Research On The Resistance Of PLA Fiber To Wet-hot, Dry-hot, Acid And Alkali

The PLA has passed through more than half a century. Now oil plastic, man made fiber and plastic film can be replaced by PLA materials. The PLA fiber has many advantages, such as soft smooth feeling, subdued softness, wearing comfortable, high strength and elongation and so on. But there are still some prominent problems in heat resistance and acid-resistance.According to the problem in PLA fiber's development and production, the PLA fiber will be characterized firstly by SEM, DSC and IR in this paper, then painstaking study has been made of its wet-dry, hot-dry, acid and alkali resistance. This paper can provide reference for the improving property and the determination of processing condition of the PLA fiber and fabric.In this paper, scanning electron microscope(SEM),X-ray diffraction(XRD),differential scanning calorimeter (DSC) and Fourier Transform infrared Absorption Spectrum(FTIR) are used to test the PLA fiber's properties before and after treating by heat,acid and alkali. The microstructure, strength and elongation, the weight loss and the thermal properties of PLA fiber are characterized. The whiteness, air-permeability and drape of PLA fabric are also characterized in this paper.The following are the results:the PLA fiber's wet-hot resistance is poor than its dry-hot resistance. When the hot wet-air temperature is more than 100℃, the PLA fiber will shrink seriously and have much loss in its strength. The handle of the PLA fabric turns harden. At the same time, the fabric will lose luster. The research through XRD, DSC, FTIR showed that its crystalline structure has changed.The PLA fiber has better dry-hot resistance. The shrinkage and the loss in strength of the PLA fiber are small and there is little influence on the fabric whiteness when the hot dry-air temperature below 110℃The fiber maybe degrade when the hot dry-air temperature over 130℃.The crystalline structure of the PLA fiber has changed when hot dry-air temperature over 150℃.The property of the PLA fiber will be injured seriously when the pH value is eleven. The hot aqueous alkali will lead to the breaking of macromolecular chain and the property of the PLA fiber and the fabric will be injured seriously.The PLA fiber and fabric will not be injured seriously when the pH value is nine point four and the alkali aqueous temperature is not high. The PLA fiber and the fabric is less injured when the acidic aqueous temperature below 100℃and the pH value is three point two.