Mechanical properties and recyclability of thermoplastic elastomer composites of white rice husk ash-ethylene/propylene/diene terpolymer-polypropylene

Abstract

Rice husk, which is usually regarded as an agricultural waste, when burnt produces a silica rich ash known as white rice husk ash (WRHA). This low cost and environmental friendly ller derived from a renewable source has been incorporated into an elastomer rich ethylene/propylene/diene terpolymer (EPDM)-polypropylene (PP) matrix to prepare thermoplastic elastomer composites, by melt mixing in a Brabender plasticorder. Elastomer components of the composites were dynamically cured in the presence of WRHA. Mechanical properties and recyclability of these composites were investigated with reference to the dynamic curing and curing agent concentration. The processability of the composites was also investigated using Brabender torque as the indicator. It was observed that WRHA does not interrupt the dynamic curing process and mechanical properties are substantially enhanced with increased curing agent concentration up to an optimum concentration. It was found that composites cured at low curing agent concentration are recyclable. An increase in the concentration of curing agent increases the Brabender stabilisation torque indicating an increase in crosslink density (decrease in processability). Corresponding composites lled with a commercial grade of silica were also prepared and their mechanical properties and recyclability were compared with WRHA lled composites. Results showed that WRHA lled composites exhibit properties comparable to the silica lled grades, indicating the potential of WRHA as an alternative ller for thermoplastic elastomer composites. Possibly, large scale use of WRHA could help alleviate the environmental issue of disposal of the waste rice husks.

The Influence of Fiber Length and Concentration on the Physical Properties of Wheat Husk Fibers Rubber Composites

“…International Journal of Polymer Science 5 Table 4: Volume fraction of EPDM due to swelling in Chloroform. where V ro is the volume fraction of rubber in the unfilled vulcanizates, V r f is the volume fraction of rubber in the filled vulcanizates, φ is the volume fraction of the filler, and c is the constant characteristic of the filler which indicates the degree of adhesion [22][23][24][25][26][27][28][29][30].…”

“…They had indicated that the incorporation of natural fibers into polymers could improve some desired properties. However, less attention has been paid to the incorporation of natural fibers to form elastomeric composites [21][22][23][24][25][26][27][28][29][30]. These composites exhibit combined behavior of the soft, elastic rubber matrix, and the stiff strong fibrous reinforcement.…”

Tensile properties, swelling, and water absorption behavior of rice‐husk‐powder‐filled polypropylene/(recycled acrylonitrile‐butadiene rubber) composites

“…Although a large number of published papers exists on PP/RH composites [7–14], and the use of white rice husk ash (WRHA) and black rice husk ash (BRHA) in plastics [15–29], there was no work reported on the use of recycled acrylonitrile‐butadiene rubber (NBRr) in PP in the presence of RHP filler. The objective of this work was to explore the mechanical properties, swelling behavior, and water absorption capacity of PP/NBRr/RHP composites.…”

Comparative study of silica‐, nanoclay‐ and carbon black‐filled EPDM rubbers

“…Carbon black (CB), silica, and clay are the classical examples. Many investigations on EPDM blends have been carried out to study the effects of CB,2–17 silica,13, 18–24 clay,25–27 and white rice husk ash (WRHA)28, 29 on the electrical properties and the curing characteristics as well as the physical properties of the filled EPDM. These research efforts are briefly reviewed below.…”

“…Mechanical properties, recyclability, and curing behavior of WRHA‐ and silica‐filled EPDM/PP thermoplastic elastomers at loadings up to 50 phr were compared 27, 28. The curing rate was increased with increasing WRHA loading, whereas the opposite trend was observed for silica‐filled vulcanizates.…”