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Title: Ultraviolet weathering of WPCs coextruded with a clear cap layer

Source: Proceedings of the 5th International Wood Fibre Polymer Composites Symposium : natural fibre to building and furniture products: contributing to the green growth, 2011 September 26-27, Biarritz, France. Paris, France : FCBA Institut Technologique, 2011: 12 p.

Author(s)Matuana, Laurent M.; Stark, Nicole M.; Jin, Shan

Publication Year: 2011  View PDF »

Category: Conference Proceedings
Associated Research Project(s):   FPL-4706-2A

Abstract: This study examined the effect coextruding a clear HDPE cap layer onto HDPE/wood-flour composites has on the discoloration of coextruded composites exposed to accelerated UV tests. Chroma meter, XPS, SEM, and UV vis measurements accounted for the analysis of discoloration and degree of oxidation of both uncapped (control) and coextruded composites before and after UV exposures. Two separate discoloration characteristics occurred in the discoloration of composites. For uncapped WPCs (control), chemical changes due to photooxidation resulted in darkening followed by physical changes, including loss of colored wood components from the surface, as well as increased roughness on the surface, which led to lightening of WPCs. By contrast, because a hydrophobic cap layer prevented the loss of colored components from the surface, coextruding a clear hydrophobic HDPE cap layer over WPCs significantly decreased the discoloration during the weathering process. Photooxidation of wood components at the interface accounted for the discoloration of coextruded WPCs before the failure of cap layer. Moreover, as the cap layer absorbed a specified amount of UV light and reduced oxygen available to interface, it decreased the photooxidation rate at the interface compared to that at the WPCs surface.

Keywords: Wood-plastic composites, polyethylene, color fading, composite materials, deterioration, weathering, accelerated life testing, wood flour, extrusion process, injection molding of plastics, ultraviolet radiation, oxidation, surface roughness, discoloration, accelerated testing, HDPE, photostabilizers, durability, surface properties, ultraviolet absorber, exposure tests, hydrophobicity, failure

Publication Review Process: Non-Refereed (Other)

File size: 776 kb(s)

Date posted: 10/06/2011
RITS Product ID: 40588
Current FPL Scientist associated with this product
Stark, Nicole M.
Research Chemical Engineer
  

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