Nitrile rubber/hindered phenol exterminated hyperbranched polyester materials with improved damping and mechanical performance

Effects of chain polarity of hindered phenol on the damping properties of polymer-based hybrid materials: insights into the molecular mechanism

For hindered phenol (HP)/polymer-based hybrid damping materials, the damping properties are greatly affected by the structure variation of HPs. However, the unclear relationship between them limits the exploitation of such promising materials. Therefore, three HPs with different chain polarity were synthesized to explore the relationship in this paper. The structures of the HPs were firstly confirmed by Nuclear Magnetic Resonance Spectrum, Fourier Transform Infrared Spectroscopy (FT-IR) and X-ray Diffraction (XRD). For further prepared HP/polyurethane hybrids, FT-IR and XRD were also adopted to confirm the hydrogen bonding interactions and micromorphologies. And, Molecular dynamics simulation was further used to characterize the effects of polarity variation on the hydrogen bonding interactions and chain packing of the hybrids in a quantitative manner. Then, combined with dynamic mechanical analysis, the relationship between the chain polarity variation of the hindered phenols and the damping properties was established.

Towards a Stable and High-Performance Hindered Phenol/Polymer-Based Damping Material Through Structure Optimization and Damping Mechanism Revelation

Although hindered phenol/polymer-based hybrid damping materials, with excellent damping performance, attract more and more attention, the poor stability of hindered phenol limits the application of such promising materials. To solve this problem, a linear hindered phenol with amorphous state and low polarity was synthesized and related polyurethane-based hybrid materials were prepared in this study. The structure and state of the hindered phenol were confirmed by nuclear magnetic resonance spectrum, Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). The existence of intermolecular hydrogen bonds (HBs) between hindered phenol and polyurethane was confirmed by FT-IR, and the amorphous state of the hybrids was confirmed by XRD. Moreover, by a combination of molecular dynamics simulation and dynamic mechanical analysis, the relationship between the structure optimization of the hindered phenol and the high damping performance of the hybrids was quantitatively revealed. By constructing the synthetic hindered phenol, the intramolecular HBs between hindered phenols were restricted, while the strength and concentration of the intermolecular HBs increased by increasing the amount of hindered phenol. Thus, intermolecular interactions were enhanced, which lead to the compact chain packing of polyurethane, extended chain packing of hindered phenol, and good dispersion of hindered phenol in polyurethane. Therefore, the stability of the hindered phenol and the damping properties of the hybrids were both improved. The experiment results are expected to provide some useful information for the design and fabrication of high-performance polymeric damping materials.

Molecular-level insight of hindered phenol AO-70/nitrile-butadiene rubber damping composites through a combination of a molecular dynamics simulation and experimental method

The damping properties of AO-70/NBR composites get a noteworthy increase with the introduction of AO-70—max tan δincreased by 66.9%.