Ching Wen Lou

Recycling Polyester and Polypropylene Nonwoven Selvages to Produce Functional Sound Absorption Composites

The consumption of polypropylene and polyester makes up over 50% by weight in the nonwoven industry and consequently the waste generated from them increases gradually every year. In this study, the polyester and polypropylene nonwoven selvages were recycled to produce functional composites. First, the two kinds of selvages were shredded and mixed in the proportion1:1, and then stirred well. The functional sound absorption composites were produced by a compress molding technique with proper parameters. Sawdust was also added in the composites to investigate the influence of processing parameters and materials on the sound absorption efficiency of the composites. The sound absorption coefficients were measured according to ASTM E 1050 by an impedance tube. The results revealed that the average of the sound absorption coefficients increased with the thickness of the composites, but decreased with the density. The effect of adding sawdust to the sound absorption efficiency of the composites was not obvious from this work.

Manufacturing and Properties of PLA Absorbable Surgical Suture

Polylactic acid (PLA) is a polymer that has good biocompatibility, good biodegradability and excellent mechanical properties. The modulus of elasticity and the thermoplastic ability of PLA can satisfy the need for the carrier material of the cell to grow in bone tissue engineering, such as in regeneration and repair of bone and cartilage tissue. The PLA multifilament was twisted using different twisting parameters and a rotor-twister to fabricate United States Pharmacopoeia (U.S.P.) size 5-0 and 7-0 surgical sutures. The best tensile strengths were 3.1 and 12.3 N, and the coefficients of variation were 3.70% and 1.75%. The PLA suture was then scoured with 1 wt% sodium hydroxide to eliminate impurities, and the knot-pull strengths decreased to 1.66 and 6.84 N for 7-0 and 5-0 PLA sutures, respectively, but still conforming to the U.S.P. knot-pull strength standard. An in vitro hydrolysis test was performed at 37°C by immersing 5-0 PLA suture in physiological saline (0.9 wt% NaCl aqueous solution); the knot-pull strength decreased by 12% after 28 days.

Mechanical Properties of Highly Elastic Complex Yarns with Spandex Made by a Novel Rotor Twister

Elastic fibers are mostly used in elastic textiles. In this study, we develop a novel and original method to make highly elastic complex yarns using a self-designed, multi-section drawing frame and rotor twister. We examine the mechanical properties of these elastic complex yams. Their maximum breaking tenacity is high when the speed of the rotor is 4000 rpm and the wrapping count of the textured nylon filaments is either 2.5 or 3.0 turns/cm. These data are useful for the textile industry.

Manufacturing techniques and electrical properties of conductive fabrics with recycled polypropylene nonwoven selvage

In this research, an original rotor twister machine, with a speed of 8000 rpm, spun complex ply yarns from recycled polypropylene nonwoven selvage (PPNS) and various metal wires. The core yarn was pieces of 30 g/m2 recycled PPNS and the wrap yarns were 80 μm stainless steel wires. Furthermore, 80 μm stainless steel wires and 80 μm copper wires, parallel to the core yarns, reinforced the complex ply yarns. Yarns were manufactured with wrap numbers of 0.5, 1.5, 2.5, 3.5, and 4.5 turns/cm. Complex fabrics were woven with the complex ply yarns as the weft yarns and PVC-coated PET filaments as the warp yarns. These fabrics were evaluated for surface resistivity and electromagnetic shielding effectiveness (EMSE). The presence of copper reinforcement wires was found to lower the surface resistivity of the fabrics. The lowest surface resistivity was recorded for a fabric woven from yarns with a wrap number of 4.5 turns/cm; that surface resistivity was 28.7 Ω/sq. EMSE measurements showed that fabrics with varied lamination angles provided good electromagnetic shielding. The optimum EMSE measured in this research was 56.1 dB on incident frequency as 2.36 GHz, for a fabric with 0°/90°/0°/90°/0°/90° lamination angles.

A Comparison of Epithelial Cells, Fibroblasts, and Osteoblasts in Dental Implant Titanium Topographies

The major challenge for dental implants is achieving optimal esthetic appearance and a concept to fulfill this criterion is evaluated. The key to an esthetically pleasing appearance lies in the properly manage the soft tissue profile around dental implants. A novel implant restoration technique on the surface was proposed as a way to augment both soft- and hard-tissue profiles at potential implant sites. Different levels of roughness can be attained by sandblasting and acid etching, and a tetracalcium phosphate was used to supply the ions. In particular, the early stage attaching and repopulating abilities of bone cell osteoblasts (MC3T3-E1), fibroblasts (NIH 3T3), and epithelial cells (XB-2) were evaluated. The results showed that XB-2 cell adhesive qualities of a smooth surface were better than those of the roughened surfaces, the proliferative properties were reversed. The effects of roughness on the characteristics of 3T3 cells were opposite to the result for XB-2 cells. E1 proliferative ability did not differ with any statistical significance. These results suggest that a rougher surface which provided calcium and phosphate ions have the ability to enhance the proliferation of osteoblast and the inhibition of fibroblast growth that enhance implant success ratios.

