Static and Dynamic Properties of Thermoplastic Matrix/Natural Fiber Composites

In this research, composites based on kenaf/hemp/flax fibers in polypropylene and biodegradable polylactic acid matrices are investigated and compared to similar glass fiber/polypropylene composites. Mechanical properties in terms of tensile, vibration-damping and impact behavior are experimentally evaluated. Vibration test results over a wide frequency range are presented. The effects of laminates composition and compaction level on mechanical and dynamic properties are reported and discussed. Anisotropy due to process procedure is also considered. The reinforcement of thermoplastic matrices by means of discontinuous natural fibers (kenaf, hemp and flax) significantly improves stiffness and strength. The presence of fibers affects the low-energy impact response; on the other hand, fiber debonding during failure contributes to energy absorption capability. Indications are reported for a suitable comparison between thermoplastic (both polypropylene or poly-lactic acid)/natural fiber and polypropylene/glass composites for their possible employment in applications where good vibration-acoustic damping capability and impact resistance are required.