Effect of SiO₂ Particles on the Crystallization and Formation of Hydrogen Bonding in Biobased Polyamide 56

Abstract

As PA56 cannot have 100% intermolecular hydrogen bonds (HBs) regardless of how the molecular chains are arranged, the crystallization properties of PA56 are not as good as those of petroleum-based nylon. To replace petroleum-based nylon and broaden the applications, it is necessary to improve the crystallization properties of PA56 and elaborate the relationship between crystallization and hydrogen bonding. In this work, nano-SiO2 with different particle sizes was chosen as the nucleation agent of biobased PA56, and the isothermal and nonisothermal crystallization of PA56 were investigated by differential scanning calorimetry (DSC). It was shown that SiO2 can significantly improve the crystallization properties of PA56 composites, especially for SiO2 with a smaller size. Furthermore, the influence of SiO2 on the formation of hydrogen bonds during the crystallization process was also studied by in situ Fourier transform infrared (FTIR) spectroscopy. The addition of SiO2 into PA56 plays a role in the increase of the conversion of the free carbonyl group to the hydrogen-bonded carbonyl group, which accelerates the formation of intermolecular HBs. The increase of HBs may be the factor for the improvement of the crystallization rate.

Achieving anti‐moisture absorption and high thermal properties in bio‐based polyamide 56/F‐based heat‐resistant agent composites through crystal regulation

“…The low‐temperature peak exhibits only a slight shoulder peak, which is caused by the melting of primary crystals formed in the ordinary cooling process, while the high‐temperature peak is a wide asymmetric melting peak, which is due to the melting of crystals formed by the recrystallisation of the PA56 composite by secondary heating. Moreover, there is an obvious melting recrystallisation peak in the range of 230–250°C, which is related to crystal defects 19,36 …”

“…Moreover, there is an obvious melting recrystallisation peak in the range of 230-250 C, which is related to crystal defects. 19,36 It can be observed from Figure 2b that the melting peak areas of PA56, PA56/PFS, and PA56/PFT are not significantly different and that the melting point of PA56 is not significantly changed by PFS and PFT. However, the melting recrystallisation peak area of PA56/PFS and PA56/PFT is smaller than that of PA56, which indicates that the addition of PFS and PFT leads to the generation of crystals of PA56 with fewer defects.…”

Three-Dimensional Cross-Linking Network Coating for the Flame Retardant of Bio-Based Polyamide 56 Fabric by Weak Bonds

“…ing peak, a melting-recrystallization peak and a small melting peak in the second heating curves [57,58]. The incorporation of flame retardants did not significantly alter the melting temperature (Tm), but it lowered the crystallization temperature (Tc).…”

Bio‐based Polyamide 56: Recent advances in basic and applied research

“…[38][39][40][41][42] Wang et al 43 demonstrated that SiO 2 has a better heat resistance and higher specific surface area. Xun et al 44 investigated that two SiO 2 particles with different sizes were selected as nucleating agents to evaluate the effect of content and particle size on the nonisothermal and isothermal crystallization of PA56. They pointed out that the smaller SiO 2 particles were more efficient to increase the crystallization of PA56 because of their larger surface area to volume ratio and stronger interaction between the inorganic phase and PA56 matrix.…”