New compounder for plastics processing
21.03.2023 Nowadays, interdisciplinary materials development can only be achieved to a limited extent without technological plastic processing methods. The wood-based materials laboratory of the Institute for Materials and Wood Technology is therefore expanding its infrastructure with a new compounder that allows the production of bio-based polymers and wood-plastic composites (WPC) on a laboratory scale.
With the existing micro compounder, the researchers have so far been able to process approx. 100 g of plastic per hour. With the new system, it is possible to process up to 10 kilos per hour. Thus, the company’s own competencies in the field of plastics processing can be reinforced with regard to bio-based materials, natural fibre-reinforced plastics and wood-plastic composites (WPC). Furthermore, plastics processing is to be increasingly used in research projects. It will also be incorporated into teaching, allowing students to acquire a more complete knowledge of materials during their studies.
The focus at the moment is on gaining experience with the new plant. In the future, however, new materials developments are planned with regard to developing more sustainable building materials. For example, trials could be conducted combining natural fibres such as hemp or nettles with biopolymers, e.g. plastics derived from biomass sources instead of petrochemicals.
How does the new plant work?
In the compounder, the ingredients of the 1st feeder (e.g. polymers) are mixed with those of the 2nd feeder (e.g. wood chips) with the help of a twin-screw extruder and heated. The result is a viscous extrudate that runs continuously out of the compounder in the form of a strand of approx. 3 mm in diameter. The mass is cooled in a water bath or on a conveyor belt and cut into small pieces in the granulator. These are then remelted and further processed in order to be reused. The new plant has a modular design. Thus, as an alternative to the compounder, a kneading mixer can also be used to blend and soften the thermoplastic compound.