Po Ching Lu

Effects of yarn types and fabric types on the compliance and bursting strength of vascular grafts.

The use of vascular grafts to replace damaged native vessels plays a significant role in clinical cardiovascular disease treatment. Comparable mechanical properties of small-diameter vascular grafts to that of native vessels are crucial and challenging. This study examines how different fabrics and yarns influence the mechanical properties of vascular grafts and evaluate the effectiveness of vascular grafts being used as native vessels. Five wrapped yarns are made into braids, warp knits, and weft knits. These knits are incorporated with PVA via freeze-thawing in order to form vascular grafts that are evaluated with circular properties and bursting strength tests. The test results indicate that the number of freeze-thawing cycles is related to the compliance and bursting strength of vascular grafts. In addition, the combination of spandex fibers improves the compliance of both the fabrics and vascular grafts.

Preparation and applications of polyamide 6/IRM® tooth root composite filling material

Intermediate restorative material (IRM®) is the most commonly used temporary filling material. This research mixed IRM with Polyamide 6 (Nylon 6) fibers, forming the Nylon/IRM tooth root composite filling materials. Tests such as setting time, degree of solubility, compressing strength, and micro-leakage were carried out to examine the properties of the Nylon 6/IRM® composite material. The result showed that there was no significant difference in the setting time and degree of solubility after adding the Nylon 6 fibers. The loading after the yielding point of the Nylon 6/IRM® was more than 250 N; micro-leakage was found on the 13th day.

Effect of twist coefficient and thermal treatment temperature on elasticity and tensile strength of wrapped yarns

Twisting is an important process in the manufacture yarns for textiles and has an influence on woven fabrics, knitted fabrics, and braided fabrics made with such yarns. This study aims to determine how twist coefficients and thermal treatment temperatures influence tensile strength, elongation, and elastic properties of the resulting wrapped yarns. Polyester (PET) yarns and spandex fibers were twisted into PET/PET wrapped yarns and PET/spandex wrapped yarns, and during the process the thermal treatment temperatures as well as twist coefficients controlled by rotor speed were changed. The results show that variations in twist coefficient do not influence the tensile strength and elongation of the PET/PET wrapped yarns. However, an increase in twist coefficient results in an increase in tensile strength and a decrease in elongation of PET/spandex wrapped yarns. The elongation of PET/spandex wrapped yarns thermally treated at 160℃ is lower than that of untreated PET/spandex wrapped yarns by 86%. In addition, the residual stress and permanent deformation of PET/spandex wrapped yarns both decrease as a result of the increasing thermal treatment temperature.

Manufacturing Technique and Property Evaluations of PET/Gelatin Composite Tubular Braids

This study examine the influence of gelatain with different concentrations on the physical property of the PET/Gelatin composite tubular braids. PET fibers are braided into tubular braids on a braider, and then immersed in gelatin solution with various concentrations to form PET/Gelatin composite tubular braids. The tensile strength and water contact angle of the braids are then tested to determine the their physical properties. The experiment results show that an increasing concentration of gelatin does not result in a significant varation in tensile strength, but a decreased displacement only.

Manufacturing Technique and Stab-Resistance Evaluation of Three-Dimensional Nylon 6/LPET Compound Nonwoven Fabrics

This study aims to examine the influence of the temperatures of heat treatment on the puncture-resistance of Nylon6/LPET compound nonwoven fabrics. Polyamide 6 (Nylon 6) fibers and low-melting-point polyester (LPET) fibers are combined and undergo a heat treatment to make three-dimensional (3-D) Nylon 6/LPET compound nonwoven fabrics through a nonwoven process. The nonwoven fabrics are tested for their dynamic puncture resistance, constant rate puncture resistance, and impact strength. The experiment results show that when thermally treated at a high temperature, the compound nonwoven fabrics are rendered with a lower dynamic puncture resistance and a lower constant rate puncture resistance, but a greater impact strength.

