started the mixture became deep blue purple the mixture was heated to 130 u00b0 c and kept at this temperature for 48 h although the mixture had become deep red its viscosity was not significantly increased the reaction mixture was allowed to cool to 60 u2013 70 u00b0 c and water was added to precipitate the polymer the resulting mixture was warm at 60 u2013 70 u00b0 c overnight under the nitrogen the resulting bright yellow solids were collected by suction filtration washed with diluted ammonium hydroxide and large amount of water the polymer was finally dried under reduced pressure 0 05 mmhg at 200 u00b0 c for 150 h to give essentially quantitative yield u03b7 0 07 dl g 0 5 solution in msa at 30 0 u00b1 0 1 u00b0 c anal calcd for c 33 h 20 n 2 o 3 c 80 47 h 4 09 n 5 69 o 9 75 found c 78 69 h 4 34 n 5 27 o 10 81 polymerization of ab 2 monomer in ppa p 2 o 5 at 130 u00b0 c into a 250 ml resin flask equipped with a high torque mechanical stirrer nitrogen inlet and outlet a pressure regulator and an addition port ppa 83 assay 80 g was placed and.