Polyurethane composites in situ molecularly reinforced by supramolecular nanofibrillar aggregates of sorbitol derivatives

1,3:2,4-di-O-benzylidene-D-sorbitol (DBS) can self-assemble into supramolecular nanofibers in the precursor of polyurethane followed by gelation. After UV-initiated polymerization, in situ supramolecular nanofibers reinforced polyurethane composites can be obtained. SEM studies indicate that the in situ formed supramolecular nanofibers can induce the composite interface at the molecular level, greatly improving interface compatibility of the fibers and matrices. Static and dynamic mechanical analysis indicated that the tensile strength of 12 wt% DBS nanofibers reinforced polyurethane was 2.8 times higher than that of pure polyurethane. Their breaking elongation was 2.5 times higher than that of conventional glass fibers reinforced polyurethane. In comparison with conventional fiber reinforced polymers, the utilizing of in situ formed supramolecular nanofibers not only reinforce, but also toughen the polymer matrices, and show the advantage of reducing the weight and maintaining transparency of the polymers.