Tribological Properties of Nano-ZrO<sub>2</sub> and PEEK Reinforced PTFE Composites Based on Molecular Dynamics

Polytetrafluoroethylene (PTFE) is a polymeric material with excellent self-lubricating properties. In this study, in order to improve the wear resistance of PTFE, the PTFE matrix was filled with soft-phase polyetheretherketone (PEEK) particles and hard-phase nano-ZrO<sub>2</sub> particle...

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Main Authors: Yuan Qi, Bugong Sun, Yang Zhang, Gui Gao, Peng Zhang, Xiaobao Zheng
Format: Article
Language:English
Published: MDPI AG 2023-04-01
Series:Lubricants
Subjects:
Online Access:https://www.mdpi.com/2075-4442/11/5/194
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author Yuan Qi
Bugong Sun
Yang Zhang
Gui Gao
Peng Zhang
Xiaobao Zheng
author_facet Yuan Qi
Bugong Sun
Yang Zhang
Gui Gao
Peng Zhang
Xiaobao Zheng
author_sort Yuan Qi
collection DOAJ
description Polytetrafluoroethylene (PTFE) is a polymeric material with excellent self-lubricating properties. In this study, in order to improve the wear resistance of PTFE, the PTFE matrix was filled with soft-phase polyetheretherketone (PEEK) particles and hard-phase nano-ZrO<sub>2</sub> particles in varying volume ratios. A linear reciprocating friction tester was used to test the tribological properties of the PTFE composites. Optical microscopy (OM) and scanning electron microscopy (SEM) were utilized to observe the formation and evolution of the transfer film on the surface of the counterpart metal during the friction process. Molecular dynamics simulation software (Materials Studio MS) was used to simulate and analyze the frictional behavior between the molecular structures of PTFE composites and the counterpart iron atoms on a microscopic scale. The results showed that the uniformity and firmness of the transfer film had an important influence on the wear resistance of the material. PEEK and ZrO<sub>2</sub> nanoparticles were able to improve the firmness and formation rate of the transfer film, respectively, resulting in significant improvement in the wear resistance of PTFE (volume wear rate reduced from 7.7 × 10<sup>−4</sup> mm<sup>3</sup>/Nm for pure PTFE to 1.76 × 10<sup>−6</sup> mm<sup>3</sup>/Nm for nano-ZrO<sub>2</sub>/PEEK/PTFE). Molecular dynamics simulations revealed that the poor wear resistance of PTFE was due to significant interlayer slippage within its molecular chains. PEEK molecular chains could effectively adsorb PTFE molecular chains and formed a strong bond. ZrO<sub>2</sub> nanoparticles also contributed to the overall stability of the PTFE matrix. Both soft and hard fillers significantly inhibited interlayer slippage between PTFE molecular chains, enhancing the shear deformation resistance of the material and thus improving the wear resistance of PTFE composites.
