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Chemical modification of wood particles for the production of wood-plastic composites using N-methylol compounds and paraffin

 
: Schirp, A.; Stoll, B.; Mai, C.; Richter, E.; Militz, H.

Canadian Natural Composites Council -CNCC-; Forest Products Society -FPS-; Forest Products Laboratory -FPL-:
Ninth International Conference on Wood & Biofiber Plastic Composites. Proceedings : May 21-23, 2007, Monona Terrace Community & Convention Center, Madison, Wisconsin, USA
Madison, Wisc.: FPS, 2007
ISBN: 1-892529-50-5
ISBN: 978-1-892529-50-3
S.243-252
International Conference on Wood & Biofiber Plastic Composites <9, 2007, Madison/Wis.>
Englisch
Konferenzbeitrag
Fraunhofer WKI ()

Abstract
Swelling due to water uptake and lack of dimensional stability have been identified as significant disadvantages of wood-plastic composites (WPC). The objective of this study was to improve WPC hydrophobicity by impregnation of thewood filler with three chemical modification reagents based on N-methylol compounds (for example, 1,3-dimethylol-4,5-dihydroxyethyleneurea [DMDHEU]) and paraffin which are used as wrinkle-resistant finishes in the textile industry. Three formulations based on polypropylene as the thermoplastic matrix material were used to manufacture injection-molded WPCs. The results show that water uptake and dimensional expansion of WPCs based on chemically modified wood particles were significantly reduced while no improvement of the mechanical properties was observed. Hence, the chemical modification reagents used do not act as coupling agents in WPCs.Weight losses in WPCs due to soil and Basidiomycete fungi were approximately 5 percent or less, irrespective of chemical modification of the wood filler. Flexural strength and stiffness of WPCs exposed to soft-rot fungi in a modified DIN V ENV 807 test were significantly reduced; however, this reduction is likely due to the combined effects of soil micro-organisms and moisture. Flexural strength and stiffness of WPCs containing maleic anhydride-modified polypropylene were reduced due to Basidiomycete decay; however, a slight improvement in resistance against soft-rot and wood-decay fungi was observed for WPCs based on wood particles modified with DMDHEU.

: http://publica.fraunhofer.de/dokumente/N-69451.html