Yarn hairiness has remained an issue of enormous interest in the field of yarn spinning research, since it directly affects yarn quality. In this work, a new method for the reduction of yarn hairiness is presented by attaching a simple effective air suction system to the web detaching zone of a conventional carding machine immediately behind crushing rollers. The slivers produced were almost free from dust or short loose fibers. Yarn properties such as hairiness, tenacity, elongation at break and evenness were evaluated. The ring-spun yarn that was produced was called Vacuum Cleaned Carded yarn or VCC yarn, due to the removal of the short fibers by air suction. The properties of VCC yarns were compared with those of conventionally produced reference yarn sample. Comparison of the results showed that the hairiness of optimum VCC yarn decreases by approximately 20%, while its tenacity, elongation at break and evenness were significantly improved. It was also found that the VCC yarn exhibited better spinning stability and was more environmentally friendly than the reference yarn.
Conventional lead aprons are rather heavy and uncomfortable for the wearer and also crack easily due to bending during both usage and storage. Coating of textiles with certain compounds provides protection against ionizing radiation. However, coated garments may have reduced flexibility and breathability. The principle aim of this study is development of a lightweight textile-based X-ray radiation shielding. The shielding fabric, while capable of significantly attenuating X-rays, relative to current conventional aprons is more intrinsically flexible, breathable, economical, easy to maintain, and crack resistant. Samples of fabrics were woven using melt-spun polypropylene monofilament yarns containing lead and tin particles. Shielding properties of the samples was measured using a high-purity germanium detector. Results showed that the samples composed of higher metal particles concentration and higher metal density and atomic number exhibited higher attenuation capability. Mechanical properties of the samples were evaluated. Furthermore, insignificant changes in the attenuation capability of samples due to abrasion and laundering processes occurred.
An experimental study was carried out to investigate the effect of temperature on the mechanical properties and the fracture mechanism of wood-plastic composites (WPCs) under tension. The specimens were prepared via injection molding of various weight fractions of pine wood particles and high-density polyethylene (with and without coupling agent, maleic anhydride-grafted polyethylene (MAPE)). The deformation and fracture behaviors of the samples at different temperatures were studied using a portable microscope setup during the test. The results indicated the significant effect of the test temperature on the fracture mechanism of WPC specimens. At room temperature, the dominant fracture mechanism for the samples without MAPE was debonding, whereas wood cracking was the dominant fracture mechanism in the presence of MAPE. At high temperatures, debonding was prominent over wood cracking in all samples (with and without MAPE), whereas at low temperatures (below 0 C) wood cracking was the dominant fracture mechanism.
In literature, liquid–liquid (L–L) phase separation has been widely adopted as the principle technique by which polymeric membranes are produced. However, the promotion of L–L phase separation as the means of controlling membrane morphology is still debatable. Thus, this work aims to introduce a facile and cost‐effective technique for controlling the morphology of poly(vinylidene fluoride) (PVDF) hollow fiber membranes (HFMs). The proposed technique is based on promotion of L–L phase separation which can be achieved through two different approaches: 1) reducing the distance between locations of dope and binodal curve through locating spinning dope on nonsolvent (water)/solvent (2‐pyrrolidone)/polymer (PVDF) ternary phase diagram by increasing of nonsolvent content and maintaining of polymer concentration at initial level; 2) simultaneous occurrence of thermally and nonsolvent induced phase separation (TNIPS). It is found that L–L phase separation promotion based on the above described approaches yields to PVDF HFM with partially double‐layered structure, enhanced mechanical properties, higher porosity, and smaller average pore radius with the potential to purify textile wastewater containing C.I. Disperse Violet 33. The proposed technique is advantageous due to lack of need for additives or post‐treatment process for HFM synthesis.
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