Creep recovery of random ethylene-octene copolymer melts with varying comonomer content

Deriving comprehensive structural information on long-chain branched polyethylenes from analysis of thermo-rheological complexity

“…In the last years, the analysis of the complex modulus, viscosity, and compliance as a function of time or shear rate/frequency dependencies as well as the analysis of relaxation spectra have added knowledge to the behavior of LCB-PE [34,[37][38][39][40][41][42][43][44][45][46][47][48][49]. Other quantities used for the rheological analysis of LCB-PE include the recoverable compliance [43,47,[50][51][52][53][54] and the strain-hardening in elongation induced by long-chain branches [16,[55][56][57][58][59]. However, except for the η0-Mw-relation, the abovementioned indicators are influenced additionally by the molar mass distribution in a non-trivial way and so far it has not been possible to clearly distinguish between effects of branching and molar mass distribution in rheology as both have rather similar behavior.…”

Creep and Dynamic Mechanical Analysis Studies of Peroxide‐Crosslinked Ethylene‐Octene Copolymer

“…To the authors best knowledge, only few articles deal with the creep behavior of EOCs. Namely, Patham and Jayaraman21 examined the effect of co‐monomer content on creep recovery of EOCs. Kamphunthong and Sirisinha22 studied the creep behavior of silane/water‐crosslinked EOC.…”

Branching structure and strain hardening of branched metallocene polyethylenes

“…The structure of these materials, supposedly lightly branched, may differ from the random, solutionpolymerized BMP materials studied here. They do not report how their sample was made or the branching level, but Patham and Jayaraman (2005) reported that it corresponds to sample EO1 in their study, which had a very high level of comonomer and was referred to as an elastomer. The extensional stress growth coefficients g þ E ðt; _ Þ of the more highly branched samples HDB 5-7 were determined using a M€ unstedt extensional rheometer [M€ unstedt (1979)].…”

“…First, our samples are homopolymers, which makes them different from commercial copolymers and from many others used in experimental studies that contain a-olefin comonomers. Patham and Jayaraman (2005) reported the effect of octene content on the linear viscoelastic (LVE) properties of metallocene polyethylenes, and Mills et al (2008) studied the effect of high comonomer content on extensional flow behavior. Although it has been shown that comonomer interacts with long-chain branching to influence rheological properties and their temperature dependence {via their activation energy [Wood-Adams and Costeux (2001)]}, copolymerization is not expected to have a strong effect on extensional flow behavior.…”