INTRODUCTION Cellulose acetate butyrate(CAB) is an abundant and promising cellulose derivative with renewable and potentially biodegradable characteristics.Though having melts processability compared with the parent cellulose,CAB still suffers relatively high melt viscosity and a narrow window between the melt flow temperature and the decomposition temperature compared to typical commodity plastics or fibers.Moreover,the rigid nature of cellulose backbone contributes to the stiffness and brittleness of CAB which limits its application.