Blends of cellulose with polyacrylonitrile prepared from N, N-dimethylacetamide-lithium chloride solutions

Abstract

Blend films of cellulose with polyacrylonitrile were obtained over the whole composition range from solutions in N, N-dimethylacetamide-lithium chloride by coagulation in a non-solvent. Visual inspection and optical microscopic observation gave no indication of phase separation in any of the blends. Detailed characterization of the state of miscibility was carried out by wide-angle X-ray diffraction, differential scanning calorimetry and dynamic mechanical measurements. The wide-angle X-ray diffraction patterns of the blends were composed of the diffraction rings from the individual polymer crystals, but qualitative estimates showed that the degree of crystallinity was low, especially in the cellulose component. From an estimation of the glass transition temperature by differential scanning calorimetry and dynamic mechanical techniques, it was found that the blends exhibited considerable miscibility at the molecular level in the amorphous regions above 50wt% cellulose content. A possible explanation of the results is presented through consideration of a specific interaction between the hydroxyl groups of cellulose and the nitrile groups of polyacrylonitrile.