Influence of surfactants on interaction forces between polyethylene surfaces in a hydrocarbon solvent

Book ChapterThe polyolefins, mainly polyethylene and polypropylene particles, are used as an active filler material in polymer-polymer blends and are being used for the modification of asphalts to provide for high-load, low-maintenance road construction. The stability of prepared blends depends on the interaction forces between polyolefin filler and the matrix and/or between two polyolefin filler surfaces in the polymeric matrix. Various additives, especially surfactants, can be used to modify these interactions and improve the stability of polymer blends. In current research, direct force measurements between polyethylene (PE) surfaces in n-tetradecane, a nonaqueous solvent imitating the polymer matrix, were performed in the presence oflauric acid and dodecylamine using the AFM colloidal probe technique. Additionally, the zeta potential of polyethylene particles in the presence of surfactants in n-tetradecane was measured. The interaction forces between the polyethylene surfaces can be described as a combination of electrical double layer repulsion and steric repulsion between polymer chains extending into the n-tetradecane solvent. The addition of surfactant to the n-tetradecane was found to increase the repulsive force between the PE surfaces. The strongest repulsion was observed for dodecylamine. Additionally, the temperature effect on the interactions in n-tetradecane was studied. It was found that steric repulsion between the PE surfaces increases with an increase in temperature

Atomic force microscopy investigation of interaction forces between polyethylene and asphaltene surfaces

Book ChapterMany petroleum-derived asphalts used for road construction exhibit poor rheological properties. These properties of asphalt can be improved by addition of various polymer fillers to the asphalt blend. Recycled polyolefines, especially polyethylene and polypropylene have been used as the asphalt modifying fillers. Unfortunately the polyolefine-asphalt mixtures are not stable and have a tendency to separate because of the chemical incompatibility of the components. In our research, surfactants were used to improve polymer-asphalt compatibility. Interaction forces between a polyethylene particle and a polyethylene surface and between a polyethylene particle and an asphaltene-surface were measured in surfactant solutions in n-tetradecane and pyridine using the atomic force microscopy colloidal probe technique. Dodecylamine, lauric acid and lauric alcohol (C12E4) were used as surfactants. The most pronounced change the interactions was observed for polyethylene-polyethylene surfaces in the solution of lauric acid. At the same conditions polyethylene-asphaltene interactions were decreased. The most increase was the increase in the repulsion range (to 26 nm) between the spherical PE probe and flat polyethylene surface for 10~3 M n-tetradecane solution of ethoxylated lauryl alcohol (C12E4). In the case of lauric acid the interaction range extended to 24 nm and for dodecylamine to 21 nm. The interaction between the polyethylene sphere and flat asphaltene surface extended to 16 nmfor dodecylamine, to 18 nmfor lauryl alcohol ethoxylated (C12E4) and to 14 nmfor lauric acid

2014, 373−386 Physicochemical Problems of Mineral Processing

Abstract: Ionic liquids are widely used in supported ionic liquid membranes technology, especially in gas separation and purification processes. This work characterizes the ability of ionic liquids to wet commercially available porous supports used for such purposes. Characterization of supports and membrane phases was carried out in order to determine factors influencing wetting process. Experimental method based on capillary rise is widely used for porous media characterization (i.e. pore radius, contact angle). Measurements of penetration distance or liquid mass are two main experimental methods, in which the Washburn equation is a basic instrument to analyze the obtained results. However, polymeric porous supports do not meet Washburn assumptions and the method is loaded with human errors, so the sessile drop method was used. The rate of wetting influences swelling effects and therefore changes in permeation path during gas separation processes are observed. Influence of ionic liquids structure on wetting and swelling of porous supports was investigated. The families of 1-alkyl-3-methylimidazolium (C n mim), ammonium (N nnnn ), 1-alkyl-1-methylpyrrolidinium (C n Pyrr) and 1-alkylpyridinium (C n Py) compounds with variable alkyl chain lengths in cation structures and changeable anions were taken into account in wetting and swelling experiments

Wetting of supports by ionic liquids used in gas separation processes

Abstract. Ionic liquids were found to be selective solvents for separation of gases. They are widely used in supported ionic liquid membranes (SILMs) technology, especially in gas separation and purification processes. This work has characterized commercially available porous membranes employed in such purposes. Characterization of supports and membrane phases was carried out in order to determine factors influencing membrane stability. Scanning electron microscopy (SEM) was used to determine morphology of membrane surface

Insights into hydrodynamics of spinning fluids reactor

Spinning fluids reactor (SFR) is one of the most efficient gas-liquid contacting system with high potential of application in many fields. The unique solution of SFR is the contacting of two spinning fluids which generated centrifugal force. The aim of this study was to investigate the pressure field distribution on the inner surface of reactors dispersing element. Obtained results confirm the high heterogeneity of the field pressure in the reactor system with a cylindrical wall. This is due to the low tangential force generated by rotating liquid on a cylindrical wall, and pressure drop in the locations of surface irregularities. The change of the sparger element to conical shape element increases the pressure exerted by fluid on the wall. In this case the effects of solid particles and inequality in the fluid flow are negligibly small compared to the measured pressure exerted on the sparger element

