Graphical Abstract Figure
Effect of pore size on EHD film. Pore size is a key factor in influencing the tribological properties of porous polyimide, as it significantly affects the elastohydrodynamic (EHD) film on the contact surfaces
Graphical Abstract Figure
Effect of pore size on EHD film. Pore size is a key factor in influencing the tribological properties of porous polyimide, as it significantly affects the elastohydrodynamic (EHD) film on the contact surfaces
Abstract
Pore size is critical to the oil-storage performance and tribological properties of porous polyimide (PPI). To study the effect of pore size, four PPIs with different pore sizes and similar porosities were fabricated. The mechanical, oil-absorption, and tribological properties of the PPIs were investigated. According to the results, PPIs with larger pores demonstrate faster oil absorption and a higher oil-filling rate. However, larger pores contribute to a rougher surface and lower oil retention. These dual effects result in PPIs with larger pores displaying a low friction coefficient at low speeds but a high friction coefficient at high speeds. The effect of pore sizes on elastohydrodynamic (EHD) film and Stribeck curves were discussed from seepage effect and viscoelasticity of PPI, respectively. The permeability of the four PPIs was calculated based on mercury intrusion test results. Larger pores lead to higher permeability of PPI at lower pressure, which makes it easier to reduce thickness of EHD film, causing high friction and wear. The damping effect of PPIs, rather than a viscous flow, results in a slight increase in friction coefficient at high speed under micro-oil lubrication. Considering the tribological and oil-absorption properties, the preferred particle size of polyimide molding powder is 25–48 μm.
References
1.
Lin
, Y.
, He
, R.
, Xu
, Y.
, Zhang
, J.
, Wetzel
, B.
, and Zhang
, G.
, 2023
, “Significance of Nickel Particles on Reducing Friction and Wear of Polyimide Subjected to Harsh Boundary Lubrication Conditions
,” Tribol. Int.
, 178
, pp. 108063
–108074
. 2.
Gao
, X.
, Chen
, H.
, Yan
, H.
, Huang
, C.
, Wu
, L.
, and Wang
, T.
, 2023
, “Superlubricity by Polyimide-Induced Alignment
,” Friction
, 11
(9
), pp. 1690
–1707
. 3.
Xue
, Y. H.
, Yan
, S. C.
, and Chen
, Y.
, 2022
, “Thermomechanical and Tribological Properties of Polyimide and Polyethersulfone Blends Reinforced With Expanded Graphite Particles at Various Elevated Temperatures
,” J. Appl. Polym.
, 139
(28
), pp. 52512
–52528
. 4.
Zhang
, D.
, Wang
, C.
, Wang
, Q.
, and Wang
, T.
, 2019
, “High Thermal Stability and Wear Resistance of Porous Thermosetting Heterocyclic Polyimide Impregnated With Silicone Oil
,” Tribol. Int.
, 140
, pp. 105728
–105738
. 5.
Lv
, M.
, Wang
, C.
, Wang
, Q.
, Wang
, T.
, and Liang
, Y.
, 2015
, “Highly Stable Tribological Performance and Hydrophobicity of Porous Polyimide Material Filled With Lubricants in a Simulated Space Environment
,” RSC Adv.
, 5
(66
), pp. 53543
–53549
. 6.
Jia
, W.
, Yang
, S.
, Ren
, S.
, Ma
, L.
, and Wang
, J.
, 2020
, “Preparation and Tribological Behaviors of Porous Oil-Containing Polyimide/Hollow Mesoporous Silica Nanospheres Composite Films
,” Tribol. Int.
, 145
, pp. 106184
–106192
. 7.
Yan
, Z.
, Jiang
, D.
, Fu
, Y.
, Qiao
, D.
, Gao
, X.
, Feng
, D.
, Sun
, J.
, Weng
, L.
, and Wang
, H.
, 2018
, “Vacuum Tribological Performance of WS2–MoS2 Composite Film Against Oil-Impregnated Porous Polyimide: Influence of Oil Viscosity
,” Tribol. Lett
, 67
(1
), pp. 2
–12
. 8.
Zhang
, D.
, Wang
, T.
, Wang
, Q.
, and Wang
, C.
, 2017
, “Selectively Enhanced Oil Retention of Porous Polyimide Bearing Materials by Direct Chemical Modification
,” J. Appl. Polym.
