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In this article, we have studied the thermal, chemical, and mechanical properties of the polyurethane artificial leather. Polyurethane artificial leathers were made from polyol, diisocyanate, chain extender, a catalyst, polyester circular knitted fabric, and warp knitted fabric. After manufacturing the artificial leathers, the properties of six different samples were investigated according to the NCO index. The equivalence ratios of the isocyanates to polyols containing a hydroxyl group are referred to as the NCO index. Samples were synthesized with an NCO index of 1.0, 1.4, and 1.8 by changing the weight ratio of diisocyanate. The result showed that as the NCO index increased, the unreacted NCO functional groups and cross-link increased and the mechanical properties of the polyurethane artificial leather were increased. The mechanical properties of circular knitted fabric polyurethane artificial leather were superior than warp knitted fabric polyurethane artificial leather.

Polyethylene based carbon fibers were studied using high density polyethylene(HDPE) fibers and linear low density polyethylene(LLDPE) fibers with various melt flow index. The draw ratio of the polyethylene fibers and the sulfonation mechanism were investigated under hydrostatic pressures of 1 and 5 bar in the first time. The influence of the melt flow index of polyethylene and types of polyethylene fibers on the sulfonation reaction was studied. Carbon fibers were prepared through the sulfonation of LLDPE fibers possessing side chains with a high melt flow index. The polyethylene fibers, which exhibited thermoplastic properties and plastic behavior, were cross-linked through the sulfonation process. Their thermal properties and mechanical properties changed to thermoset properties and elastic behavior. Although sulfonation was performed under a hydrostatic pressure of 5 bar, it was difficult to convert the highly oriented polyethylene fibers because of their high crystallinity, but partially oriented polyethylene fibers could be converted to carbon fibers. Therefore, the effect of fiber orientation on fiber crosslinking, which has not been reported in previous literature, has been studied in detail, and a new method of hydrostatic pressure sulfonation has been successful in thermally stabilizing polyethylene fiber. Hydrostatic sulfonation was performed using partially oriented LLDPE fibers with a melt flow index of 20 at 130 °C for 2.5 h under a hydrostatic pressure of 5 bar. The resulting fibers were carbonized under the following conditions: 1000 °C, 5 °C/min, and five minutes. Carbon fibers with a tensile strength of 2.03 GPa, a tensile modulus of 143.63 GPa, and an elongation at break of 1.42% were prepared.

PVC coated fabric is a useful structural material mainly used as a roof material because of its lightweight, flexibility. However, the main issues of this PVC coated fabric product is that it is damaged such as tensile failure, peel, and tear when exposed to extreme environments such as strong rain and wind owing to its inferior mechanical properties. Various studies have been reported to improve the mechanical properties of PVC coated fabric, there have been no significant improvement. Therefore, in this study, to improve the mechanical properties of the PVC coated fabrics, applied the low viscosity PVC resin and 4 [Formula: see text] 4 matt weave structure polyester fabric. In addition, the mechanical properties of PVC coated fabrics with various viscosity PVC resins (D10, D8, D5, D2 and D0) were investigated and the mechanical properties of PVC coated fabrics with various weaving structure such as plain weave structure (1 [Formula: see text] 1), matt weave structure (2 [Formula: see text] 2, 3[Formula: see text] 3, and 4 [Formula: see text] 4) were studied. The PVC coated fabric fabricated by low viscosity PVC resin (D10), the tensile strength, tear load, and peel strength improved about 3%, 11%, and 29% compared to the PVC coated fabric fabricated by high viscosity PVC resin (D0). The mechanical properties of the PVC coated fabric fabricated by 4 × 4 matt weave structure polyester fabric was superior to the 1 × 1 plain weave structure polyester fabric and 2 × 2, 3 × 3 matt weave structure polyester fabrics because of the low crimp rate and low intersection point of the warp yarn and weft yarn of the fabric.