Dynamic Rheological Behaviors of Polyamic Acid Solution

The rheological behaviors of polyamic acid (PAA) solution are of importance for producing high performance polyimides, since the former is the precursor of the latter. The study on the rheological behaviors of the PAA solution indicated that the storage modulus G′ and loss modulus G″ exhibited quadratic and linear dependence on ω2 and ω at low frequencies, respectively. However, at high frequencies, both G′ and G″ become proportional to ω2/3. The non-Newtonian flow of polyamic acid solution was accord with time-temperature equivalence principle.