Papers by Keyword: Nonwoven Fabric

Abstract: The melt jet spinning process has been used for production of consistently fine nonwoven fibers. The process was applied to produce the biodegradable nonwoven fabric such as poly (lactic acid) (PLA). However, the rigid nonwoven PLA fibers limited the application of nonwoven. To improve the nonwoven fiber flexibility, the fabrication of PLA/PBS blend nonwoven fabric using melt jet spinning process under various process conditions was studied. In the melt jet spinning process, the nozzle temperature is varied between 250 to 280 °C. The performance metric evaluation is comprised of fiber diameter, fiber crystallinity, mechanical property and contact angle. The fiber diameter, crystallinity and tensile strength of PLA/PBS blend nonwoven fabric decreased with increasing nozzle temperature. The optimum process condition of the PLA/PBS nonwoven fabric production was found at nozzle temperature of 280 °C to produce the nonwoven fiber with average diameter of 5.1 μm. The forming temperature has no effect on the hydrophilic properties of PLA/PBS nonwoven fabric. The melt jet spinning process was successfully applied for the biodegradable polymer to produce the environmentally friendly products.

Abstract: The use of plant fibers as a reinforcement for fragile matrices could be an option to improve the sustainability of the construction materials. These reinforcements can be in different forms as short fibers, long fibers or woven or nonwoven fabrics. The mechanical performance of the composites is significantly related to the adhesion between the matrix and the fibers. In the case of nonwoven reinforcement, to get good adhesion, the penetration of the paste is a key point. That is why this study addresses the relationship between rheology, penetration through the nonwoven fabrics and the mechanical properties of various lime pastes with different contents of water and metakaolin (MK). The effect of the binder’s grinding is also evaluated. The results indicate that MK pastes with higher w/b ratios penetrate better into nonwovens, Grinding has a negative effect on penetrability despite improving the mechanical properties of the pastes.

Abstract: Polyamines are water-soluble polyelectrolytes with the amino groups that can be used to attach the polymers onto functional surfaces of fibrous materials. In addition, polyamines can be readily modified by (super) nucleophilic groups such as (alkyl) aminopyridines that enhance the polymer’s ability to promote hydrolysis of organophosphorous chemical warfare agents. Furthermore, attachment of hydantoin moieties augments the number of the imide, amide, or amine groups on the polyamine’s chain, which provides oxidizing properties to the resulting modified polyamine after halogenation. We report on polyamines with side chains modified to contain both (4-aminopyridine, APy) and 5-(4-hydroxybenzylidene) hydantoin (HBH) functionalities with enhanced content of the active bromine. Virucidal activity of the APy-and HBH-modified polyallylamine against human coronavirus (type 229E) was tested both in solution and on nylon-cotton fabric. The polymers appeared to be effective in inactivation of the coronavirus, at both low concentrations and short exposure times.

Abstract: Electromagnetic wave shielding effectiveness of the nonwoven fabrics was measured in the wide operating frequency range, namely 0.4GHz to 20GHz. The shielding effectiveness of the nonwoven fabric was below 45dB in the range of 0.04GHz to 15GHz and then it increased to above 45dB in the range of 15GHz to 20GHz. To enhance the electromagnetic wave shielding effectiveness of the nonwoven fabrics, 3 minutes H₂ plasma treatment of the nonwoven fabrics was carried out under the microwave plasma-enhanced chemical vapor deposition system. By H₂ plasma treatment, the shielding effectiveness of the nonwoven fabrics was greatly enhanced in the whole operating frequency range. The surface electron conductivity of the nonwoven fabrics was also enhanced from 2.11×10³ S/m to 3.02×10³S/m by H₂ plasma treatment. The surface and cross sectional morphologies of the nonwoven fabrics with or without H₂ plasma treatment were investigated and compared with each other. Crystal structure variation of the nonwoven fabrics by H₂ plasma treatment was also investigated. Based on these results, the cause for the enhancement of the shielding effectiveness of the nonwoven fabrics by H₂ plasma treatment was suggested and discussed.

Abstract: Different type carbon-based fabrics, namely woven or nonwoven fabric, were employed to investigate the electromagnetic wave shielding effectiveness of the fabrics in the wide operating frequency range, namely 0.4GHz to 40GHz. The surface and cross sectional morphologies of the fabrics, their electrical conductivities, and their electromagnetic wave shielding effectiveness were investigated. In the case of woven fabric, the value of the electrical conductivity was much different according to the measuring direction in the woven fabric. For the nonwoven fabric, however, this value was independent on the measuring direction. The shielding effectiveness of the woven fabric was above 20dB in the range of 0.04GHz to 4GHz and then it decreased to below 20dB in the range of 4GHz to 40GHz. In contrast, the shielding effectiveness of nonwoven fabric was above 40dB in the whole operating frequency range in this work. Based on these results, the dependence of the shielding effectiveness of the woven or nonwoven fabrics according to the operating frequency and the optimal shielding effectiveness material in the wide operating frequency range was suggested and discussed.

Abstract: Insufficient endothelialization of stent grafts tends to cause a problem of thrombosis formation. Because the structure of nanofibers, generally defined as fibers with a diameter below 1 μm, resembles the structure of an extracellular matrix, nanofibers are applied to scaffolds for regenerative medicine. Using nanofibers as the covering material of the stent graft can be expected to solve the problem of the stent graft. Previous studies have shown that a porous scaffold offers better surfaces to anchor and culture endothelial cells than a nonporous scaffold. Therefore, fibers with nanoorder dimples are expected to promote endothelialization. As a method of forming the dimple shape on the surface of the PET fiber, there is a method utilizing a difference in the volatilization rate of the solvent in the high humidity environment in the electrospinning method. For practical application of the stent graft to artificial blood vessels, the mechanical properties of the dimpled PET fiber should be clarified. In this study, the mechanical properties of single nanofibers and nonwoven fabrics of PET fibers with dimples on their surface were evaluated by tensile test. By forming the dimple shape on the fiber surface, the tensile strength of single PET fibers with dimples was 90 % lower than that of single PET fibers with a smooth surface. In the fabrication process of nonwoven fabric, the addition of EG delayed the volatilization of the PET solution, and the fibers adhered to each other. The bonding between the fibers contributed to the tensile strength of the nonwoven fabric.

Abstract: This paper deals with the effect of weathering and biological exposure on the tensile properties of needle-punched PP nonwoven fabric. In the experiment, samples of the geotextile were exposed to the above factors for different time, and then their tensile strength was determined. The obtained results showed the significant drop in the tensile strength after the exposure to UV radiation and slight drop after soil burial test.