Study of the influence of Chitosan on selected properties of elastomeric blends

The current trend of greening production is increasingly bringing to the fore alternative types of fillers, such as biofillers, which are obtained from renewable sources or waste [1, 2]. Unfortunately, biofillers cannot be used as majority fillers due to their incompatibility with elastomer matrices and high biodegradability susceptibility [3, 4]. Therefore, the way to their efficient industrial use leads through supplementary fillers to the commonly used inorganic fillers and the partial replacement of these fillers in the blend. The influence of Chitosan as the majority filler has been investigated and its combination with carbon black filler on the elastomeric matrix of natural rubber was investigated in the presented work. The results were compared with natural rubber blends filled exclusively with carbon black. Natural rubber blends with different content of Chitosan and carbon black and their various combinations were subjected to the determination of vulcanization parameters, mechanical properties before and after thermo-oxidative aging, and scanning electron microscopy. Although the scanning electron microscopy analysis confirmed the expected negative impact of Chitosan as the majority filler on the tensile properties of the vulcanizate, its significant impact on the main vulcanization parameters such as scorch time and optimal vulcanization time was also demonstrated. In the case of blends with a combination of carbon black and Chitosan, it has been shown that Chitosan, in addition to the filler function, also acts as an antioxidant agent through its functional groups, limiting the process of degradation of mechanical properties of natural rubber blends due to their thermo-oxidative aging. It can be concluded that precisely because of its antioxidant and anti-degradation effects, Chitosan can be, in addition to carbon black filler, an excellent additional filler for elastomeric blends.     

Design and development of engineering component using natural rubber biocomposites

The potential usage of natural rubber biocomposites in engineering products was investigated. The engineering product fabricated is a rubber bush which is widely used in the automobile industry. Three different types of rubber: 25 % mol epoxidised natural rubber, 50 % mol epoxidised natural rubber and deproteinised natural rubber reinforced with eggshell powder and oil palm fibres hybrid biofillers were studied. The mould flow simulation was carried out to study the flow of the rubber in an existing mould cavity. A thermogravimetric analysis was carried out on both the eggshell powder and oil palm fibres and it was observed that the eggshell powder is more stable thermally compared to the oil palm fibres. Static test was conducted to study the static stiffness properties. Dynamic test was also conducted to study the dynamic stiffness and the loss angle. The results of the tests showed promising mechanical properties of the 25 % mol epoxidised natural rubber biocomposites. Further research should be conducted on other biofillers that is capable of improving the properties of the rubber to replace the use of carbon black in the 25 % mol epoxidised natural rubber biocomposite.