Abstract
High modulus, uniaxially drawn film and sheet were made from poly (2, 2′-dichloro-4, 4′-biphenylenepyromellitimide). The hot-drawn and thermally imidized film (15μm thick) had tenacity of 1.56GPa and initial modulus of 164GPa. In case of the sheet, the key point to obtain a high performance product was the preparation of a gel sheet for drawing which was homogeneous in through direction. The gel sheet was made by casting the poly (amic-acid) solution which was prepared in N-methylpyrrolidone/dichloroethane (DCE) (volume ratio 38/62) as the solvent and to which a cyclodehydrating agent was added, and then by drying at 40°C to remove DCE only. It was drawn at room temperature and heat treated stepwise to 300°C. The flexural modulus of the resultant sheet with thickness of 0.32mm reached 106GPa.
