Synthesis and characterization of nylon 18 18 and nylon 18 adamantane

Abstract

Nylon 18 18 and nylon 18 1,3-adamantanedicarboxylic acid (ADA) have been synthesized via melt polycondensation and characterized by thermal and spectroscopic techniques. Good film forming behavior combined with film toughness and flexibility indicate reasonable molecular weights for both. The higher aliphatic content of nylon 18 18 leads to increased resistance to common organic solvents over commercial nylons. Crystallization of nylon 18 18 combines hydrogen bonding of the amide units with a more significant contribution from van der Waals forces than possible for lower aliphatic content nylons due to the greater aliphatic chain lengths. Solid state 15 N CP/MAS NMR indicates a mostly amorphous polymer, with crystalline regions comprised of the thermodynamically stable a-form generally adopted by even-even nylons. Nylon 18 ADA as-produced is completely amorphous as determined by differential scanning calorimetry. However, solution cast samples of nylon 18 ADA shows some ordered structures that can grow into more stable crystals with annealing. These crystals, once melted, do not recrystallize possibly due to chain rearrangement inhibited by bulky adamantly-groups. V

Polyamides – Still Strong After Seventy Years

“…Aramaki and Maekawa [50] claimed a polyamide in which 1,4-CHDA constituted between 10 and 80% of the diacid segments, with an aliphatic diamine, and they stated this polymer as suitable for automotive, electrical, electronic, industrial, and domestic uses because of its resistance to heat, light, moisture, and mechanical stress. Bennett et al [44] polymerized an 18-carbon diamine with the tricyclic 1,3-adamantanedicarboxylic acid (ADA) [51] (see Formula 5) to make a fully amorphous polymer which melted at around 100 8C. This did not represent an improvement over the other polymer which they made, namely partially crystalline PA 1818, which had T g of 45 8C…”

“…The higher polyamides have been studied, with the objective of reducing some of the polarity and obtaining properties somewhat closer to those of the polyolefins. Bennett et al [44] prepared nylon 1818. Ehrenstein et al [25] made PA 624 and PA 634 (6 34) to develop a compatibilizer for nylon/olefin blends.…”

Ferroelectric behavior and polarization mechanism in odd‐odd polyamide 11,11

“…Among the semicrystalline polymers, polyamides, commonly called nylons, attract particular attention . On the one hand, they are one of the most important engineering materials with excellent physical properties such as high modulus, toughness, abrasion resistance, and good temperature resistance . Conversely, amide groups in polyamides have a dipole moment as high as 3.7 D , compared to 1.52 D in that for PVDF, and, thus, strong piezoelectric and ferroelectric activities can be expected.…”

Improvement of polyamide 1010 with silica nanospheres via in situ melt polycondensation

“…Polyamides with long aliphatic segments such as poly(iminosebacoyl imniodecamethylene) (PA1010) have lower amide density than PA66 but higher melting transition temperature than general‐purpose plastics. Such a polyamide can act as a functionalized polyethylene and exhibits peculiar properties and they have found applications in coatings and compatibilizer for polyamide and polyolefin [4–7]. Yet, development of polyamide‐based materials with high thermal and mechanical performance has been an important subject in this field.…”