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Autori: Alex Dragomirescu, Jim Waters, Jim Nash, Don Brissette
Editorial: Progress in Woodfibre-Plastic Composites 2004 Conference, Toronto, 2004.
Durability performances of a composite material manufactured from reclaimed thermoplastics reinforced with natural fibres were tested. This paper presents weathering evaluation of the commercial product Enviroshake®, a “high tech” composite roofing material that replicates the look of a cedar shake. An extensive testing program designed to assess the ageing process of this composite was employed over one year period. Studies were performed on virgin and regrind material. Specimens were subjected to direct weathering (roofing panel exposed 27 degrees South), accelerated weathering (UV light), accelerated chemical attack (strong oxidizing agents such as hydrogen peroxide, sodium hypochlorite, sodium percarbonate), freezing/thawing/water absorption cycles (24 hours at -20oC, 2 hours at room temperature, 22 hours soaking), and salt spray testing (corrosive environments). The results indicate a quasi-constant fading over time, and a desired silvery-gray colour of shakes after four to five months of direct outdoor exposure. None of the samples showed any signs of cracking, spalling, or other forms of deterioration. Overall, the product showed non significantly weathering degradation after 50 weeks outdoor exposure, 7000 hours UV exposure, 100 cycles freezing/thawing/water absorption or 20 weeks salt fog testing.
Cuvinte cheie: composites, natural fibres, thermoplastics, weathering, durability