Study of rubber composites between natural rubber and Mahogany Shell Powder (MHSP) and potential for pavement block

Abstract

Abstract This research was aimed to study the feasibility of using mahogany fruit shell powder as filler in rubber and investigated in properties of obtained vulcanized rubber. As mahogany fruit shell contains 75.61% holocellulose, 13.54% lignin and 11.02% extractives [1]. Hence the fruit shell should be able to act as reinforcement in rubber materials [2]. In this study, mahogany fruit shell was milled into small particles with the particle size of approximately 60 micrometres follow by ASTM D 422 - Standard Test Method for Particle-Size Analysis of Soils. The particle was characterized for their thermal stability. The morphology of mahogany fruit shell powder, MHSP, was flake like particle and can be used as reinforcement fillers in natural rubber. As NR is generally sensitive to O2 thus ethylene propylene diene monomer, EPDM, would be laminated on the top of NR/MHSP composites. The rubbers were formulated with efficient vulcanization system and contain 10, 20, 30, 40 and 50 phr of MHSP. The rubber compounds were characterized for cure characteristic parameter such as scorch time, cure time, minimum and maximum torque. Rubber vulcanizates were prepared using compression molding and characterized for their morphology, mechanical properties, thermal degradation, hardness and weathering resistance. In order to improve environment stability and abrasion resistance of the NR/MHSP composites, EPDM/MHSP were prepared and laminated on NR/MHSP and vulcanized. The laminated vulcanizated composites possessed the properties follow Thai Industrial Standard for rubber paving blocks could be obtained. The results also showed that NR filled with 50 phr of MHSP in NR and in EPDM gave the properties follow the standard and has high potential for outdoor rubber paving block.