Thermoplastic coatings from precursor systems with extreme reactivity for in-line hybrid-fiber production

In the state of the art, thermoplastic glass fiber reinforced plastics (GFRP) suffer from mechanical properties insufficient for high-performance applications. This is primarily due to imperfect impregnation of the glass fibers and consequently a non-ideal microstructure of the composite. To overcome this issue, we previously introduced a novel approach for coating of individual glass filaments directly within the spinning process (in-line polymerization). While the process itself has been implemented successfully, the used monomers and respective polymeric coatings were model systems, without regard to the material properties of the coating itself. As this aspect is obviously of supreme importance for the later composite, we herein discuss potential precursors that result in suited mechanical properties and still fit into the narrow frame, defined by the process conditions. It is shown that several highly reactive and mechanically desirable acrylic monomers can be readily copolymerized without significant loss of reactivity. Those are shown to yield ideal combinations of hard and soft properties. Alternatively, mechanical properties of the polymer can be adjusted by incorporation of reactive low molecular soft resins. Again, the highly reactive character of the precursor is retained and suitable material properties are obtained.