Patent ID: 8920891

Claim:
An azide-modified composition, comprising the reaction product of: (a) a first composition comprising a LMW polyethylene component; and a HMW polyethylene component, and (b) a second composition comprising a coupling amount of at least one polysulfonyl azide, and wherein the first composition has a substantially single peak in an LTD (Lamellar Distribution Thickness) curve, and has an I5 from 0.01 to 0.5 g/10 min; and wherein the concentration of polysulfonyl azide is up to 200 μg/g, and wherein the azide-modified composition has a PENT (Pennsylvania Notch Test) value of greater than 1,000 hours at 80° C., and at an applied stress of 2.4 MPa, and wherein the azide-modified composition has a density greater than 0.940 g/cc, a flow rate ratio (I 21 /I 5 ) from 15 to 50, and a viscosity at 0.01 sec −1 , 190° C., from 272,000 to 340,000 Pa·s, and wherein the LMW polyethylene component has a density from 0.955 to 0.980 g/cc, and is an ethylene homopolymer or an ethylene/C3-C10 aliphatic alpha-olefin copolymer; and wherein the HMW polyethylene component has a density from 0.920 to 0.932 g/cc, and is an ethylene homopolymer or an ethylene/C3-C10 aliphatic alpha-olefin copolymer, and where the HMW polyethylene component and the LMW polyethylene component are made in-situ, in one or more polymerization reactors, in the presence of one or more Ziegler-Natta catalyst systems.