Mechanical properties and drop-weight impact performance of injection-molded HDPE/birch fiber composites

Abstract

Natural-fiber-reinforced composites offer various advantages over synthetic composites, including low density, useful mechanical properties and environmental friendliness. In spite of the progress achieved in the field, the mechanical performance of these composite materials has yet to be fully characterized, particularly in terms of impact resistance. In this study, we measured the drop weight impact, Izod impact strength, hardness, tensile strength and elastic modulus of birch-fiber-reinforced HDPE obtained by injection molding. Drop weight impact energy absorbed was constant and independent of fiber content whereas impact strength was inversely proportional to fiber content. Material toughness decreased slightly at 40% fiber. The Shore D hardness of virgin HDPE increased from 50.6 at 0% fiber to 74.6 at 30% fiber. The improvement of the elastic modulus of a composite containing 40% fiber was 27.2% superior to that reported for similar material made by compression molding. The corresponding improvement in tensile strength was superior by 19.7%. Birch-fiber-reinforced HDPE could be an adequate alternative to technical polymers widely used in several industrial sectors.

Keywords

• Natural fiber
• High-density polyethylene
• Birch fiber composites
• Drop-impact behavior
• Izod test
• Hardness