Influence of Thermally Treated Polytetrafluoroethylene on the Tribological Properties of Ultra-High Molecular Polyethylene

В данной работе исследовано влияние термически обработанного политетрафторэтилена (ПТФЭ) на свойства и структуру сверхвысокомолекулярного полиэтилена (СВМПЭ). Приведены результаты исследования прочности при сжатии, плотности и триботехнических характеристиках полимерных композитов на основе СВМПЭ, наполненного с исходным ПТФЭ и с термической обработкой. Показано, что введение в СВМПЭ политетрафторэтилена с термической обработкой приводит к улучшению износостойкости в 4 раза и прочности при сжатии до 50 % по сравнению с полимерной матрицей. Структурными исследованиями показано, что улучшение износостойкости связано со снижением окислительных процессов при трении за счет дискретно распределенных частиц термически обработанного ПТФЭ. Благодаря высокой износостойкости разработанные материалы могут найти применение в узлах трения машин и техникиIn this work, the effect of heat treatment of polytetrafluoroethylene (PTFE) on the properties and structure of ultrahigh molecular weight polyethylene was studied. The results of a study on compression, density and tribological characteristics of polymer composites based on UHMWPE filled with initial PTFE and with heat treatment are presented. It is shown that the introduction of polytetrafluoroethylene with heat treatment leads to an improvement in wear resistance by a factor of 4 and compressive strength up to 50 % compared to the polymer matrix. Structural studies have shown that the improvement in wear resistance is associated with a decrease in oxidative processes during friction due to discretely distributed particles of heat-treated PTFE. Due to the high wear resistance, the developed materials can be used in friction units of machines and technical equipmen

Surfactant Effects on Structure and Mechanical Properties of Ultrahigh-Molecular-Weight Polyethylene/Layered Silicate Composites

In this study, the reinforcement of ultrahigh-molecular-weight polyethylene (UHMWPE) with biotite was investigated. The biotite filler was mechanically activated with different dry surfactants to improve its compatibility with UHMWPE and decrease agglomeration among biotite particles. Alkyldimethylbenzylammonium chloride (ADBAC) and cetyltrimethylammonium bromide (CTAB) were selected as cationic surfactants. The tensile strength of composites containing 1 wt % of CTAB-treated biotite was increased by 30% relative to those with untreated biotite, but was unchanged with ADBAC treatment of the same biotite content. The stereochemistry of the surfactant may be critical to the composite structure and mechanical properties of the material. The stereochemistry of CTAB was preferable to that of ADBAC in enhancing mechanical properties because the stereochemistry of ADBAC impedes favorable interactions with the biotite surface during mechanical activation

Mechanical and Tribological Properties of Polytetrafluoroethylene Composites Modified by Carbon Fibers and Zeolite

Currently, lightweight and high-strength polymer composites can provide weight savings in the automotive and process equipment industries by replacing metal parts. Polytetrafluoroethylene and polymer composites based on it are used in various tribological applications due to their excellent antifriction properties and thermal stability. This article examines the effect of combined fillers (carbon fibers and zeolite) on the mechanical, tribological properties, and structure of polytetrafluoroethylene. It is shown that the introduction of combined fillers into polytetrafluoroethylene retains the tensile strength and elongation at break at a content of 1–5 wt.% of carbon fibers, the compressive stress increased by 53%, and the yield stress increased by 45% relative to the initial polymer. The wear resistance of polymer composites increased 810-fold compared to the initial polytetrafluoroethylene while maintaining a low coefficient of friction. The structural features of polymer composites are characterized by X-ray diffraction analysis, infrared spectroscopy, and scanning electron microscopy

Mechanical and Tribological Properties of Polytetrafluoroethylene Modified with Combined Fillers: Carbon Fibers, Zirconium Dioxide, Silicon Dioxide and Boron Nitride

The introduction of combined fillers can effectively improve the mechanical and tribological properties of polytetrafluoroethylene (PTFE). In this work, three different types of nanosized fillers (zirconium dioxide, silicon dioxide, and boron nitride) were introduced in a carbon fiber-reinforced polymer matrix for the development of polymer composite materials (PCM). Tensile and compressive testing were carried out, and the hardness of created PCM was evaluated. It is shown that the compressive strength of PCM increased by 30–70%, and the hardness, increased by 38–55% compared to the initial PTFE. The tribological properties of the developed PCM were evaluated under dry friction conditions. An analysis of the results of an experimental study of wear confirmed that the inclusion of combined fillers (two- and three-component) in PTFE significantly increased wear resistance compared to the polymer matrix with a slight increase in the coefficient of friction. It has been shown that the introduction of three-component fillers has an antagonistic effect on the wear resistance of PCMs compared to two-component fillers. The thermodynamic properties of the composites were analyzed by differential scanning calorimetry and a thermomechanical analyzer. The surface morphology of polymer composites after wear testing was studied by IR spectroscopy and scanning electron microscopy to investigate and suggest a possible mechanism for increasing the wear resistance of the developed composites

