Methods for estimating intrinsic viscosity

Billmeyer, Fred W.

doi:10.1002/pol.1949.120040107

Cited by 70 publications

(43 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Viscosity measurements were performed in PE solutions in chloroform at a concentration of 0.5 dL/g using an Ubbelohde viscometer at 25 C. The relative (g r ), the specific (g sp ), and the reduced (g red ) viscosity were determined. The intrinsic viscosity ([g], dL/g) can be calculated using one of the eight expressions reported by Billmeyer 37 (Table III) and the viscosity measurement of a single-concentration polymer solution. More specifically, the interactions in each polymer-solvent system define which equation fits the experimental data best, considering that the calculated g values (assumed equal to [g]) should C).…”

Section: Product Characterizationmentioning

confidence: 99%

Production of biodegradable polyesters via enzymatic polymerization and solid state finishing

Kanelli

Douka

Vouyiouka

et al. 2014

J of Applied Polymer Sci

View full text Add to dashboard Cite

The synthesis of aliphatic polyesters (PEs) derived from diols (1,4-butanediol and 1,8-octanediol) and diacids or their derivatives (diethyl succinate, sebacic acid, 1,12-dodecanedioic acid, and 1,14-tetradecanedioic acid) was achieved in order to produce poly(butylene succinate) (PE 4.4), poly(octylene sebacate) (PE 8.10), poly(octylene dodecanate) (PE 8.12), and poly(octylene tetradecanate) (PE 8.14). The herein suggested procedure involved two stages, both sustainable and in accordance with the principles of "green" polymerization. The first comprised an enzymatic prepolymerization under vacuum, in the presence of diphenylether as solvent using Candida antarctica lipase B as biocatalyst, whereas a low-temperature postpolymerization step [solid state polymerization (SSP)] followed in order to upgrade the PEs quality. In the enzymatically synthesized prepolymers, the range of number-average molecular weight attained was from 3700 to 8000 g/mol with yields reaching even 97%. Subsequently, SSP of PE 4.4 and 8.12 took place under vacuum or flowing nitrogen and lasted 10-48 h, at temperatures close to the prepolymer melting point (T m 2 T SSP varied between 4 C and 14 C). The solid state finishing led to increase in the molecular weight depending on the prepolymer type, and it also contributed to improvement of the physical characteristics and the thermal properties of the enzymatically synthesized PEs.

show abstract

Section: Product Characterizationmentioning

confidence: 99%

Production of biodegradable polyesters via enzymatic polymerization and solid state finishing

Kanelli

Douka

Vouyiouka

et al. 2014

J of Applied Polymer Sci

View full text Add to dashboard Cite

show abstract

“…The relative viscosity (h rel ) of PA is the ratio of the viscosity of a solution of 8 (2)]: [22] ½h ¼ 1 3 (3)]: [21] ½h ¼ 3:…”

Section: Solution Viscometrymentioning

confidence: 99%

Nanocatalysis in Polyamide 6.6 Solid‐State Polymerization

Boussia

Konstantakopoulou

Vouyiouka

et al. 2010

Macro Materials & Eng

View full text Add to dashboard Cite

Solid‐state polymerization (SSP) of a poly(hexamethyleneadipamide) (PA 6.6)/clay nanocomposite system was studied. SSP runs were performed in a fixed‐bed reactor, at temperatures 160–200 °C and reaction times up to 8 h. The influence of clay presence on the PA 6.6 SSP rate constant was herewith quantified for the first time to prove significant acceleration of the SSP process. A catalysis mechanism was suggested, according to which the positive effect of clay is of a synergistic origin attributed to nucleated crystal morphology, that increased the concentration of reactive end groups in the amorphous regions, to chain extension performed by clay SiOH groups, and to thermal protection of the polyamide matrix due to the presence of the nanoparticles. magnified image

show abstract

“…The Huggins plot, 27 the Fuoss-Mead plot, 28 and the Billmeyer plot 29 were combined to determine the intrinsic viscosity ½ and the Huggins constant k 0 . The shear-rate effect on ½ was negligible (less than 2%) even for the highest M w sample ATPC3M.…”

Section: Viscometrymentioning

confidence: 99%

Solution Properties of Amylose Tris(Phenylcarbamate): Local Conformation and Chain Stiffness in 1,4-Dioxane and 2-Ethoxyethanol

et al. 2009

View full text Add to dashboard Cite

Light and small-angle X-ray scattering, sedimentation equilibrium, viscosity, circular dichroism, and infrared absorption measurements have been made on 1,4-dioxane (DIOX) and 2-ethoxyethanol (2EE) solutions of seven amylose tris(phenylcarbamate) samples ranging in molecular weight from 2 Â 10 4 to 3 Â 10 6 . Analyses of gyration radius, scattering function, and intrinsic viscosity data in terms of the wormlike chain model yield Kuhn segment lengths of 22 AE 2 nm and 16 AE 2 nm in DIOX and 2EE, respectively, and a contour length per residue of 0:33 AE 0:02 nm in both, showing that the amylose derivative chain has high stiffness and a contour length slightly shorter than the known value 0.37-0.40 nm for amylosetriesters in the crystalline state. These results are consistent with the intramolecular hydrogen bonding between the C=O and NH groups of the neighbor repeating units detected by infrared absorption and also with the locally regular (or helical) conformation indicated by circular dichroism.

show abstract

Methods for estimating intrinsic viscosity

Abstract: A number of equations are suggested for estimating intrinsic viscosity from one measurement of relative viscosity at a convenient concentration. Experimental data illustrate the validity of the equations.

Cited by 70 publications

References 2 publications

Production of biodegradable polyesters via enzymatic polymerization and solid state finishing

Production of biodegradable polyesters via enzymatic polymerization and solid state finishing

Nanocatalysis in Polyamide 6.6 Solid‐State Polymerization

Solution Properties of Amylose Tris(Phenylcarbamate): Local Conformation and Chain Stiffness in 1,4-Dioxane and 2-Ethoxyethanol

Contact Info

Product

Resources

About