Search

Polyimide (PI) has good mechanical properties and thermal stability, while high coefficient (COF) and wear rate limit its wide application. In order to endow PI with better friction and wear resistance, Mo2Ti2C3 MXene was used as solid lubricant to prepare Mo2Ti2C3/PI nanocomposites with different content of Mo2Ti2C3. The effect of the amount of Mo2Ti2C3 on the tribological behavior of PI was explored and the tribological mechanism was also analyzed Tribological tests showed that at 1.2 wt% of Mo2Ti2C3 addition, the composite material demonstrated superior friction and wear resistance, exhibiting a 19.9% decrease in the COF and a 79.7% decrease in the wear rate compared to single PI due to the good self‐lubricating properties of Mo2Ti2C3 MXene. Moreover, Mo2Ti2C3 can also effectively assist PI to form sleek transfer films without interruption or gaps on the steel balls, resulting in a reduced friction COF and wear rate of the material. This work demonstrates that Mo2Ti2C3 MXene is an aussichtsreich additive for polymers to improve the tribological properties and broadens the applications of Mo2Ti2C3/PI composites in friction material area. Highlights: Mo2Ti2C3 significantly improves the tribological performance of polyimide.The thermal properties of Mo2Ti2C3/polyimide are enhanced by the introduction of Mo2Ti2C3.The minimum coefficient of Mo2Ti2C3/PI composites was only 0.246 at the 1.2 wt% content of Mo2Ti2C3.The wear rate of Mo2Ti2C3/PI composites was decreased by 79.7% at the 1.2 wt% addition of Mo2Ti2C3.Mo2Ti2C3 promotes the establishment of tribo‐film to protect the Mo2Ti2C3/PI composites from friction. [ABSTRACT FROM AUTHOR]

Polyimide (PI) is a special engineering plastic, widely involved in mechanical components, instruments, and petrochemicals. However, single PI material is inevitably subject to wear and tear in practice, which leads to weakened material properties. In this work, Ti3C2Tx@SiO2 was prepared to enhance the wear resistance and lubrication properties of PI by intercalating SiO2 into the interlayer of Ti3C2Tx sheets. Ti3C2Tx@SiO2/PI composites were fabricated in two steps to test the tribological performances. SiO2 particles change the form of interfacial friction from sliding to rolling, thus relieving direct friction between material and steel ball. So, the composites have a minimum COF (COF = 0.33) when the content of Ti3C2Tx@SiO2 is 0.80 wt%. Moreover, the average value of wear rate was 0.24 × 10−5 mm3/(N·m) when Ti3C2Tx@SiO2 content was 1.60 wt%, which was 91.0% lower compared to the PI matrix. During the friction process, the abrasive chips of the material migrate to the surface of the steel ball to form a transfer film, which protects the material and thus reduces the wear rate. Therefore, the hybrids Ti3C2Tx@SiO2 are effective and important wear‐resistant agents and solid lubricants to improve the wear resistance and lubricity of PI or other polymer materials. Highlights: SiO2 insert Ti3C2Tx is a key factor in changing sliding friction into rolling friction, effectively reducing the COF.The average wear rate was 91.0% lower than that of the polyimide matrix when Ti3C2Tx@SiO2 content was 1.60 wt%.The minimum COF of Ti3C2Tx@SiO2/PI composites reached 0.33 when the content of Ti3C2Tx@SiO2 was 0.80 wt%.The transfer film effectively reduces further wear of the material during friction. [ABSTRACT FROM AUTHOR]

• A ternary solid lubricants SiO 2 /Ti 3 C 2 /PTFE was prepared by solution dispersion. • The minimum wear rate of STP/PI composites was only 0.18 × 10−5 mm3/(N·m) when the solid lubricants content was 2.0 wt%. • The minimum COF of STP/PI composites reached 0.29 when solid lubricants content was 2.0 wt%. • The SiO 2 /Ti 3 C 2 /PTFE solid lubricants favors the formation of transfer film to protect polyimide from friction. Polyimide is widely used in aerospace, electronics and electrical appliances, automotive, chemical and other fields due to its high temperature stability, excellent mechanical properties. However, polymer materials are often subjected to severe wear and tear under complex operating conditions due to their poor lubrication performance. Therefore, the improvement of lubrication performance is a key strategy to extend the service life of polyimide. Herein, a ternary solid lubricant SiO 2 /Ti 3 C 2 /PTFE (STP) is innovatively prepared by solution dispersion for reducing the friction of polyimide to increase the lubricity. Specifically, SiO 2 and PTFE are intercalated accordion-like Ti 3 C 2 nanosheets, thereby causing the nanosheets to slide relative to each other under external frictional stress. Then, STP was introduced into polyimide to prepare the ultra-wear-resistant and self-lubricating composites by blending. The results of the study showed that the STP significantly enhanced the lubrication properties of the composites, the lowest coefficient of friction (0.29) of the composites is 22.81 % lower than that of the polyimide. In addition, the inclusion of hybrids helps to form a transfer film, which effectively improves the abrasion performance of polyimide, and the lowest wear rate (0.18 × 10−5 mm3/(N·m)) was 93.35 % lower than that of polyimide. [Display omitted] Ternary solid lubricant STP effectively enhances the lubrication characteristics of polyimide and reduces wear rate. [ABSTRACT FROM AUTHOR]

Ti 3 C 2 T x MXene was cooperated with polyimide (PI) to improve the wear resistance of the PI matrix under complex working conditions. Compared to the pristine PI, the Ti 3 C 2 T x /PI composites have excellent frictional properties, specifically, the coefficient of friction is 0.32 and the wear rate is 0.62 × 10−5 mm3/(N·m). The composites formed a transfer film on the contact surface during the friction process, and the transfer film prevents direct contact between tribo-couples. The results studied by Raman and XPS showed that the transfer film contains TiO 2 that is derived from oxidized Ti 3 C 2 T x. Moreover, the tribological mechanism has been summarized as two aspects: On one hand, the relative sliding of the Ti 3 C 2 T x lamellae transfers the sliding stress. On the other hand, a transfer film is created between Ti 3 C 2 T x /PI composites and steel ball during friction that prevents further wear of the material. All in all, two-dimensional MXene can effectively improve the wear resistance of the polymer matrix and has the potential to be used in friction-protective layers under complex working conditions. [Display omitted] • The tribological properties could be tuned by changing the content of 2D Ti 3 C 2 T x. • The wear rate of PI composites was reduced by 15.38% with incorporating 0.80 wt% of 2D Ti 3 C 2 T x. • The formation of transfer films on the couterfaces is significant for acting as friction-protective layers. [ABSTRACT FROM AUTHOR]