Prediction of Melt State Poly(α-olefin) Rheological Properties:  The Unsuspected Role of the Average Molecular Weight per Backbone Bond

Fetters, Lewis J.; Lohse, David J.; García-Franco, César A.; Brant, Patrick; Richter, D.

doi:10.1021/ma025659z

Cited by 118 publications

(205 citation statements)

References 22 publications

Supporting

Mentioning

183

Contrasting

Order By: Relevance

“…This approach is based on the concept [57][58][59][60][61] of the packing length (p) that combines the conformational and volume filling properties of a chain into a parameter independent of chain length. The packing length (p) is defined by the unperturbed chain dimension, polymer density (r) and the Avogadro number (N a ) as follows:…”

Section: Calculated Rheological Parametersmentioning

confidence: 99%

Synthesis and Rheological Properties of Poly(5‐n‐hexylnorbornene)

Müller¹,

Kreiling²,

Dehnicke³

et al. 2006

Macro Chemistry & Physics

Self Cite

View full text Add to dashboard Cite

Summary: Poly(5‐n‐hexylnorbornene) (PHNB) was obtained in high molecular weight and high yields by vinyl‐type polymerization of 5‐n‐hexyl‐2‐norbornene (endo/exo = 77/23) with [NiBr(NPMe3)]4/B(C6F5)3 as catalyst precursor. The combination of size exclusion chromatography with on‐line light scattering and intrinsic viscosity measurements allowed the Mark‐Houwink expressions to be evaluated in tetrahydrofuran. The unperturbed chain dimensions for poly(5‐n‐hexylnorbornene) were estimated via the extrapolation procedure of Burchard‐Stockmayer‐Fixman. This evaluation of the unperturbed chain dimension in turn permits the calculation of the entanglement molecular weight and the plateau modulus via the packing length model. This allows the determination of rheological properties for these materials where conventional rheology measurements are difficult, or impossible.[η]‐M data for PHNB in THF at 35 °C.magnified image[η]‐M data for PHNB in THF at 35 °C.

show abstract

Section: Calculated Rheological Parametersmentioning

confidence: 99%

Synthesis and Rheological Properties of Poly(5‐n‐hexylnorbornene)

Müller¹,

Kreiling²,

Dehnicke³

et al. 2006

Macro Chemistry & Physics

Self Cite

View full text Add to dashboard Cite

show abstract

“…The characteristic ratio of R 2 g 1=2 = M M 1=2 w was 0.46 based on small-angle neutron scattering (SANS) measurements (Fetters et al, 2002). The polymer blends were prepared by a solution-mixing procedure to ensure the thorough blending of the two different species at the molecular level.…”

mentioning

confidence: 99%

Probing the flow-induced shish-kebab structure in entangled polyethylene melts by synchrotron X-ray scattering

2006

View full text Add to dashboard Cite

In-situ rheo small-angle X-ray scattering (SAXS) and rheo wide-angle X-ray diffraction (WAXD) techniques were used to investigate the flow-induced crystalline structure in entangled melts of ultrahigh-molecular-weight polyethylene (UHMWPE)/low-molecular-weight polyethylene (LMWPE) blends (0, 2 and 5 wt% of UHMWPE). Immediately after a step shear at 415 K, SAXS and WAXD results confirmed that only the shish structure was formed in the melts without kebabs. The topological deformation of entangled UHMWPE chains in the blend was responsible for the formation of shish. The missing kebab growth in the presence of shish indicated that secondary nucleation of coiled chains on the shish surface was frustrated at high temperatures close to the equilibrium melting temperature (418.5 K). When the temperature was quenched to 407 K, both blends (but not pure LMWPE) clearly exhibited oriented kebab growth. An Avrami analysis was applied to investigate the nucleation and growth of kebabs. Results indicated that kebabs were probably grown under athermal nucleation and diffusion-controlled conditions. In addition, the crystallization rate under predetermined nucleation was strongly governed by the concentration of shish.

show abstract

“…This correlation comes from an observation of how the dimensions of chains depend on a simple feature of the chemical architecture, which is m b , the molecular weight per backbone bond [37]. In Fig.…”

Section: Models Of Chain Dimensionsmentioning

confidence: 99%

“…6 satisfies the main objective of a reasonable estimate of l p for most polyolefins in the melt. The clearest outlier is syndiotactic polypropylene (sPP), which is known to have large chain dimensions due to a preponderance of trans rotations [37]. The variation of l p with m b is mostly due to changes in the "thickness" of the chain (i.e., how much of the chain is in the side branches instead of in the backbone), but also is partly a result of differences in chain stiffness (i.e., the tendency for trans vs. gauche rotations).…”

Section: Models Of Chain Dimensionsmentioning

confidence: 99%

The Critical Role of Anionic Polymerization for Advances in the Physics of Polyolefins

Lohse

2015

Anionic Polymerization

Self Cite

View full text Add to dashboard Cite

This chapter shows how the great power and versatility of anionic polymerization, which has been described in the rest of this book, has been used to develop an improved understanding of the basic physical principles that underlie the performance of polyolefin materials. When these synthetic tools are employed to polymerize dienes and are then combined with controlled saturation methods, a wide panoply of saturated hydrocarbon polymers can be made. These products can serve as models for commercial polyolefins, which is the most widely used class of synthetic polymers and which continues to develop at a strong pace. The ability to make such models with highly controlled chain architectures, plus the ability to label the molecules for use in techniques such as NMR and neutron scattering, has provided polymer physicists with means to understand polyolefin physics at a deep level. This has been used to determine the size of polyolefin chains (both in dilute solution and in melt state), the ways that polyolefins mix, how their rheology depends on the chemical structure of the chains, and how long branches control their performance. This chapter covers not only the scientific results of this research, but also how these can be applied in the development of novel, useful polyolefin products.

show abstract

Prediction of Melt State Poly(α-olefin) Rheological Properties: The Unsuspected Role of the Average Molecular Weight per Backbone Bond

Cited by 118 publications

References 22 publications

Synthesis and Rheological Properties of Poly(5‐n‐hexylnorbornene)

Synthesis and Rheological Properties of Poly(5‐n‐hexylnorbornene)

Probing the flow-induced shish-kebab structure in entangled polyethylene melts by synchrotron X-ray scattering

The Critical Role of Anionic Polymerization for Advances in the Physics of Polyolefins

Contact Info

Product

Resources

About