Evaluation and Application of a Commercial Single Capillary Viscometer System for The Characterization of Molecular Weight Distribution and Polymer Chain Branching

Kuo, Cheng-Yih; Provder, Theodore; Koehler, M.

doi:10.1080/01483919008049095

Cited by 18 publications

(9 citation statements)

References 10 publications

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“…This SEC system detected eluting polymer with an in-line viscometric (VISC) detector and a differential refractive index (DRI) detector. The determination of molecular weight distribution averages followed the general procedures previously described . Mark−Houwink constants were determined using the general methodology recently described …”

Section: Methodsmentioning

confidence: 99%

Preparation and Characterization of a Branched Bacterial Polyester

1999

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The preparation, rheological behavior, and solution properties of branched poly(3-hydroxy butyrate)-co-(3-hydroxy valerate), PHBV, are described. Branching is produced by the use of dicumyl peroxide (DCP) during the reactive extrusion of PHBV. The shear viscosities of reactively extruded PHBV and the straight-chain polymer of similar molecular weight are nearly identical, but the reactively extruded PHBV's elongational viscosity is considerably higher. High elongational viscosity of these polymers results from a branched structure produced when extrusion is carried out in the presence of small amounts of DCP (0.025-0.3 wt %). Strain hardening is observed in the elongational response of the branched PHBV at all deformation rates and increases with increasing concentrations of DCP. Study of the solution properties of the linear and branched PHBV indicates larger hydrodynamic volume compared to that of polystyrene of comparable molecular weight. Mark-Houwink plots, observed for PHBV, exhibited increasing nonlinearity with increasing DCP content. Trifunctional branching frequencies computed on the basis of intrinsic viscosity ratios indicated explosive growth in branching, possibly due to the generation of microgel, when branching reactions are initiated with a DCP level exceeding 0.2 wt %.

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Section: Methodsmentioning

confidence: 99%

Preparation and Characterization of a Branched Bacterial Polyester

1999

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“…Viscosity detectors measure the pressure drop in a capillary, or a set of capillaries, to estimate specific viscosity of the solution. Single capillary viscometers [54] are usually strongly effected by any fluctuations in the flow of mobile phase and are typically used with a syringe pump to alleviate this problem. Alternatively, pulsation effects can be eliminated when two capillaries are used in series.…”

Section: Viscosity Detectorsmentioning

confidence: 99%

Size-exclusion chromatography—a review of calibration methodologies

Kostanski

Keller

Hamielec

2004

Journal of Biochemical and Biophysical Methods

165

134

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“…higher molecular density) secondary, branched type II structures. 18,26,27 As the branch length was increased, there was an increase in the intrinsic viscosity [ Fig. 3(B)].…”

Section: Discussionmentioning

confidence: 97%

Branched chitosans: Effects of branching parameters on rheological and mechanical properties

Aggarwal

Matthew

2007

J Biomedical Materials Res

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Chitosan continues to be studied as a promising biomaterial for tissue repair and regeneration applications. However, chitosan structures show a large reduction in tensile strength in the wet state. Methods for improving the wet strength of chitosan materials may broaden its applicability as a tissue scaffold for applications requiring significant load bearing capacity. In this study, the role of molecular architecture in defining the mechanical properties of hydrated chitosan membranes was examined. Specifically, branched chitosan molecules were synthesized with a range of branch lengths and branch densities. Physical and mechanical properties were characterized using viscometry, FTIR spectroscopy, and tensile testing measurements, and the results were correlated with the postulated architecture of the linear and branched chitosan materials. Both branch density and branch length were found to influence the mechanical properties of chitosan membranes. For example, high-molecular-weight (600 kDa) chitosans grafted with 80 kDa branches exhibited up to twofold increases in both tensile strength and extensibility. FTIR results indicated that these increases correlated with enhanced levels of hydrogen bonding in the branched materials. Vascular smooth muscle cells cultured on cast membranes of the branched chitosans exhibited no differences in adhesion or spreading as compared to the linear polymer. The results indicate that the mechanical properties of chitosan materials can be improved by the induction of a branched molecular architecture.

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Evaluation and Application of a Commercial Single Capillary Viscometer System for The Characterization of Molecular Weight Distribution and Polymer Chain Branching

Cited by 18 publications

References 10 publications

Preparation and Characterization of a Branched Bacterial Polyester

Preparation and Characterization of a Branched Bacterial Polyester

Size-exclusion chromatography—a review of calibration methodologies

Branched chitosans: Effects of branching parameters on rheological and mechanical properties

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