The structure and molecular orientation of polytetrafluoroethylene coatings deposited from active gas phase

Рогачев

et al. 2016

Polym. Adv. Technol.

Polytetrafluoroethylene (PTFE) composite coatings doped copper acetate and polyurethane (PU) were prepared on rubber substrate by low‐energy electron beam dispersion technique. The effects of dopant and glow discharge treatment on the surface morphology, structure and tribological properties of the coatings were investigated. The results showed that Cu–PTFE composite coatings form uniform surface and dense column structure with spherical aggregations under glow discharge treatment. PU coating shows the large size of protuberance structure but PU–PTFE coating presents spherical structure. Both of the coatings become relative dense and smooth after discharge treatment, and Cu–PU–PTFE composite coatings possess a smoother surface and lower polar component of surface energy. Cu doping weakens the crystallinity and ordering degree of composite coatings, but glow discharge increases the ordering degree and branched structure of C―H groups. Friction experiment indicated that Cu fails to improve the wear resistance of PTFE coatings but glow discharge treatment can do it. Cu–PU–PTFE coatings after discharge treatment have the higher wear resistance and lower coefficient of friction. Copyright © 2016 John Wiley & Sons, Ltd.

Section: Introductionmentioning

confidence: 95%

Structure and tribological properties of Cu-PU-PTFE composite coatings prepared by low-energy electron beam dispersion with glow discharge

Рогачев

et al. 2016

Polym. Adv. Technol.

“…Here, the polymerization process occurs on the substrate surface. [12,18] Another possibility, the polymerization of dispersion products directly occurs in the active gas phase forming high molecular fragments before arriving onto substrate surface. These fragments are captured at the active zone of substrate surface.…”

Section: Resultsmentioning

confidence: 99%

“…In this process, dispersion products contain numerous active charged particles forming active gas flow. [12] Therefore, the composition and energy of active gas phase, generated from electron beam dispersion to the polymer bulk, control the molecular structure and properties of polymer coatings.…”

Section: Introductionmentioning

confidence: 99%

“…It greatly improves the performance of rubber products in many applications, such as wettability, weather resistance, friction resistance, permeability, adhesion, and antistatic property. Recently, a variety of techniques are available to fabricate polymer coatings like electrochemical synthesis, [6] self-assembly, [7] sol-gel, [8] plasma polymerization, [9] pulsed laser ablation, [10] ion beam, [11] vacuum evaporation (thermal, electron beam) [1,12] , and sputtering technique. [13,14] Although many of the polymer coatings can be fabricated from solution methods, these films suffer easily from the contamination of residual solvent or impurities present in the solution.…”

Section: Introductionmentioning

confidence: 99%

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Growth feature of PTFE coatings on rubber substrate by low-energy electron beam dispersion

Рогачев

et al. 2015

Polym. Adv. Technol.

Polytetrafluoroethylene (PTFE) coatings were prepared on Si and acrylonitrile-butadiene rubber substrates by lowenergy electron beam dispersion. The effects of substrate nature, distance of target to substrate (d ts ) and coatings thickness on the surface morphology, structure, and tribological properties of the coatings were investigated. The results showed that substrate nature affects the shape and size distribution of surface conglomerations of PTFE coatings due to the interaction process of active dispersion particles with underlying polymer layer. Surface energy of PTFE coatings decreases first with the coatings thickness increases to 1.25 μm and then slowly increases with the thickness. Structure defects (pore, interstice, and so on) in the coatings increase with the thickness increases but reduce significantly with the d ts increases. PTFE coating prepared at the d ts of 20 cm had a higher intensity of the amorphous absorption bands. Friction experiment indicated that the destroyed area of the coatings in the friction region decreases with increases the coatings thickness but increases with the d ts . The rubber modified by PTFE coatings with spherical structure possesses a higher stability in the friction process and a lower coefficient of friction.

“…Improved efficiency of the modified seals largely depends on the physic‐chemical processes of the formation of surface layer on rubber products under the different modification conditions, as well as on the structure and properties of the formed surface coatings. As previously noted , a quite promising technique applied for adjusting the molecular structure and properties of polymer coatings is plasma discharge treatment in the electron beam dispersion to polymer target. This process could improve the wear resistance of rubber substrate by coated polymer layer with expected structure and properties.…”

Section: Introductionmentioning

confidence: 97%

Modification of Cu‐PE‐PTFE composite coatings on rubber surface by low‐energy electron beam dispersion with glow discharge

Polymer Engineering & Sci

et al. 2017

Polytetrafluoroethylene (PTFE) composite coatings doped with copper acetate and polyethylene (PE) were fabricated on rubber substrate by electron beam dispersion technique. The effects of dopant nature and glow discharge treatment on morphology, structural and tribological properties of the coatings were investigated. The results showed that Cu and PE doping change the surface structure of PTFE-based composite coatings due to the chemical reactions between the dispersion products. Cu-PE-PTFE coatings show the columnar and layered growth models without and with discharge treatment. Cu adding decreases the crystallinity, branched degree and unsaturated degree of PE coatings, but increases the branched degree and unsaturated bonds in the PE-PTFE coatings. Glow discharge enhances the crystallinity and ordering degree of composite coatings. Friction experiments indicated the significant difference of composite coatings in the nature of their destruction during friction. PE-PTFE coating is characterized of the brittle fracture with clear failure boundaries but Cu-PE-PTFE coating shows a rough surface without cracking and delaminating after friction. Cu doping increases the dynamic coefficient of friction of PE and PE-PTFE composite coatings, but discharge plasma decreases the dynamic coefficient of friction. Cu-PE-PTFE composite coating after discharge treatment has the decreased dynamic coefficient of friction and improved wear resistance. POLYM. ENG. SCI., 58:103-111, 2018.