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Tribomechanical properties of ultrahigh molecular weight polyethylene (UHMWPE) composites filled with chopped glass fiber (CGF) functionalized by two silane-containing modifiers in order to increase the adhesion between the filler and a non-polar matrix have been investigated. A comparison between two commercially available adhesion promoters (Penta 1006 and KH550) was carried out, and their effectiveness was shown from the standpoint of increasing the wear resistance of composites (more than 2 times) in a wide range of loads and sliding velocities. [ABSTRACT FROM AUTHOR] more...

In contrast with neat polymers, filled polymeric composites of ultrahigh molecular weight polyethylene (UHMWPE) are certainly more efficient in manufacturing industrial products (for instance, when reinforcing fibers are loaded). An experimental-theoretical technique for designing a polymer composite with specified properties is discussed in the paper. An approach to determine control parameters (phase composition, physical and mechanical properties, etc.) in order to design a composite with prescribed effective properties or providing them within a predetermined range is proposed. With the use of the approach based on the experimental data analysis in concern of effective characteristics versus the values of the control parameters, corresponding response surfaces of the physical-mechanical characteristics are constructed in the space of states. This allows one to determine the correct and reachable values of the control parameters. The calculated response surfaces make it possible to reveal the range of values of control parameters for specified characteristics of multicomponent reinforced extrudable UHMWPE polymer composites. [ABSTRACT FROM AUTHOR] more...

The key set of mechanical and tribotechnical properties of UHMWPE composites fabricated from polymer powder particles of different size (units and tens of microns) was measured and analyzed. It is shown that specimens of neat UHMWPE grades GUR4120 and GUR2122 are characterized by close values of wear resistance at mild triboloading parameters PV = 18 and 30 N m/s. Also, filled composites based on two polymer matrices with different initial powder sizes have almost identical wear resistance at all used triboloading conditions. The role of permolecular structure and crystallinity degree in development of tribochemical processes at the friction surface in terms of providing tribotechnical properties of UHMWPE composites is discussed. [ABSTRACT FROM AUTHOR] more...

Polymer-polymeric UHMWPE composites filled with polypropylene grade 21030 powder were fabricated: (i) by hot isostatic pressing (HIP) of two-component powder mixtures; and (ii) by 3D-printing through fused deposition modeling (FDM) from pellets obtained by extrusion mixing and consequent milling of the same polymer component mixture. It is shown that the formed permolecular structure plays a decisive role in providing tribotechnical and mechanical properties of extrudable polymer-polymeric composites with ultrahigh-molecular-weight polyethylene matrix. [ABSTRACT FROM AUTHOR] more...

Mechanical and tribotechnical properties of UHMWPE composites filled with carbon fibers of various dimensions (nanometer, micrometer and millimeter) under various loads and sliding velocities (60 N × 0.3 m/s, 60 N × 0.5 m/s, 140 N × 0.3 m/s, 140 N × 0.5 m/s) were studied. It is shown that at the moderate triboloading conditions (60 N × 0.3 m/s) the nanofibers are most efficient fillers in the sense of providing highest wear resistance that is governed by their action as solid lubricant (wear resistance increases by 2.7 times). Under the severe tribotesting conditions (140 N × 0.5 m/s) long carbon fibers (l = 2 mm) exhibit highest efficiency since they bear the action of the compressive and shearing loads from the counterbody. In doing so, they protect the polymer composite surface from intense wear ensuring doubling of the wear resistance. [ABSTRACT FROM AUTHOR] more...

The impact of the fillers shape and physical-mechanical characteristics upon effective properties of ultra-high-molecular weight polyethylene (UHMWPE) composites is studied. Composites filled with finely dispersed polytetrafluoroethylene (PTFE) with an average particle size 3 µm were the matter of research. To improve adhesion of the polymer filler (PTFE powder) to the UHMWPE matrix the treatment of the powder mixtures in a planetary ball mill (so called mechanical activation) was used. The latter allows increasing the specific surface area of the filler. For this reason, when modeling the shape of the inclusions subjected to the pre-treatment they were taken in the form of a “gear”. However, formation of new chemical bonds due to the treatment was not taken into consideration. In doing so the effect of mechanical activation was considered through attaining to the initially round shape PTFE particles the shape of a gear. Comparison of simulation results with experimental data has shown that the revealed effects satisfactorily explain the specified impact of the mechanical activation. [ABSTRACT FROM AUTHOR] more...

Mechanical and tribotechnical properties of UHMWPE composites filled with short carbon fibers (CF) under dry sliding friction and various testing conditions (PxV) were studied. It is shown that loading of short carbon fibers into UHMWPE gives rise to increase of strength properties of the composites (elasticity modulus, yield strength) by the factor of 1.5-2 and wear resistance up to 2 times. It is suggested that high-strength wear-resistant UHMWPE composites loaded with short carbon microfibers can be used in tribounits under severe conditions (at loads up to 140 N and sliding velocities up to 0.5 m/s). [ABSTRACT FROM AUTHOR] more...

The mechanical and tribotechnical characteristics of UHMWPE based composites filled with basalt microparticles and fibers under dry friction and various test conditions (P•V) have been studied. It is shown that from the position of increasing resistance to wear under dry sliding friction, basalt particles and fibers during reinforcement of the UHMWPE matrix are equally effective at moderate loading and speed: the wear resistance of composites has increased by 1.5 times with a content of 10 wt. % filler while the coefficient friction -- in 1.8 times. Mechanisms of wear of polymer composites based on UHMWPE filled with particles/fibers of basalt under different conditions of triboloading have been discussed. [ABSTRACT FROM AUTHOR] more...

Mechanical and tribotechnical characteristics of biocompatible, antifriction and extrudable composites based on ultrahigh molecular weight polyethylene (UHMWPE) as well as hybrid matrix "UHMWPE + PTFE" with biocompatible hydroxyapatite filler under the dry friction and boundary lubrication were investigated. A comparative analysis of effectiveness of adding the hydroxyapatite to improve the wear resistance of composites based on these two matrices was performed. It is shown that the wear intensity of nanocomposites based on the hybrid matrix is lower than that for the composites based on pure UHMWPE. Possibilities of using the composites of the polymer "UHMWPE–PTFE" mixture as a material for artificial joints implants are discussed. [ABSTRACT FROM AUTHOR] more...