Functional Hyperbranched Polymers Using Ring-Opening Metathesis Polymerization of Dicyclopentadiene with Monoterpenes

A general method for the synthesis of hyperbranched functional polymers in monoterpenes is described. During the polymerization of dicyclopentadiene, metathesis reactions between the growing polymer chain and monoterpenes produced soluble well-defined polymers. The molecular weight, intrinsic viscosity [eta], and glass transition temperature (T-g) values resulting from chain transfer to monoterpenes depended on the mode of monomer addition but generally decreased as follows: d-limonene > limonene oxide > beta-pinene. Calculation of the Mark-Houwink-Sakarada values by gel permeation chromatography suggested that, in solution, the branched poly(dicyclopentadiene) had a smaller hydrodynamic volume than polynorbornene. Characterization by NMR spectroscopy indicated the hyperbranched polymer had a complex structure composed of linear, terminal, semidendritic, and dendritic units.