Determination of Molecular Weight of Nylon

Waltz, J. E.; Taylor, G.

doi:10.1021/ac60007a006

Cited by 157 publications

(35 citation statements)

References 4 publications

(3 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…As phenol was not a good solvent for the determination of the carboxyl end groups because after equivalent point, it reacts with the base, the benzyl alcohol is used instead. Even though the conductance found was lower than that expected for the solvent previously used (phenol-ethanol-water) and the cut point of the two straight lines was not so sharp, the results obtained by conductometric titration were in agreement with the ones obtained by titration using an indicator [7]. In this research work to analyze the amine and carboxyl end-group is necessary to dissolve the sample of polymer under study, which considerably increases the time needed for the determination.…”

Section: Introductionsupporting

confidence: 82%

Conductometric titration as a technique to determine variation in conductivity in perfluorosulfonic acid materials for fuel cells and electrolyzers

Lavorante

Franco

2017

Int J Energy Environ Eng

View full text Add to dashboard Cite

One important requirement for a polymeric material to be used as a membrane in fuel cells or water electrolyzers is its high ionic conductivity. In this research work the redeveloped conductometric titration was used to determine conductivity variation with the objective to improve the precision of the determination and reduce the time of operation. Results obtained by changing the experimental conditions of the techniques: reaction rate and conductometric titration, which are two related techniques, are presented. The reaction rate allows to know the chemical kinetics of the neutralization reaction between Nafion Ò 117 membrane and a solution of sodium or potassium hydroxide, the order or pseudo-order reaction and the half-life period. This last parameter is used to carry out the conductometric titration which permits to determine the total acid capacity of this type of polymeric materials. The experimental conditions studied are: type and time of agitation and working temperature control. Good results were obtained in the techniques where the nitrogen bubble stirring was applied, throughout the determination. This procedure ensures a liquid medium with properties near isotropy, suitable for this analysis. The temperature controlled by a thermostat allows isolating the system of temperature variations and permits to compare the results between determinations. Time reduction was *48 times lower, if 24 h is considered necessary to reach reaction equilibrium.

show abstract

Section: Introductionsupporting

confidence: 82%

Conductometric titration as a technique to determine variation in conductivity in perfluorosulfonic acid materials for fuel cells and electrolyzers

Lavorante

Franco

2017

Int J Energy Environ Eng

View full text Add to dashboard Cite

show abstract

“…Previous optical density measurements had shown that the dye was thermally stable for several hours at 100°C. It was found that the equivalents of pure acid dye absorbed at saturation agreed well with the equivalents of NH,-end groups as determined by conductometric titration [3,4]. -The effect of the NH2-end content on dyeing rate was determined by using a commercial grade of C.I.…”

Section: Introduction Zmentioning

confidence: 58%

Effect of Fiber and Dyebath Variables on the Rate of Acid Dyeing of Nylon 6, 6

Bell

1968

Textile Research Journal

View full text Add to dashboard Cite

The results of an experimental study of the effects of several variables on the acid dyeing of nylon are presented. The dyeing rate was directly proportional to the number of amino-end groups (dye sites) in the fiber for the two dyes tested; the dyeing rate approached zero as the number of dye sites approached zero. The dyeing rate was the same for samples with viscosity average molecular weights of ∼25,000 and 30,000, but was somewhat higher for a ∼22,000 M v sample, as might be expected from the dependence of other properties on molecular weight. The dyeing rate is shown to be linearly related to 1/√ d , where d is the denier per filament. The molecular size of the acid molecule used in the acid dyebath was investigated, and no effect was found for formic, acetic, propionic, and hexanoic acids. An effect is found on both rate and saturation, however, if the larger and more polarizable napthoic acid is used. Sodium chloride and sodium sulfate, when added to the dyebath, decrease both the dye absorbed at saturation and the rate of dye diffusion, although they offer benefits as leveling agents. The effect of sodium chloride is considerably greater than for sodium sulfate.

show abstract

“…The degree of hydration of the monomer crystals was quantitatively determined by conductimetric titration of the amino end groups (Waltz & Taylor, 1947;Macchi, Morosoff & Morawetz, 1968), as well as by gravimetric techniques.…”

Section: Chemical Characterizationmentioning

confidence: 99%

Crystal data for the dihydrate and anhydrate of 11-aminoundecanoic acid

Rigotti¹,

Rivero²,

Macchi³

et al. 1981

J Appl Cryst

View full text Add to dashboard Cite

X-ray and electron diffraction studies were made on the two phases of l l-aminoundecanoic acid, C1~H21NO2. Origin of specimensSamples of 11-aminoundecanoic acid (11-AUA) from different origins (Aldrich Chem. Co., m.p. 459-460 K; and Ato Chimi., m.p. 460-461 K) were purified by recrystallization in mixtures of 100 ml 95% ethanol/24 ml water per gram of amino acid, reaching a final melting point of 461 K. Single crystals of the monomer, adequate for X-ray studies, were as well obtained from the same solvent system or from mixtures of 1-butanol and water. Under these conditions, the monomer crystallized with two molecules of water per molecule of amino acid (phase I), and all attempts to obtain anhydrous crystals (phase II) by direct crystallization from solutions were unsuccessful. The anhydrous phase could only be prepared by a solid-state dehydration reaction which transformed the hydrated single crystals into polycrystalline aggregates of the anhydrous specimen (phase II). The reaction proceeded with such a high retention of crystallographic order and orientation that the polycrystalline specimens of phase II were just adequate for single-crystal work.

show abstract

Determination of Molecular Weight of Nylon

Cited by 157 publications

References 4 publications

Conductometric titration as a technique to determine variation in conductivity in perfluorosulfonic acid materials for fuel cells and electrolyzers

Conductometric titration as a technique to determine variation in conductivity in perfluorosulfonic acid materials for fuel cells and electrolyzers

Effect of Fiber and Dyebath Variables on the Rate of Acid Dyeing of Nylon 6, 6

Crystal data for the dihydrate and anhydrate of 11-aminoundecanoic acid

Contact Info

Product

Resources

About