Specifically, the DMF-soluble fractions increased as follows: P(I-co-II)-1: 29%; P(I-co-II)-0.98: 51%; P(I-co-II)-0.94: 61%. The fractions that were insoluble in DMF were also found to be insoluble in chloroform, DMSO, acetonitrile, and ethanol, but were slightly soluble in formic acid and hydrochloric acid