Co-operative Formation of Monolithic Tungsten Oxide-Polybenzylene Hybrids via Polymerization of Benzyl Alcohol and Study of the Catalytic Activity of the Tungsten Oxide Nanoparticles

Hard and brittle monolithic tungsten oxide-polybenzylene nanohybrids can be obtained in one step by reacting tungsten iso-propoxide with benzyl alcohol. In a first step, crystalline tungsten oxide W18O49 nanowires with a diameter of about 1.5 nm form via ether elimination reaction. Subsequently, the large residue of the benzyl alcohol is transformed to dibenzyl ether, which then polymerizes to polybenzylene, incorporating the nanoparticles into the forming polymer. The catalytic effect of the tungsten oxide nanowires on the quantitative formation of polybenzylene is proven by reacting them in different concentrations and at varying temperatures either with benzyl alcohol or with dibenzyl ether. Complete polymerization of benzyl alcohol is achieved within just 30 min by using a particle-to-monomer molar ratio of 1:115 at 160 degrees C. Lower reaction temperatures (100-130 degrees C) or higher ratios (1:340 and 1:680) prolong the reaction time to several hours. Further studies show that the tungsten oxide nano particles are able to completely polymerize various other alcohols with an aryl methanol group.