Synthesis and Characterization of Copolymers of Nylon 11 and Nylon 12

摘要

A series of copolymers was prepared from 11-aminoundecanoic and 12-aminododecanoic acids by melt-condensation at 210 degree C in sealed tubes under vacuum. Mole percentages of nylon 12 monomer were 0, 15, 35, 50, 65, 85, and 100 percent in the feed. The amide group was labelled using nitrogen 15-labelled amino acids available through the Gabriel synthesis (only the 1:1 copolymer was enriched with nitrogen-15). Solid-state carbon 13 (at 100.6 MHz) and nitrogen 15 (at 20.3 MHz) NMR spectroscopy, differential scanning calorimetry, wide-angle x-ray diffraction, and infrared spectroscopy were used to characterize the copolymers. Solid-state nitrogen 15 NMR spectra showed a smooth shift of the main peak position from 84 ppm for alpha-nylon 11 to 89 ppm for gamma-nylon 12 for the as-prepared copolymers. Similar behavior was seen from amide V and VI modes which