Bio-based polylactic acid (PLA) thermoplastics are relatively environmentally friendly and easy to recycle, while composite materials such as carbon fiber are more durable. According to foreign media reports, German scientists claim that they have developed a new type of all-lactic acid composite material that effectively combines the advantages of the two.
Unlike traditional petroleum-based plastics, polylactic acid is made from renewable resources such as corn starch, cassava, and sugar cane. As long as there are related facilities, they can all be recycled. If the conditions are suitable, it can also be biodegraded within a few years to become an industrial compost. This material, like other single-type plastics, does not have the unique mechanical strength or rigidity of composite materials. However, the composite material is composed of at least two mixed substances, so the recycling process is relatively complicated, and the recycling cost is usually too high.
In this case, researchers at the Fraunhofer Institute for Chemical Technology developed a composite material woven from polylactic acid fibers. In this material, polylactic acid fibers are fixed in the polylactic acid matrix.
In fact, the fibers and matrix of this material are made of two different types of bioplastics, the former has a higher melting point than the latter. During the production process, solid fibers are embedded in a liquid matrix (consisting of melted PLA particles), and then the matrix becomes solid. The recovery process is accomplished by melting the fiber and matrix at different temperatures.
Fraunhofer said that PLA composites are stronger and harder than "pure" plastics. It is said to be able to "compete with commercial composites of self-reinforced polypropylene." More importantly, the energy consumed during its manufacturing process is half that of petroleum-based composite materials, and the amount of carbon dioxide produced per kilogram of material is half that of the latter.
If this technology is further developed, PLA composite materials are expected to be applied in sports, automotive and medical fields. The research and development of this material belongs to the European Union Bio4self project. Participating in the project also include: the Danish University of Science and Technology, the Belgian Textile Research Center (CENTEXBEL) and the Danish Comfil company.