In situ filling of SiO₂ nanospheres into PTFE by sol–gel as a highly wear‐resistant nanocomposite

Abstract

In situ filling of nanomaterials into polymers facilitates the dispersion of the nanofillers and their interface combination with the matrices, and reduces the agglomeration encountered in the nanocomposites prepared by a mechanical mixing method. Polytetrafluoroethylene (PTFE) nanocomposites filled with SiO2 nanospheres (SNS) were fabricated by an in situ sol–gel method in this paper. The SNS in situ filled was highly dispersed in PTFE and showed an excellent combination with the matrix, and the fabricated SNS/PTFE nanocomposites were found a pronounced improvement in stiffness, hardness, glass transition temperature, and hydrophobicity in comparison with the pristine PTFE and the ones prepared by mechanical mixing with the same content. Furthermore, significantly reduced coefficients of friction and volume wear rates were observed on the SNS/PTFE nanocomposites prepared by in situ sol–gel. An operating temperature high up to 200°C and very low volume wear rate were accessible on the optimized SNS/PTFE nanocomposite by in situ filling. The methodology, in situ filling of nanofillers into matrices, might pave a way to prepare nanocomposites with excellent mechanical, thermal, and tribological properties.

Two-dimensional clay nanosheet-reinforced polytetrafluoroethylene composites and their mechanical/tribological studies

“…Pure polymers do not generally have desirable tribological characteristics; however, mixing them with other materials can improve their frictional properties. There are many reports of progress in using polymeric composites for engineering components such as gears, supports, ball bearings, tyres, rollers, plastic belts, clutch and brake pads, bone joints, and artificial teeth [8][9][10][11].…”

Tailoring Biotribological Performance of Polytetrafluoroethylene Nanocomposites through Control of Diameters and Aspect Ratios of In Situ Filled Hydroxyapatite Nanowires

“…In contrast, the decreased aspect ratios of the HAP NWs filled may weaken their capability of stress transfer, rendering the nanocomposites a decrease in the ability of interlaminar shear and antifriction. [57][58][59] PTFE nanocomposites were fabricated by an in situ method under solvothermal conditions, and the fabrication realized a high dispersion degree of HAP NWs in the matrix and an excellent interface combination by means of in situ nucleation and growth of the nanofillers. This method for the fabrication of PTFE nanocomposites with HAP NWs may be instructive for controllable synthesis of the composites for nanosized biomedical ceramics.…”

Effect of Nanofillers on Tribological Properties of Polymer Nanocomposites: A Review on Recent Development

“…Silicon dioxide (SiO 2 ), also known as silica, is a common filler used for polymer materials for properties’ enhancement [ 101 ]. SiO 2 nanospheres (SNS) were incorporated into the PTFE matrix as a solid lubricant [ 102 ]. In situ filling afforded an excellent dispersion in the PTFE matrix and increased the cohesive energy density of PTFE when compared to the mechanical mixing method, as shown in Figure 8 .…”

“…Most works suggested that transfer film formation alters the contact dynamic of the tribo-pairs from plowing of asperities into sliding of two smooth polymeric surfaces, thus reducing wear. Nevertheless, some found that WR is independent of the condition of the transfer film upon which it is slid, and a non-continuous transfer film is the consequence of low WR [ 102 , 153 ]. Figure 15 also shows the effect of sliding conditions on tribological behaviors of a polymer nanocomposite.…”

“… Scanning electron microscopic images of PTFE nanocomposites powder prepared by ( a ) in situ filling (2SNS/PTFE) and ( b ) the mechanical mixing method (2SNS/PTFE-M) (Reproduced with permission from G. Shi, Q. Wang, T. Sun, X. Yan, Journal of Applied Polymer Science; published by Wiley, 2020) [ 102 ]. …”