Mechanical properties of date palm fiber reinforced composites

Mechanical properties of several laminates of date palm leave (DPL) reinforced composites are investigated. Three different processes to construct these composite laminates are assessed. These are wet lay-up with simple vacuum bagging, autoclaving with vacuum bagging and Vulcan press moulding. Several fiber orientation and dimensions are tested. Two types of resins are selected. The first is a high temperature curing Phenolic (phenol formaldehyde) resin. The second is a two-component Bisphenol resin with amine-based slow curing agent. The average tensile strength ranged between 127.4 and 152.3 MPa for long unidirectional fibers and 8.4 to 62.6 MPa for short and medium length fibers respectively (depending on process and resin type). The Bisphenol laminates have better mechanical properties. These laminates have consistently 25 to 50% higher tensile strength than Phenolic laminates. The bending strength ranged between 120.6 and 342.3 MPa (at 500 mm/min loading speed) depending on fiber length. Short fiber Bisphenol laminates have excellent fatigue life characteristics (over 466,000 and 653,000 cycles at 70% and 60% of maximum stress loads respectively). The process parameters and resin types have significant effects on the laminate properties. The water absorption of the laminates ranged between 2.3 to 5.8% for the Phenolic laminates (depending on the test method and manufacturing process used). The water absorption of Bisphenol laminates ranged between 10 and 40%. The produced laminates were very stable to handle all required machining processes as construction panels. They were successfully subjected to several machining processes such as milling, end milling, hack sawing and drilling.