No abstract

SUMMARYBall milling technique was used for deposition of the polytetrafluoroethylene (PTFE) coating on the powder of TiFe intermetallic compound. Measurement of pressure-composition hydrogen absorption isotherms revealed that the polymer-coated TiFe intermetallic compound kept its hydrogen storage ability. The TiFe/PTFE material demonstrated resistance to surface poisoning even after a prolonged exposure to air and was not subjected to pulverization during multiple hydrogenation-dehydrogenation cycles.

Since obtaining a highly oriented structure based on a large-scale commercial ultra-high molecular weight polyethylene (UHMWPE) is considered very difficult due to its high molecular weight and melting index, modifying the structure of these cheap commercial UHMWPE brands into a supra-molecular structure with fiber-forming properties by adding a small amount of polyethylene wax (PE-wax) will provide the possibility to obtain highly oriented UHMWPE products with enhanced mechanical and tribological properties. In this work, highly oriented UHMWPE/PE-wax films were prepared. The PE-wax affected the UHMWPE as an intermolecular lubricant. The obtained lamellar structure of the UHMWPE/PE-wax composites had a better processability. The UHMWPE and UHMWPE/PE-wax structures for the xerogels and the films were studied by using differential scanning calorimetry and scanning electron microscopy. The PE-wax presence enhanced the mechanical properties of the UHMWPE/PE-wax films to a high degree. The highest average value of the tensile strength was 1320 MPa (an increase of 78%) obtained by adding a PE-wax content of 1.0 wt.%, and the highest average value of the Young’s modulus was 56.8 GPa (an increase of 71%) obtained by adding a PE-wax content of 2.0 wt.%. The addition of the PE-wax increased the work of fracture values of the UHMWPE/PE-wax films up to 233%. The formation of the cavities was observed in the virgin UHMWPE films more than in the UHMWPE/PE-wax films, and the whitening of the oriented films was related to the crystallization process more than to the cavitation phenomenon. The coefficient of friction of the oriented UHMWPE/PE-wax films improved by 33% in comparison with the isotropic UHMWPE, and by 7% in comparison with the oriented virgin UHMWPE films.

Structural, mechanical, and thermal properties of polyphenylene sulfide (PPS) filled with Al-Cu-Fe quasicrystals particles were studied. It was shown that the introducing of quasicrystalline fillers into the polymer matrix results in the increase in Young’s modulus, hardness, and toughness of the polymer. Quasicrystalline fillers can improve thermal properties of PPS, including heat resistance index, Vicat softening temperature, thermal diffusivity, and thermal conductivity.

Possibility of the polyimide (PI) films waste recycling by solid-state mechanochemistry was investigated in this study. Obtained PI powder was used for development of thermostable blends and multicomponent tribocompositions, which include additions of carbon black, ultradispersive diamond powder, and quasicrystalls. PI films waste treatment was provided in high-energy planetary ball mill. Powder compositions were mixed by low-energy planetary ball mill. Bulk samples were obtained by compression molding. Structural and thermal properties of initial polymers and composite materials were determined from scanning electron microscope, differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical analysis and fourier transform infrared spectroscopy. Tribological tests of composite materials were provided in dry sliding regime on ''pin-on-disk'' tribometer. Finally, optimal regimes of polymer composite materials producing were obtained.