MICROWAVE RADIATIONS FOR HEAT-SETTING OF POLYESTER FIBERS

The use of radio and microwave frequency is gainingimportance for industrial applications such asheating, drying, and other processing. The mostimportant advantage of using microwave is that it isnon-contact or localized heating and the heat isproduced within the material. This can be much moreeffective than indirect heating where the heatpropagation is by heat conduction through thematerial. We have been investigating the influence ofmicrowave radiation on different fibers for the lastfew years. In the present investigation we usedmicrowave frequency of 2450 MHz to investigate itseffect on polyester fibers. The polyester fibers wereheat set in air as well as a liquid, which acted as alossy substances. The liquid was chosen on the basisof earlier experiments, which showed the maximumeffect. A comparative study was also carried outusing conventional heating in silicone oil.Using the method of X-ray Diffraction (XRD) wecalculated the changes in % crystallinity andorientation. It was found that as the time of treatmentunder microwave radiation increased from 15 sec. to120 sec. the order factor was found to increase from0.32 to 0.71.The crystalline orientation as determinedfrom the azimuthal scan was also found to increase.Such structural changes can be highly beneficial forthe processing of fabric in industry. The microwaveradiation process is fast, reliable and energy saving.