The Influence of intensity mixing on the digestion process

The basics of convection, mechanical, hydraulic and bubbling mixing used in methane fermentation technologies are discussed. The impact of the intensity of mechanical mixing on the quality and quantity of biogas as well as the course of the fermentation process was evaluated. The influence of the paddle agitator speed rate on quasi-continuous fermentation was investigated. Fermentation was carried out under mesophilic conditions with a hydraulic retention time of 21 days. A 10% increase in biogas production was observed with the increase of the speed of mixing from 60 to 70 min-1 without a significant change in the composition of biogas and other process parameters

Wetting processes in supported ionic liquid membranes technology

Ionic liquids are widely used in supported ionic liquid membranes technology, especially in gas separation and purification processes. This work characterizes the ability of ionic liquids to wet commercially available porous supports used for such purposes. Characterization of supports and membrane phases was carried out in order to determine factors influencing wetting process. Experimental method based on capillary rise is widely used for porous media characterization (i.e. pore radius, contact angle). Measurements of penetration distance or liquid mass are two main experimental methods, in which the Washburn equation is a basic instrument to analyze the obtained results. However, polymeric porous supports do not meet Washburn assumptions and the method is loaded with human errors, so the sessile drop method was used. The rate of wetting influences swelling effects and therefore changes in permeation path during gas separation processes are observed. Influence of ionic liquids structure on wetting and swelling of porous supports was investigated. The families of 1-alkyl-3-methylimidazolium (Cnmim), ammonium (Nnnnn), 1-alkyl-1-methylpyrrolidinium (CnPyrr) and 1-alkylpyridinium (CnPy) compounds with variable alkyl chain lengths in cation structures and changeable anions were taken into account in wetting and swelling experiments

Separation of CO2 from flue gas in air-sparged hydrocyclone (ASH) reactor

Laboratory results of an initial study on CO2 removal from gas mixture by means of the air-sparged hydrocyclone (ASH) technology are reported. The CO2 absorption rate into sodium hydroxide aqueous solution was studied on a laboratory and pilot scale. The air flow rate was 900 dm³/min and the alkaline solution flow rate was 15 dm³/min in the case of pilot scale. The influence of CO2 concentration, pH of the liquid phase, the gas flow rate, and the alkaline solution flow rate on the efficiency of the process was investigated. An increase in the alkaline concentration significantly enhanced the CO2 absorption. A very low distribution of bubble sizes enhanced the carbon dioxide absorption, too

Evaluation of tribological properties of lubricants based on Hersey’s–Stribeck’s characteristics

W pracy przedstawiono wyniki badań dotyczących właściwości tribologicznych - na podstawie charakterystyk Herseya–Stribecka, substancji smarujących takich jak syntetyczna baza olejowa PAO-6, olej perfluoropolieterowy PFPE Fomblin Y 04 oraz ciecz jonowa CJ 006, tj. bis(trifluorometylosulfonylo)imid-3-metylo-1-propylopirydynowy. Badanie przeprowadzono w Zakładzie Tribologii, Inżynierii Powierzchni i Logistyki Płynów Eksploatacyjnych Wydziału Mechanicznego Wojskowej Akademii Technicznej na uniwersalnym nano/mikrotesterze UNMT, wyprodukowanym przez CETR (Centrum for Tribology) w USA. Badania zostały zrealizowane przy różnych obciążeniach, a mianowicie 0,25 N, 5 N i 50 N. Zróżnicowały one substancje smarujące pod względem właściwości tribologicznych, ukazując wpływ zmiany prędkości tarcia oraz obciążenia węzła tarcia na wartość współczynnika tarcia. Najlepsze właściwości tribologiczne, szczególnie przy większych obciążeniach, wykazała ciecz jonowa.The content of the paper presents the results of investigations of selected lubricants. The study led to obtaining Hersey’s-Stribeck’s curves and to comparison of the lubricating properties of lubricants belonging to different groups such as hydrocarbon oils, perfluoropolyether oils (PFPE), and ionic liquids. The following liquids were evaluated for tribological properties: PAO-6 polyalphaolefin oil base, CJ 006 ionic liquid (3-methyl-1-propylpyridinium bis(trifluoromethylsulphonyl)-imide) and Fomblin Y 04 synthetic perfluoropolyether oil. The research was carried out using the universal nano/micro tribotester (UNMT-CETR, CA, USA) at the Department of Tribology, Surface Engineering and Service Fluids Logistics, Faculty of Mechanical Engineering, Military University of Technology. The study consisted of friction of a ball bearing steel (100 Cr 6) with a round specimen of a certain roughness (ball-on-disc). Friction occurred in rotational motion of the specimen, at different rotational speeds at constant radius and at constant load (0.25 N; 5 N; 50 N). The friction node was lubricated with the tested liquid