Optimisation of Tensile Strength by Means of Taguchi and Response Surface Methods For Silicone Dielectric Elastomer

Abstract

Silicone dielectric elastomer (DE) can be utilised as a smart material to harvest energy from wave besides other applications such as actuator and sensor. Previous works have been conducted to increase permittivity and electrical break down without destroying the pristine softness of elastomer via incorporation of high permittivity filler, network reinforcing filler, copolymerisation, micro capsulation, and etc. Among these works, incorporation of filler for enhancement of electrical and mechanical properties is desired due to not undergoing complex chemical synthesis and reaction, producing so-called a composite silicone DE. Chitosan, cellulose, and silica are fillers that commonly used as network reinforcing agents in silicone DE. Chemical-synthesised silica is commonly used in preparing silicone DE composite for a strong network. In this project, cellulose and chitosan are investigated for bio-based fillers as network reinforcing agents in silicone DE due to sustainability and environmental conservation, replacing chemical-synthesised silica. Based on this previous work, data of tensile strength of prepared film samples was used for optimising filler type, filler loading, and solvent concentration via Taguchi and Response Surface Method (RSM). The optimisation criterion of  Taguchi was “the bigger the better”, where high stress and strain at break are desired for good performance of silicone DE in wave energy harvester. The optimised tensile strength via Taguchi was compared to Response Surface Method (RSM) by means of Design-Expert software using central composite design to express the responses. The optimised tensile strength by Taguchi indicates that high stress and strain at break occur when utilising 1% and 3% chitosan, and when the silicone mixture was mixed with 60% heptane. On the other hands, high stress and strain at break optimised by RSM is obtained by incorporating 3% cellulose and 60% of heptane in silicone dilution mixture. The optimised stress and strain at break via Taguchi and RSM are rather different and hence validation on tensile strength of sample films at abovementioned conditions need to be performed experimentally.