Isophthalic acid has high M.P so can not dissolve in mixture at temperature below 150c, after this it will react with the alcohol molecules to form the polymer with the increase in temperature.

I think there is problem in alcohol acid ratio or you may not use any esterification catalyst. Kindly send me the recipe so that i will be able to adjust, on [email protected]

Dear Fatemeh,

IPA is very difficult to dissolve due to its crystal form and high melting point (347 oC). It generally reacts and may also dissolve at the same time in the reaction mixture at temperatues a little bit above 300 oC