RING-OPENED METATHESIS POLYMERS FROM CYCLOHEXENYLNORBORNENE AND RELATED DIELS-ALDER ADDUCTS OF CYCLOPENTADIENE WITH VINYL AND DIVINYL CYCLOHYDROCARBONS

5-(3-Cyclohexen-1-yl)-2-norbornene [CHNB] has been shown to form a ver y lightly crosslinked polymer (T-g = 127 degrees C) with good elongati on via ring-opening metathesis polymerization (ROMP). Based on swellin g behavior with added norbornadiene dimer, the low crosslink density i s ascribed to much less than 0.5% participation by the cyclohexenyl ri ng. Compared to dicyclopentadiene (DCPD), CHNB polymerizations were le ss exothermic, required less catalyst, and exhibited greater molding l atitude, which are advantageous for Reaction injection Molding (RIM). Styrene-isoprene and sty rene-ethylene/butylene block copolymers were effective impact modifiers for polyCHNB, forming large particle morpho logies. Small rubber particles formed from styrene-butadiene block cop olymers were not effective for impact enhancement of polyCHNB, in cont rast to polyDCPD. Rubber-modified polyCHNB retained impact resistance four to six times longer than polyDCPD samples when aged in air at 50- 70 degrees C. Related RIM-ROMP of liquid monomer mixtures prepared by cyclopentadiene cycloadditions with 4-vinyl-1-cyclohexene, cis-1,3-div inylcyclopentane, 3,5-divinylcyclopentene or cis-2,4-divinylbicyclo [3 .3.0] oct-6-ene formed highly crosslinked, less ductile copolymers wit h T(g)s as high as 206 degrees C. (C) 1997 John Wiley & Sons, Inc.