Bisphenol A-carbonic acid copolymer

Bisphenol A-carbonic acid copolymer is a polyester in which dihydric (or polyhydric) phenols are linked together by carbonate bonds. Bisphenol A-carbonic acid copolymer is the toughest of all thermoplastics. They are transparent, strong, autoclavable, and non-toxic. Its brittle temperature is 135°C. Bisphenol A-carbonic acid copolymer has good oxidative stability, mainly because it does not contain secondary and tertiary carbon atoms. The polymer is stable in air for a long time. At higher temperatures, some oxidation and crosslinking will occur. Ultraviolet light is strongly absorbed by polycarbonate, causing cracking and degradation. However, this effect is limited to the surface and no deep deterioration will occur. Therefore, although the film may become brittle when weathered, the molded parts will not be seriously affected. Bisphenol A-carbonic acid copolymer can be melt processed by all standard techniques, although its melt viscosity is quite high. The polymer has a wide range of uses, and the largest application is in the electronics/business machine field for parts such as connectors, terminals and covers.

There are two methods for the synthesis of polycarbonate, one is the phosgene method, and the other is the transesterification method. Phosgene method: The phosgene method is also called solvent method and interfacial polycondensation method. It is a polycarbonate prepared by interfacial polycondensation of bisphenol A sodium salt and phosgene under normal temperature and pressure. The phosgene production process is mainly divided into the following steps: phosgenation. Add the prepared bisphenol sodium salt to the phosgenation kettle, then add dichloromethane to the phosgenation kettle, start stirring, when the temperature in the kettle drops to 20°C, pass in phosgene at a constant speed for the phosgenation reaction . When the pH of the reaction medium is 7-8, stop phosgene, and the phosgenation reaction ends. Polycondensation. Add phosgenate, 25% lye, catalyst, trimethylbenzylammonium chloride and molecular weight regulator phenol, etc. into the reactor. Under stirring, continue the reaction at 25-30℃ for 3-4h, the reaction is For exothermic reaction, cold water should be used for cooling. When the reaction is terminated, the upper alkaline salt solution is separated and separated by standing, and 5% formic acid is added to neutralize the material until the material is slightly acidic. The upper acid aqueous phase is separated, and the reaction solution is subjected to post-treatment after neutralization. Post-processing. The post-treatment is to remove the salt in the resin on the one hand, and to remove the low molecular weight and unreacted bisphenol A in the resin on the other hand. The salt removal generally adopts the water washing method, that is, the neutralized resin solution is stirred with water to wash away the salt in the resin until the washing water does not contain chloride ions. The precipitation method is generally used for low molecular substances. That is, the resin solution after water washing is added with a precipitation agent to make the polycarbonate precipitate in powder or granular form. Precipitating agents can use alcohols, ketones, petroleum ether, toluene or xylene. The conversion efficiency of the phosgene method is high, generally above 90%, and the relative molecular mass can be as high as (15-20)×104, but the molecular mass is too high and it is difficult to form. Therefore, molecular weight regulators are commonly used to control the molecular weight below 104. Transesterification method: The transesterification method is also called the melt polycondensation method. It does not use solvents during polymerization and does not require solvent recovery equipment. The product can be directly discharged and granulated, but the reaction time is longer and needs to be carried out under high vacuum and high temperature. . Due to the high viscosity of the reaction materials, it is difficult to heat exchange and uniform mixing of the materials during the reaction process, and it is difficult to obtain high molecular weight products. The transesterification method is to carry out bisphenol A and diphenyl carbonate in the presence of a basic catalyst under high temperature, high vacuum and melting conditions. Take bisphenol A: diphenyl carbonate=1: (1.05-1.1), the reaction temperature is high, the transesterification reaction speed is fast, but bisphenol A is prone to decomposition when it exceeds 180℃, so the initial stage of the transesterification reaction can only be 180℃ Upper temperature limit. The catalysts for the transesterification reaction include sodium benzoate, lithium acetate, chromium acetate, cobalt acetate and potassium hydride. The dosage is 0.0025% of bisphenol A. The transesterification process has three steps: transesterification. After adding bisphenol A and diphenyl carbonate to the transesterification kettle to melt, add a catalyst, and perform transesterification at about 175°C under a vacuum of 6650 Pa as the first stage reaction. After a large amount of phenol is evaporated from the reaction system, the temperature is increased to 200-230°C, and the by-product phenol is continuously evaporated under a vacuum of 1330-5320Pa. When the steaming volume is 80%-90% of the theoretical volume, the transesterification is over. Chlorine was used to press the reactants into the polycondensation kettle. In the polycondensation reaction, the reactants after the transesterification are stirred and vacuum (133Pa), and the temperature in the kettle is controlled to 295-300°C for polycondensation to remove phenol and diphenyl carbonate. As the reaction progresses, the melt viscosity of the product increases. High, the molecular weight increases until the desired index. After the post-treatment polycondensation reaction is completed, heat at 300°C for 2-5h in an inert gas, discharge the melt, soak the pellets with 10% hydrochloric acid solution to remove the alkali metal ions of the alkaline catalyst, and then wash with ion-free water until the pH value is equal to 7. Package after the final drying.

Used for making shirts, bedding, tablecloths, work clothes, etc.; used for optical disc substrate materials. Used as electronic and electrical parts, machinery and textile industry parts, building structural parts, aviation transparent materials and parts, foam structural materials, etc.

Molecular Weight:290.31
Hydrogen Bond Donor Count:4
Hydrogen Bond Acceptor Count:5
Rotatable Bond Count:2
Exact Mass:290.11542367
Monoisotopic Mass:290.11542367
Topological Polar Surface Area:98
Heavy Atom Count:21
Complexity:236
Covalently-Bonded Unit Count:2
Compound Is Canonicalized:Yes