Use of dispersants in polymerization
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This post was last edited by caocheng on 2011-9-15 16:19. After adding soft water and monomer to the polymerization reactor, the dispersant was added about 15 minutes later due to the bottom valve; will this affect the establishment of the subsequent reaction system? Is this one of the reasons for the rough product?
Yes, because the monomers will undergo self-polymerization under the action of the catalyst, which will make the material coarser!
Reply to 2# pvc11: Could you please explain in more detail? I haven’t added the dispersant yet – what is it that catalyzes its self-polymerization? Could it be that once the time for adding the dispersant has passed, the monomers release some HCl, making the system slightly acidic and thus causing the subsequent reactions to proceed abnormally?
The dispersant was added late: 1. The initiator had not yet been added; 2. Due to the bottom valve, as long as there is no shortage of dispersant, it can be added to the reactor. It will not affect the production of crude material
Theoretically, it shouldn’t have any impact, as your initiator hasn’t been added yet, so it doesn’t affect the establishment of the reaction system.
Reply to 4# lpf2011: We really can’t find the cause now. One of our reactors has produced two batches of crude material in a row, and it’s impossible to determine what’s causing this
It is possible to check the curves for reaction temperature, pressure, and stirring power to see if the problem lies during the reaction process rather than during the feeding process.
Reply to 6# Zhu Mu: If two batches of crude material are produced from the same reactor, issues related to the quality of the raw materials or errors in the manual feeding process can be ruled out. "After adding soft water and monomer to the polymerization reactor, the dispersant was added about 15 minutes later due to the bottom valve. If this is the reason for the issue with coarse particles, please explain in detail what exactly caused the delay in adding the dispersant due to the bottom valve! Did anything abnormal occur with this reactor during the reaction, or were any valves operated (such as for venting or recovery)?
The last edit to this post was made by lpf2011 on 2011-9-14 at 02:28. Reply to 3# Zhu Mu: Self-agglomeration is a slow oxidation process; without stirring, coarse particles may form when free radicals combine with monomers, but this is not the main reason. The main causes of roughness are monomers, dispersants, and chloride ions. By addressing these two main causes and investigating step by step, the day when the problem with the rough material will be solved will arrive.
Check whether it is due to incomplete rinsing after adding the dispersant and initiator, or whether there is internal leakage in the valves
Start by checking each item, beginning with whether the dispersant has lost its effectiveness, whether the dosing tank for the dispersant measures the correct amount, whether there is internal leakage in the dispersant valves, and whether there are leaks in the pipes