Abstract: The present invention provides novel polyolefin compositions having variable hardness and/or toughness properties. The polyolefin compositions include: a polyolefin prepared by the metathesis of an olefin monomer using a ruthenium or osmium carbene catalyst; and one or more hardness and/or toughness modulators. The polyolefin is preferably poly(dicyclopentadiene), or poly-DCPD. Also provided are articles of manufacture, such as molded parts, produced from the polyolefin compositions. The disclosed compositions are useful in marine, recreational and sports products.

Abstract: The invention discloses a composition comprising one or more density modulators dispersed in a polymer matrix wherein the matrix is prepared by the metathesis of an olefin monomer using a ruthenium or osmium metal carbene catalyst. The composition may use a catalyst of the formula wherein: M is ruthenium or osmium; X and X1 are either the same or different and are any anionic ligand; L and L1 are either the same or different and are any neutral electron donor; R and R1 are either the same or different and are each independently hydrogen or a substitutent selected from the group consisting of C1-C20 alkyl, C2-C20 alkenyl, C2-C20 alkynyl, aryl, C1-C20 carboxylate, C1-C20 alkoxy, C2-C20 alkenyloxy, C2-C20 alkynyloxy, aryloxy, C2-C20 alkoxycarbonyl, C1-C20 alkylthio, C1-C20 alkylsulfonyl and C1-C20 alkylsulfinyl, wherein each of the substituents is substituted or unsubstituted.