| Abstract
| - Acyclic diene metathesis (ADMET) polymerization was used as a newsynthetic route to aclass of processable, hydrophobic, and crystalline polymers whichcontain only aromatic and aliphatichydrocarbon units in their backbone.Poly(p-phenylene octylene) (PPPO), as afirst example, was preparedby the ADMET polymerization of 1,4-bis(pent-4-ene)benzene,followed by the catalytic reduction of theresulting unsaturated polymer. The weight-average molecularweights of the polymers obtained withthis method were in the range of 13 000−25 000.Poly(p-phenylene octylene) was found to behighlysoluble in common solvents and to have a melting temperature of around90 °C, which enabled meltprocessing into fibers and films without decomposition. Wide-angleX-ray diffraction and annealingexperiments on PPPO revealed two different crystalmodifications. The polymer, as precipitated fromthe reaction mixture, predominantly forms the kinetically preferredmodification α, while the annealingof pristine PPPO almost exclusively leads to thethermodynamically more stable modification β.
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