Mono-dispersed Ag nanoparticles decorated graphitic carbon nitride: An excellent lubricating additive as PPESK composite film

Beibei Chen,Zhe Dong,Jiaye Li,Mengjie Zhang,Gai Zhao,Kan Zhang

doi:10.1007/s40544-021-0487-3

Beibei Chen, Zhe Dong + Show 4 more

Open Access

https://doi.org/10.1007/s40544-021-0487-3

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Abstract

Studies show that two dimensional (2D) nanomaterial and its hybrid have a great promise in tribology for the special laminar microstructure. However, the majority of performed investigations about 2D graphitic carbon nitride (g-C3N4) nanosheets are most focused on energy storage, catalysis, adsorption, rarely tribology. In the present study, g-C3N4 supporting mono-dispersed Ag nanoparticle hybrid (g-C3N4/Ag) is prepared, and its microstructure and chemical composition are determined. More specifically, the tribological performance as the lubricating additive of poly phthalazinone ether sulfone ketone (PPESK) composite is investigated using the ball-on-disc friction tester. Moreover, the corresponding enhancement mechanism is well proposed based on the experimental analysis and theoretical simulation. Obtained results show that Ag nanoparticles with a size of about 10–20 nm are homogeneously anchored on g-C3N4 nanosheets, favoring for good compatibility between g-C3N4/Ag and PPESK. It is found that when 0.3 wt% of g-C3N4/Ag is added to PPESK, the friction coefficient and wear rate of PPESK decrease by 68.9% and 97.1%, respectively. These reductions are mainly attributed to the synergistic self-lubricating effect of Ag nanoparticles and g-C3N4 nanosheet, the formation of transfer film, as well as the limited effect of g-C3N4/Ag on the shear deformation of PPESK composite film. Furthermore, it is found that the proposed g-C3N4/Ag-PPESK composite still keeps reasonable friction-reducing and wear-resistant properties under heavy loads and high rotating speeds. The present study demonstrates that the proposed g-C3N4/Ag hybrid is an excellent lubricating additive for polymer composites.

Highlights

Studies show that friction and wear are two of the most important factors influencing the life of mechanical equipment
The EDS analysis demonstrates the existence of Ag element on the worn surface. This is because the g-C3N4/Ag hybrid is gradually exposed on the sliding surface with the proceeding of friction and wear
Experiments show that the proposed hybrid greatly improves the tribological performance of poly phthalazine ether sulfone ketone (PPESK)

Summary

Introduction

Studies show that friction and wear are two of the most important factors influencing the life of mechanical equipment. Further investigations show that nanomaterials with two dimensional (2D) layered structures such as graphene/graphene oxide [11], MoS2 nanosheets [12], and hexagonal boron nitride (h-BN) nanosheets [13] have superior characteristics such as large specific surface, ease of shear, and good self-lubricating properties In this regard, investigations have demonstrated that adding 2D layered nanomaterials greatly improves the tribological performance of polymers. They found that as 10 wt% of g-C3N4 is added to the PI, optimized friction-reducing and wear-resistant properties of PI can be obtained This is mainly because g-C3N4 with good self-lubricating property facilitates the formation of continuous transfer film on the counterpart surface during sliding contact [22]. The enhancement mechanism of g-C3N4/Ag will be discussed based on theoretical simulation using Materials Studio software and worn surface analysis

Materials

Preparation of PPESK composite film

Characterization

Results and discussion

Analysis of the worn surface

Conclusions