Journal of Applied Research of Chemical -Polymer Engineering

Abstract Research subjec: Polyethylene surfaces are often modified because of different reasons such as cleaning, etching, change in the performance of the surface, and surficial precipitation. One of the surfaces in the blow molded applications that must be treated in order to be ready for the adhesion of the labels is the surface of the bottle of the hygiene detergents, being the purpose of this research. In this paper, gliding arc plasma device is used at atmospheric pressure with air gas to modify the surface of polyethylene sheets in order to change their structure.
Methods: Various analyzes such as AFM, SEM and XPS tests have been used to investigate the changes in the chemistry and physics of polyethylene surface after plasma modification. Optical emission spectroscopy (OES) has also been used to identify plasma elements.
Findings: The contact angle between the water droplet and the polyethylene surface reached 46.96 ° after 40 s of treatment, while this contact angle was 66.53 °‌ before plasma treatment. The decrease in the contact angle size of the water droplet and the sample surface indicates the hydrophilicity of the polyethylene surface after plasma modification. The surface free energy of polyethylene was calculated before and after plasma modification using the Owens-Wendt-Rabel Kaelble method. The surface energy of polyethylene has increased from 42.20 mj.m^-2 in the control sample to 60.32 mj.m^-2 in the modified sample. The increase in surface roughness of the modified sample with gliding arc plasma was confirmed by AFM test. The surface roughness of polyethylene in the control sample was 47.18 nm, while the roughness in the modified sample increased to 59.86 nm. The XPS test confirmed the presence of oxygenated and nitrogenous functional groups on the surface of the modified sample. This test also showed the formation of C−C=O and C−O−C bonds on PE surface.

Abstract One of the problems for use of rubber in various industries is the surface tension at the surface of rubbers, which results in the crack on the surface, fracture of the rubber and reduces its service life. These tensions are caused by contacting the rubber component with the metal surface and the friction between two surfaces. Roughness of the surface, the composition of the rubber compound, the environmental factors, test conditions and etc. affect the friction between rubbers – metal. Surface roughness plays an important role in sliding between two surfaces and mainly controls friction behavior. On the other hand, roughness effect on the coefficient of friction is controllable using a suitable lubricant. In the present study regarding to the application of JP4 as an aviation fuel, the effect of JP4 fuel as a lubricant was investigated in the reduction of the sliding friction coefficient between the NBR and aluminum surfaces with different roughness. Experimental studies showed, friction coefficient has a good correlation with the mean surface roughness (Ra). By applying JP4 lubricant, the coefficient of friction decreased by about 75%. JP4 fuel as lubricant has changed the trend of varying friction coefficient from decreasing to increasing regard to the surface roughness.

Abstract Recently, flexible and environmental-friendly aerogel blankets have attracted considerable attention. In this work, the novel silica aerogel/basalt blanket was prepared using basalt fibers via a two-step sol-gel process followed by an ambient drying method and immersing the basalt fiber layer into silica sol. The silica aerogel particles were characterized by FTIR, FE-SEM and nitrogen adsorption analysis. The morphology, hydrophobic properties and surface roughness of neat basalt fiber and its aerogel blanket were also investigated. The density if 0.34 g/cm³, the porosity of 85%, mean pore size of 7±1.5 nm and the surface area of 750 m²/g for the nanostructured silica aerogel particles are obtained. The formation of nanostructured silica aerogel particles on the surface of basalt fibers in the sol-gel process were efficiently occurred leading to a strong hydrophobicity the blanket samples (contact angle of 114°) compared to the hydrophilic neat basalt fibers. The surface roughness of basalt fiber in the blanket samples was increased due to the fiber surface coating with silica aerogel particles. Increasing the sol volume in the synthesis process increased the basalt surface roughness from 3.6μ to 11μ.