FLAME RETARDANCY FOR BIOPOLYMERS

Homogeneous distribution of the flame retardants in the biopolymer matrix is necessary to achieve optimum flame retardancy. The coupling with the polymer matrix should be achieved through the specially developed, reactive flame retardants. Irradiation with accelerated electrons was used as a new method for bonding the flame retardants to the matrix. The properties of the polymers are modified through the triggering of crosslinking and coupling reactions that can be controlled via the radiation dose. In the tests, an additive proved to be effective in which the crosslinking reaction outweighed the degradation of the polymer by the irradiation. Other additives were also tested extensively. In addition, flame retardant formulations based on biopolyamides (PA) for injection molding were developed as part of the project, and the crosslinkability under the influence of E-Beam was investigated for the first time.

Results
The biopolyamides PA610, PA1010 and PA11 used can be crosslinked very effectively with the help of a crosslinking additive. The positive effect of adding wood particles on the flame retardant performance was demonstrated. The heat release rates were able to be reduced by adding wood, while at the same time shortening the ignition times. The crosslinking of the developed materials leads to a novel property profile: for example, an increase in tensile strength and tensile modulus with a reduction in notched impact strength was demonstrated for almost all PA-based formulations. The project has also shown that the production of crosslinkable formulations and their processing have many parallels to the well-known conventional fossil-based plastics. Bio-based plastics can therefore replace conventional plastics in many applications and their range of properties can be further optimized through radiation crosslinking. This opens up new possibilities in the field of E&E, especially for applications in the automotive industry – with enormous potential!