Materials that exhibit highly nonlinear behaviour are intricate to study. This is due to their physical properties, as they possess a very large deformation. Silicone rubber is among the materials that can be classified as possessing such characteristics, despite their being soft and frequently applied in medical applications. Due to their low mechanical properties, however, it is believed that a filler addition could enhance them. This study, therefore, aims to investigate the effect of the addition of bamboo cellulosic filler to silicone rubber in terms of its compressive properties in order to quantify its material constants using the hyperelastic theory, specifically the Neo-Hookean and Mooney–Rivlin models. The specimens’ compressive properties were also compared between specimens immersed in seawater and those not immersed in seawater. The findings showed that the compressive properties, stiffness, and compressive strength of the bamboo cellulosic fibre reinforced the silicone rubber biocomposites, improved with higher bamboo filler addition. Specimens immersed in seawater showed that they can withstand a compressive load of up to 83.16 kPa in comparison to specimens not immersed in seawater (up to 79.8 kPa). Using the hyperelastic constitutive models, the Mooney–Rivlin model displayed the most accurate performance curve fit with the experimental compression data with an R2 of up to 0.9999. The material constant values also revealed that the specimens immersed in seawater improved in stiffness property, as the C1 material constant values are higher than for the specimens not immersed in seawater. From these findings, this study has shown that bamboo cellulosic filler added into silicone rubber enhances the material’s compressive properties and that the rubber further improves with immersion in seawater. Thus, these findings contribute significantly towards knowledge of bamboo cellulosic fibre–reinforced silicone rubber biocomposite materials.

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The development of environmentally benign silicone composites from sugar palm fibre and silicone rubber was carried out in this study. The mechanical, physical, and morphological properties of the composites with sugar palm (SP) filler contents ranging from 0% to 16% by weight (wt%) were investigated. Based on the uniaxial tensile tests, it was found that the increment in filler content led to higher stiffness. Via dynamic mechanical analysis (DMA), the viscoelastic properties of the silicone biocomposite showed that the storage modulus and loss modulus increased with the increment in filler content. The physical properties also revealed that the density and moisture absorption rate increased as the filler content increased. Inversely, the swelling effect of the highest filler content (16 wt%) revealed that its swelling ratio possessed the lowest rate as compared to the lower filler addition and pure silicone rubber. The morphological analysis via scanning electron microscopy (SEM) showed that the sugar palm filler was evenly dispersed and no agglomeration could be seen. Thus, it can be concluded that the addition of sugar palm filler enhanced the stiffness property of silicone rubber. These new findings could contribute positively to the employment of natural fibres as reinforcements for greener biocomposite materials.

Due to high flexibility and elasticity, silicone rubber has been widely used in many applications especially in medical and industrial sectors. However, pure silicone rubber experiences weak tensile strength and this can be improved via filler addition. Therefore, this paper aims to produce a new type of silicone biocomposite (Arenga pinnata-silicone biocomposite) and assess its mechanical properties, physical properties and morphological characteristics. The effects of Arenga pinnata filler on the silicone rubber are investigated by comparing the mechanical properties between pure silicone rubber and 12 wt.% Arenga pinnata-silicone biocomposite. Uniaxial tensile test was conducted on these soft materials to obtain stress-strain data, which then converted into engineering stress-stretch (σE-λ) data. These experimental data were fitted to Neo-Hookean and Mooney-Rivlin models to acquire the material constants. Its physical characteristic was studied via density test and the morphological surface on the break surface was examined using Scanning Electron Microscope (SEM). The average maximum tensile strength of the specimen with the addition of 12 wt.% Arenga pinnata filler is found to be 0.65 MPa. This signifies a decrease of its strength compared to pure silicone rubber (average maximum tensile strength = 0.85 MPa). However, in contrary, it is found that the presence of Arenga pinnata fibre has increased the stiffness and density of the silicone rubber. When comparing to experimental data, it could be observed that both Neo-Hookean and Mooney-Rivlin models could mimic better the elastic behaviour of the 12 wt.% Arenga pinnata-silicone biocomposite compared to pure silicone rubber. Observing the SEM images, no agglomerations of Arenga pinnata filler can be seen thus conforming good dispersion of the filler. The images also show good fibre adhesion between the filler and the matrix. Therefore, it can be concluded that the addition of Arenga pinnata filler has enhanced properties of pure silicone rubber. In addition, this study promotes the benefits of utilising natural fibres as fillers in composite materials.

Due to the excellent chemical flexibility and elastic properties of silicone rubber, Arenga pinnata‐silicone rubber biocomposites were introduced as a candidate for sealing applications. Its sealing properties were investigated via compressive properties between oil soaked and unsoaked specimens. Compression test based on ASTM D395 was employed to obtain the compression sets and its material constants are acquired using hyperelastic material models i. e. Neo‐Hookean and Mooney‐Rivlin models. Unsoaked specimens consist of 0 wt %, 4 wt %, 8 wt % and 16 wt % fibre content while for soaked specimens, only those with 0 wt % (lowest) and 16 wt % (highest) were prepared for comparison purposes. The results indicated that 16 wt % soaked specimens exhibit the highest compressive stress compared to both soaked and unsoaked 0 wt % specimens, while the compression sets of both 0 wt % and 16 wt % soaked specimens showed lower values compared to all unsoaked specimens. Using hyperelastic material models, the 16 wt % soaked specimens indicated higher material constants than unsoaked specimens while pure silicone showed the opposite. Thus, this study has found that the silicone biocomposites have the capability in sealing applications as its compressive stress shows superior properties especially for soaked specimens compared to pure silicone rubber.

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