Thus, water absorption is made harder, and the material swells less and more slowly. ... 

The processing and processes of microceUular-foamed wood plastic composites have been the subject of a recent review [48]. 

Due to its low thermal stability, wood flour is usually used as filler only in plastics that are processed at temperatures lower than about 200 °C. The majority of wood-plastic composites use polyethylene as the matrix (Figure 15.2). This is, in part, due to that fact that much of the early wood-plastic composites were developed as an outlet for recycled film. Polypropylene is more commonly used in automotive applications, and polyethylene is more commonly used in exterior building applications. 

Mold can form on surfaces of wood-plastic composites. Mold growth has been ascribed as arising from various effects, among them moisture sorption by the wood flour, buildup of organic matter on the composite surfaces, and the lubricants used in processing of the composites. The relative contribution of these factors to mold growth is uncertain. Although mold does not reduce the structural performance of the composite, it is an aesthetic issue. 

Processing wood plastic composites (WPG) into profiles by extrusion for building and construction applications is one of the most exciting bnsinesses of recent years. Growth observed is such that WPG applications are already very high (at least 30% a year in... 

Since the 1940s, lumber producers and manufacturers have used a chemical compound mixture that contains inorganic arsenic, copper, and chromium called chromated copper arsenate (CCA) as a wood preservative. CCA is usually injected into wood by a high pressure process to saturate wood products with the chemicals, to produce pressure-treated lumber , (between 75 and 90% of the arsenic used in the United States is estimated to be used for wood preservation).For more information on wood and wood-plastic composites used in construction, see Chapter 9. 

Lee KY, Bharadia P, Blaker JJ, Bismarck A (2012c) Short sisal fibre reinforced bacterial cellulose polylactide nanocomposites using hairy sisal fibres as reinforcement. Compos A 43 2065-2074 Lei Y, Wu Q (2010) Wood plastic composites based on microfibrillar blends of high density polyethylene/poly(ethylene terephthalate). Bioresour Technol 101 3665-3671 Liu D, Zhong T, Chang PR, Li K, Wu Q (2010) Starch composites reinforced by bamboo cellulosic crystals. Bioresour Technol 101 2529-2536 Liu H, Xie F, Yu L, Chen L, Li L (2009) Thermal processing of starch-based polymers. Prog Polym Sci 34 1348-1368... 

Chapter 5 discusses in detail the current application of recycled PET. In particular, the applications of recycled PET are discussed in the fields of food packaging, construction, textile industry, injection moulding and other manufacturing processes, wood-plastic composites and so on. On the other hand. Chapter 6 describes the optical properties of polyolefins upon recycling. Optical properties of different plastics play a key role in packaging applications, so this chapter primarily focuses on the different structural aspects and properties of isotactic polypropylene. 

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