Advanced Materials Research Vol. 910

Abstract: The electronic appliance is capable of emitting electromagnetic waves that will cause the damage of electrical equipment and influence peoples health. In this study, stain steel filament (SS filament) and 75D PET filament were used to manufacture SS/PET composite yarn The SS/PET composite yarn were made by the wrapping machine, which the core yarn is stain steel filament, wrapped yarn is 75D PET filament and the wrapping layers is varied as one and two. After that, the composite yarn is fabricated by the automatic sampling loom into composite woven fabrics. The composite SS/PET woven fabrics were under the tests of electromagnetic shielding effectiveness (EMSE) and air permeability. The test results revealed that the EMSE of the one-layer composite woven fabric is 9.5 dB at 900 MHz, but the EMSE decreases as test frequency increases. When laminating layer added to three layers, the EMSE raise up to 12.6 dB. The EMSE of composite woven fabric reached at 29.9 when the laminated angle is 45°. And the air permeability decreases as the laminate layer increases, which the thickness of sample affect air to pass through the sample.

Abstract: This study proposes a novel manufacturing method, a hollow braiding technique, to make reticular tubes. Coronary stents for coronary arteries have to have a size equal to the size of the arteries, and as a result, material and diameter of stents are both critical designed parameters. By using a hollow braiding technique and a braiding machine, 316L stainless steel fibers are made into coronary stents with an internal diameter of 3 mm, which meets the requirement of coronary arteries. The experiment results show that the hollow braiding technique can effectively braid reticular tubes with an internal diameter of 3 mm. In addition, variation in tooth number on the take-up gear can influence the braiding angle but does not influence the stability of the braiding structure and metal cover rate. In this study, the hollow braiding technique successfully produces coronary stents in the form of reticular tubes with a size equal to coronary arteries.

Abstract: For purpose of saving energy and avoiding injuries, foam composite with excellent resilience property was successfully prepared consisting of inflame-retarding nonwoven, spacer fabric and PU/additive foam. Effects of foam density, additives (vermiculite, perlite) content and opening ratio of spacer fabric on resilience rate were explored respectively. Experimental result shows that 50 kg/m³ foam density of PU foam had the lower resilience rate when containing 10 wt%-20 wt% vermiculites. Perlite P2 addition produced optimal resilience property comparing other types of additives in PU foam. Resilience rate decreased with increase of opening ratio of spacer fabric when containing 5 wt% additions.

Abstract: Factories have increased the mechanical equipment on a mass scale as a result of quick growth of global industry, and the unbearable sounds that machines create while operating become noise. Therefore, versatility of building materials that are highly correlated to human habitat has been gaining attention. This study combines and then needle-punches fire-retardant polyester (PET) fibers and recycled Kevlar selvages to make PET/Kevlar nonwoven fabrics, which are then combined with Polyurethane (PU) foams, a product yielded after Polyol and Isocyanate (MDI) foam and cure, to form PET/Kevlar/PU foam composite boards. During the process, PET fibers and Kevlar fibers are blended with various ratios and the density of the PU foams is varied. The resilience rate, burst strength, and sound absorption of the resulting composite boards are tested. The test results show that increasing Kevlar selvages can heighten the resilience rate but decreases the burst strength of the composite boards.

Abstract: This study aims to examine the influence of graphene nanosheets (GNs) on the morphology and electrical property of polyvinyl alcohol (PVA) nanofiberous mats. GNs (0.03 %, 0.05 %, 0.1 %, and 0.3 %) are added to PVA solution, and then electrospun into PVA/GNs nanofiberous mats. A viscosity measurement and electrical conductivity measurement are performed on the samples to determine their properties. The experiment results show that when the content of GNs increases from 0.1 % to 0.3 %, the fiber diameter of PVA/GNs nanofiberous mats increases from 166 nm to 239 nm, the conductivity slightly increases, but the viscosity greatly increases. An increment in viscosity causes the beads to form complete fibers, which is in line with the outcome of scanning electron microscopic (SEM) observation.

Abstract: Polymeric material, which is commonly used in packaging, has been widely applied due to the fact that it is lightweight and chemical resistant. Being non-degradable, polymeric waste can thus only be eliminated by burning, and subsequently, there is a rising need for degradable polymeric material to manage this manner of disposal. This study thus uses degradable, low-melting-point polylactide (LMPLA) fibers and recycled polyester (RPET) fibers to make nonwoven fabrics for packaging. The tensile strength, tear strength, and air permeability of the nonwoven fabrics are then tested. The experiment results show that a 40% of RPET fibers can effectively promote the mechanical properties of the LMPLA nonwoven fabrics.

Abstract: For application as surface layer of PU composites for the future, puncture resistance and inflame retarding property are both considered. Therefore, in this preliminary study, we discussed effect of Nylon fiber fineness and hot pressing on tensile, tear and puncture resistance properties of fiber composite composed of inflame retarding nonwoven and Nylon/PET nonwoven. Result shows that, Fiber composite with finer Nylon fibers exhibited higher tensile strength and puncture resistances. Hot pressing decreased tensile strength, tear strength and puncture resistance by 5-mm needle penetration, but increased puncture resistance by 2-mm needle penetration.

Abstract: In this research, the B/A/S composite yarns were fabricated using the stainless steel wires as core yarn, antibacterial nylon and bamboo charcoal polyester filaments as inner wrapped yarn and outer wrapped yarn, respectively. The composite yarns with a wrapping number of 8, 11, 14 turns/cm were fabricated on a hollow spindle spinning machine. Furthermore, the composite fabrics were woven with the B/A/S composite yarns as weft yarns and the PET as the warp yarns. These fabrics were evaluated in terms of far infrared (FIR) emissivity and the air permeability. The presence of the bamboo charcoal was found to increase the FIR emissivity. The highest of the FIR emissivity was obtained when the weft yarns with a wrapping number of 11 turns/cm. The lamination numbers of the woven fabrics varied from 1-5 layers. The far infrared emissivity and air permeability of the woven fabrics was 0.94 and 268 cm³/cm²/s when the lamination numbers was 2 layers and the wrapping number was 11 turns/cm.

Abstract: In this study, two agents (a foaming agent and a hardener) are mixed to form rigid polyurethane (PU) foams with various densities, which are separately poured into a mold with a three-dimensional (3D) fabric to form 3D fabric/foam composites. The mechanical property and sound absorbency of the composites are examined. The experiment results show that an increasing density of the two-agent mixture results in a more compact PU foam, a 31 % increase in bursting strength, and a greater resilience, but also a decrease in the sound absorbency coefficient. In sum, variations in the density of the mixture have an impact on the physical properties of the fabric/foam composites, the derived results of which can thus be further applied to product designs.

Abstract: This study uses a single screw extruder to make short coir (SC), an agricultural waste, high-strength short glass fiber (SGF), and polypropylene (PP) into pellets, which are then made into wood plastic composites (WPC) on an injection machine. During the process, maleic anhydride grafted polypropylene (PP-g-MA) is used as a coupling agent to improve the interfacial adhesion between coir and PP as well as between SGF and PP. A tensile strength test, flexural strength test, and Izod impact strength test are performed on the samples to examine the mechanical properties. The experiment results show that when the content of SGF increases from 3 wt% to 12 wt%, the tensile strength increases from 26.08 MPa to 36.68 MPa, and flexural strength increases from 36.01 MPa to 49.91 MPa, but the Izod impact strength decreases from 286.16 J/m to 218.14 J/m. In addition, the addition of 2 wt% of PP-g-MA improves the interfacial adhesion between matrices (PP) and reinforcement (SC or SGF), thereby fortifying the mechanical properties of the composites.