High Density Polyethylene/Pistachio Shell Flour/Nanoclay Composites - Effect of Accelerated Weathering Conditions on Mechanical Properties, Relative Brightness and Total Colour Change

This study investigates the effect of the addition of nanoclay (Cloisite 20A) on some mechanical properties, % relative brightness (ΔL _rel ) and total colour change (ΔE _ab ) of high density polyethylene (HDPE)/pistachio shell flour (PSF) composites when exposed to accelerated weathering conditions. X-ray diffraction (XRD) patterns of samples containing 3 and 6 per hundred composite (phc) of nanoclay indicated partial exfoliation and intercalation. The tensile modulus and tensile strength of HDPE/PSF composites (without nanoclay) decreased when the exposure time increased to 1500 h, while the tensile modulus and tensile strength increased. For samples with nanoclay, ΔL _rel and ΔE _ab increased upon accelerated weathering conditions up to 500 h, and thereafter remained constant. But results show that ΔL _rel and ΔE _ab increased significantly upon accelerated weathering exposure in HDPE/PSF samples up to 1500 h. Scanning electron microscopy (SEM) results after 1500 h exposure to weathering condition showed signs of the presence of cracks in samples without nanoclay, unlike the samples with nanoclay.