Birch Bark Composite for Automobiles

Important results from the project

The project ideas concerning light weight solutions for automotive industry based on birch bark (BB) raw material were verified in this feasibility study project. Composites in both solid and porous forms have been created and tested, in which BB particles were used as fillers in the thermoplastic matrixes. The results have indicated good opportunities for BB to replace minerals as fillers in plastics, which can result in the composites of similar mechanical strength but much lighter in weight and in the meantime better sound absorption (or sound transmission loss) properties.

Expected long term effects

The results have indicated good opportunities for birch bark (BB) to replace minerals as fillers in plastics and give a double-win possibility. First, to replace mineral fillers in thermoplastics with BB results in the composites of similar mechanical strength but much lighter in weight and in the meantime, the composites show better sound absorption (sound transmission loss) characteristics. Second, BB is from a renewable source. It is presently treated as waste and burnt for energy. Hence, to make BB as fillers in plastics will create added values for forestry industry.

Approach and implementation

The project started with collection and processing different birch bark (BB) portions into different particle sizes. Chemical emission of bark materials was analyzed. Composites having of different amounts of BB particles and polypropylene (PP) were made and their mechanical properties measured. Sound absorption (transmission loss) characteristics of raw BB materials and composites and their responses to UV radiation, temperature and humidity were also studied. The measured values were compared with those of the pure PP and commercial composites containing mineral fillers.