Static and dynamic mechanical behavior of doum palm (Hyphaene thebaica) nut reinforced HDPE composites

The quest to discover more and to enhance the qualities of agro-residue for use as natural reinforcement of polymers continues to attract the attention of researchers because of the environmental friendliness. Hyphaene thebaica also known as doum palm is a fruit tree native to the Nile in Egypt and found in abundance in many parts of Africa. Doum palm fruit contains probably the hardest and toughest known nut. The doum palm nuts (DPN) are the most under-used hard-nut despite their abundance in nature. This study presents the potential doum palm nut particles (DPNp) as natural reinforcement for high density polyethylene (HDPE). Properties of DPN such as density, hardness and weight loss due to heating were determined. HDPE/DPNp composites were produced by reinforcing HDPE with 30, 35, 40 and 45% DPNp particles of two different sizes. The particle sizes 600 μm and 710 μm led to classifying the composites as X-composite and Y-composite respectively. The static and dynamic mechanical properties of the composites were determined and compared with the those of pure HDPE. Results showed that HDPE and DPNp can be formed into light and attractive components. Loading HPDE with DPNp significantly improve static mechanical properties of HDPE such as tensile strength, hardness, stiffness and resistance to impact failure by 50%, 200%, 800% and 1500% respectively. The HDPE/DPNp composites also had better dynamic mechanical properties. The ability of the composites to maintain load bearing capacity under dynamic conditions was superior to that of HDPE.