Morphology and thermal properties of nylon copolymers containing dimer acid, adipic acid, and hexamethylenediamine

Abstract

The effects of the molar ratio of adipic acid to total diacid on the phase morphology and thermal properties of nylon copolymers containing dimer acid, adipic acid, and hexamethylenediamine were investigated. A significant structural transition from the c form to a and b mixture forms occurred with increasing molar ratio. Meanwhile, the content of the crystals increased markedly. A r-p* hyper conjugation effect was present in all of the as-prepared samples. A strong r-p* hyper conjugation effect could decrease the average distance between interchain amide groups and suppress the scission of the CAN bond through the formation of highly combining aza double-bond C¼ ¼N groups, which would, consequently, make the nylon copolymer much more stable. Differential scanning calorimetry-thermogravimetric analysis results indicate that the low thermal stability of the nylon copolymers with higher molar ratios of adipic acid to total diacid was simply due to the formation of cyclopentanone and caprolactam at 350-4208C, whereas for the nylon copolymers with lower molar ratios, the scission of the CAC bond at 430-5008C directed the pyrolysis of the main chain.

Toughened and hydrophobically modified polyamide 11 copolymers with dimer acids derived from waste vegetable oil

“…Wang et al . studied the relationship between the morphology and thermal properties by the addition of adipic acid . However, there have been few reports studying the relationship between changes in the crystallization and mechanical properties obtained by controlling the formation of interchain hydrogen bonds and the density of the amide groups in PA11.…”

Effect of intercalating agents on structure and properties of dimer acid‐based polyamide modified by in situ doping of Na‐montmorillonite

“…In recent years, researches and applications of dimer acid have caused a wide attention because of its distinctive properties . However, mechanical properties of the materials were bad comparatively.…”

Mechanical and thermal properties of dimer acid based nylon 636/Nylon 66 copolymers

“…However, they are still far from conventional polyamide materials, and research work that is focused on enhancing polymer properties has developed. An effective approach for improving the thermal and mechanical properties of DA‐based nylons is its association with anther compound or the incorporation of fibers in the matix . Cavus and Gürkaynak used the monofunctional reactant to modify dimer acid based polyamides (DAPAs), and they concluded that the formation of interchain hydrogen bonds and the density of the amide groups remarkably affected the crystallization and the physical properties.…”

“…Cavus and Gürkaynak used the monofunctional reactant to modify dimer acid based polyamides (DAPAs), and they concluded that the formation of interchain hydrogen bonds and the density of the amide groups remarkably affected the crystallization and the physical properties. Wang et al studied the influence of adipic acid on the morphology and thermal properties and determined the way adipic acid affected the thermal degradation properties. Hablot et al studied the morphology and thermal and viscoelastic behavior of DAPAs reinforced with highly refined cellulose fibers.…”