Could Flame-Retardant Bioplastics Soon Be Used in AM?

Materials used in electrical engineering or electronics must conform to high demands. This is especially the case since these materials must have properties such as flame resistance. It is well known that in this case plastics meet the necessary flame retardancy requirements needed for use in electrical engineering and electronics, but what about flame-retardant bioplastics? Researchers at the Fraunhofer WKI and the Fraunhofer IAP have asked themselves this question in joint collaboration with industrial partners and have already been able to celebrate initial successes in the course of their research not only developing flame-retardant bioplastics but also showing that the materials are compatible with additive manufacturing.

Before the research results of the Fraunhofer Institutes, there was no known bio-based flame-retardant that would be suitable for the development of bioplastics. With this challenge in mind, the focus was therefore on a halogen-free flame retardant that would be extremely cost-effective to use, since it is needed primarily in extremely small quantities. At the beginning of the research project for the development of bio-composite materials suitable for both electrical engineering and electronics, the focus was on the production of new, bio-based flame retardants. For this purpose, syntheses based on bio-based alcohols and phosphorus-containing compounds were carried out.

Together with Hager Electro, for example, they produced a tunnel slide made of flame-retardant polybutylene succinate (PBS) (photo credits: Fraunhofer WKI | Manuela Lingnau)

A New Flame-Retardant Bioplastic Innovation

However, in order for the flame retardant factor to be given in the first place, it is important to understand that the uniform distribution of the flame retardant within the matrix of the PLA biopolymer is required. To achieve this bonding of the flame retardant to this matrix, electron beam crosslinking was used, which is a non-thermal process. While this process is extremely common when it comes to plastics, it is not yet very proven with bioplastics. To change this, however, the properties of the polymers must be modified.