Lightweight Polypropylene Composites Reinforced by Long Switchgrass Stems

Abstract

Switchgrass (SG) stems with lengths up to 10 cm have been used as reinforcement to make lightweight composites with polypropylene (PP) webs. The long SG stems, with simple cut or split and without chemical treatment, were used directly in the composites. Utilizing SG stems for composites not only increases the values of SG but also provides a green, sustainable and biodegradable material for the composites industry. Lightweight composites are preferred, especially for automotive applications due to the potential saving in energy. In this research, the effects of manufacturing parameters on the properties of composites have been studied. Although the tensile properties of SG stem are significantly worse than jute fiber, SG stem with low bulk density is found to better reinforce the lightweight composites. Compared with the jute-PP composites of the same density (0.47 g/cm 3 ), composites reinforced by the split SG stems have 56% higher flexural strength, 19% higher modulus of elasticity, 15% higher impact resistance, 63% higher Young's modulus, 52% lower tensile strength, and similar sound absorption property. The SG-PP composites with optimized properties have the potential to be used for industrial applications such as the support layers in automotive interiors, office panels and ceiling tiles.

Green composites: An overview

“…Switchgrass, which grows on marginal lands, is a self‐seeding crop, which requires low amounts of fertilizers. Switchgrass stems were studied to reinforce PP for industrial applications in the area of automotive interiors [ 15], and it was found that, compared to a jute‐PP composite of the same density, the composite reinforced by switchgrass stems had higher modulus, higher flexural strength, higher impact resistance, and similar sound absorption properties. Another example is Indiangrass, a perennial native grass of North America that readily invades sites with bare soil such as old abandoned farm fields, reclaimed lands, and roadsides.…”

Preparation, structure, and properties of biocomposites based on low‐density polyethylene and lignocellulosic fillers

“…Fibrous particles give a reinforcing effect to a composite, which leads to an increase in tensile strength . In addition to wood flour, advantageous fillers include abaca, jute, flax , millet , bamboo, coffee chaff , corn stalks, wheat straw, hemp, and kenaf . However, there are many types of available lignocellulosic feedstocks, not previously used for creating biocomposites.…”

Use of eco‐friendly epoxy resins from renewable resources as potential substitutes of petrochemical epoxy resins for ambient cured composites with flax reinforcements

“…processed by conventional extrusion-compounding, injection, hot-press molding, etc. [15][16][17][18][19][20][21] Also, new biobased polymers such as polylactic acid (PLA), polyhydroxyalcanoates (PHAs), starch and protein-based polymers, etc. have been reported as matrices with natural fiber reinforcements.…”