Influence of core-shell composition ratio on morphology and mechanical properties for wet-spun bicomponent cellulose acetate-polyacrylonitrile fibers

Bicomponent cellulose – polyacrylonitrile (PAN) core-shell fibers were produced using coaxial wet spinning. Varying the core-shell composition ratio resulted in changes in the morphology, mechanical and thermal properties of the fibers. When cellulose was the core polymer the fibers had irregular, circular cross-sectional morphology, with the PAN shell containing voids increasing in size from the shell towards the core. When PAN was utilized as the core, fibers showed a spiral core morphology and long, finger-shaped voids extended from the shell surface to the core-shell interface. The mechanical properties of the fibers exhibited double-fracture behavior, increased stiffness, and a reduction in plastic strain. The bicomponent fibers showed two decomposition temperatures, and the first decomposition temperature increased with cellulose acetate content. This work highlights the flexibility in properties that can be obtained via bicomponent wet spinning using polymers that are unable to be melt-processed.