Über hochpolymere Verbindungen, 126. Mitteil.: Vergleich der osmotischen und viscosimetrischen Molekulargewichts‐Bestimmungen an polymerhomologen Reihen

Staudinger, H.; Schulz, G. V.

doi:10.1002/cber.19350681232

Cited by 99 publications

(12 citation statements)

References 34 publications

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“…Systematic studies of hyperbranched structures were started in the 1940s, a few years after Staudinger and Schulz had noted a dramatic difference between properties of linear and branched polymers of identical composition . The term ‘hyperbranched’ appeared relatively recently and immediately attracted the attention of researchers, resulting in the synthesis of new hyperbranched polymers (HBPs) and investigation of their properties…”

Section: Introductionmentioning

confidence: 99%

Conformational and hydrodynamic parameters of hyperbranched pyridylphenylene polymers

Цветков

Gubarev

Lebedeva

et al. 2016

Polymer International

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Hydrodynamic and optical methods were applied to study conformational and physical properties of hyperbranched pyridylphenylene polymers in dilute solutions. The samples were synthesized using Diels–Alder polycyclocondensation. It was demonstrated that hydrodynamic properties of the studied macromolecules were typical for compact non‐percolated spheres. Optical and electro‐optical methods revealed information regarding the shape and asymmetry of the macromolecules (p ≈ 1.4). The contributions of optical shape effect to the observed flow birefringence of polypyridylphenylene solutions and intrinsic anisotropy of polarizability were evaluated and analysed. It was shown that varying the polymer composition (i.e. the degree of branching) caused considerable changes in the anisotropy of optical polarizability of the polymers. Dramatic difference of the electro‐optical properties in non‐polar (toluene) and polar (tetrachloroethane) solvents was found; this difference was related to the orientational correlation of polar solvent molecules with respect to the macromolecules. Dynamic properties were studied by non‐equilibrium electric birefringence which had a reasonable agreement with the dimensions estimated from hydrodynamic data. © 2016 Society of Chemical Industry

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Section: Introductionmentioning

confidence: 99%

Conformational and hydrodynamic parameters of hyperbranched pyridylphenylene polymers

Цветков

Gubarev

Lebedeva

et al. 2016

Polymer International

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“…The characterization of branching both qualitatively and quantitatively has been the focus of polymer researchers for over seventy years 34,35. Currently, the detection of branching still poses a significant challenge to polymer scientists.…”

Section: Characterizationmentioning

confidence: 99%

Recent Advances in the Study of Multifunctional Initiators in Free Radical Polymerizations

Scorah

Dhib

Penlidis

2007

Macro Reaction Engineering

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An overview of a systematic investigation of a tetrafunctional peroxide initiator's behaviour is presented. The study focuses on three main areas of research: kinetic experiments, polymer characterization and modelling efforts. The kinetic investigation compared the behaviour of the tetrafunctional initiator (JWEB50) to that of a monofunctional counterpart (TBEC) for a variety of monomers. Although higher rates of polymerization were generated with JWEB50 for all monomers investigated, switching from a mono‐ to a tetrafunctional initiator actually decreased the polymer molecular weight for methyl methacrylate. While chromatographic characterization methods were able to detect branching in polystyrene samples produced with JWEB50, this was not the case for poly(methyl methacrylate). However, evidence of branching was clearly observed for both polystyrene and PMMA when rheological methods were employed. In order to explain the experimental results, a mathematical model was developed. Through its use, the concentration and chain length of various polymer structures (i.e., linear, star or coupled stars) was found to depend upon monomer type and reaction conditions.

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“…The characterization of branched polymers has been the focus of innumerable studies since their existence was postulated roughly 70 years ago 1, 2. Much of the fundamental understanding of branching and its influence on dilute solution and rheological properties began with specific molecular architectures such as stars and combs (see Refs 3–7.…”

Section: Introductionmentioning

confidence: 99%

Characterization by dilute solution and rheological methods of polystyrene and poly(methyl methacrylate) produced with a tetrafunctional peroxide initiator

Scorah

Tzoganakis

Dhib

et al. 2006

J of Applied Polymer Sci

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Polystyrene (PS) and poly(methyl methacrylate) (PMMA) samples produced by the bulk homopolymerization of styrene and methyl methacrylate with a tetrafunctional peroxide initiator (JWEB50) are characterized in detail by various solution and rheological methods. For comparison purposes, ''linear'' PS and PMMA samples were produced under similar conditions with a monofunctional initiator (TBEC). The four sample types were characterized by size exclusion chromatography (SEC) setups to determine molecular weight, radius of gyration, and intrinsic viscosity distributions. Contraction factors were calculated and indicated evidence of branching for polystyrene produced with JWEB50 while no such effects were observed with PMMA. The rheological behavior of the samples was subsequently investigated by performing oscillatory shear and creep experiments. Compared to the ''linear'' material, samples produced with JWEB50 exhibited a reduction in zero-shear viscosity that was attributed to long-chain branching. Retardation spectra were calculated based on creep data and converted to dynamic compliances that were then combined with the oscillatory data. This provided master curves spanning a much wider frequency range than could be obtained experimentally. Examination of various viscoelastic functions showed evidence of long-chain branching for both polystyrene and poly(methyl methacrylate) samples produced with JWEB50.

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Über hochpolymere Verbindungen, 126. Mitteil.: Vergleich der osmotischen und viscosimetrischen Molekulargewichts‐Bestimmungen an polymerhomologen Reihen

Cited by 99 publications

References 34 publications

Conformational and hydrodynamic parameters of hyperbranched pyridylphenylene polymers

Conformational and hydrodynamic parameters of hyperbranched pyridylphenylene polymers

Recent Advances in the Study of Multifunctional Initiators in Free Radical Polymerizations

Characterization by dilute solution and rheological methods of polystyrene and poly(methyl methacrylate) produced with a tetrafunctional peroxide initiator

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