Catalyst Activity and Selectivity in ROMP of Dicyclopentadiene Induced by Some Tungsten Systems

The present work focuses on recent results obtained in polymerization of dicyclopentadiene (DCPD) to linear polydicyclopentadiene (LPDCPD) using two families of highly active and selective tungsten-based catalytic systems. Polydicyclopentadiene, prepared in excellent yield from endo-DCPD with catalysts consisting of WCl6 or WOCl4 and organosilicon compounds, has been structurally characterized by various spectroscopic techniques as well as by DSC and TGA measurements. Microstructure investigations by IR and 13C NMR indicated a prevailingly cis double bond configuration. The linear polymer had a glass-transition temperature of 53°C and exhibited good thermal and electrical properties. The product displayed an appreciable solubility in various organic solvents. From solutions of the linear polymer, elastic and resistant films having a superior adhesion capacity on many solids (wood, metal, plastic materials) could be produced. Alternatively, the catalytic system derived from tungsten tetraphenylporphyrinate and diisobutylaluminoxane, lead to linear polydicyclopentadiene with a predominantly trans configuration at the carboncarbon double bonds. The latter catalytic system behaved in a “living” fashion and allowed polymers with monomodal and narrow molecular weight distribution to be prepared. Block copolymers from dicyclopentadiene with cyclopentene and cyclooctene have also been synthesized. Data recorded in this research provide information concerning the activity and selectivity of the two types of catalytic systems and enable comparison between the structure and configuration of the active sites, the nature of the initiation and propagation reactions, the reaction mechanism and stereochemistry.