, 134
(29
), pp. 45106
–45113
. 9.
Ruan
, H.
, Zhang
, Y.
, Wang
, Q.
, Wang
, C.
, and Wang
, T.
, 2022
, “A Novel Earthworm-Inspired Smart Lubrication Material With Self-Healing Function
,” Tribol. Int.
, 165
, pp. 107303
–107313
. 10.
Bertrand
, P. A.
, and Carré
, D. J.
, 1997
, “Oil Exchange Between Ball Bearings and Porous Polyimide Ball Bearing Retainers
,” Tribol. Trans
, 40
(2
), pp. 294
–302
. 11.
Chen
, W.
, Zhu
, P.
, Liang
, H.
, and Wang
, W.
, 2022
, “Characteristic Parameter to Predict the Lubricant Outflow From Porous Polyimide Retainer Material
,” Tribol. Int.
, 173
, pp. 107596
–107604
. 12.
Li
, J.
, Liu
, J.
, Li
, K.
, Zhou
, N.
, Liu
, Y.
, Hu
, X.
, Yin
, S.
, and Wang
, G.
, 2023
, “Tribological Properties of Oil-Impregnated Polyimide in Double-Contact Friction Under Micro-Oil Lubrication Conditions
,” Friction
, 11
(8
), pp. 1493
–1504
. 13.
Wang
, J.
, Zhao
, H.
, Huang
, W.
, and Wang
, X.
, 2017
, “Investigation of Porous Polyimide Lubricant Retainers to Improve the Performance of Rolling Bearings Under Conditions of Starved Lubrication
,” Wear
, 380–381
, pp. 52
–58
. 14.
Gao
, S.
, Han
, Q.
, Zhou
, N.
, Pennacchi
, P.
, and Chu
, F.
, 2022
, “Stability and Skidding Behavior of Spacecraft Porous Oil-Containing Polyimide Cages Based on High-Speed Photography Technology
,” Tribol. Int.
, 165
, pp. 107294
–107307
. 15.
Chen
, W.
, Wang
, W.
, Liang
, H.
, and Zhu
, P.
, 2022
, “Study on Lubricant Release-Recycle Performance of Porous Polyimide Retainer Materials
,” Langmuir
, 38
(37
), pp. 11440
–11450
. 16.
Yin
, Y.
, Shi
, P.
, Zhang
, S.
, Jiang
, Y.
, Qing
, T.
, Wang
, Y.
, Qian
, L.
, Zhang
, J.
, and Chen
, L.
, 2023
, “Improving Tribological Performance of Porous Polyimide by Surface Polishing
,” ACS Appl. Polyme.
, 5
(9
), pp. 6808
–6816
. 17.
Wang
, C.
, Zhang
, D.
, Wang
, Q.
, Ruan
, H.
, and Wang
, T.
, 2020
, “Effect of Porosity on the Friction Properties of Porous Polyimide Impregnated With Poly-α-Olefin in Different Lubrication Regimes
,” Tribol. Lett
, 68
(4
), pp. 102
–111
. 18.
Ruan
, H.
, Zhang
, Y.
, Song
, F.
, Wang
, Q.
, Wang
, C.
, and Wang
, T.
, 2022
, “Efficacy of Hierarchical Pore Structure in Enhancing the Tribological and Recyclable Smart Lubrication Performance of Porous Polyimide
,” Friction
, 11
(6
), pp. 1014
–1026
. 19.
Chen
, W.
, Wang
, W.
, Zhu
, P.
, and Ge
, X.
, 2023
, “Effects of Pore Size on the Lubrication Properties of Porous Polyimide Retainer Material
,” Friction
, 11
(8
), pp. 1419
–1429
. 20.
Dunn
, A. C.
, Sawyer
, W. G.
, and Angelini
, T. E.
, 2014
, “Gemini Interfaces in Aqueous Lubrication With Hydrogels
,” Tribol. Lett.
, 54
(1
), pp. 59
–66
. 21.
Xu
, X.
, Shu
, X.
, Pei
, Q.
, Qin
, H.
, Guo
, R.
, Wang
, X.
, and Wang
, Q.
, 2022
, “Effects of Porosity on the Tribological and Mechanical Properties of Oil-Impregnated Polyimide
,” Tribol. Int.
