Molecular insights into the damping mechanism of poly(vinyl acetate)/hindered phenol hybrids by a combination of experiment and molecular dynamics simulation

Abstract

The fundamental mechanism of the improved damping properties of poly(vinyl acetate) (PVAc) contributed by the introduction of hindered phenol was systematically elucidated by two-dimensional infrared (2D IR) spectroscopy, dynamic mechanical analysis (DMA), differential scanning calorimeter (DSC), X-ray diffraction (XRD) and molecular dynamics (MD) simulation. 2D IR results revealed the hydrogen bonds (H-bonds) evolution from intermolecular H-bonds to H-bonds network of PVAc/hindered phenol. Subsequent DMA results revealed that the damping properties of PVAc exhibited two different degrees of the improvement due to the addition of hindered phenol. Meanwhile, DSC results showed that all hybrids were miscible as concentration fluctuations change irregularly. According to the XRD observation of only amorphous hindered phenol existing in PVAc matrix, further MD simulation,based on an amorphous cell, characterized the number of H-bonds, the binding energy and the fractional free volume (FFV) of the hybrids. It was observed that the variation tendency of the simulation data was in accordance with the experimental results. * Therefore, the damping mechanism of PVAc/hindered phenol hybrids was proposed through a detailed analysis on the synergy effects of the number of intermolecular H-bonds and binding energy between PVAc and hindered phenol as well as the FFV or dynamic heterogeneity.

Designing a Polymer-Based Hybrid with Simultaneously Improved Mechanical and Damping Properties via a Multilayer Structure Construction: Structure Evolution and a Damping Mechanism

“…Therefore, to prepare a useful polymer-based hybrid with excellent comprehensive performance, a multilayer system with thermoplastic polyurethane (TPU) and polyvinyl acetate (PVAc) as a matrix was prepared in this study by combining our previous works [35,36]. In order to regulate interface interactions between TPU and PVAc, HP as an HB donor was added into the TPU matrix.…”

Molecular Insights Into Chain Length Effects of Hindered Phenol on the Molecular Interactions and Damping Properties of Polymer‐Based Hybrid Materials

“…During dynamic processes, the destruction and re‐construction of the intermolecular HBs bring additional external energy dissipation. Thus, the damping factor (tan δ) and the effective loss peak area (TA, i.e., the area under the tan δ versus temperature curve where tan δ ≥ 0.3) of the hybrids are significantly improved . Because of the importance of the intermolecular HBs, numerous experimental methods, such as infrared spectroscopy , temperature‐dependent infrared spectroscopy , two‐dimensional infrared spectroscopy , and nuclear magnetic resonance , are adopted to verify the existence of the HBs in detail.…”

“…Thus, the damping factor (tan δ) and the effective loss peak area (TA, i.e., the area under the tan δ versus temperature curve where tan δ ≥ 0.3) of the hybrids are significantly improved . Because of the importance of the intermolecular HBs, numerous experimental methods, such as infrared spectroscopy , temperature‐dependent infrared spectroscopy , two‐dimensional infrared spectroscopy , and nuclear magnetic resonance , are adopted to verify the existence of the HBs in detail. Moreover, to further reveal the hydrogen‐bonding damping mechanism, molecular dynamics (MD) simulation is adopted to study the HBs between common HPs and polar polymers at the atomic or molecular level .…”

“…Because of the importance of the intermolecular HBs, numerous experimental methods, such as infrared spectroscopy , temperature‐dependent infrared spectroscopy , two‐dimensional infrared spectroscopy , and nuclear magnetic resonance , are adopted to verify the existence of the HBs in detail. Moreover, to further reveal the hydrogen‐bonding damping mechanism, molecular dynamics (MD) simulation is adopted to study the HBs between common HPs and polar polymers at the atomic or molecular level . The simulation results show that the number of intermolecular HBs, the value of binding energy, and fractional free volume (FFV) determine the damping properties of the hybrids.…”

Composition Distribution, Damping and Thermal Properties of the Thickness-Continuous Gradient Epoxy/Polyurethane Interpenetrating Polymer Networks

“…Firstly, interface friction is the main factor to influence the damping property [49]. Numbers of the interfaces are directly affected by the solubility of the components.…”