comprising a conjugated diene compound and having a hydroxyl group at the terminal block copolymer or its hydrogenation product marketed by kuraray company use of a polymer in the nanocomposite material that is in the same polymeric family as the polymer in the remainder of the composition is expected to provide good compatibility between the components the cover compositions incorporating the nanocomposite material were manufactured using conventional compounding techniques the particular cover composition percentages of the two ball types are provided below in table 1 the balls were tested for spin rate and speed when hit with an 8 iron and with a driver and for surface hardness on the shore d scale the balls also were tested for shear resistance using a robot to simulate real life impact conditions at 80 mph club head speed three of each type of ball were used for this testing each ball was assigned a numerical score from 1 no visible damage to 5 substantial material displaced and these scores were averaged for each ball type to produce the shear resistance numbers below in addition to the balls incorporating nanocomposite material several golf balls currently available on the market were tested for the same parameters these balls included the professional tour balata and hp tour manufactured by titleist corporation of fairhaven mass and also the inergel pro and inergel pro distance manufactured by taylor made golf company of carlsbad calif results of the tests are show below in table.