| abstract |
High modulus filaments are melt-spun from polyimide-esters derived from I 6-hydroxy-2-naphthoic acid, a diphenol and 4-carboxy-N-(p-carboxyphenyl)-phthalimide; II 6-hydroxy-2-naphthoic acid, an aromatic dicarboxylic acid 4-hydroxy-N-(p-hydroxyphenyl)phthalimide; or III 6-hydroxy-2-naphthoic acid, 4-hydroxybenzoic acid and 4-carboxy-N-(p-hydroxyphenyl)phthalimide. The polyimide esters are optically anisotropic in the melt. As-spun filaments from these polymers can be heat treated while free from tension to increase their tenacity. |