Conformation de polyamides aromatiques en solution diluée dans l'acide sulfurique concentré, 1. Étude par viscosité et diffusion de la lumière

Arpin, Michel; Strazielle, C.

doi:10.1002/macp.1976.021770220

Cited by 41 publications

(7 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The intrinsic viscosity of the whole polymer is obtained from the DV detector: ( 4 ) where vsp ( v ) is the specific viscosity at retention volume v, and m is the total mass of polymer injected. The absolute MWD is calculated using a universal calibration curve and the intrinsic viscosity at each retention volume:…”

Section: Size-exclusion Chromatography (Sec)mentioning

confidence: 99%

N‐methylation of wholly aromatic polyamides for size‐exclusion chromatography

Mourey

Guistina

Bryan

et al. 1992

J of Applied Polymer Sci

View full text Add to dashboard Cite

SYNOPSISWholly aromatic polyamides, including poly ( 1,4-phenyleneisophthalamide) and poly ( 1,4-phenyleneterephthalamide) are N-methylated to render them soluble in N,N-dimethylformamide, a common size-exclusion chromatography eluent. The procedure N-methylates 50-55% of the total amide linkages in these two examples, permitting reproducible measurement of their absolute molecular weight distributions using differential viscometry detection. There is no observable degradation in molecular weight resulting from the Nmethylation, provided the excess methylating reagent is destroyed shortly after completion of the derivatization by quenching with potassium acetate. The validity of the molecular weight data obtained by the method is confirmed by light-scattering measurements on derivatized polymer and by comparison to the molecular weight of underivatized polymer that can be approximated from the intrinsic viscosity in concentrated sulfuric acid. The method is applicable to a variety of wholly aromatic polyamide structures. Examples are given.

show abstract

Section: Size-exclusion Chromatography (Sec)mentioning

confidence: 99%

N‐methylation of wholly aromatic polyamides for size‐exclusion chromatography

Mourey

Guistina

Bryan

et al. 1992

J of Applied Polymer Sci

View full text Add to dashboard Cite

show abstract

“…Dans une etude physico-chimique r6cente que nous avons entreprise de ces systemes grace a 1'emploi syst6matique de la diffusion de la lumiere, de la visco-sim6trie, de la chromatographie sur gel permeable et de la birefringence d'6coulement [2,3], nous avons caract6ris6 toute une gamme d'6chantillons de poly-(t6r6phtalamide de paraphenylene) et de poly(parabenzamide), de masses mol6culaires comprises entre 3 000 et 65 000. Nous avons 6tudi6 ensuite la conformation et la rigidite de leurs chaines en solution dans 1'acide sulfurique concentr6.…”

unclassified

“…11 est juste de signaler avant de poursuivre une serie de communications, qui vient de paraitre (Du Pont de Nemours [4]), et qui contribue 6galement à elucider le probleme. 2. Microscopie en lumière polaris6e.…”

unclassified

See 1 more Smart Citation

Étude de la phase nématique d'un poly (téréphtalamide de paraphénylène)

1977

View full text Add to dashboard Cite

2014 On a étudié au moyen de la microscopie optique et de la diffraction des rayons X les solutions concentrées anisotropes d'un poly(téréphtalamide de paraphénylène) dans l'acide sulfurique pur. On a mis en évidence la texture à fils caractéristiques des cristaux liquides nématiques et on a discuté ses traits principaux. On a ensuite déterminé l'évolution de la distance d'approche des macromolécules en fonction de la dilution ; on peut en conclure que celles-ci ont une conformation très étirée, proche de la conformation à l'état cristallin.

show abstract

“…PBA was prepared from p-aminobenzoic acid following the method of Yamazaki et al [7] as described in more detail elsewhere [6]. The intrinsic viscosity in 96% HlS04 at 25' was 1.54 dl/g, corresponding to M, = 10,500 [8,9]. X-500 was prepared by the method of Preston [2].…”

Section: Methodsmentioning

confidence: 99%

Ultrahigh‐modulus fibers from rigid and semirigid aromatic polyamides

Alfonso

Bianchi

Ciferri

et al. 1978

J. polym. sci., C Polym. symp.

View full text Add to dashboard Cite

Intrinsic viscosity, concentrated‐solution viscosity, and fiber properties of poly(p‐benzamide) (PBA) and the polyterephthalamide of p‐aminobenzhydrazide (X‐500) are presented. PBA yields high‐modulus fibers from solution spinning of anisotropic dopes, and X‐500 yields high‐modulus fibers from isotropic solutions. Both polymers exhibit a wormlike conformation. However, with a low‐molecular‐weight PBA (10,500) an essentially rigid conformation prevails. The viscosity of both polymers goes through a maximum and a minimum on increasing polymer concentration. However, for PBA the maximum and minimum are observed at low shear stress, and for X‐500 the discontinuity is observed only at high shear rate. The initial modulus of low‐molecular‐weight PBA fibers is unaffected by LiCl concentration but increases with polymer concentration of anisotropic dopes. X‐500 (molecular weight, 41,000) is unable to form an anisotropic solution at rest. The initial modulus of X‐500 is unaffected by LiCl but depends slightly on polymer concentration. Both shear and elongational flow contributions appear to be secondary for truly stiff polymers. Orientation is controlled by polymer concentration, and the modulus of low‐molecular‐weight PBA attains the ultrahigh level even for “as‐spun” fibers. On the contrary, control of shear and elongational parameters is shown to be essential, and feasible, in order to match the as‐spun modulus of PBA, with semirigid polymers unable to form anisotropic solutions at rest.

show abstract

Conformation de polyamides aromatiques en solution diluée dans l'acide sulfurique concentré, 1. Étude par viscosité et diffusion de la lumière

Cited by 41 publications

References 3 publications

N‐methylation of wholly aromatic polyamides for size‐exclusion chromatography

N‐methylation of wholly aromatic polyamides for size‐exclusion chromatography

Étude de la phase nématique d'un poly (téréphtalamide de paraphénylène)

Ultrahigh‐modulus fibers from rigid and semirigid aromatic polyamides

Contact Info

Product

Resources

About