Research On Performance&Degradation Property Of PLA Fabrics

The PLA fiber is a new kind of synthetic fiber. Previous studies focused on the structure of PLA fiber, properties of the yarn, processing technology of PLA fiber and corresponding fabric and mechanical properties of PLA knitted fabrics. However, there were not many studies about the performance of PLA knitted fabrics. Therefore, research on the performance of the PLA knitted fabrics is very important for the application of PLA knitted fabrics in apparel.PLA fiber is a kind of eco-kindly fiber, Today, because the environmental load increasingly aggravates, it is very meaningful from the angle of waste utilization and environmental protection to study on how to make the PLA fibers degrade into low molecular substances through simple processing.In this thesis, a comparative study was carried out on the performance of5knitted fabrics that contain PLA fiber,2knitted fabrics that contain Coolmax and8knitted fabrics that contain cotton. The performance included the low stress mechanical properties, the anti-pilling performance and the thermal-wet comfortable properties.The low stress compress properties and the low stress tensile properties of the fabrics were tested under standard atmosphere conditions by using Instron3380electronic universal material test system. The test results showed that:As for the fabrics tested,PLA58/Tencel35/Spandex7kintted fabric had the smallest filling power and RC,two cotton fabrics had the largest filling power; PLA58/Tencel35/Spandex7kintted fabric was hard to tensil.a cotton knitted fabric was easy to tensil.The anti-pilling performance of fabrics were tested under standard atmosphere conditions by using M227pilling test system.The results shown that:The anti-pilling performance of fabrics that contain PLA fiber was not only related to the structure of PLA fiber.but also related to the the structure of fibers that blended with PLA fiber.both of the grade of anti-pilling performance on PLA/Tencel knitted fabrics were2.5,they had bad anti-pilling performance,and the grade of anti-pilling performance on another PLA fiber blended fabric was5,it had a good anti-pilling performance.It cannot be lumped together.The thermal resistance performance was tested by YG606E type of of thermal resistance tester,the result shown that:The thermal resistance of fabrics that contains PLA fiber were lower,which is suitable to wear in summer; fabrics that contain cotton had higher thermal resistance.The thermal resistance would get higher if the fabric density increased for the fabrics with same or similar thickness. Accordingly, the fabrics that contains PLA were more approprite to make garments worn in autumn and winter.The maximum Instantaneous thermal flow was tested by KES-F7,the results shown that Knitted fabric containing PLA fiber had a strong sense of cold exposure and issuitable for worn in summer when the weather is not very cold. Cotton knitted fabrics had a strong sense of warm and it was suitable for making underwear that worn in cold weather.The air permeability was tested by YG461E Digital Type Air Permeability Tester. It was founded that there was no regular of the air permeability on the13kinds of fibrics.and the area modulus of stitch of the fabrics played an important role in the air permeability.The wicking effect was tested by LCK800wicking effect tester,the results shown that:the wicking hight of Bamboo70/PLA30kintted fabric and PLA58/Tence135/Spandex7kintted fabric were the highest, the wicking hight of3cotton fabrics were the lowest.The water vapor permeability was tested by LEY-216C water vapor permeability Tester.the results shown that:water vapor permeability of the Bamboo70/PLA30kintted fabric was the largest among all the tested fabrics,The fiber composition of fabric will affect the amount of water vapor permeability of the knitted fabric.The OMMC was tested by MMT. The results showed that the fabrics that contain PLA fiber were poor in OMMC,so was the fabrics that contain Coolmax and the fabrics that contain cotton.The overall thermal-wet comfort was analyzed by grey clustering analysis. It was founded that the PLA60/Tence140knitted fabric Bamboo70/PLA30knitted fabric and Coolmax knitted fabric were the best on overall thermal-wet comfort. Cotton60/PLA40and Modal55/Cotton25/PLA20were the worst on overall thermal-wet comfort.Through the degradation experiment, it was shown that with time went by, the degradation of knitted fabrics were inceresed, and degradation rate of Bamboo70/PLA30knitted fabric was the highest,the degradation degree of3knitted fabrics on40℃was higher than20℃,and no matter what kind of degradation temperature,the degradation degree Bamboo70/PLA30was the highest.