The tensile properties of skin in vivo and in vitro were investigated experimentally. The uniaxial and biaxial extension properties of the back of a hand in vivo and chicken skin in vitro are measured in detail by using a fine tensile tester. We found that their initial properties characteristically have extreme nonlinearity and hysteresis. These properties are similar to the properties of fiber assemblies, that is, woven and knitted fabrics used for clothing materials. The stress relaxation of chicken skin in vitro was also investigated. The results show the strain and temperature dependence of these properties. These properties of skin should be considered as basic data related to the materials of products used in close contact with the human skin, for example, clothing materials.
To obtain fundamental data for designing comfortable women's foundation garments, we analyzed waist-nipper factors that affect subjective feeling (compressive feeling, comfort and silhouette-satisfaction) and physiological responses (heart rate, skin blood flow, skin and oral temperature) in terms of materials, structure, size and clothing pressure. Seven women were employed as subjects. The clothing pressure was not dependent on the tensile property of individual parts of the materials used for waist-nipper, but on the tensile property of the waist-nipper viewed as a composite object, including structure. The changes in physiological variables were smaller with the waist-nipper having a large non-stretch area than with that having a small non-stretch area. However, the former type of waist-nipper caused higher compressive feeling and discomfort. When the waist-nipper mostly composed of stretch materials were worn, size had great effects on clothing pressure, subjective feeling and physiological responses. The effects of clothing pressure on physiological responses were highest at the center of the abdomen.
Cotton fabrics modified by carboxymethylation to the degree of substitution (DS) of 0.02∼0.16 were separated into the salt-type CM-Cotton-Na with more water swelling and the acid-type CM-Cotton-H with less water swelling. The two types of cotton fabrics were treated with a commercially available cellulase product. For CM-Cotton-Na and CM-Cotton-H, the weight loss and the saccharification activities of the cellulase decreased with DS of 0.10 or less. The modification by carboxymethylation for cotton fabrics inhibited apparently the catalytic reaction of the cellulase. For CM-Cotton-Na and CM-Cotton-H, the cellulase showed the minimum value of the weight loss activity at DS of 0.10 and that of the saccharification activity at DS of 0.14. For CM-Cotton-Na, the cellulase exhibited larger value of the weight loss activity and smaller value of the saccharification activity at DS of 0.16 compared to the unmodified cotton fabric. We discussed that the endo-type cellulase attacked positively to CM-Cotton-Na with DS of 0.10 or more because of its more water swelling, but attacked negatively to CM-Cotton-H because of its less water swelling. On the other hand, the exo-type cellulase was inhibited to attack the modified cotton fabrics with DS of 0.10 or more.
In this study, we found that Pseudomonas broth (PB) after cultivating Pseudomonas aeruginosa for two weeks had antibacterial ability to Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginoa and Escherichia coli. Interestingly, most of fibers, especially in the protein fibers, treated with antibacterial materials that Pseudomonas aeruginosa secreted under the alkaline condition maintained the antibacterial ability to Staphylococcus aureus and Klebsiella pneumoniae. These results suggest that the antibacterial mate-rials that Pseudomonas aeruginosa secreted in PB are available for dying conversion with antibacterial effect.
The conjugated staple fiber of polyester (PET) and polypropylene was divided by the alkaline hydrolysis under the high pressure conditions over 100 MPa. The decomposition of the sea element, PET, was accelerated with the temperature and pressure. The addition of the cationic surfactant also enhanced the reaction rate when the concentration was more than 0.5 g/L. At high surfactant concentration, the acceleration effect was saturated. The high-pressure alkaline hydrolysis gave the fine polypropylene staple fiber by complete elimination of the sea matrix.