PVC suspension polymer pH buffer ammonium bicarbonate
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When ammonium bicarbonate is used as the pH buffer for suspension polymerization, the drying load increases. I don’t know the reason, the mechanism, and how to solve it. Please enlighten me! !
It may be caused by the increased oil absorption rate of PVC resin.
Haha, I can see you here. You asked me last time, but then I went home and forgot about it. Sorry! The preparation method for our 70 kettle is 100KG ammonium bicarbonate + 900KG deionized water, which means the concentration is 10%, and 60KG solution is added to each kettle. When you say the drying load is large, does it mean that the particles after polymerization are larger? The purpose of adding ammonium bicarbonate is to adjust the pH value. Check the quality of the ammonium bicarbonate to see if there are any other impurities. Check the pH value of the polymerization system.
I agree with what the third floor said, as the oil absorption rate increases, water should be easier to escape without causing an increase in load.
What does the large drying load you mentioned reflect? Is it because the blower load has increased?
The main reaction is when the drying temperature increases. A slight decrease in the control temperature will produce excessive volatile matter. We have tested the oil absorption rate and found no major changes.； In addition, the quality of ammonium bicarbonate has also been discussed, but the nearby market cannot provide industrial-grade products, only ordinary chemical fertilizers, and the pH value of the system cannot be tested under our current conditions.
Main ingredients of ammonium bicarbonate for agricultural use: N%=17%,H2O%
I'm just worried that other impurity ions, such as chloride ions, are mixed into the ammonium bicarbonate. Have you tried changing back to the original buffer?
Changing back to the original buffer solved the problem immediately. Will chloride ions affect drying? What is the main mechanism?