Some of the bioplastics are certainly compostable, but a mechanical recovery can still be preferred, as the material can be used several times. The current recycling system for plastics, however, has not yet been adapted to these new plastics and the risk is that the bioplastics may contaminate the pure recycling streams of the traditional plastics. What then happens to the properties of the recycled material? Concern has been expressed that the incorporation of bioplastics drastically degrades the properties of a conventional petroleum-based plastic. However, no scientific attempts have yet been made to confirm or deny this concern. The current project aims to clarify this environmentally and economically important issue.