Ultrahigh molecular weight polymers in dilute solutions

Bercea, Maria; Ioan, Catalina; Ioan, Silvia; Simionescu, Bogdan C.; Simionescu, C. I.

doi:10.1016/s0079-6700(99)00007-6

Cited by 25 publications

(18 citation statements)

References 186 publications

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“…In dilute solution, the viscosity of polymer solutions in the solvent provides considerable information on the chemical nature of the polymers because it reflects the physicochemical state of individual polymer chains. 27,28 The parameters of critical concentration (C * ) and Huggins constant (K H ) of solutions in the dilute concentration regime are used, where C * refers to the onset concentration to produce molecular entanglement, which is given by eq. …”

Section: Resultsmentioning

confidence: 99%

Electrospinning of polylactide fibers containing silver nanoparticles

Kim

Lee

2010

Macromol. Res.

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Biodegradable polylactide (PLA) nanofibers containing silver nanoparticles were prepared by electrospinning. Solutions of PLA in dichloromethane/N,N-dimethylacetamide (DMAc) with different amounts of silver nitrate (AgNO 3 ) were used to spin nanofibers. DMAc was used as a reducing agent for Ag + ions in the PLA solution.In the dilute solution system, the intrinsic viscosity and Huggins constant of the PLA/Ag solutions decreased at AgNO 3 concentrations < 6 wt% whereas they increased at 9 wt% AgNO 3 . On the other hand, dichloromethane/ DMAc was found to be a good solvent with a similar solvating power to the Huggins constant results. The solution properties of the viscosity and electrical conductivity of the spinning solutions are strongly affected by the addition of AgNO 3 . The mean diameters of the PLA/Ag nanofibers containing 0, 3, 6 and 9 wt% of AgNO 3 were 400.9±0.1, 352.6±0.3, 313.1±0.2 and 482.8±0.2 nm, respectively. The silver nanoparticles contributed to the formation of thinner PLA/Ag nanofibers. When the PLA nanofibers contained 6 wt% AgNO 3 , silver nanoparticles with an average size of 4.9 nm were distributed homogeneously in the PLA nanaofibers.

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Section: Resultsmentioning

confidence: 99%

Electrospinning of polylactide fibers containing silver nanoparticles

Kim

Lee

2010

Macromol. Res.

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“…In the present case, with experimental conditions close to the above ones, for a molecular weight of 80,000 g/mol, R G and R H can be evaluated to 13 nm and 6.5 nm from the Flory theory considering that the radius for a linear and flexible chain in a good solvent varies according to the molecular weight with an exponent of 0.6 (radius $ M 0.6 ) [34].…”

Section: Resultsmentioning

confidence: 90%

Surface-initiated reversible addition–fragmentation chain transfer polymerization from “clickable” polypropylene surface modified by iodine plasma activation

Couturaud

Mas

Robin

2015

European Polymer Journal

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“…44 When temperature increases, however, the mobility of polymer and solvent molecules increases and finally overcomes the lattice energy of the equilibrium solvent bridges. The equilibrium solvent bridges in Scheme II collapse by escaping the less polarized solvent molecules first.…”

Section: Resultsmentioning

confidence: 99%

Molecular Characterization on the Anomalous Viscosity Behavior of Cellulose Solutions in N,N-Dimethyl Acetamide and Lithium Chloride

Khaliq

Kim

2016

Macromol. Res.

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The physical properties of dilute cellulose solutions in N,N-dimethyl acetamide (DMAc) including 9 wt% lithium chloride (LiCl) were investigated in terms of concentration, temperature and molecular weight of cellulose. Over the concentration range of 0.01 to 2.5 g/dL, the viscosity of the cellulose solutions exhibited a lower critical solution temperature (LCST) behavior which proved thermoreversible between 30 and 60 o C. The LCST behavior was further supported by dynamic light scattering measurement. In the extremely dilute concentration range, 0.01 to 0.08 g/dL, the reduced viscosity (η red ) of cellulose solutions was increased with decreasing concentration. The anomalous coil expansion with decreasing concentration could be explained by the increase of the conductivity of cellulose solutions with decreasing concentration, which was also verified by dynamic light scattering experiment. In the concentration range of 0.1 and 2.5 g/dL, both cellulose solutions gave a drastic increase of η red in the vicinity of the critical concentration (C*), 0.9 g/dL. The slope of the curve of η red vs. concentration was higher for the cellulose of higher molecular weight, but it did not change with temperature between 30 and 60 o C.

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Ultrahigh molecular weight polymers in dilute solutions

Cited by 25 publications

References 186 publications

Electrospinning of polylactide fibers containing silver nanoparticles

Electrospinning of polylactide fibers containing silver nanoparticles

Surface-initiated reversible addition–fragmentation chain transfer polymerization from “clickable” polypropylene surface modified by iodine plasma activation

Molecular Characterization on the Anomalous Viscosity Behavior of Cellulose Solutions in N,N-Dimethyl Acetamide and Lithium Chloride

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