Dissertation > Industrial Technology > General industrial technology > Materials science and engineering > Functional Materials

The Study on Preparation and Application of Photochromic Microcapsules

Author JinLing
Tutor PeiGuangLing
School Beijing Institute of Clothing Technology
Course Materials Science
Keywords Situ polymerization Spirooxazine Photochromic Microcapsules Discoloration of fabric
Type Master's thesis
Year 2008
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Photochromic materials in printing, security, packaging, especially in the defense industry has a wide range of applications. Organic photochromic material has discolored sensitive, bright color, but are vulnerable to environmental factors such as temperature, light, pH, and oxygen and lead to oxidative deterioration, fatigue resistance, and impact of its application in the field of textiles. This article contains the photochromic material spirooxazine PCE solution as the core material, melamine resin wall material, SDS as emulsifier, PVA as dispersing agents, photochromic microcapsules were prepared by in situ polymerization technique and applied to textiles, preparation of photochromic fabric. Experimental Study of the influence of light-induced discoloration of the solution concentration of their photochromic properties, the influence of the morphology and the intensity of the surface of the microcapsules, the formaldehyde / melamine molar ratio; emulsifying speed, emulsification time, the concentration of the emulsifier, the concentration of the dispersing agent, and acidification time conditions of light cause discoloration microcapsules surface morphology and particle size distribution; explore photochromic micro capsule sealing and discoloration of wall material / core material volume ratio and emulsification equipment light. Using optical microscopy, scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), laser particle size analyzer instrument light performance photochromic microcapsules were characterized. Obtained by calculating the wall thickness of the photochromic microcapsules. Acetylacetone method to detect the free formaldehyde content in the light-induced discoloration of the microcapsules, and the preparation of photochromic fabric the soaping resistance and rubbing fastness test. The results show that when the the discolored solution concentration of 0.75%, to obtain the best color effect; formaldehyde / melamine molar ratio of 3/1, the stirring speed of 1000rpm, the emulsification time was 40min, acidified time 0.5h, emulsifier concentration. 0.5%, and a dispersing agent concentration of 0.2%, the volume of the wall material / core material ratio 4/1, and the obtained photochromic microcapsules appear purple in sunlight, and can be achieved rapidly reversible color reaction; photochromic micro The capsules in the free formaldehyde content of 35 ~ 142mg/kg, found GB18401-2001 formaldehyde content defining a predetermined standard. The mechanism of high-speed emulsifying prepared photochromic microcapsules coated onto the surface of the knitted fabric, can quickly in sunlight photochromic reversible discoloration fabric, the fabric has a good resistance to soaping and rubbing fastness.

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