Comparative Characterization of Hot-Pressed Polyamide 11 and 12: Mechanical, Thermal and Durability Properties

Abstract

Chemically speaking, polyamide 11 (PA11) and polyamide 12 (PA12) have a similar backbone, differing only in one carbon. From an origin point of view, PA11 is considered a bioplastic polyamide composed from renewable resources, compared to oil-based PA12. Each of them has a number of advantages over the other, which makes their selection a challenging issue. Depending on the target application, diverse assessments and comparisons are needed to fulfill this mission. The current study addresses this research gap to characterize and compare PA11 and PA12 manufactured by the hot press technique in terms of their mechanical, thermal and durability properties for the first time, demonstrating their potential for future works as matrices in composite materials. In this regard, different characterization techniques are applied to the hot-pressed polymer sheets, including X-ray diffraction (XRD), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The mechanical performance of the PA11 and PA12 sheets is compared based on tensile tests and shore hardness measurement. The durability behavior of these two polyamides is evaluated in water and relative humidity conditions at different aging times. The experimental results show the ductile behavior of PA12 with respect to the quasi-brittle PA11. Both have a relatively small water and moisture gain: 1.5 wt% and 0.8 wt%, respectively. The higher crystallinity of PA12 (2.1 times more than PA11) with γ-phase is one of the leading parameters to achieve better mechanical and durability properties. The FTIR spectra displayed slight acid hydrolysis. Accordingly, absorbed water or moisture does not cause plasticization; thus, neither hardness nor dimension changes.

Novel Thermoplastic Composites Strengthened with Carbon Fiber-Reinforced Epoxy Composite Waste Rods: Development and Characterization

“…Bahrami et al [ 29 ] reported large differences in the tensile behaviors of PA11 and PA12 polymers. While PA11 exhibited a quasi-brittle behavior, PA12 demonstrated a highly ductile behavior, showing a higher tensile strength, Young’s modulus, and strain at failure.…”

“…Two commercially available thermoplastic polymeric resins were selected and used as matrices in the shape of pellets, namely, PA11 and PA12, both of which were provided by Arkema (Barcelona, Spain). These polyamides were selected due to their relatively low melting points, which leads to lower energy consumption during production and to their outstanding mechanical properties, including high tensile strength, high impact and fatigue resistance, high chemical and aging resistance, and low moisture absorption [ 29 ].…”

Fabrication of Nylon-6 and Nylon-11 Nanoplastics and Evaluation in Mammalian Cells

“…The nylon-6 particles labeled with NR and ATRB showed similar absorption bands distinctive of the polymer; however, the bands associated with the fluorescent molecule were absent ( Figure S6 , ESI†). For nylon-11 NPs, the characteristic absorption bands include 3301 cm −1 and 2919 cm −1 (N–H stretch), 2851 cm −1 (C–H vibration of the methylene groups), 1638 cm −1 (amide I), 1546 cm −1 (amide II), and 1467 cm −1 (C–H bending) [ 74 , 75 ]. The incorporation of NR and ATRB within the nylon-11 NPs did not result in detectable absorption bands from the fluorophore ( Figure S6 , ESI†).…”

Synthesis and characterization of ultra‐tough crosslinked polyamide with hybrid polymer networks equipping strong hydrogen bonds

“…Interestingly, as the Figure 7, the tensile section of cPA was observed by SEM. Some cPAs with rich hydrogen‐bonding networks exhibited complex and large‐scale cracks on the tensile section, these cracks enable the ability of cPAs to withstand large deformations without breaking easily, which was related to the delay and redistribution of the accumulation of local stress by flexible hydrogen bonds 22,26,27 . Especially for the stretch curve of BH37, three distinct regimes of tensile modulus were observed.…”

“…Some cPAs with rich hydrogen-bonding networks exhibited complex and large-scale cracks on the tensile section, these cracks enable the ability of cPAs to withstand large deformations without breaking easily, which was related to the delay and redistribution of the accumulation of local stress by flexible hydrogen bonds. 22,26,27 Especially for the stretch curve of BH37, three distinct regimes of tensile modulus were observed. The first regime was the linear elastic region at initial strain (ε < 2%), and the stress increased rapidly with increasing strain.…”