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Some rheological properties of solutions and blends of hydrogenated polybutadiene

1984; Wiley; Volume: 71; Issue: 1 Linguagem: Inglês

10.1002/polc.5070710109

1936-0959

William W. Graessley, V. R. Raju,

Material Dynamics and Properties

Abstract This article describes work with model polymers to explore the effects of long branches on polyethylene melt rheology. Dynamic moduli were measured at two or more temperatures on melts, blends, and solutions of linear (L) and star (B) hydrogenated polybutadiene (HPB). Enhancement factor Γ and temperature coefficient (flow activation energy E a ) were determined from viscosity data and correlated with arm molecular weight M b and volume fraction of the star component Φ. As in other species, Γ for a given branch point functionality is roughly an exponential function of Φ 11/6 M b in entangled melts and solutions. In contrast with other species, however, ( E a ) B and ( E a ) L are different; ( E a ) B – ( E a ) L is directly proportional to Φ M b , and the degree of thermorheological complexity varies primarily with ( E a ) B – ( E a ) L . In blends with linear HPB of comparable viscosity, Γ for the star component remains essentially constant, and ( E a ) B – ( E a ) L is directly proportional to the volume fraction of the star component.