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Rathish Rajan: Biocomposites with improved water resistance, impact strength and anti-static properties

Tampere University
LocationHervanta Campus, Konetalo, auditorium K1702 (Korkeakoulunkatu 6, Tampere)
9.9.2022 12.00–16.00
Entrance feeFree of charge
Natural fibres absorb water which makes them incompatible with the hydrophobic polymers and leads to weak moisture resistance. Ultimately, this affects the mechanical properties of the biocomposites. In his doctoral dissertation, MSc. Rathish Rajan utilized chemical modification methods for improving the water resistance and mechanical properties of the biocomposites reinforced with viscose fibre. Rajan found that the silane coupling agent treatments improve significantly both water resistance and the mechanical properties of the biocomposites. He also studied anti-static biocomposites which could be an alternative to fossil-based conductive plastic compounds.

Several chemical modification methods are utilized for modifying the natural fibres intended to be used as reinforcement in the biocomposites. Among them, the silane coupling agent modification offers improved fibre-matrix adhesion in addition to increasing the water resistance of the composites by modifying the fibre surface.

“The chemical modification of natural fibres adds another step to composite manufacturing and creates chemical waste that requires waste treatment. More environment friendly methods need to be adopted for this purpose,” says Rathish Rajan.

Wood plastic composites are materials made of wood fibre or wood flour (side-stream from timber industry) and predominantly, thermoplastic polymers such as polypropylene and polyethylene. This material is currently used mainly in the building and construction industry. Conductive plastics based on fossil-based thermoplastic polymers are available in the market for use in applications demanding thermal or electrical conductivity.

“Using electrically conductive fillers as additives in wood plastic composite offers a sustainable material option for the conductive plastic market,” he states.

The silane coupling agent modification method adopted in Rajan’s thesis for viscose fibre showed a significant increase in water resistance and impact strength of the unsaturated polyester composites compared to other chemical modification methods. In a different approach, instead of modifying the fibre, Rajan studied the modification of epoxy resin, thereby creating less process waste during the composite manufacturing.

“The effectiveness of the resin modification was confirmed by the increase in the mechanical properties of viscose fibre reinforced composites. Also, in my research, I developed sustainable, anti-static wood plastic composites by incorporating graphene nanoplatelets to replace fossil-based conductive plastic compounds,” Rajan concludes.

MSc. Rathish Rajan hails from India. He currently works as an RDI specialist at Centria University of Applied Sciences in Kokkola.

The doctoral dissertation of MSc. Rathish Rajan in the field of Materials Science and Engineering titled Tailoring the Properties of Biocomposites by Silane Coupling Agents and Graphene Nanoplatelets will be publicly examined at the Faculty of Engineering and Natural Sciences at 12 o’clock on Friday, 9 September 2022, in Konetalo, auditorium K1702, (Korkeakoulunkatu 6, Tampere). The Opponent will be Professor Patrik Fernberg, Luleå University of Technology, Sweden. The Custos will be Professor Jyrki Vuorinen, Tampere University.

The dissertation will soon be available online at the

You can follow the event also via remote connection (Panopto).

Photo: Markus Kunelius