1 H NMR spectra of PA56, PA66 and PA56/66 copolyamides.
The chemical structures of the PA56/PA66 copolymers were analyzed using 1 H-NMR spectroscopy, as displayed in Figure 2. Signals were observed at approximately 3.3 ppm (a) and 2.4 ppm (b) and...
Quantitative Determination of PA6 and/or PA66 Content in …
For determination of the PA content in plastic waste, we developed a fast degradation method, whereby PA6 completely depolymerizes into 6-ACA and PA66 into AA and HMDA (Figure 1). Oligomers and side products in the final reaction mixtures of PA6 and PA66 were not detected by 1 H NMR (Figure S1).
Synthesis and characterizations of random copolyamide PA(56-co …
2024年7月24日 · Fig. 1 shows the 1 H NMR spectra of PA56, PA66, and represented copolyamides. The hydrogen atoms marked in Scheme 1 are labeled on the 1 H NMR spectra. The resonance signal of the methylene protons in 5N6C and 6N6C segments cannot be distinguished in 1 H NMR spectra.
Mechanism of the temperature-dependent degradation of polyamide …
2007年11月1日 · Using FTIR and solid-state 13 C NMR spectroscopies, we have investigated the early degradation stages of hot-pressed PA66 upon exposure to water over the temperature range of 25 °C–90 °C. The degradation was found to involve both molecular oxygen and radical intermediates, and proceeds via the formation of an imide.
Biobased Copolyamides 56/66: Synthesis, Characterization and ...
The structures, compositions, behaviors, and crystallization kinetics of the co-PAs were investigated through proton nuclear magnetic resonance (1 H NMR) spectroscopy, gel permeation chromatography (GPC), Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), polarized optical microscopy (POM), and X-ray ...
Biobased Copolyamides 56/66: Synthesis, Characterization and
2022年8月17日 · The structures, compositions, behaviors, and crystallization kinetics of the co-PAs were investigated through proton nuclear magnetic resonance (1H NMR) spectroscopy, gel permeation chromatography (GPC), Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), polarized optical microscopy (POM), and X-ray ...
Standard 13 C NMR spectra of PA10T, PA6T, PA106, and PA66.
Standard high resolution ¹³C NMR spectra of PA10T, PA6T, PA106, and PA66 were obtained by a nonacidic solvent mixture of HFIP and CDCl3. Several chemical shifts were found extremely sensitive...
¹³C NMR spectra of PA66 and FR‐PA66 samples: (a
A novel halogen‐free flame retardant copolyamide 6,6 (FR‐PA66) was prepared successfully by in situ polymerizing with adipic acid hexamethylene salt and 2‐carboxy ethyl (phenyl) phosphinic acid...
Direct observation of the thermo-oxidative degradation of PA66 …
2023年9月1日 · Based on the radicals detected by ST-ESR and CL-ESR and the chemical structure changes shown by IR and NMR, we consider that the thermo-oxidative reactions of PA66 start with the oxygen attack. Since oxidation reactions tend to be automatic chain reactions by radical species, we focus here on the initiation reactions.
High heat resistance and good melt spinnability of a polyamide …
PA66-co-10%6T contains less benzene ring, while it has higher crystallinity, compared with PA66-co-20%6T. Under the combined effects of benzene ring content and crystallinity, these two copolymers show similar strength and modulus. PA66 had a larger elongation at break because it is a flexible molecular chain of aliphatic group.