Cross-linkable thermoplastics, and processes of making and using same

A process of making a cross-linkable thermoplastic polymer comprising:

• a) thermally imidizing and/or chemically imidizing a solution of polyamic acid formed from a solution of monomers comprising:
• i) a first monomer having the following structure:
• Y is selected from one of the following moieties:
• where L is a bivalent linker selected from the one of following moieties:
• O, C═O, SO2, C(CF3)2, C(CF3)Ph, and —O-(pC6H3)—C(CF3)2-(pC6H4)—O—;
• ii) a second monomer having the following structure:
• each Z is independently O, CH2, or C═O;
• at least one of R1, R2, R3 and R4 is phenylethynyl, with the remainder of R1, R2, R3 and R4 each independently being H or phenylethynyl:
• iii) optionally a third monomer having the following structure:
• H2N—Ar—NH2
• wherein Ar is:
• and
• iv) an aprotic polar solvent;
• wherein said monomer solution comprises a molar ratio of said first monomer to combination of said second and third monomer of from about 0.8:1 to about 1.2:1, and the total weight percent, based on total monomer solution weight, of said first, second and third monomers is from about 2% to about 40%,
• thereby forming a solution of polymer in the aprotic polar solvent, said polymer having the following structure:
• wherein
• each X is independently O2, CH2, or C═O;
• at least one of R1, R2, R3 and R4 is phenylethynyl, with the remainder of R1, R2, R3 and R4 each independently being H or phenylethynyl;
• each Y is independently selected from one of the following moieties:
• where each L is independently a bivalent linker selected from the one of following moieties:
• O, C═O, SO2, C(CF3)2, C(CF3)Ph, and —O-(pC6H4)-C(CF3)2-(pC6H4)-O-;
• each Ar is independently:
• each a is from 0.01 to 1;
• and n is an integer from about 3 to about 200;
• b) precipitating said polymer out of said polymer solution;
• and
• c) removing the precipitated polymer from solvent.