A Low Shear Viscometer with Automated Recording and Application to High Molecular Weight Polystyrene Solutions

Meyerhoff, Guenther; Appelt, Bernd K.

doi:10.1021/ma60071a037

Cited by 56 publications

(21 citation statements)

References 2 publications

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“…This sample is chosen because it contains very high weight percent of styrene, 95%, that mostly resembles, among different samples, linear homopolystyrene references. The exponent for linear polystyrene is 0.70, in agreement with those reported in the literature 33, 34. The exponents for comb‐on‐comb and conventional graft polystyrenes are 0.27, much smaller than that of linear ones, indicating a decreased level of interaction between solvent and polymer in these samples.…”

Section: Resultssupporting

confidence: 89%

Synthesis and solution properties of well‐defined comb‐on‐comb graft polymers

Sun¹,

Yu²,

He³

et al. 2008

J. Polym. Sci. A Polym. Chem.

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Well-defined comb-on-comb copolymers of styrene, isoprene, and amethyl-styrene are prepared through cascade ''grafting-onto'' methods. The polymer main chain is prepared by nitroxide-mediated radical polymerization while the branches are prepared by anionic polymerization. The ''grafting-onto'' approach employs the coupling chemistry of macromolecular anions, such as polystyryllithium, polyisoprenyllithium, or poly(a-methylstyryl)lithium, toward either benzyl chloride or epoxy ring on precursor backbones. Thus a series of ABA-, ABB-, and ABC-type comb-on-comb copolymers are prepared and characterized by gel permeation chromatography equipped with a multi-angle laser light scattering detector and a viscometer. Unusual ''U-shaped'' dependences of radius of gyration, R g , on molecular weight are observed for comb-on-comb products, which are attributable to delayed elution of the densely grafted copolymers from GPC columns. The result also shows that the comb-on-comb copolymers exhibit morphologies from hard sphere to cylindrical rod, depending on the length ratio of the main chain to the branches. V V C 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: [5518][5519][5520][5521][5522][5523][5524][5525][5526][5527] 2008

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Section: Resultssupporting

confidence: 89%

Synthesis and solution properties of well‐defined comb‐on‐comb graft polymers

Sun¹,

Yu²,

He³

et al. 2008

J. Polym. Sci. A Polym. Chem.

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“…In addition, the universal calibration 35 for the SEC data analysis works well for C-PS as shown in Figure S7 Although the SEC-TD method is widely used to measure intrinsic viscosity of polymers, the accuracy of the method needs to be examined vis-a-vis the data obtained by the traditional method using capillary viscometers and extrapolation to the zero concentration. For the purpose, we compare the L-PS data measured by the SEC-TD method in this study with three sets of literature data that are most frequently cited as references: Meyerhoff and Appelt ([η] L = 1.363 × 10 −4 M 0.714 in THF, 25°C), 38 Strazielle and Herz ([η] L = 1.4 × 10 −4 M 0.7 in THF, 25°C), 36 and Roovers ([η] L = 1.02 × 10 −4 M 0.73 in toluene, 35°C). 37 Although they do not match perfectly one another due to the experimental uncertainty and different MW range of the studies, they are remarkably similar.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Intrinsic Viscosity of Cyclic Polystyrene

et al. 2017

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The intrinsic viscosity of cyclic polystyrenes (C-PS) and linear polystyrenes (L-PS) with molecular weight (MW) ranging from 16K to 370K was measured in THF using size exclusion chromatography coupled with a triple detection system. The C-PS samples were prepared by a ring-closure reaction of telechelic linear precursor synthesized by anionic polymerization. As-synthesized C-PS samples after the ringclosure reaction contain various byproducts, and they were fractionated by liquid chromatography at the critical condition to obtain highly pure C-PS. While the intrinsic viscosity of L-PS agrees well with the literature data, C-PS shows significantly lower value than the literature values. The Mark−Houwink exponent of C-PS is 0.67, somewhat lower than 0.70 for L-PS in the good solvent over the MW range examined. Therefore, the ratio of the intrinsic viscosity of C-PS to L-PS (g′ =[ η] C /[η] L) in THF is not MW independent but decreases as MW increases (0.63 ≥ [η] C /[η] L ≥ 0.57). The trend of intrinsic viscosity agrees well with the computer simulation result. The discrepancy in [η] C from the literature values can largely be attributed to the contamination of linear byproducts in the earlier studies.

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“…In the past 40 years, the internal motions of various linear and flexible polymer chains in both good and Q solvents have been systematically studied. For example, both static and dynamic properties of polystyrene (PS), a typical representative model of flexible chains, has been extensively studied in tetrahydrofuran (THF), [21][22][23] toluene, 24,25 benzene, [26][27][28] and ethylbenzene (ETBZ). 21 In recent years, armed with a new synthesis method, 29 flexible polymer chains with high molecular weight have been successfully prepared, which makes the study of the internal motions in the intermediate q region (qR g > 1, but ql < 1) easier, where l is the length of a statistic segment.…”

Section: Introductionmentioning

confidence: 99%

Internal motions of linear chains and spherical microgels in dilute solution

Dai

Ngai

2011

Soft Matter

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It is well known that for a flexible polymer chain in dilute solution, two different types of motions mainly contribute: the translation motion of the centres of mass of individual polymer chains; and the internal modes generated from the motions of segments with respect to the centre of mass of the chain. During the past two decades, with the advances in light scattering instrumentation and sophisticated methods of data analysis, both types of motions can be distinguished in experiments and utilized for testing molecular theories of polymer chain dynamics in dilute solution. In this article, we first review some previous experiments, in particular the dynamical properties of polystyrene (PS) and polyisoprene (PIP) chains in good and theta (Q) solvents, and then our own results, including a comparative study of the internal motions of poly(N-isopropylacryl-amide) (PNIPAM) linear chains and spherical microgels under good solvent conditions. The final part of this article deals with how the solvent quality (the solution temperature) affects the internal mobility of PNIPAM linear chains and microgels.

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A Low Shear Viscometer with Automated Recording and Application to High Molecular Weight Polystyrene Solutions

Cited by 56 publications

References 2 publications

Synthesis and solution properties of well‐defined comb‐on‐comb graft polymers

Synthesis and solution properties of well‐defined comb‐on‐comb graft polymers

Intrinsic Viscosity of Cyclic Polystyrene

Internal motions of linear chains and spherical microgels in dilute solution

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