Mechanical Property Evaluation of IRM®/Chitosan Fiber Composite Temporary Filling Material

The temporary filling material seals up the tooth cavity so as to prevent bacterial leakage and the second infection in the root-end treatment. Chitosan is biodegradable, bio-resorbable, non-toxic, and antibiotic. In this study, chitosan fiber is used to enhance the temporary filling material compressive strength and the tooth bite force. IRM® is reinforced by the 2, 4 and 6 wt% chitosan fibers, respectively. And after solidified the IRM®/ Chitosan fiber composite temporary filling material was obtained. Then setting time, solution test, compressive strength and dye micro-leakage of IRM®/ Chitosan fiber composite temporary filling material were be evaluated. In result, maximum compressive strength of IRM®/ Chitosan fiber composite temporary filling material was obviously increased 200 N than IRM® matrix. As to the micro-leakage test, no trace of leakage was found on the 7th day. Consequently, IRM®/ Chitosan fiber composite temporary filling material can be a good candidate in the short-term dental clinical surgery.

Effect of manufacturing parameters and thermal treatment on the properties of tubular braids and tubular knits

Abstract Textile techniques can be applied to create two-dimensional or three-dimensional tubular fabrics. Three-dimensional tubular knits can be used in many fields, such as for medical textiles, conductive textile, composites, and tissue engineering. This study aimed to examine the effects of different yarn types on various fabrics and of different temperatures on the variations in the properties of textiles. Four types of wrapped yarn (P150, P75, S140, and S70) were made into tubular braids and knits, after which the products were thermally treated at various temperatures (120°C, 140°C, and 160°C). A shrinkage measurement, a porosity test, a braid angle test, and a tensile test were performed to evaluate the tubular braids and knits. The test results indicated that the thermal treatment temperature did not affect the porosity of the tubular braids and tubular knits. The porosity of the tubular braids was between 40.32% and 48.27%, while that of the tubular knits was between 10.15% and 35.57%. In addition, the tensile strength of both fabric types increased by 40–50%, while their displacement increased by 200–250%. In the future, the efficacy of tubular braids and tubular knits for use as vascular grafts will be examined.

Effects of Counts of PET Yarns and Spandex Fibers on the Properties of Tubular Knitted Fabrics

This study examines how the counts of PET yarns and spandex fibers influence the properties of tubular knitted fabrics. PET yarns and spandex fibers with different counts are combined to form wrapped yarns, which are then made into tubular knitted fabrics. The surface of the knitted fabrics is observed, after which the knitted fabrics are tested for their tensile strength. The test results show that the tensile strength and thickness of the tubular knitted fabrics both increase as a result of the increasing content of PET yarns; however, the content of either spandex fiber or PET yarns is not correlated with the deformation of the tubular knitted fabrics.

Characterization and Recovery Evaluation of Elastic Knitted Fabric

The present study aims to investigate the effects of the ratio of different rubber threads on the elastic, tensile, air permeability, andfar-infrared emissivity properties ofelastic warp-knitted fabric. Polyester filaments and rubber threads were applied as warp yarns while bamboo charcoal (BC)/Nylon (NY) filament was used as weft yarn to fabricate elastic knitted fabric (EKF) by using Velcro Crochet Machine. The four different ratios of rubber threads in warp direction were 0 %, 25 %, 50 % and 100 %. The result revealed that with the increase in weight ratio of the rubber thread, the air permeability decreased while the tensile elongation tended to increase in both warp and weft directions.

Manufacturing Technique and Property Evaluations of Tubular PLA/Spandex/Gelatin Composite Braids

Polylactic acid (PLA) is a synthetic polymer that has biocompatibility and biodegradation. This study aims to examine the influence of manufacturing parameters on the physical properties of tubular PLA/Spandex/Gelatin composite braids. PLA fibers and spandex are combined, braided and then immersed in gelatin solution to form tubular PLA/Spandex/Gelatin composite braids. The tensile strength, bursting strength, and porosity of the resulting braids are tested, and the experiment results show that a greater twist per inch (T.P.I.) causes a higher tensile strength and bursting strength, but does not change the porosity distinctively.