EVALUATION OF PHYSICO-MECHANICAL, WATER ABSORPTION AND THERMAL PROPERTIES OF ALSTONIA MACROPHYLLA FIBER REINFORCED POLYPROPYLENE COMPOSITES

Abstract

Alkali treated Alstonia macrophylla fiber reinforced polypropylene (PP/AS) composite was fabricated using a hot compression moulding machine through the film stacking technique. The raw fiber was subjected to alkali treatment to enhance the strong interfacial adhesion with the PP matrix. Alkali treated fiber at five levels of fiber loading (10, 20, 30, 40 and 50 vol%) was used for composite fabrication. The fabricated composites were designated as Neat PP, PP10AS, PP20AS, PP30AS, PP40AS, and PP50AS, respectively. Mechanical test results conducted in accordance with the ASTM standards revealed that tensile strength, flexural strength, impact toughness of the PP/AS composites increased with an increase in fiber loading. However, beyond 40 vol% of fiber loading, mechanical properties deteriorate. Of the prepared laminates, PP40AS composite outperformed other laminates, with 20.14%, 274.2% and 314.42% improvement in the tensile strength, flexural strength, and impact strength, respectively, when compared to neat PP laminates. The moisture absorption rate increased with the increase in fiber loading, as it leads to an increment in the number of hydroxyl groups in PP/AS composites. TGA results showed that the thermal stability of the PP laminate improved upon impregnation with alkali treated fiber. The final thermal degradation temperature of the PP/AS composite increased from 437.7 °C to 445.2 °C. FESEM analysis revealed the major mechanism endured by the PP/AS specimens during mechanical failure.