Properties Evaluation of Tencel/Cotton Nonwoven Fabric Coated with Chitosan for Wound Dressing:

In this study, different Tencel/cotton ratios and needle punching densities were used to make Tencel/cotton nonwoven, which was then coated with chitosan to fabricate a double-layer wound dressing. The nonwoven-chitosan dressing, prepared by using the immersion-precipitation phase-inversion method, had properties that could control the evaporation water loss, promote the fluid drainage, and inhibit the invasion of exogenous micro-organisms. These results indicated that the nonwoven-chitosan membrane could be a potential material for use as a wound dressing.

Production of a Polyester Core-Spun Yarn with Spandex Using a Multi-section Drawing Frame and a Ring Spinning Frame

Owing to growing demand for figure hugging and comfortable clothes made with stretchable fibers, spandex fibers are being used in underwear, diapers, hosiery, leisurewear, sportswear, jeans, and so on. In the present study a polyester core-spun yarn containing spandex fibers was made using a self-designed, multi-section drawing frame and a ring spinning frame. The mechanical properties of the core-spun elastic yarns were examined in various processing conditions. The analytical results show that when the main drawing ratio of the spandex fibers was either 2.2 or 2.7, the maximum breaking tenacity and elongation of the core-spun elastic yarns exceeded those in any other of the main drawing ratio conditions.

Effect of Fiber Arrangement on the Mechanical Properties of Thermally Bonded Nonwoven Fabrics

Anisotropy is important to the structure and application of nonwoven fabrics. The arrange ment of the fibers and their orientation distribution are related to the mechanical structure of the web. In this study, we used a doffer of the roller card accompanied by a random roller to produce nonwoven fabrics. Partial random fiber arrangement is obtained by transferring the fibers on the rollers. As a result, the ratios of tensile and tearing strengths of the random web are below 3.0 and above 0.5, respectively. We can use this novel random arrangement of fibers in webs to improve the anisotropy of nonwoven fabrics.

Evaluation of high-modulus, puncture-resistance composite nonwoven fabrics by response surface methodology

Recycled high-modulus Kevlar fibers were blended with Nylon 6 staple fibers and biocomponent low-Tm/high-Tm polyester fibers to form high-modulus puncture-resistance nonwoven fabrics via opening, mixing, carding, lapping, needle-punching, as well as hot-pressing processes. In this paper, biocomponent low-Tm/high-Tm polyester fiber content, needle-punching density, and hot-pressing temperature were changed to evaluate the tensile strength, bursting strength and static puncture resistance of resulting nonwoven fabrics as related to aforementioned three parameters based on response surface methodology. The result shows that the tensile strength is highly related to needle-punching density and hot-pressing temperature; but the bursting strength and static puncture resistance are significantly involved with the aforementioned three parameters. The tensile strength, bursting strength, and static puncture resistance all present increasing and then decreasing trend with increase of its respective concerning parameters. Moreover, the static puncture resistance strength has linear dependence on bursting strength.

Physical properties of the functional bamboo charcoal/stainless steel core-sheath yarns and knitted fabrics

In this study, bamboo charcoal/stainless steel (B/S) core-sheath yarns were made of stainless steel wires and bamboo charcoal polyester textured yarn using a rotor twister machine. The speed of rotor twister was from 7000 to 11000 rpm and the wrapped amount varied from 2 to 7 turns/cm. The tenacity of 3.08 g/d was obtained when the speed of rotor twister was 8000 rpm and wrapped amount was 4.0 turns/cm. The tensile strain of 24.9% was yielded when the speed of the rotor twister was 7000 rpm and the wrapped amount was 5.0 turns/cm. The laminated amount of the knitted fabrics varied from 1 to 6 layers. The far infrared ray emissivity of the knitted fabrics was 0.934 when the laminated amount was 2 layers and wrapped amount was 6 turns/cm. Finally, the optimum anion density of the knitted fabrics was 610 ions/cm3.