Compression Properties of Polyester Needlepunched Fabric
In the present paper, a study of the effects of fabric weight, fiber cross-sectional shapes (round, hollow and trilobal) and presence of reinforcing material on the compression properties (initial thickness, percentage compression, percentage thickness loss and percentage compression resilience) of polyester needle punched industrial nonwoven fabrics is presented. It was found that for fabrics with no reinforcing material, the initial thickness, compression, and thickness loss were higher than fabrics with reinforcing material, irrespective offiber cross-section. Compression resilience data showed the reverse trend. Initial thickness for trilobal cross-sectional fabric sample was highest followed by round and hollow cross-sectioned polyester needle punched fabrics. The polyester fabric made from hollow cross-sectioned fibers showed the least percentage compression at every level of fabric weights. The trilobal cross-sectioned polyester fabric sample showed higher thickness loss followed by round and hollow cross-sectioned polyester fabric samples respectively. The hollow cross-sectioned polyester fabric samples showed maximum compression resilience followed by round and trilobal cross-sectioned polyester samples irrespective of fabric weights. The initial thickness increases, but percentage compression, thickness loss and compression resilience decreases with the increase in fabric weight irrespective of fiber cross-sectional shapes.
Study on the Comfort of Knitted Elastic Fabrics based on Compressive Deformation Behavior
Comfort is one of the most important factors influencing the performance of apparel such as knitted elastic clothing, woven elastic shirts and elastic velvet fabrics. The compressive behavior of knitted elastic fabric affects the excellence in comfort. This study aimed to investigate the comfort of knitted elastic fabric based on compressive load. For this purpose, fabrics were produced with three different stitch densities (loop sizes), and compressive load tests were applied at three various penetration depths. According to these parameters, 9 fabric samples were prepared. Each sample was tested 30 times; therefore, the total number of examined cases was 270. The compressive load was measured using special designed tools, which were installed on the Instron tensile tester. The effects of penetration depth and loop size on compressive load were evaluated by using the CCD statistical model with four repeats of each experiment. The results indicate that the loop size and penetration depth have significant influence on the compressive load, which is modeled by a third order equation with R2 of 0.999 between applied model and experimental data. Consequently, the comfort could be predicted in terms of loop size and penetration depth. Utilizing this method can help apparel manufactures produce knitted elastic clothing with high comfort, according to the end use of garment.
ROOM- AND HIGH-TEMPERATURE MAGNETIC PROPERTIES OF Sm(CobalFexCu0.088Zr0.025)7.5 (x=0.30) SINTERED MAGNETS
The effect of Fe content on room- and high-temperature magnetic properties of Sm(CobalFexCu0.088Zr0.025)7.5 (x=0-0.30) sintered magnets, prepared by the conventional powder metallurgy method, has been systematically studied. With increasing Fe content, the remanences BT and maximum energy products (BH)max at room temperature gradually increase and reach optimal values of 1.055 T with x=0.27 for BT, and 205 kJ/m3 with x=0.21 for (BH)max, respectively, and then drop sharply with further Fe increase. An excessive addition of Fe (x≥0.24) results in rapid deterioration of permanent magnetic properties due to the formation of a considerable amount of FeCo soft magnetic phase. It was found that the effect of Fe content on high temperature stability is huge. The lower the Fe content, the smaller the temperature coefficient of coercivity. When x=0.07, a temperature coefficient of coercivity of -0.14%/K (293-723 K) can be achieved, as compared with -0.23%/K for x=0.21. BT of 0.725 T, bHc of 517 kA/m, iHc of 764 kA/m, and (BH)max of 95 kJ/m3 at 723 K were obtained, and the B-H demagnetization curve remains a straight line.