Water Absorption Behaviour and Mechanical Properties of High Density Polyethylene/ Pistachio Shell Flour Nanocomposites in Presence of Two Different Uv Stabilizers

In this research, for the first time, the effects were investigated of nanoclay as a secondary reinforcement, titanium dioxide (TiO ₂ ) and hindered amine light stabilizer (HALS) as UV stabilizers on some properties of high density polyethylene (HDPE)/pistachio shell flour (PSF) composite as the new wood plastic composite (WPC). WPCs of HDPE/PSF with different levels of nanoclay (Cloisite 20A), TiO ₂ and HALS were prepared. Some properties were investigated before exposure to weathering conditions. Design of experiments (DOE) was carried out to find the best formulation and decrease the number of tests. WPC granules were prepared by melt-mixing method using a twin screw extruder, and then moulded using an injection moulding machine to prepare samples. The results of X-ray diffractometry (XRD) indicated partial exfoliation and intercalation of samples containing 3 and 6 per hundred composite (phc) of nanoclay. The tensile strength and modulus of HDPE/PSF samples containing 3 and 6 phc nanoclay showed 20% increase compared to samples without nanoclay. The presence of TiO ₂ and HALS in the formulation did not have a significant effect on tensile properties. The nanoclay presence in HDPE/ PSF formulation improved the water absorption resistance.