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Cyclobutane-1,2,3,4-tetracarboxylic dianhydride (CBDA) is an anhydride with a cis-trans-cis configuration. It can be used to synthesise polyimide films. Polymer films have excellent heat resistance, are transparent and colourless, with transmittance ranging from 81.5% to 85.8%, and are suitable for use in high quality display materials such as liquid crystal displays. The polymers made with pyrrolidine dianhydride instead of CBDA are dark yellow in colour and have a lower transmittance in the range of 48% to 63.9%.

White to light yellow solid

cyclobutane-1,2,3,4-tetracarboxylic dianhydride and diamine monomer are used for preparation a polyimide (PI), the type of polyimide has excellent electrical characteristics and optical type, with the material prepared the PI film, in addition to having a higher rate cast visible outside, and can withstand high temperatures thirty-four Baidu. Its performance is very good, is the preparation of a liquid crystal display with an ideal material for the film.

Preparation of 1,2,3,4- cyclobutanetetracarboxylic acid dianhydride (CBDA)To a 2L quartz glass photoreactor equipped with sixteen UV lamps (300nm) , a stirrer and a cooler were attached and 250ml of ethyl acetate and 100g of maleic anhydride were added thereto followed by stirring for complete mixing. To avoid an excessive temperature increase, an air-cooling type cooler was first run and then UV light was illuminated for a photoreaction for 24h with stirring so as not to have the reactants adhered to the reactor walls. As a result, 71g of white solid was obtained. After the filtration, the white solid was dried for 24h in a vacuum dryer at 60°C Thus-obtained solid was then added to acetic anhydride, dissolved therein and slowly heated to 150°C followed by the reaction for 24h . Hot reaction solution was filtered through a filter paper to remove impurities and kept in a freezer at the temperature of 0°C or less for recrystallization for 24h to obtain a yellow solid. Thus-obtained solid was filtered and washed three times with 1,4-dioxane to remove acetic anhydride, and then dried in a vacuum oven at 60°C for 48h to obtain 64g of 1, 2, 3, 4 -cyclobutane tetracarboxylic acid dianhydride (CBDA) .