Mechanical Behavior and Morphological Study of Polytetrafluoroethylene (PTFE) Composites under Static and Cyclic
Karolina Mazur1, Aneta Gądek-Moszczak2, Aneta Liber-Kneć3
1Faculty of Materials Engineering and Physics, Institute of Materials Engineering, Tadeusz Kosciuszko Cracow University of Technology, al. Jana Pawła II 37, 31-864 Cracow, Poland.
Materials (Basel, Switzerland)
|April 3, 2021
Summary
Polytetrafluoroethylene (PTFE) composites with bronze, glass fibers, coke flakes, and graphite were tested. Mineral fillers significantly enhance static and dynamic properties, improving wear resistance and stiffness for specific applications.
Area of Science:
- Materials Science
- Polymer Engineering
- Tribology
Background:
- Polytetrafluoroethylene (PTFE) is a widely used polymer known for its low friction.
- Enhancing PTFE's mechanical properties is crucial for broader engineering applications.
- The study investigates the impact of various mineral fillers on PTFE composite performance.
Purpose of the Study:
- To characterize polytetrafluoroethylene (PTFE) based composites.
- To evaluate the effects of bronze particles, glass fibers, coke flakes, and graphite particles on PTFE.
- To compare static and dynamic mechanical properties with microstructural analysis.
Main Methods:
- Preparation of PTFE composites with varying filler concentrations (bronze 30-60 wt.%, glass fibers 15-25 wt.%, coke flakes 25 wt.%, graphite 5 wt.%).
- Static compression tests to assess mechanical strength.
- Dynamic fatigue tests (compression-compression up to 100,000 cycles) to evaluate endurance and modulus.
- Microscopic analysis of fracture surfaces.
Main Results:
- Addition of 60 wt.% bronze and other mineral fillers improved static compression test values, with a ~60% increase for 25 wt.% glass fibers.
- All tested composites showed a significant increase in modulus during dynamic tests compared to static tests.
- Composites with 25 wt.% glass fibers exhibited an 85% modulus increase, while 25 wt.% coke flakes showed a 77% increase.
- Composites with semi-spherical particles demonstrated longer service life and slower fatigue crack propagation than those with glass fibers.
- Smaller, spherical particles enhanced mechanical energy dissipation, suitable for friction applications.
- Composites with glass fiber and graphite particles are suitable for applications requiring high stiffness and low vibration.
Conclusions:
- Mineral fillers significantly enhance the static and dynamic mechanical properties of PTFE composites.
- Filler type, particle shape, and concentration critically influence composite performance.
- PTFE composites with specific fillers offer tailored solutions for friction, wear, stiffness, and vibration damping applications.
Keywords:
bronze particlescoke particlescompression testglass fibergraphite particleshysteresis loopsMore Related Videos
11:38Environmentally-controlled Microtensile Testing of Mechanically-adaptive Polymer Nanocomposites for ex vivo Characterization
Published on: August 20, 2013
10.4K
09:54Author Spotlight: Enhancing Fiber Composite Laminate Quality with the Wet Hand Lay-Up/Vacuum Bag Process
Published on: June 30, 2023
2.6K
Related Concept Videos
01:21Plastic Behavior
349
A material's elastic behavior is characterized by the disappearance of stress once the load is removed, allowing the material to return to its original state. However, when stress surpasses the yield point, yielding commences, marking the onset of plastic deformation or permanent set. This change from elastic to plastic behavior is influenced by the peak stress value and the duration before the load is removed. An intriguing observation occurs when a specimen is loaded, unloaded, and...
349
01:21Fatigue
355
Fatigue occurs when materials rupture under repeated or fluctuating loads, even at stress levels far below their static breaking strength. It typically results in brittle failure, even for ductile materials. It is a critical consideration in designing machines and structural components subjected to repetitive or varying loads. The nature of these loadings can range from fluctuating loads like unbalanced pump impellers causing vibrations to repeatedly bending a thin steel rod wire back and forth...
355
01:23Behavior of Concrete Under Compressive Load
379
Concrete exhibits specific behaviors under different compressive loads. Understanding this is crucial for understanding its structural integrity. When concrete undergoes uniaxial compression, it tends to develop cracks that run parallel to the direction of the force. These parallel cracks stem from localized tensile stresses that occur perpendicular to the compression direction. Additionally, angled cracks may appear due to the formation of shear planes.
As the concrete specimen fractures under...
As the concrete specimen fractures under...
379
01:12Temperature Dependent Deformation
265
In a nonhomogeneous rod made up of steel and brass, restrained at both ends and subjected to a temperature change, several steps are involved in calculating the stress and compressive load. Due to the problem's static indeterminacy, one end support is disconnected, allowing the rod to experience the temperature change freely. Next, an unknown force is applied at the free end, triggering deformations in the rod's steel and brass portions. These deformations are then calculated and added...
265
01:11Bending of Members Made of Several Materials
385
In analyzing a structural member composed of two different materials with identical cross-sectional areas, it is crucial to understand how their distinct elastic properties affect the member's response under load. The analysis involves assessing stress and strain distributions using the transformed section concept, which accounts for variations in material properties.
Hooke's Law determines stress in each material, stating that stress is proportional to strain but varies due to each material's...
Hooke's Law determines stress in each material, stating that stress is proportional to strain but varies due to each material's...
385
01:18Residual Stresses in Bending
379
In the study of elastoplastic members subjected to bending moments, understanding the loading and unloading phases is crucial for assessing material behavior and structural integrity. During the loading phase, as the bending moment increases, the material initially responds elastically, adhering to Hooke's Law, where stress is directly proportional to strain. When the load exceeds the yield strength, plastic deformation occurs, resulting in permanent strain and deformation that remains even...
379