Advancements in industrial machinery and manufacturing equipment require more reliable and efficient polymer tribo-systems which operate in conditions associated with increasing machine speeds and a lack of cooling oil. The goal of the current research is to improve the tribological properties of elastomeric composites by adding a solid lubricant filler in the form of ultrafine polytetrafluoroethylene (PTFE) with the chemical formula [C₂F₄]_n and recycled polytetrafluoroethylene (r-PTFE) powders. PTFE waste is recycled mechanically by abrasion. The elastomeric composites are prepared by mixing a nitrile butadiene rubber with a phenol-formaldehyde resin and PTFE powders in an extruder followed by rolling. The deformation-strength and tribological tests of r-PTFE elastomeric composites are conducted in comparison with the ultrafine PTFE composites. The latter is based on products of waste fluoropolymer processing using a radiation method. The deformation-strength test shows that the introduction of ultrafine PTFE and r-PTFE powder to the composite leads to a decrease in strength and elongation at break, which is associated with the poor compatibility of additives and the elastomeric matrix. The friction test indicates a decrease in the coefficient of friction of the composite material. It is determined that the 15 wt.% filler added in the elastomeric matrix leads to a reduction in the wear rate by 20%. The results obtained show the possibility of using ultrafine PTFE powder and r-PTFE for creating elastomeric composites with increased tribological properties. These research results are beneficial for rubber products used in many industries, mainly in mechanical engineering.

A promising direction in polymer material processing is the development of self-reinforced polymer composites (SRPMs), representing a relatively new group of composite materials. The self-reinforcement method allows for materials of one polymer to be combined with different molecular, supramolecular, and structural features. The high adhesive and mechanical properties of SRPMs are due to the formation of a homogeneous system with no inter-phase boundary. Moreover, self-reinforcement considers the possibility of using polymer waste to create high-strength composites, which reduces the environmental load. In the current work, the phase composition, structure, and properties of SRPMs based on polytetrafluoroethylene (PTFE) were studied. SRPMs were prepared by mixing industrial and regenerated PTFE powders and then subjected to pressing and sintering. Two types of regenerated PTFE were used for the SRPM preparation: a commercial PTFE of the TOMFLON^TM trademark and mechanically grinded PTFE waste. The degree of crystallinity of the obtained materials (41–68%) was calculated by XRD analysis; the crystallite size was determined to be 30–69 nm. Thermal analysis of the composites was carried out by the DSC method in the temperature range of 25–370 °C. The characteristics of thermal processes in self-reinforced composites correlate with the data from structural studies of XRD and FTIR analyses. The results of dynamic mechanical analysis showed that the introduction of regenerated PTFE powder into an industrial one increased the elasticity modulus from 0.6 GPa up to 2.0–3.1 GPa. It was shown that the phase state of the SRPMs depended on the method of processing polymer waste (the type of regenerated PTFE) that determined the heat resistance and mechanical properties of the obtained composite material.

Представлены результаты исследования модифицированных пленок полиэтилена в плазме скользящего разряда. Доказано, что модификация поверхности пленок в плазме является более экологичной и ресурсоэффективной по сравнению с химической модификацией. Модифицированные пленки полиэтилена были исследованы с помощью инфракрасной спектроскопии, растровой электронной микроскопии и метода краевого угла смачивания. Пленки полиэтилена после плазменной модификации приобрели гидрофильные свойства, вызванные изменением химической структуры поверхности полимера. Благодаря улучшенным контактным свойствам модифицированные пленки полиэтилена представляют интерес в качестве материала основы для создания полимерно-рулонных гидроизоляционных...

Представлены результаты исследования влияния плазмы скользящей дуги на физико-механические свойства гидроизоляционного полиэтилена. Согласно теории плазмохимического травления процесс модификации пленок полиэтилена и стабилизированного полиэтилена, в основе которого протекают процессы ионизации, возбуждения и диссоциации кислород- и азотсодержащих молекул на атомы с последующим формированием гидроксильных групп, синглетного кислорода, супероксида, озона, гидроксильных, гидроперекисных и карбоксильных групп. Доказано, что после модификации наблюдается изменение значений относительного удлинения. Испытание значений относительного удлинения при времени модификации 10 с для пленок полиэтилена и 15 с для стабилизированного полиэтилена составляет 230 % в обоих случаях, а максимальная нагрузка разрушения - 51,6 и 95,7 Н соответственно. При воздействии низкотемпературной плазмы скользящего разряда на поверхности пленки наблюдаются процессы плазмохимического травления, не влияющие на массу пленок, однако приводящие к изменению значений относительного удлинения в допустимых значениях. Достигнутые результаты свидетельствуют об улучшении адгезионных и прочностных свойств пленок ПЭ и СтПЭ, что является более эффективным методом модификации по сравнению с...

Polyethylene (PE) films are widely used as waterproofing materials on the surfaces of metal pipelines. Poor adhesion of PE films to a metal substrate reduces durability, leading to shorter service life and higher economic costs. The current research aims to study the modification of PE films in atmospheric pressure gliding arc plasma (GAP). The adhesion properties of the modified films were investigated using the contact angle method and adhesion work calculations. During the modification process, the GAP treatment duration and deflector nozzle angle of attack were optimized to 10 s and 135°, respectively. It was established that the adhesion work increased from 62.1 to 141.3 mJ/m² after 10 s GAP modification compared to untreated PE. GAP modifying of PE films for 30 s or more is impractical, as the increase in the adhesion work ceases after that. It was found that surface roughness R_max increased by up to 4.1 times after 10 s GAP modification compared with nontreated PE. The PE films acquired hydrophilic properties after plasma modification, due to changes in the polymer surface’s chemical structure. The results of IR spectroscopy studies indicated oxidation of the film surface, an increase in the concentration of surface polar groups (-COOH, OH, C=O), and the formation of double bonds (C=C), which led to improved adhesive properties. A study of the electret properties showed that the observed decline and subsequent stabilization of values occurred within the first 24 h. Mechanical tests indicated improved performance of the GAP-modified PE films compared to the non-treated ones in the PE–mastic–PE and PE–mastic–steel systems. Due to their enhanced contact properties, the modified PE films are of interest as a base material for creating waterproofing materials.