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Gone through a difficult process, more than half a century of polylactic acid can be used as alternative materials of the existing petroleum-based plastics, synthetic fibers and films. Polylactic acid fiber has the advantage of soft, shiny and soft, take comfort, strength and elongation and high, but there are also poor heat resistance and resistance to acid and alkali outstanding problems. In this paper, the problem exists in the actual production of polylactic acid fiber applications, based on the characterization and analysis of polylactic acid fiber structure, its resistance to heat, dry heat resistance, acid and alkali resistance, in-depth research. Expectations of these studies, a deeper understanding of the structure and properties of polylactic acid fiber, and provide reference for polylactic acid fiber performance improvements, the determination of the fiber and fabric processing conditions. In this paper, scanning electron microscopy, wide-angle X-ray diffraction, differential scanning calorimetry, infrared spectroscopy test the performance of untreated and after different dry heat and moist heat, acid and alkali solution treatment polylactic acid fiber research. Wherein the fiber structure and performance mainly includes: the fiber morphology and microstructure fibers strong stretch resistance, shrinkage, weight loss rate, and thermal properties, and further including processing before and after the performance of the fabric include: whiteness, breathability and drape resistance. Through experiments and analysis that the polylactic acid fiber wet heat resistance than its poor resistance to dry heat. The moist heat treatment of a temperature of 100 ° C or above, the fibers will occur serious shrinkage and greater breaking strength loss; The fabrics feel sclerosis, loss of luster. The instrument analysis results show that the heat and humidity treatment, the polylactic acid crystal structure has changed, the main chain part of the fracture, the binding force of the secondary bonds weakened. Polylactic acid fiber good resistance to dry heat, dry heat treatment below 110 ℃, polylactic acid fiber shrinkage smaller, the strength decreased less fabric whiteness less affected; prolonged dry heat treatment temperature exceeds 130 ° C. easily lead to fiber degradation; when the dry heat treatment temperature is 150 ° C, the crystal structure has changed. pH = 11 alkali solution properties of polylactic acid fiber damage. High temperature caustic soda treatment makes the molecular chain breakage, deterioration of the performance of the fibers, and the comfort and appearance properties of the fabric are subject to greater damage. At low temperature, pH = 9.4 of caustic soda solution basic polylactic acid fiber and fabric will not cause major damage, security alkali treatment conditions fall within the scope of practice. When the processing temperature below 100 ° C, pH = 3.2 a strong acidic solution was less damage to the fiber and fabric.
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