EFFECT OF THE OXIDATIVE POWER OF IODINATION ON THE OPTICAL-PROPERTIESOF ALPACA FIBERS

This study deals with the changes in the optical properties of Alpaca fibres due to the effect of the oxidative power of iodine on the struc tural characteristics of Alpaca fibres. The diffraction of a He-Ne las er beam was used to measure the dimensional parameters, transverse sec tional shape and area of the Alpaca fibre sections. Optical and scanni ng electron microscopes were used to confirm the geometrical parameter s of the cross-sections. Two methods were applied for the measurement of the refractive indices and birefringence of the Alpaca wool fibres. The first was concerned with the application of multiple-beam Fizeau fringes in transmission before treating the fibre with iodine. The sec ond method made use of a double refracting interference microscope (th e Pluta polarizing interference microscope). The double beam technique was considered the most suitable in determining the mean refractive i ndices and the double refraction of the samples after the iodine treat ment. Large changes were observed in the values of the refractive indi ces due to the iodination process, while the birefringence exhibited n o appreciable change. Examination of the Alpaca fibres by X-ray diffra ctometry showed that the crystalline parts had been completely decompo sed and degraded due to the effect of I2, which causes oxidative sciss ion of the intermolecular disulphide bonds of the keratins.