The tribological, mechanical, and thermal properties of an epoxy crosslinking network incorporated with 3C‐SiC nanoparticles, serving as a metal‐free friction material were investigated by molecular dynamics simulations. The considered models encompass pure epoxy materials with 35%, 50%, 65%, and 80% crosslinking degrees, as well as 3C‐SiC/epoxy composite materials at the same crosslinking levels. Glass transition temperature (
Tribological interactions of 3D printed polyurethane and polyamide with water-responsive skin model
Abstract 3D printing in the textile and fashion industry is a new emerging technology. Applications of 3D printing for designing clothes and other wearable accessories require tribological and biological understanding of 3D printing plastics against the complex human skin to mitigate skin-friction related ailments such as calluses and blisters. This study provides tribological insight in search of an optimal 3D printable material that has minimal friction against the skin. Two low friction 3D printable materials, thermoplastic polyurethane (TPU) and polyamide (TPA) were chosen and tribological testing was carried out against a water responsive skin model. The skin model was synthesized using a gelatine based model made with cotton and crosslinked with glutaraldehyde. Tribological testing of TPU/TPA against the skin model in dry and wet conditions were made. The higher coefficient of friction (COF) was observed in the wet condition compared to the dry condition. To overcome the higher friction, TPA/TPU-sodium polyacrylate composites were prepared by heat pressing that significantly reduced COF of TPU and TPA by ∼ 40% and 75%, respectively, in wet conditions.
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- Award ID(s):
- 1852578
- NSF-PAR ID:
- 10219637
- Date Published:
- Journal Name:
- Friction
- ISSN:
- 2223-7690
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract T g) of the eight models was analyzed, and the result shows augmenting crosslinking density and addition of 3C‐SiC nanofillers improveT gof all models. Fractional free volume of each model was quantified to reflect the features of epoxy materials and influence the properties at the atomic scale. Frictional force, normal force, and coefficient of friction (COF) were calculated to elucidate the tribological performance of the epoxy‐based materials. The introduction of 3C‐SiC nanofillers reduces COF. With nanofillers, higher crosslinking degree brings lower COF except 80% crosslinking degree, while without nanofillers, higher COFs are obtained with 35% and 80% crosslinking degrees. 3C‐SiC/epoxy composite with heightened crosslinking degree demonstrates superior Young's modulus, elevated tensile stress, and relatively smaller strain. Thermal conductivity analysis highlights the positive impact of both increased crosslinking density and incorporation of 3C‐SiC nanofillers on heat transfer. Temperature elevation further enhances thermal conductivity. -
Metallic friction materials currently used in industry may adversely impact the environment. Substitutions for metals in friction materials, on the other hand, can introduce operational safety issues and other unforeseeable problems such as thermal-mechanical instabilities. In this work, a molecular dynamics model has been developed for investigating the effects of material composition, density, and surface asperities on the tribological properties of inorganic 3C-SiC under various contact conditions at the atomic level. Predictions on the following results have been made: (1) elastic modulus, (2) tensile strength, (3) thermal conductivity, and (4) friction coefficient. The research findings can help improve the design of metal-free friction materials against thermal-mechanical failures. Parametric studies were performed by varying a number of conditions including (1) ambient temperature, (2) sliding speed, (3) crystal orientation, (4) asperity size, (5) degree of asperity intersection, (6) types of loading, and (7) surface contact. Plastic deformation and material transfer were successfully modeled between two sliding pairs. Some of the computational results were validated against existing experimental data found in the literature. The evaluation of wear rate was also incorporated. The model can easily be extended to deal with other nonmetallic friction composites.more » « less
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1007/s40544-020-0472-2
