Comparison Of The Rheological Properties Of Concentrated-Solutions Of A Rodlike And A Flexible Chain Polyamide

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dc.contributorVirginia Techen
dc.contributor.authorBaird, Donald G.en
dc.contributor.authorBallman, R. L.en
dc.contributor.departmentBiomedical Engineering and Mechanicsen
dc.contributor.departmentChemical Engineeringen
dc.date.accessed2014-03-11en
dc.date.accessioned2014-03-26T17:35:17Zen
dc.date.available2014-03-26T17:35:17Zen
dc.date.issued1979en
dc.description.abstractThe steady state shear rheological properties of solutions of a rodlike polyamide, poly_p_phenyleneterephthalamide (PPT), in 100% sulfuric acid have been compared with those of solutions of a flexible chain polyamide, nylon 6,6 in the same solvent. For solutions of similar concentration (c) and molecular weight (M), it was found that the primary normal stress difference (N1) and the viscosity (_), compared at the same shear rate (__), were an order of magnitude greater for solutions of PPT. It was believed that this behavior could be accounted for through the formation of an enhanced entanglement network in the PPT solutions. Plots of the zero shear viscosity(_0) versus cM_w, where M_w is the weight average molecular weight, for both systems revealed that "bends" occurred in the data corresponding to a critical entanglement molecular weight (Mc) of 1180 for PPT (this corresponds to 30 main chain atoms (z)) and to 5260 (z=330) for nylon 6,6. More significantly, _0 was found to be proportional to (cM_u)6.8 for solutions of PPT and to (cM_w)3.4 for nylon 6,6 solutions. _ versus __ curves were similar in shape for both systems and could be reduced to the same master curve with the only difference being that the relaxation times or shifting factors were considerably greater for the PPT solutions. This suggested that the process of destroying entanglements may be similar for both polymers. The overlap parameter c[_], where [_] is the intrinsic viscosity, provided a much better correlation of _0 data from the two sets of solutions than did the segment contact parameter cM_w. This suggested that the structural variable controlling the onset of entanglements may be a parameter such as the radius of gyration. Because of the inability of rodlike molecules to coil around each other, further insight into the nature of entanglements is obtained.en
dc.format.mimetypeapplication/pdfen
dc.identifier.citationJ. Rheol. 23, 505 (1979); http://dx.doi.org/10.1122/1.549530en
dc.identifier.doihttps://doi.org/10.1122/1.549530en
dc.identifier.issn0148-6055en
dc.identifier.urihttp://hdl.handle.net/10919/46808en
dc.identifier.urlhttp://scitation.aip.org/content/sor/journal/jor2/23/4/10.1122/1.549530en
dc.language.isoenen
dc.publisherAIP Publishingen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.titleComparison Of The Rheological Properties Of Concentrated-Solutions Of A Rodlike And A Flexible Chain Polyamideen
dc.title.serialJournal of Rheologyen
dc.typeArticle - Refereeden
dc.type.dcmitypeTexten

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