Effect of Bis (2-Aminoethyl) Adipamide/Adipic Acid Segment on Polyamide 6: Crystallization Kinetics Study

Abstract

The crystallization behavior of novel polyamide 6 (PA6) copolyamides with different amounts of bis (2-aminoethyl) adipamide/adipic acid (BAEA/AA) segment was investigated. The wide-angle X-ray diffraction (WAXD) results showed that as the amount of BAEA/AA segment increased to 10 mole%, the crystalline forms of all PA6 copolyamide were transferred from the stable α-form to the unstable γ-form because of the complex polymer structure. According to studies of crystallization kinetics, the Avrami exponent (n) values for all copolyamide samples ranged from 1.43 to 3.67 under isothermal conditions, implying that the crystallization is involved in the two- to three-dimensional growth at a high temperature of isothermal condition. The copolyamides provided a slower crystallization rate and higher crystallization activation energy (ΔEa) than neat PA6. Polyamide containing 10 mole% of BEAE/AA content exhibited a unique crystallization behavior in the coexistence of the α and γ forms. These results deepen our understanding of the relationship between BAEA/AA content, crystal structure, and its crystallization behavior in low-melting PA6, and they make these types of copolyamides useful for their practical application.

New Strategy and Polymer Design to Synthesize Polyamide 66 (PA66) Copolymers with Aromatic Moieties from Recycled PET (rPET)

“…In terms of crystallization kinetics, both copolyamides isothermally crystallized under the 230–240 and 240–250 °C temperature ranges, respectively (Figures S14 and S15), and the crystallization rate of both copolyamides gradually decreases with increasing isothermal temperature, which shows the evolution of relative crystallinity ( X ( t )) associated with time. For most polymers, the crystallization curves expressed a “sigmoidal” shape owing to the slow growth rate during the initial and end stages of crystallization. , Figure S14 shows the isothermal crystallization curves of PA66-25 and PA66/6T under different isothermal conditions, and their Avrami parameters are listed in Table S2. Interestingly, the isothermal curves of PA66-25 exhibited an incomplete sigmoidal shape for all isothermal processes, which may indicate the rapid occurrence of thermal nucleation at an initial stage.…”

“…For most polymers, the crystallization curves expressed a "sigmoidal" shape owing to the slow growth rate during the initial and end stages of crystallization. 12,21 Figure S14 shows the isothermal crystallization curves of PA66-25 and PA66/6T under different isothermal conditions, and their Avrami parameters are listed in Table S2. Interestingly, the isothermal curves of PA66-25 exhibited an incomplete sigmoidal shape for all isothermal processes, which may indicate the rapid occurrence of thermal nucleation at an initial stage.…”

“…The utilization of BAHT-AA comonomer with PA66 salt as a major monomer for the synthesis of semiaromatic copolyamides has not been mentioned in the literature yet. In this current work, based on our previous reports, the semiaromatic diamine of BAHT has been successfully synthesized by the aminolysis reaction between PET waste and hexamethylenediamine (HMDA), ,,− which is deployed in the modification and synthesis of polyamides. Furthermore, the difference between the PA66/6T polyamides obtained by the conventional synthesis method and the PA66 copolyamides obtained by our method are systematically discussed under the same chemical structure composition and are compared with thermal analysis, wide-angle X-ray diffraction (WAXD), mechanical performance, crystallization kinetics, as well as relaxation and rheological behavior.…”

Effect of Silver Nanoparticles on the Melting Behavior, Isothermal Crystallization Kinetics and Morphology of Polyoxymethylene

“…However, this is i >> g in regime III [17]. In addition, it can be used to calculate G of POM/Ag nanocomposites by using the isothermal crystallization data, as shown in Equation 6 [41]:…”

“Polymer Analysis” Section, in Journal Polymers

“…A selection of cutting-edge “Hot Papers” published in the Polymer Analysis section of Polymers is presented at the end of this Editorial [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ].…”