I'm working as R&D chemist
while i was synthesizing poly acrylic acid by using free radical polymerization it gives me a brown color at the end of the reaction and low viscosity does this have relation with the molecular weight? and how to control it, im using redox system for initiation.
Dear Muhammad Abd El-Haleem, the temperature depends of the type of initiator system used. Generally, redox couples operate at low temperatures close to room temperature. Low molecular weight may be due to two reasons:
- the inhibitor was not eliminated before running the polymerization
- presence ox oxygen, i.e., no deaeration using an innert gas.
The dark color may be a Witness of formation of oxidation products. My Regards
Abdelkader BOUAZIZ
dear sir, i tried running this synthesis reaction at low temperature but it gives me low viscous and brown color
all conditions are suitable for the polymerization i.e.., removing the oxygen from the media...
now my question what is the optimum temperature of the reaction and how to control the molecular weight??
What about the inhibitor? Is it eliminated? As I told you, it is the initiator (type or system) choosen which decides. I have done the polymerization in a lab work during my graduation at 80 °C with peroxides and at 20 °C with a redox couple potassium persulfate/sodium metabisulfite. Any initiator has a window of operating temperature with the corresponding reaction time. My Regards
Hi;
The pH, the redox couple and their molar ratio as well as the initiator/monomer molar percentage are the key parameters for successful polymerization. For more information, please consult the following link: https://patents.google.com/patent/WO2013150056A1/en.
With my best regards
Abdelkader BOUAZIZ
sir i didn't use inhibitor,
i used peroxide once after 20 min from the polymerization it gives me rubber like mass and the temp. rapidly increased form 80 to 110 deg.
Dear Muhammad Abd El-Haleem, inhibitors are already in your monomers. They are used by manufacturers to stabilize vinylic and acrylic monomers (mainly liquid monomers) against autopolymerization, light, ..., and other sources. Elimination of inhibitors is done prior to polymerization by washing, extraction, distillation, column chromatography, .... My Regards
Hello. I am researching the synthesis of polycarboxylate and polyacrylic acid. In the synthesis stage of polyacrylic-styrene, the material made does not have the necessary adhesion and elasticity. What should I do to increase the elasticity of my product? The reaction temperature is 70 degrees Celsius.
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