Gas permeability coefficients of isomeric aromatic polyamides obtained from 4,4'-(9-fluorenylidene) diamine and aromatic diacid chlorides

• Published in: Polymer bulletin (Berlin, Germany) Vol. 49; no. 2-3; pp. 165 - 172
• Main Authors: LOPEZ-NAVA, Ramon, VAZQUEZ-MORENO, Flavio S, PALI-CASANOVA, Ramon, AGUILAR-VEGA, Manuel
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 01.11.2002; Berlin Springer Nature B.V; New York, NY
• Subjects: Applied sciences; Aramid fibers; Chlorides; Coefficients; Diamines; Exact sciences and technology; Miscellaneous; Organic polymers; Permeability; Physicochemistry of polymers; Polyamide resins; Properties and characterization; Substitutes; Thermal decomposition; Thermodynamic properties; Substituent effect; Nylon; Gaseous diffusion; Phthalic derivative polymer; Aromatic polymer; Free volume; Experimental study; Density; Glass transition temperature; Solution polymerization; Thermal stability; Thermal properties; Gas permeability; Diffusion coefficient
• ISSN: 0170-0839; 1436-2449
• DOI: 10.1007/s00289-002-0094-z

SummaryThree isomeric aromatic Polyamides were synthesized using as a basis 4,4'-(9-fluorenylidene) diamine and different phtalic diacid chlorides. The influence of structural changes on Polyamide properties when the phthalic moiety changed from para linked, poly(fluoreny1idene terephthaloyl amide), BFA/TERE, to meta linked, poly(fluoreny1idene isophthaloyl amide), BFA/ISO, phenyl substitution or meta linked phenyl Substitution with a large Pendant group, poly(fluoreny1idene tertbutyl isophthaloyl amide), BFA/TERT, on these Polyamides were assessed. Thermal properties measurements indicate that BFA/TERE has the highest thermal decomposition temperature above 450° and Tg, while BFA/ISO and BFA/TERT have thermal properties that are only slightly lower. Gas permeability coefficients of the three isomeric aromatic Polyamides were measured at different temperatures. The results indicate that BFA/TERT has the largest permeability and diffusion coefficients while BFA/ISO Shows the lowest. These results are attributed to a larger fractional free volume in the former compared to the later. Permeability coefficients for all gases tested Show an Arrhenius type behavior with temperature for these aromatic polyamides.