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spelling doaj.art-59a873057f0d49a3a629bfdfbb82392e2023-11-18T02:10:33ZengMDPI AGLubricants2075-44422023-04-0111519410.3390/lubricants11050194Tribological Properties of Nano-ZrO<sub>2</sub> and PEEK Reinforced PTFE Composites Based on Molecular DynamicsYuan Qi0Bugong Sun1Yang Zhang2Gui Gao3Peng Zhang4Xiaobao Zheng5Mechanical and Electronical Engineering College, Gansu Agricultural University, Lanzhou 730070, ChinaMechanical and Electronical Engineering College, Gansu Agricultural University, Lanzhou 730070, ChinaMechanical and Electronical Engineering College, Gansu Agricultural University, Lanzhou 730070, ChinaState Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, ChinaMechanical and Electronical Engineering College, Gansu Agricultural University, Lanzhou 730070, ChinaMechanical and Electronical Engineering College, Gansu Agricultural University, Lanzhou 730070, ChinaPolytetrafluoroethylene (PTFE) is a polymeric material with excellent self-lubricating properties. In this study, in order to improve the wear resistance of PTFE, the PTFE matrix was filled with soft-phase polyetheretherketone (PEEK) particles and hard-phase nano-ZrO<sub>2</sub> particles in varying volume ratios. A linear reciprocating friction tester was used to test the tribological properties of the PTFE composites. Optical microscopy (OM) and scanning electron microscopy (SEM) were utilized to observe the formation and evolution of the transfer film on the surface of the counterpart metal during the friction process. Molecular dynamics simulation software (Materials Studio MS) was used to simulate and analyze the frictional behavior between the molecular structures of PTFE composites and the counterpart iron atoms on a microscopic scale. The results showed that the uniformity and firmness of the transfer film had an important influence on the wear resistance of the material. PEEK and ZrO<sub>2</sub> nanoparticles were able to improve the firmness and formation rate of the transfer film, respectively, resulting in significant improvement in the wear resistance of PTFE (volume wear rate reduced from 7.7 × 10<sup>−4</sup> mm<sup>3</sup>/Nm for pure PTFE to 1.76 × 10<sup>−6</sup> mm<sup>3</sup>/Nm for nano-ZrO<sub>2</sub>/PEEK/PTFE). Molecular dynamics simulations revealed that the poor wear resistance of PTFE was due to significant interlayer slippage within its molecular chains. PEEK molecular chains could effectively adsorb PTFE molecular chains and formed a strong bond. ZrO<sub>2</sub> nanoparticles also contributed to the overall stability of the PTFE matrix. Both soft and hard fillers significantly inhibited interlayer slippage between PTFE molecular chains, enhancing the shear deformation resistance of the material and thus improving the wear resistance of PTFE composites.https://www.mdpi.com/2075-4442/11/5/194tribologytransfer filmmolecular dynamicsPTFEPEEKZrO<sub>2</sub> nanoparticles
spellingShingle Yuan Qi
Bugong Sun
Yang Zhang
Gui Gao
Peng Zhang
Xiaobao Zheng
Tribological Properties of Nano-ZrO<sub>2</sub> and PEEK Reinforced PTFE Composites Based on Molecular Dynamics
Lubricants
tribology
transfer film
molecular dynamics
PTFE
PEEK
ZrO<sub>2</sub> nanoparticles
title Tribological Properties of Nano-ZrO<sub>2</sub> and PEEK Reinforced PTFE Composites Based on Molecular Dynamics
title_full Tribological Properties of Nano-ZrO<sub>2</sub> and PEEK Reinforced PTFE Composites Based on Molecular Dynamics
title_fullStr Tribological Properties of Nano-ZrO<sub>2</sub> and PEEK Reinforced PTFE Composites Based on Molecular Dynamics
title_full_unstemmed Tribological Properties of Nano-ZrO<sub>2</sub> and PEEK Reinforced PTFE Composites Based on Molecular Dynamics
title_short Tribological Properties of Nano-ZrO<sub>2</sub> and PEEK Reinforced PTFE Composites Based on Molecular Dynamics
title_sort tribological properties of nano zro sub 2 sub and peek reinforced ptfe composites based on molecular dynamics
topic tribology
transfer film
molecular dynamics
PTFE
PEEK
ZrO<sub>2</sub> nanoparticles
url https://www.mdpi.com/2075-4442/11/5/194
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AT bugongsun tribologicalpropertiesofnanozrosub2subandpeekreinforcedptfecompositesbasedonmoleculardynamics
AT yangzhang tribologicalpropertiesofnanozrosub2subandpeekreinforcedptfecompositesbasedonmoleculardynamics
AT guigao tribologicalpropertiesofnanozrosub2subandpeekreinforcedptfecompositesbasedonmoleculardynamics
AT pengzhang tribologicalpropertiesofnanozrosub2subandpeekreinforcedptfecompositesbasedonmoleculardynamics
AT xiaobaozheng tribologicalpropertiesofnanozrosub2subandpeekreinforcedptfecompositesbasedonmoleculardynamics