Isothermal Crystallization Kinetics Study of Fully Aliphatic PA6 Copolyamides: Effect of Novel Long-Chain Polyamide Salt as a Comonomer

Abstract

N1, N6-bis (4-aminobutyl) adipamide (BABA) diamine and sebacic acid (SA), also called BABA/SA polyamide salt, were used in a typical melt polymerization processes of polyamide 6 (PA6) to form a series of PA6-BABA/SA copolyamides. The effects of BABA/SA on the isothermal crystallization kinetics of PA6-BABA/SA were studied for the first time. An isothermal crystallization analysis demonstrates that the PA6-BABA/SA matrix provided a higher crystallization rate and shorter half-crystallization time than virgin PA6 did. The degree of crystallization of the PA6-BABA/SA30 matrix was also the lowest among all of the samples considered herein. This result is attributed to the high nucleation efficacy of a small amount of BABA/SA in the crystallization of PA6. Values of the Avrami exponent (n) from 1.84 to 3.91 were observed for all of the polyamide samples, suggesting that the crystallization was involved via a two- to three-dimensional growth mechanism. These findings deepen our understanding of the structure–property relationship of PA6-BABA/SA copolyamides, favoring their practical application.

Appraisal of ε‐Caprolactam and Trimellitic Anhydride Potential as Novel Chain Extenders for Poly(lactic acid)

“…The ATR‐IR spectrum of CAP shows CN bands at 1,200 and 1,655 cm −1 due to the amide groups, some bands at 3,000–3,290 cm −1 related to the stretching vibrations of (NH) bonds, and the band at 690 cm −1 due to the out of plane vibration of (NH) bond . Additionally, the bands at 2,854, 2,928, and 2,968 cm −1 are attributed to the symmetric and asymmetric stretching of (CH) bonds into (CH 2 ) and the ones at 1,485, 1,439, 1,417, and 1,366 cm −1 correspond to (CH 2 ) bending.…”

Comparative Screening of the Structural and Thermomechanical Properties of FDM Filaments Comprising Thermoplastics Loaded with Cellulose, Carbon and Glass Fibers

“…Such solvent evaporates after the first heating cycle and latter resulted in higher T g(ii) . For GF-PA6 composite filament, similar thermal properties (second heating, T g (ii) = 67.1, Tm = 206 and Tmc = 171 • C) were observed comparing the neat PA6 (second heating, T g (ii) = 65.9, T m = 211 and T mc = 170 • C) as mentioned in the literature [36]. Due to the similar T mc obtained after adding glass fibers in the PA6 matrix, they do not act as nucleating agent for PA6 matrix, which otherwise resulted in composites with higher T mc .…”

“…This might be due to an overloading of cellulose fibers (15 wt.% from TGA) added as filler in the PLA matrix, which hindered the flexibility of PLA polymeric chains and led to a limited crystallization of PLA. Similarly, for GF-PA6 and CF-PET composites with glass fibers (30 wt.%) and carbon fibers (15 wt.%), a reduction in X c2M (24.8% and 32.2%, respectively) was observed compared to the X c2M of the matrices, PA6 and PET (28% [36] and 35% [27], respectively). From previous observations, glass fibers are more likely to act only as a reinforcing agent for PA6 while only carbon fibers are considered as a nucleating agent for PET.…”

Effect of thermoplastic resin transfer molding process and flame surface treatment on mechanical properties of carbon fiber reinforced polyamide 6 composite

“…In addition, the crystallization kinetics were determined by the degree of supercooling. The high supercooling condition works as a high cooling rate condition . Under the high supercooling (low curing temperature), there was not enough time to adjust the crystal structure between the PA 6 molecular chains; consequently, the amorphous structure was formed.…”

“…The high supercooling condition works as a high cooling rate condition. [30][31][32] Under the high supercooling (low curing temperature), there was not enough time to adjust the crystal structure between the PA 6 molecular chains; consequently, the amorphous structure was formed. In contrast, under low supercooling, a more stable crystal structure was formed.…”