Synthesis and Photo-Alignment Properties of Novel Polyimides with Cyclobutane-1, 2, 3, 4-Tetracarboxylic Dianhydride (CBDA)

To improve effectiveness of photo-alignment, new polyimides containing cyclobutane-1, 2, 3, 4-tetracarboxylic dianhydride (CBDA) were designed including 4, 4′-diaminobenzophenone (DABP) and carbohydrazide by amide bond. For evaluating polyimides, a mole ratio of 4, 4′-diaminobenzophenone(DABP) and carbohydrazide was controlled to 0:100, 30:70, 50:50, 70:30, 100:0. The mixed solid contains 15wt% of solvent which is n-methyl-2-pyrrolidone (NMP). The synthesized polyimide was analyzed using the Fourier transform infrared (FT-IR). We obtained polar dichroic ratios and evaluate alignment of liquid crystal. For more aggressive photo-decomposition of polyimide, the photoreactions employing triplet mechanism and the double fragmentation reactions were carried out.