جستجوی مقالات مرتبط با کلیدواژه "antibacterial paper" در نشریات گروه "صنایع چوب و کاغذ"

Some medicinal herb extracts have the antibacterial capability. On the other hand, herb extract is one of the organic, natural, and environmentally friendly substances. In recent years, the production of environmental and safe packaging materials has attracted the attention of scientists and industrialists. Paper is one of the biodegradable and less cost options for packaging in various industries, including the food industry. Also, the raw materials of paper can be modified and changed with different materials. As a result, paper fibers can be treated with herb extracts and used in the production of renewable papers with antibacterial properties.

In this research, thyme (Zataria Multiflora) was used for extraction. The thyme obtained from the research farm was dried and then powdered. Powdered thyme was treated via ultrasonication. In this method, two amplitudes of 40 and 60 amplitudes and three time levels of 3, 6, and 9 minutes were used for extraction. Then the papers were treated with herbal extract prepared in two amounts of 15 and 20% based on the dry weight of the paper by spraying. The antibacterial properties of the papers were investigated with Escherichia coli and Staphylococcus aureus bacteria. The chemical structure of materials extracted from the thyme extract investigated by fourier transform infrared spectrum (FTIR) analysis. Also, gas chromatography (GC-MASS) analysis was used to investigate the components of thyme extract. The optical properties of the paper, including brightness and opacity, and the strengths properties of the produced papers were measured by tensile, tear, and burst strengths.

The highest inhibition zone diameter in the treated paper with the thyme extracted by ultrasonic method was 20 mm in 40 amplitude and 9 minutes for Escherichia coli bacteria. Also, the highest inhibition zone diameter for Staphylococcus aureus bacteria was 14 mm in 60 amplitude and 6 minutes. According to the results of the papers analysis, the papers showed better antibacterial properties and higher inhibition zone against the Escherichia coli bacteria. The chemical compounds in the thyme extract including various substances such as hexane and furans. The most important chemical components that caused the antibacterial properties of the papers is carvenone, which was observed in the thyme extract. The results of the strength test of the treated papers showed that the sample of the thyme extracted by the ultrasonic method at 40 amplitudes, 3 minutes, and the 20% consumption amount based on the dry weight of the paper has the highest tensile and burst index. As well as, the highest tear index of the treated papers was in the treated sample with the thyme extracted at 60 amplitudes, 3 minutes, and 15% consumption amount based on the dry weight of the paper. The results of the optical tests showed that the opacity of the papers decreased and the brightness increased.

The results of this research showed that the paper as a biodegradable and environmentally friendly material has the ability to be treated with herbal and natural antibacterial materials such as the thyme extract. Also, the herbal extracts are a suitable alternative to inorganic and metallic materials in the production of materials with antibacterial properties due to the herbal extracts are cheap, available and natural materials.

These days, researchers in all fields are looking to develop new products using new technologies including nanotechnology. The objective of this study was to evaluate the performance of selenium nanoparticles in the paper coating formulations in order to improve the antibacterial, physical and mechanical properties of paper. The paper was coated with selenium nanoparticles with concentrations of 100 and 200 ppm accompanied by cationic starch. The paper surface coated with nanoselenium particles and starch has been characterized using ATR-FTIR and SEM. The results have showed that selenium nanoparticles had a good effect on inhibiting the growth rate of both Staphylococcus aureus and Escherichia coli. At equal consumption levels, the growth rate of Staphylococcus aureus decreased more than that of Escherichia coli. The growth rate of Staphylococcus aureus bacterium in the control and nanoselenium 200ppm coated paper specimens were 91.93% and 8%, respectively. Density and thickness of the paper sheets increased in the paper coated with cationic starch and nanoparticles in comparison with uncoated paper. Water absorption and water vapor Transmission Rate in nanoselenium coated samples were lower than starch coated samples and coatings had a significant effect on the rate of resistance to air in the paper. It is also seen increasing concentration of nanoparticles had no significant effect on the burst and tear indexes.

By developing attention to environmental issues and to the increasing attention of human society to health issues the use of environmentally friendly antibacterial compounds such as plant extracts for the production of antibacterial paper is very interesting. On the other hand, due to the high volatility of these environmentally friendly compounds, it is expected that encapsulating them in materials such as chitosan can increase their stability and control of release into the paper structure. Therefore, in this study, ethanolic extract of pomegranate peel in chitosan was encapsulated by ion gelation method and applied to the surface of the paper by spray method. The structural properties of pomegranate peel extract such as total phenol, total flavonoid and their antioxidant activity were investigated. Structural, barrier such as antibacterial activity and resistance properties of the prepared paper were also investigated. The results showed that nanocapsules of about 160 nm were obtained by ion gelation method, which were able to increase the antibacterial activity of the modified paper by about 35 mm against Staphylococcus aureus. In addition, the antibacterial activity of nanocapsule-modified paper was about two weeks higher than that of pure extract-modified paper. On the other hand, the presence of chitosan in the structure of nanocapsules also led to improved physical and resistance properties of the modified paper

Securities such as banknotes are permanently in contact with the human body according to their type of use and they are handed out daily among different people. This method of application makes these papers extremely contaminated and increases the possibility of transmission of pathogens by them. Therefore, the creation of self-cleaning properties in these types of papers is necessary. Titanium dioxide is one of the most widely used materials in papermaking that nowadays, its nanometer dimensions are considered as a photocatalyst. In this study, direct attachment of titanium dioxide nanoparticles to cellulosic fibers by controlled hydrolysis TiCl4 with urea in the presence of cellulose fibers was used which the homogenization of the suspension was done by ultrasonic waves. The cellulose fibers used were linter cotton fiber. The results of antibacterial and photocatalytic tests showed a very good performance against gram-positive and gram-positive bacteria and methylene blue degradation, respectively, but the results of mechanical and optical tests of the papers were undesirable and limit the use of these particles without applying any modifying method.