, 170
, pp. 107502
–107513
. 22.
Lu
, Y.
, and Liu
, Z.
, 2013
, “Coupled Effects of Fractal Roughness and Self-Lubricating Composite Porosity on Lubrication and Wear
,” Tribol. Trans
, 56
(4
), pp. 581
–591
. 23.
Guegan
, J.
, Kadiric
, A.
, Gabelli
, A.
, and Spikes
, H.
, 2016
, “The Relationship Between Friction and Film Thickness in EHD Point Contacts in the Presence of Longitudinal Roughness
,” Tribol. Lett
, 64
(3
), pp. 33
–48
. 24.
Ye
, J.
, Li
, J.
, Qing
, T.
, Huang
, H.
, and Zhou
, N.
, 2021
, “Effects of Surface Pore Size on the Tribological Properties of Oil-Impregnated Porous Polyimide Material
,” Wear
, 484–485
, pp. 204042
–204052
. 25.
Ruan
, H.
, Shao
, M.
, Zhang
, Y.
, Wang
, Q.
, Wang
, C.
, and Wang
, T.
, 2022
, “Supramolecular Oleogel-Impregnated Macroporous Polyimide for High Capacity of Oil Storage and Recyclable Smart Lubrication
,” ACS Appl. Mater.
, 14
(8
), pp. 10936
–10946
. 26.
Hamrock
, B.
, and Dowson
, D.
, 1977
, “Isothermal Elastohydrodynamic Lubrication of Point Contacts: Part III-Fully Flooded Results
,” ASME J. Lubr. Tech.
, 99
(2
),
pp. 264
–275
. 27.
Shin
, C.-H.
, 2022
, “Alternative Flow Model of Anisotropic Porous Media
,” J. Nat. Gas Sci. Eng.
, 108
, pp. 104829
–104846
. 28.
Masoodi
, R.
, Pillai
, K. M.
, and Varanasi
, P. P.
, 2007
, “Darcy's Law-Based Models for Liquid Absorption in Polymer Wicks
,” AIChE J.
, 53
(11
), pp. 2769
–2782
. 29.
Niessner
, J.
, Berg
, S.
, and Hassanizadeh
, S. M.
, 2011
, “Comparison of Two-Phase Darcy's Law With a Thermodynamically Consistent Approach
,” Transp. Porous Media
, 88
(1
), pp. 133
–148
. 30.
Putignano
, C.
, 2020
, “Soft Lubrication: A Generalized Numerical Methodology
,” J. Mech. Phys. Solids
, 134
, pp. 103748
–103760
. 31.
Galda
, L.
, Sep
, J.
, Olszewski
, A.
, and Zochowski
, T.
, 2019
, “Experimental Investigation Into Surface Texture Effect on Journal Bearings Performance
,” Tribol. Int.
, 136
, pp. 372
–384
. 32.
Bhushan
, B.
, and Ko
, P. L. J. A. M. R.
, 2003
, “Introduction to Tribology
,” Appl. Mech. Rev.
, 56
(1
), pp. B6
–B7
. 33.
Kocun
, M.
, Mueller
, W.
, Maskos
, M.
, Mey
, I.
, Geil
, B.
, Steinem
, C.
, and Janshoff
, A.
, 2010
, “Viscoelasticity of Pore-Spanning Polymer Membranes Derived From Giant Polymersomes
,” Soft Matter
, 6
(11
), pp. 2508
–2516
. 34.
Nguyen
, T.
, Li
, J.
, Sun
, L.
, Tran
, D.
, and Xuan
, F.
, 2021
, “Viscoelasticity Modeling of Dielectric Elastomers by Kelvin Voigt-Generalized Maxwell Model
,” Polymers
, 13
(13
), pp. 2203
–2221
. 35.
Zhang
, H.
, Lu
, T.
, Zhang
, Q.
, Zhou
, Y.
, Zhu
, H.
, Harms
, J.
, Yang
, X.
, Wan
, M.
, and Insana
, M. F.
, 2020
, “Solutions to Ramp-Hold Dynamic Oscillation Indentation Tests for Assessing the Viscoelasticity of Hydrogel by Kelvin-Voigt Fractional Derivative Modeling
,” Mech. Mater
, 148
, pp. 103431
–103446
. 
