Morphological and structural-rheological relationship in epiclon-based polyimide/hydroxypropylcellulose blend systems

Blends of hydroxypropyl cellulose (HPC) in lyotropic phase have been prepared with a new epiclon- based poly(amic acid) (PAA) or its corresponding polyimide (PI). The flow behaviour of their mixed solutions in N,N-dimethylacetamide (DMAc) was investigated by means of shear viscometry and oscillatory shear tests. The effect of composition, temperature and shear rate on the rheological functions reflects the orientation or mobility of the chain segments in the shear field. Specific interactions, such as the hydrogen bonds between PAA and the liquid crystalline component, stabilized the resulted morphology. The band texture, typical for lyotropic HPC solutions, evidencing different intensities and dimensions is observed from atomic force microscopy images in PAA/HPC and PI/HPC blends. The paper pursues some aspects concerning the obtaining of mixed alignment layers used in display devices.