Afsaneh Topa; Atamalek Ghorbanzadeh; Davood Efhamisisi
Abstract
The plasma has different effects on the surface wettability of wood, depending on the treatment conditions and the type of gas used. The hdrocarbon gases usually destroy hydrophilic groups on the surface of wood and cause hydrophobicity by creating microscopic rough structures. In this study, glide plasma ...
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The plasma has different effects on the surface wettability of wood, depending on the treatment conditions and the type of gas used. The hdrocarbon gases usually destroy hydrophilic groups on the surface of wood and cause hydrophobicity by creating microscopic rough structures. In this study, glide plasma treatment with methane was used to hydrophilize the surface of the wood and create weathering resistanc. The poplar wood (Populus deltoides) were exposed to glide plasma under various laboratory conditions such as time of exposure, voltage, frequency, distance between electrodes as well as flow of inlet gas and outlet gas with methane inside a reactor. Then the surface properties of wood were studied using scanning electron microscope (SEM), measurement of water drop contact angle, ATR‐FTIR spectroscopy, roughness survey, and colorimetry. The specimens were then subjected to the accelerated weathering using the Gardner weathering wheel and their properties were checked again. The SEM images showed that the plasma creates a warty layer on the surface of the wood which could be due to the deposition of new materials or the physical effects of plasma (surface etching). The plasma treatment significantly increased the contact angle of the water droplet on the surface of the treated samples. The treated samples had a higher surface roughness than the control samples. The surface of treated samples was generally darker than the control. After exposure to the accelerated weathering, the effect of treatments on surface hydrophobicity was largely lost. The treated samples had less roughness changes than the control after exposure to the weathering, and also their dark color changed to silver-gray. The use of glide plasma with methane gas showed the great potential for creating hydrophobic surfaces on the wood, but it did not last long and lost its effectiveness due to weathering.
Pulp and paper
somayeh heydari; Ahmad Reza Saraeyan; Mohamadreza Dehghani firozabadi; Alireza Shakeri; babak shokri
Abstract
Ethylene vinyl alcohol (EVOH) copolymer is of semi crystalline materials with excellent barrier properties to gases. Also, it has shown outstanding chemical resistance. Despite its low gas permeability, EVOH copolymer displays poor water and water vapor resistance. In this study, Trimethoxymethylsilane ...
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Ethylene vinyl alcohol (EVOH) copolymer is of semi crystalline materials with excellent barrier properties to gases. Also, it has shown outstanding chemical resistance. Despite its low gas permeability, EVOH copolymer displays poor water and water vapor resistance. In this study, Trimethoxymethylsilane (as hydrophobic coating) was deposited by Plasma Enhanced Chemical Vapor (PECVD) method on the coated paper with Ethylene vinyl alcohol in order to improve the paper's barrier properties of moisture transmission. Coating by PECVD method was done in the certain conditions of time 6 min and pressure 300 m Torr. Different treatments were applied for power including 50, 70 and 90W.Then contact angle was measured in order to determined improvement of the paper's barrier properties of moisture transmission . The result showed that papers which were coated with Trimethoxymethylsilane had higher contact angle water 55.7% more than the control. The results revealed that the best condition was obtained by 50 W power. The structural and chemical properties of deposited layer were observed with Fourier Transform infrared spectroscopy- Attenuated Total Reflectance (FTIR-ATR) and Energy Dispersive X-ray Spectroscopy (EDS). The results confirmed bonding of silane on the surface EVOH polymer.
Pulp and paper
Mohaddeseh Ramezanpour-Charvadeh; Hamid reza Rodi; Hossein Jalali-Torshizi; Hamidreza Ghomi marzdashti
Abstract
DOR:98.1000/1735-0913.1398.34.76.66.1.9.1578 A need for control of pathogenic microorganisms in contaminated environments has motivated to prepare the products including antibacterial papers resisting against growth of such creatures. Different methods and materials have been used to make these papers. ...
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DOR:98.1000/1735-0913.1398.34.76.66.1.9.1578 A need for control of pathogenic microorganisms in contaminated environments has motivated to prepare the products including antibacterial papers resisting against growth of such creatures. Different methods and materials have been used to make these papers. The purpose of current research is to fabricate silver nanoparticle by means of plasma method and investigate the effect of adding it to the Kraft pulp on the properties of resulting papers. To do this, silver nanoparticles have been fabricated in optimized conditions of 1 kHz frequency, 2 A current and 4 kV voltage, using an instrument developed in Laser and Plasma Research Institute, Shahid Beheshti University. The DLS test confirmed the average size of silver particles at nano scale ( 41.2 nm). Then, the prepared silver nanoparticles were added by levels of 0, 25, 50 and 75 ppm to the Kraft pulp accompanying by cationic polyacrylamide (CPAM) as a retention aid to about 0.05 based on oven dry of fibers. The results of paper properties evaluation (having basis weight 60±3 g/m2) have shown that addition of silver nanoparticles synthesized by plasma method lead to loss of paper strength characteristics. The paper brightness has also exhibited a meaningful decrease. However, the paper opacity and antibacterial property develop significantly in the consumption levels higher than 50 ppm.
