Effect of Stoichiometric Imbalances on the Melt Condensation Polymerization of Poly(dodecamethylene terephthalamide) Studied by Intrinsic Viscosity and (13)C-NMR

Lon J. Mathias, University of Southern Mississippi
Christopher Lange, University of Southern Mississippi
William L. Jarrett, University of Southern Mississippi
Lon Mathias, University of Southern Mississippi

Abstract

Poly(dodecamethylene terephthalamide) (PA-12,T) was synthesized by melt condensation polymerization of 12,T salt with 0, 1, 3, 5, or 10% molar excess of 1,12-diaminododecane (DA), terephthalic acid (TA), or benzoic acid (BA). Intrinsic viscosities (IV) (0.5 g/dL in 96% H(2)SO(4) at 25 degrees C) were measured to determine relative molecular weight differences. IV was highest for reactions containing 1 and 3 mol % excess DA (1.36 and 1.31 dL/g, respectively), followed by the product of pure 1 : 1 salt (1.25 dL/g). For all concentrations of excess TA and BA, IV was decreased. (13)C-NMR chemical shifts for DA, TA, and BA end groups were identified and their concentrations determined by comparison with the intensity of main chain polymer peaks. A log-log plot of IV versus number average molecular weight calculated from 13C-NMR data shows a linear trend with Mark-Houwink constants of K = 55.8 x 10(-5) dL/g and alpha = 0.81. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 116: 3388-3395, 2010