“…So, the formation of a hard surface fluorinated layer during fluorination of UHMWPE and its composites (Case I) containing graphite nanoplates, montmorillonite, molybdenum disulfide, and shungite as fillers [136,137] leads to improvement of the wear resistance of samples. An increase in the surface layer stiffness during surface treatment of UHMWPE fibers (Case II) by fluorination and oxyfluorination results in higher total Young's modulus (Table 3) for its composites with LDPE matrix [130,131].…”
Section: Mechanical Properties Of Polymers and Composites After Direct Fluorinationmentioning
Direct fluorination of polymers is a widely utilized technique for chemical modification. Such introduction of fluorine into the chemical structure of polymeric materials leads to laminates with highly fluorinated surface layer. The physicochemical properties of this layer are similar to those of perfluorinated polymers that differ by a unique combination of chemical resistance, weak adhesion, low cohesion, and permittivity, often barrier properties, etc. Surface modification by elemental fluorine allows one to avoid laborious synthesis of perfluoropolymers and impart such properties to industrial polymeric materials. The current review is devoted to a detailed consideration of wetting by water, energy characteristics of surfaces, adhesion, mechanical and electrical properties of the polymers, and composites after the direct fluorination.
“…So, the formation of a hard surface fluorinated layer during fluorination of UHMWPE and its composites (Case I) containing graphite nanoplates, montmorillonite, molybdenum disulfide, and shungite as fillers [136,137] leads to improvement of the wear resistance of samples. An increase in the surface layer stiffness during surface treatment of UHMWPE fibers (Case II) by fluorination and oxyfluorination results in higher total Young's modulus (Table 3) for its composites with LDPE matrix [130,131].…”
Section: Mechanical Properties Of Polymers and Composites After Direct Fluorinationmentioning
Direct fluorination of polymers is a widely utilized technique for chemical modification. Such introduction of fluorine into the chemical structure of polymeric materials leads to laminates with highly fluorinated surface layer. The physicochemical properties of this layer are similar to those of perfluorinated polymers that differ by a unique combination of chemical resistance, weak adhesion, low cohesion, and permittivity, often barrier properties, etc. Surface modification by elemental fluorine allows one to avoid laborious synthesis of perfluoropolymers and impart such properties to industrial polymeric materials. The current review is devoted to a detailed consideration of wetting by water, energy characteristics of surfaces, adhesion, mechanical and electrical properties of the polymers, and composites after the direct fluorination.
“…The chemical-morphological transformation of UHMWPE as a result of sequential bulk and surface modifications provides the possibility of controlling the free surface energy of the formed materials and, as a result, their wear resistance, as well as other tribological and adhesive characteristics, studied in. 51 A clear increase in wear resistance as a result of fluorination was observed for all experimental samples (Figure 10). Figure 10.The effect of fluorination on the wear of UHMWPE and composites based on it.…”
The paper investigates the effect of bulk and surface modification on the adhesive and tribological properties of ultra-high molecular weight polyethylene (UHMWPE) and shows that bulk modification with nano- and micro-sized modifiers (montmorillonite, shungite, exfoliated graphite) mainly reduces the friction coefficient but leads to a decrease in the wear resistance of the corresponding composites. It is found that gas-phase surface fluorination provides an increase in the wear resistance of experimental samples in all cases due to a combination of nanotexturing and chemomorphological transformations of the surface layers of the modified polymers. The significant dependence of the nanotexture on the technique and mode of modification is demonstrated using the original approaches to the quantitative characterization of the experimental samples’ surfaces’ scanning electron microscopy-images (formed with the scanning electron microscope). It is shown that the surface fluorination not only makes possible to significantly compensate for the increase of the friction coefficient of bulk-modified UHMWPE in comparison with the original one but also provides a nonlinear multiplicative increase in the wear resistance.
“…Some polymer material surface modification methods (e.g., fluorination, sulfonation, corona discharge treatment, etc.) were considered in [58,59]. The most impressive achievement is that of the surface superhydrophilicity for a number of initially hydrophobic polymers that was demonstrated in [59] as a consequence of the oxyfluorination -the gas-phase modification of the samples by mixtures of helium, fluorine and oxygen.…”
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