No abstract

No abstract

Melamine-formaldehyde microcapsules containing eicosane were prepared by in situ polymerization. The characterization of the microcapsules, including the particle size and size distribution, morphology, thermal properties, and stability, was carried out. The prepared microcapsules were added to polyester knit fabrics by a conventional pad-dry-cure process to develop thermoregulating textile materials. The morphology, thermal properties, and laundering properties of the treated fabrics were also investigated. The microcapsules were spherical and had melamine-formaldehyde shells containing eicosane. The microcapsules were strong enough to secure capsule stability under stirring in hot water and alkaline solutions. The heat storage capacity increased as the concentration of the microcapsules increased. The thermoregulating fabrics had heat storage capacities of 0.91-4.44 J/g, which depended on the concentration of the microcapsules. The treated fabrics retained 40% of their heat storage capacity after five launderings.

ABSTRACT:Polyester knit fabrics were treated with phase-change-material microcapsules by a pad-dry-cure method with a polyurethane binder. The treated fabrics were evaluated in terms of the thermal properties, air permeability, moisture vapor permeability, moisture regain, low-stress mechanical properties, and hand, with respect to the add-on of microcapsules. The surface morphology of the treated fabrics was investigated with scanning electron microscopy. The low-stress mechanical properties of the treated fabrics, including the tensile, shear, bending, surface, and compression properties, were measured with the Kawabata evaluation system for fabrics (KES-FB). As the add-on increased, the heat storage capacity of the treated fabrics increased. The treated fabric with 22.9% add-on was capable of absorbing 4.44 J/g of heat. The air permeability and moisture vapor permeability decreased, whereas the moisture regain increased, with an increase in the add-on. The tensile linearity and geographical roughness increased, whereas the resilience, bending, and shear properties decreased with an increase in the add-on. The fabrics became stiffer, less smooth, and less full as the add-on increased, and thus the total hand value decreased.

ABSTRACT:The effect of the molecular weight of chitosan on antimicrobial activity was investigated using three chitosans of different molecular weights [1800 (water soluble), 100,000, and 210,000] and similar degrees of deacetylation (86 -89%). Cotton fabrics were treated with chitosan by the pad-dry-cure method. The molecular weight dependence of the antimicrobial activity of chitosan was more pronounced at a low treatment concentration. Chitosans with molecular weight of 100,000 and 210,000 effectively inhibited Staphylococcus aureus at a 0.5% treatment concentration. Chitosan with a molecular weight of 1800 was effective against S. aureus at a 1.0% treatment concentration. Escherichia coli was effectively inhibited by chitosan with a molecular weight of 210,000 at a 0.3% treatment concentration and by chitosans with a molecular weight of 1800 and 100,000 at a 1.0% treatment concentration. Proteus vulgaris was effectively inhibited by chitosans with molecular weight of 100,000 and 210,000 at a 0.3% treatment concentration and by chitosan with a molecular weight of 1800 at a 0.5% treatment concentration. None of the chitosans significantly inhibited Klebsiella pneumoniae and Pseudomonas aeruginosa below a 1.0% treatment concentration. Chitosans with high molecular weights were more effective in inhibiting bacterial growth than chitosans with low molecular weights.