Properties of amorphous and crystallizable hydrocarbon polymers. II. Rheology of linear and star‐branched polybutadiene

Rochefort, Willie E.; Smith, Gregory G.; Rachapudy, H.; Raju, V. Ramachandra; Graessley, William W.

doi:10.1002/pol.1979.180170705

Cited by 94 publications

(55 citation statements)

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“…These results are in contrast to those reported by others from studies of linear and star branched polystyrene 22 and polybutadiene. 23 They also observed some enhancement of ho and broadening of the relaxation spectrum resulting from the introduction of branching. However, accompanying change in the G' contribution relative to that of the G" was not so apparent compared with our study.…”

Section: --------------------------mentioning

confidence: 94%

Morphological, Rheological, and Mechanical Properties of Polyamide 6/Styrene-Acrylic Acid Copolymer Blends

Kim

Chae

1993

Polym J

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ABSTRACT:The morphology, rheological and tensile properties of polyamide 6 (PA6)/poIy(styrene-co-acrylic acid) (SAA) blends were examined as a function of the acrylic acid (AA) content in SAA. It was found that the AA unit in copolymers has a pronounced effect upon the morphology of the blends. The dispersed phase size was significantly reduced with increasing AA content in SAA. A reduction in the particle size of the dispersed phase resulted in improvement in tensile properties of the blends.KEY WORDS Morphology / Rheological Properties / Tensile Properties / Polyamide 6 / Poly(styrene-co-acrylic acid) / Domain Size / Chemical Reaction / Long Branching / Polystyrene (PS) and polyamide 6 (P A6) are two important classes of polymers. PS is widely used as an injection molding and vacuum forming material due to low cost, good mold ability, low moisture absorption, good dimensional stability, good electrical insulation properties, and colorability. The principal limitations of PS, however, are its brittleness, inability to withstand the temperature of boiling water and mediocre oil resistance. PA6 is an engineering thermoplastic material. It finds many applications in eletrical, mechanical, and automotive parts due to its very high strength, wear and heat resistance, ease of fabrication, and excellent barrier properties to oils. However, it has not become a commodity plastic material because of its relatively high cost. Therefore it is desirable to compromise properties and cost by blending PS and PA6.It is often difficult to obtain good dispersion in polymer blends whose components are essentially insoluble in each other, particularly for blends of a polar polymer such as P A6 with a nonpolar polymer such as PS. Several authors l -9 have reported that the presence of a block or graft copolymer of appropriate chemical structure provides lowering of the interfacial energy and an improvement of the interfacial adhesion between the two phases. The final morphological effect is reduction in particle size of the dispersed phase in the blend. For example, in the case of polystyrene (PS)/polyethylene (PE) blends, Heikens et al. 7 observed that the dimensions of the PE domains decreased with the addition of PSco-PE graft and block coplymers. Recently attempts were made to compatibilize immiscible polymer pairs by introducing a specific interaction between constituents of individual polymer chains. It has been reported that copolymers of methyl methacrylate and 4-vinylpyridine were miscible poly(butyl acrylate-eo-acrylic acid) through specific interaction.loIn this work, acrylic acid (AA) was introduced into PS to enhance the compatibility of PA6 and PS blend, and the morphology, rheological and tensile properties of P A6/SAA blends were examined as 1023

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confidence: 94%

Morphological, Rheological, and Mechanical Properties of Polyamide 6/Styrene-Acrylic Acid Copolymer Blends

Kim

Chae

1993

Polym J

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“…They also probed that this relation is a master curve for linear polybutadienes of different molecular weight, but not for star-branched samples; the values of J , is of the same order of magnitude as conventional LDPEs 52) . It is not possible to extract straight conclusions from these data, however we have to remind that several authors 36,51,[53][54][55][56] …”

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confidence: 91%

Rheological criteria to characterize metallocene catalyzed polyethylenes

Vega

Fernández

Santamarı́a³

et al. 1999

Macromol. Chem. Phys.

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SUMMARY: Dynamic viscoelastic and capillary extrusion rheometry measurements were carried out with a series of 13 metallocene catalyzed polyethylenes and copolymers of ethene and 1-hexene. The structural parameters were analyzed by size exclusion chromatography (SEC) and 13 C NMR, showing that the molecular weights range from M -w = 80 000 to 308 000, the polydispersity index from 2 to 3.5 and the degree of short chain branching (SCB) from 0 to 13.8 SCB/1 000 C. In order to extract the maximum information from the experimental data, the following rheological methods were used: a) Viscosity and relaxation time dependence on molecular weight M ). d) log G 9 versus log G 9 9plots. e) Storage compliance J 9 dependence on storage modulus G 9 . f) Phase angle d dependence on complex modulus G*. g) Relaxation spectra. h) Dependence of the exponent n of the power law model for the viscosity function g (_ c ) on of molecular weight. i) Analysis of the critical rate for sharkskin. These methods, except the last one, allow to separate the samples into three different groups, at least when low frequencies (below 10 -1 Hz) or times higher than 10 s are involved. The definition of these groups cannot be undertaken considering only the molecular parameters obtained by SEC and 13 C NMR. Analyzing our rheological results in comparison with long chain branched polyethylenes (LCB) and looking at the theoretical aspect of the dynamics of long branched chains, we assume that among our samples there are five linear (non-LCB, Group I) polyethylenes and two groups of slightly long chain branched polyethylenes, which differ in the number of branches.

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“…Methods have also been developed to vary the lengths and placements of the branches with a high degree of control. Much of this work has been on polystyrene [100][101][102][103][104] and polydienes [105][106][107][108][109][110][111]. In this section the work that has been done on model polyethylenes made by saturating low-vinyl polybutadienes with many levels and kinds of branching will be described.…”

Section: Lcb In Polyethylenementioning

confidence: 99%

“…As this chapter is about the way that anionic polymerization has been applied to polyolefin physics, for the most part this section will discuss the studies of model saturated polybutadienes [105,106,143,144,[148][149][150][151][152][159][160][161]. (For details of the polymers used and the experimental methods, please see the particular references.)…”

Section: Effects Of Lcb On Melt Rheologymentioning

confidence: 99%

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

Lohse

2015

Anionic Polymerization

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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.

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Properties of amorphous and crystallizable hydrocarbon polymers. II. Rheology of linear and star‐branched polybutadiene

Cited by 94 publications

References 15 publications

Morphological, Rheological, and Mechanical Properties of Polyamide 6/Styrene-Acrylic Acid Copolymer Blends

Morphological, Rheological, and Mechanical Properties of Polyamide 6/Styrene-Acrylic Acid Copolymer Blends

Rheological criteria to characterize metallocene catalyzed polyethylenes

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

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