Modern cars, boats, and sports goods are made of strong and lightweight synthetic composite materials. One spends less energy and fuel when driving a car or a bike with a composite frame. A new trend is to improve such advanced materials' sustainability and end-of-life disposal options using environmentally friendly natural plant fibres.
Flax is the strongest plant fibre. It is geographically relevant for Europe and doesn't need irrigation or pesticides. It also yields long fibres and captures CO2 while growing. Interestingly, flax fibres vibrate many times less than metals and synthetic fibres. Materials strengthen with flax may increase comfort when driving on bumpy roads or playing tennis.
Treatment of fibres with water molecules strengthens biocomposite
Like many other materials, products and structures made of biocomposites have limitations that restrict their use in high-end engineering applications. For example, the flax fibre reinforced biocomposites bear little resistance to external loads and they soften in humidity of more than 60 percent. These features are the most critical technical problems in terms of biocomposite durability. They also prevent wider exploitation of flax for industrial outdoor structures.
In his dissertation, Javanshour proposes a series of fibre modification techniques which protects natural plant fibres from breaking. For example, the biocomposites he developed withstand 100 % more impact than their unmodified counterparts and are comparable to traditional glass fibre reinforced plastics. The methods developed by Javanshour are adaptable to various polymers and processing methods and can reduce the energy consumption of manufacturers.
"One very interesting and industrially relevant outcome was that I found a way to make flexible and strong biocomposites by using moisture-pre-conditioned fibres. This makes humidity, known as the enemy of biocomposites, an asset. It will positively impact companies' and consumers' experience and durability perception of biocomposites. Especially if we want to use biocomposites in the future for even more demanding and added-value engineering applications than we use today," says Farzin Javanshour.
Farzin is from Iran (Tabriz) and has worked in Tampere University's Plastics and Elastomer Technology research group since August 2018.
Public defence on Friday 9 May
The doctoral dissertation of M.Sc. (Tech) Farzin Javanshour in the field of Engineering Materials Science titled Interfacial Toughening Strategies for Impact and Fatigue Tolerant Structural Biocomposites will be publicly examined at the Faculty of Engineering and Natural Sciences at Tampere University at 12 o'clock on Friday 09.06.2023 at Hervanta campus, Sähkötalo building, and auditorium S2 (Korkeakoulunkatu 3, Tampere). The Opponents will be Associate Professor Julie Teuwen from Delft University of Technology, The Netherlands, and Doctor of Science (Technology) Olli Väntsi from MM Kotkamills Boards Oy, Finland. The Custos will be Associate Professor Essi Sarlin from Faculty of Engineering and Natural Sciences, Tampere University.
The doctoral dissertation is available online.
The public defence can be followed via remote connection (Panopto).
Photo: Zeynep Kaynar