No 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% H2SO4 at 25°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. 13C‐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 × 10−5 dL/g and α = 0.81. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

PA‐12,T was synthesized by melt condensation of 1,12‐diaminododecane (DA) and terephthalic acid salt and by solution polymerization of biscaprolactam terephthalamide (BCT) and DA in molten caprolactam. Stoichiometry of both methods were varied from 10 mol‐% excess terephthalic acid (or BCT) and 10 mol‐% excess DA and the impact on intrinsic viscosity, end group concentration and end group functionality was examined. PA‐12,T salt was then copolymerized with PA‐6,T salt and melting behavior was determined to examine the effect of random comonomers. Block copolymers were synthesized by anionic polymerization of PA‐6 with PA‐12,T macro‐coinitiators formed from the solution step‐growth reaction. The melting and solubility properties of the block copolymers were then correlated with the PA‐12,T block size and compared to randomly formed copolymers.

A 12-membered cyclic diamide monomer for nylon 64 was successfully synthesized in fairly high yield (45%). The synthesis conditions were varied to see the effect of the diamine and succinyl chloride reactants on yield. Threefold excess of 1,6-hexamethylenediamine (HDA) gave the highest yield, while further increasing the amount of HDA decreased the yield. Using N,N-diisopropylethylamine as acid scavenger resulted in the formation of two different cyclic amides, which were fully analyzed by 1 H and 13 C solution nuclear magnetic resonance spectrometry and mass spectrometry. Copolymerization of cyclic amides with ecaprolactam via an anionic route gave a block copolyamide with a two distinct endotherms in the differential scanning calorimetry analysis. However, copolymerization by the hydrolytic route gave only nylon 6 with terminal 64 units. V C 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52,[96][97][98][99][100][101][102][103]