Causes of gelation in solutions of acrylonitrile copolymers

Burd, E. Z.; Barsukov, I. A.; Крылов, А. Л.; Ivanov, V. E.; Kravchuk, V. M.; Bondarenko, I. Ya.

doi:10.1007/bf00550851

Cited by 2 publications

(2 citation statements)

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“…The effect of aluminum and other metals on gelation in the spinning solutions for the production of polyacrylonitrile fiber, nitron-S, has been investigated by Burd et al 24 It was shown that gelation in industrial spinning solutions is caused by the aluminum-iron electric pair contained in the filter press. The aluminum ions formed crosslinks the acrylonitrile copolymers leading to gelation.…”

Section: Introductionmentioning

confidence: 99%

Thermal and rheological behavior of acrylonitrile-carboxylic acid copolymers and their metal salt complexes

Bajaj¹,

Bahrami²,

Sen³

et al. 1999

J. Appl. Polym. Sci.

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ABSTRACT:The influence of acrylic, methacrylic, and itaconic acid comonomers in the nitrile oligomerization of acrylonitrile copolymers has been studied by DSC and DSC-FTIR in air and nitrogen atmospheres. Addition of metal salts in poly(acrylonitrileacrylic acid) copolymer, PA on thermal and rheological behavior has also been reported. Incorporation of CuSO 4 , FeSO 4 , ZnSO 4 , and Al 2 (SO 4 ) 3 (1 to 5 wt %) salt in the polymer solution affects its solubility in DMF. The complexes of PA with zinc sulphate, took a longer time to dissolve in DMF, whereas the complexes with Fe(SO 4 ) and Al 2 (SO 4 ) 3 are almost insoluble in DMF, perhaps due to intermolecular crosslinking. Addition of these metal salts to the PA solution also affects its Brookfield viscosity. The viscosity of 10 wt % polymer solution increases from 400 centipoise (Cps) to 1090 Cps for complex with 5% FeSO 4 (on the weight of dope solids) and 690 Cps for Al 2 (SO 4 ) 3 and 906 cps for ZnSO 4 complex. However, for CuSO 4 salt complex this value is 770 Cps. FTIR spectra shows the participation of COOH and CN group in the complex formation, which is responsible for enhanced Brookfield viscosity. Thermal behavior of the polymer-metal salt complex showed that these salts also affect the exothermic reaction. The initiation of cyclization reaction takes place at a lower temperature compared to neat acrylonitrile-acrylic acid copolymer. However, the heat liberated per unit time in N 2 atmosphere in case of neat polymer is 6.3 Jg Ϫ1 min Ϫ1 , which reduces to 5.5 Jg Ϫ1 min Ϫ1 in the case of the PA/Al complex, confirming the role of Al 2 (SO 4 ) 3 in retarding the rate of cyclization reaction.

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Section: Introductionmentioning

confidence: 99%

Thermal and rheological behavior of acrylonitrile-carboxylic acid copolymers and their metal salt complexes

Bajaj¹,

Bahrami²,

Sen³

et al. 1999

J. Appl. Polym. Sci.

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“…Whereas monovalent metal chlorides, such as lithium chloride, are reported to diminish the dope viscosity, divalent metal salts generally increases it 20, 21. Trivalent metal salts causes gelation 22. Addition of di‐ and trivalent metal ions to the dope of PAN has resulted in enhanced viscosity 23.…”

Section: Introductionmentioning

confidence: 99%

Effect of oxalic acid on the rheological properties of dope solution of poly[acrylonitrile‐co‐(methyl acrylate)‐co‐(itaconic acid)]

Devasia

Nair

Ninan

2004

Polymer International

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The very high dope viscosity of concentrated dope of poly[acrylonitrile-co-(methyl acrylate)-co-(itaconic acid)] (with M v = 10.67 × 10 5 g mol −1 ) in DMF could be diminished significantly by the addition of oxalic acid (OXA). The change in steady shear rheological behaviour caused by OXA has been analysed for the dope using a rheometer working in the viscosity mode. The temperature dependence of η 0 conformed to the Arrhenius-Frenkel-Eyring equation. G v decreased marginally with OXA concentration, and the least value was observed at an OXA concentration of 0.63 % by weight. Shear thinning behaviour was observed under higher shear rates for the terpolymer solutions in the presence and absence of OXA. The pseudoplasticity index (n) showed an abrupt initial increase on addition of OXA. The OXA concentration of 0.63 % by weight was advantageous for decreasing the viscosity of the polymer dope. The reduction in viscosity is attributed to the disturbed polymer-polymer interactions by way of H-bonding of OXA with the polymer. OXA-containing dope at higher shear rate could achieve very low viscosities.

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Causes of gelation in solutions of acrylonitrile copolymers

Cited by 2 publications

References 1 publication

Thermal and rheological behavior of acrylonitrile-carboxylic acid copolymers and their metal salt complexes

Thermal and rheological behavior of acrylonitrile-carboxylic acid copolymers and their metal salt complexes

Effect of oxalic acid on the rheological properties of dope solution of poly[acrylonitrile‐co‐(methyl acrylate)‐co‐(itaconic acid)]

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