A new type of poly(ethylene terephthalate) fibre was developed via a high‐speed spinning technique. The dyeing behaviour of this fibre in supercritical carbon dioxide was compared with that of a fibre produced by conventional methods. At lower temperature and pressure, the high‐speed spun fibre, which had inherently larger crystallite sizes and lower birefringence, showed a larger dye uptake. However, when the supercritical conditions were elevated to 125 °C and 230 bar, the dye uptake of both types of fibre increased markedly and the difference in dye uptake between the fibres was reduced. The new type of fibre showed slightly higher grades in sublimation fastness tests.
Abstract:The impregnation of hydrophobic drug, tranilast, to the poly(lactic acid) (PLA) fiber with supercritical carbon dioxide (scCO 2 ) and the release behavior of tranilast from the PLA fiber were studied. The adsorption behavior of tranilast to the PLA fiber was evaluated. Equilibrium adsorption of tranilast was obtained in 60 min. The amount of adsorbed tranilast in equilibrium was 0.3~0.5% on the weight of fiber. The apparent diffusion coefficient was estimated from the apparent adsorption curve. The order of this value was 10 -12 m 2 /s. The tensile strength and modulus of the PLA fiber treated with scCO 2 /EtOH decreased, as compared to the untreated fiber. By the scanning microspectrophotometric measurements, it was confirmed that tranilast was distributed uniformly in the PLA fiber. It was revealed that the tranilast was not crystallized in the PLA fiber. A fairly slow release of tranilast from the PLA fiber was observed in buffer solution. The amount of released tranilast after 60 days was about 20% of the total drug amount introduced into the body of a rat.
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