Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE credits
Using more recyclable material and reducing the weight of vehicles has become one of the most common objectives for car manufacturers in Europe. Among them, Volvo cars, which is one of the leaders in automotive industry when it comes to research of human safety and a sustainable future.
Fibre reinforced plastics, such as: polypropylene/ long glass fibre (PPLGF) and natural fibre reinforced polypropylene (NFPP) composites play a major role in the search for light weight and recyclability design.
Strength to weight ratio is considered to be one of the most important factors that gives fibre reinforced plastic composites their unique advantage in many industrial applications.
However, joining natural fibre reinforced polypropylene composites together with other thermoplastics efficiently is still not fully feasible.
When NFPP composite is used, joining towards other thermoplastics is possible to obtain using available welding methods which melts NFPP and the opposite material at the interface.
Infrared welding is well known for being a fast, effective, and a very reliable technology when joining plastic/plastic, especially when the two welded parts are dissimilar thermoplastics. In this research collaboration between Volvo cars and University West in Sweden, infrared welding of NFPP with PP LGF was investigated.
The aim of this project was to find the best infrared welding parameters that can be used when involving NFPP, and to investigate the weldment region and its strength compared to what can be achieved when welding two PP LGF parts.
In this research, different natural fibres types were investigated to define the best fibre that can be used when welding NFPP. Infrared welding trials were performed on NFPP and PP LGF samples with different welding setups to find the parameters that give the highest strength. This strength was measured by tensile machines for all welded samples. Differential Scanning Calorimetry (DSC) tests were also performed to determine melting temperature as well as degree of crystallinity for both NFPP and PP LGF.
The results show that, basically, infrared welding between NFPP and PP LGF proved to be feasible, but that the weldment region has lower strength. They hence provide valuable understanding about NFPP infrared welding development in automotive industry. Additional research can enhance Volvo cars' platform to enable better design for further use of NFPP in coming projects, which lead to further light weighting and lower CO2-emissions from vehicles.
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