Effect of Borpolymer on Mechanical and Structural Parameters of Ultra-High Molecular Weight Polyethylene

The paper presents the results of studying the effect of borpolymer (BP) on the mechanical properties, structure, and thermodynamic parameters of ultra-high molecular weight polyethylene (UHMWPE). Changes in the mechanical characteristics of polymer composites material (PCM) are confirmed and complemented by structural studies. X-ray crystallography (XRC), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and infrared spectroscopy (IR) were used to study the melting point, morphology and composition of the filler, which corresponds to the composition and data of the certificate of the synthesized BP. Tensile and compressive mechanical tests were carried out in accordance with generally accepted standards (ASTM). It is shown that BP is an effective modifier for UHMWPE, contributing to a significant increase in the deformation and strength characteristics of the composite: tensile strength of PCM by 56%, elongation at break by 28% and compressive strength at 10% strain by 65% compared to the initial UHMWPE, due to intensive changes in the supramolecular structure of the matrix. Structural studies revealed that BP does not chemically interact with UHMWPE, but due to its high adhesion to the polymer, it acts as a reinforcing filler. SEM was used to establish the formation of a spherulite supramolecular structure of polymer composites

Mechanical and Tribological Properties of Polytetrafluoroethylene Composites with Carbon Fiber and Layered Silicate Fillers

Mixtures of layered silicates (vermiculite and kaolinite) and carbon fibers were investigated as filler materials for polytetrafluoroethylene. The supramolecular structure and the tribological and mechanical properties of the resulting polymer composite materials were evaluated. The yield strength and compressive strength of the polymer increased by 55% and 60%, respectively, when a mixed filler was used, which was attributed to supramolecular reinforcement of the composites. In addition, the wear resistance increased by 850 times when using vermiculite/kaolinite fillers, which was due to protection of the surface by the formation of hard tribofilms

Enhanced Physical and Mechanical Properties of Nitrile-Butadiene Rubber Composites with <i>N</i>-Cetylpyridinium Bromide-Carbon Black

The physical and mechanical properties of nitrile–butadiene rubber (NBR) composites with N-cetylpyridinium bromide-carbon black (CPB-CB) were investigated. Addition of 5 parts per hundred rubber (phr) of CPB-CB into NBR improved the tensile strength by 124%, vulcanization rate by 41%, shore hardness by 15%, and decreased the volumetric wear by 7% compared to those of the base rubber-CB composite

Enhanced Physical and Mechanical Properties of Nitrile-Butadiene Rubber Composites with N-Cetylpyridinium Bromide-Carbon Black

The physical and mechanical properties of nitrile–butadiene rubber (NBR) composites with N-cetylpyridinium bromide-carbon black (CPB-CB) were investigated. Addition of 5 parts per hundred rubber (phr) of CPB-CB into NBR improved the tensile strength by 124%, vulcanization rate by 41%, shore hardness by 15%, and decreased the volumetric wear by 7% compared to those of the base rubber-CB composite

UHMWPE/CaSiO₃ Nanocomposite: Mechanical and Tribological Properties

This paper studied the effect of additives of 0.5–20 wt.% synthetic CaSiO3 wollastonite on the thermodynamic, mechanical, and tribological characteristics and structure of polymer composite materials (PCM) based on ultra-high-molecular weight polyethylene (UHMWPE). Using thermogravimetric analysis, X-ray fluorescence, scanning electron microscope, and laser light diffraction methods, it was shown that autoclave synthesis in the multicomponent system CaSO4·2H2O–SiO2·nH2O–KOH–H2O allows one to obtain neeindle-shaped nanosized CaSiO3 particles. It was shown that synthetic wollastonite is an effective filler of UHMWPE, which can significantly increase the deformation-strength and tribological characteristics of PCM. The active participation of wollastonite in tribochemical reactions occurring during friction of PCM by infrared spectroscopy was detected: new peaks related to oxygen-containing functional groups (hydroxyl and carbonyl) appeared. The developed UHMWPE/CaSiO3 materials have high wear resistance and can be used as triboengineering materials

Two-Layer Rubber-Based Composite Material and UHMWPE with High Wear Resistance

The aim of the study is the development of two-layer materials based on ultra-high-molecular-weight polyethylene (UHMWPE) and isoprene rubber (IR) depending on the vulcanization accelerators (2-mercaptobenzothiazole (MBT), diphenylguanidine (DPG), and tetramethylthiuram disulfide (TMTD)). The article presents the study of the influence of these accelerators on the properties and structure of UHMWPE. It is shown that the use of accelerators to modify UHMWPE leads to an increase in tensile strength of 28&ndash;53%, a relative elongation at fracture of 7&ndash;23%, and wear resistance of three times compared to the original UHMWPE. It has been determined that the introduction of selected vulcanization accelerators into UHMWPE leads to an increase in adhesion between the polymer and rubber. The study of the interfacial boundary of a two-layer material with scanning electron microscopy (SEM) and infrared spectroscopy (FTIR) showed that the structure is characterized by the presence of UHMWPE fibrils localized in the rubber material due to mechanical adhesion