偶氮二甲酰胺的合成及其改性研究.pdf

1、河北工業(yè)大學(xué)碩士學(xué)位論文偶氮二甲酰胺的合成及其改性研究姓名：趙美杰申請(qǐng)學(xué)位級(jí)別：碩士專(zhuān)業(yè)：應(yīng)用化學(xué)指導(dǎo)教師：潘明旺2011-05偶氮二甲酰胺的合成及其改性研究 iiSTUDY ON PREPARATION AND MODIFICATION OF AZODICARBONAMIDE ABSTRACT Azodicarbonamide (trade name: blowing agent ADC), a chemical blowing ag

2、ent with a broad use, is a nontoxic, tasteless, non-polluting, saffron azo-blowing agent. One of its much obvious features has a group of -N=N-. When heated, it will release large amounts of N2. Its gas evolution reaches

3、 200~250ml/g. The current process of ADC is as follows: biurea is synthesized from hydrazine hydrate and urea by means of acid condensation reaction, and azodicarbonamide is synthesized from biurea through oxidation reac

4、tion. The acid method is through adding a large number of sulphuric acid to the reaction system to adjust pH value of the system, which seriously corrodes the reaction equipment. Besides, it is difficult to collect and d

5、ispose the ammonium sulfate byproduct in the process. We adjust the pH value of hydrazine hydrate till weak alkaline with hydrochloric acid, rather than adjust the pH value of reaction system to reduce the adding amount

6、of hydrochloric acid. It was investigated that hydrazodicarbonamide was directly synthesized from hydrazine hydrate with a high concentration and urea. Acid was not used in the process. So the corrosion of equipment is l

7、ittle, and the process is friendly to the environment. Orthogonal test was used to optimize the synthesis conditions of azodicarbonamide. Under the optimum conditions, the gas volume of azodicarbonamide was improved by u

8、ltrasonic method. Decomposition temperature of azodicarbonamide is 195~220℃, which is far beyond melt-processing temperature of PVC resin in the range of 170~175℃. Therefore, an activator of azodicarbonamide is applied