Dear Samrat .., please have a look at the following RG thread and free acccess article. My Regards

https://www.researchgate.net/post/Is_polysulfone_soluble_or_not_soluble_in_chloroform

https://www.researchgate.net/publication/237446260_Use_of_the_polysulfone_polymer_in_NOX_detection

Sir, I have to do chloromethylation. Can I use any other solvent except chloroform for that. I tried the methods reported above but not able to get the expected results of solubility.

Please sée:

https://doi.org/10.1016/j.memsci.2019.117591

Sir, I tried solubility in DCM also but it does not get soluble.

How much time and what temperature is required?

I am not supposed to check all literature on that, however reduce concentration an increase temperature up to Tg (190-230°C). Best of Luck in your work

Thank you sir, but I tried many literatures.

Thanks a lot for your Information