The Effect of a coupling agent on mechanical properties of coconut shell powder filled natural rubber composites

Coconut Shell Powder (CSP) is an abundant lignocellulosiccomponentobtained from Coconut shells, which can be used as natural filler for rubbers and plastics to enhance their mechanical properties and biodegradability. Lignocellulosic fillers present significant properties compared to conventional mineral fillers, which are commonly used with polymers like CaCO3, silica, talc mica, etc. Further, CSP is, biodegradable, renewable, inexpensive, ecofriendly, lower in density, minimal health hazards and less abrasion to processing machinery compared to silica. Conjugating these properties with specific properties of commercial polymers could be a great value addition to both materials. CSP is incorporated into natural rubber (NR) as filler, with and without modifications with alkali solution. However, no significant enhancement in mechanical properties was exhibited.Therefore, the main objective of this study was to evaluate the effect of two coupling agents namely, Silane and Maleic Acid on physico-mechanical properties of CSP filled NR composites, in order to uplift CSP as natural filler for NR. In this study, five different NR compounds were prepared by varying CSP loading from 10phr to 50 phrin 10 phr intervals. A series of silica filled NR composites was prepared for comparison. Properties of CSP filled NR composites was inferior compared to those of silica filled NR composites. However, composites with coupling agents showed better properties compared to those prepared without a coupling agent