Supramolecular polypropylene with self-complementary hydrogen bonding system

Novel supramolecular polypropylenes (PP) having self-complementary quadruple hydrogen bonding 2-ureido-4[1H]-pyrimidinone (UPy) groups (UPy-PP) have been synthesized by functionalizing of PP. The mechanical properties donated by the network structure formed by the multiple hydrogen bonding were studied with rheological analyses and tensile tests of the UPy-PP. Unusual melt viscosity of the UPy-PP indicated that the hydrogen bonding network of the UPy was maintained in the solid state at ambient temperature whereas the hydrogen bonding was dissociated in the melting PP matrix at high temperatures of around 190 °C. Tensile tests showed that the elongation at break of the UPy-PP drastically increased at higher temperatures compared to that of non-functionalized PP (nf-PP). The results indicated that a pseudo-high molecular weight PP was easily obtained through the UPy hydrogen bonding aggregation of low molecular weight PP. These findings are applicable to improving the mechanical properties of various nonpolar polyolefins by introducing self-complementary quadruple hydrogen bonding groups as a thermal reversible network system.