| 摘要 |
The present invention is directed toward transparent films prepared from soluble aromatic copolyamides with glass transition temperatures greater than 300 C. The copolyamides, which contain pendant carboxylic groups are solution cast into films using N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidinone (NMP), or other polar solvents. The films are thermally cured at temperatures near the copolymer glass transition temperature. After curing, the polymer films display transmittances >80% from 400 to 750 nm, have coefficients of thermal expansion of less than 20 ppm, and are solvent resistant. The films are useful as flexible substrates for microelectronic devices. |
