Factors affecting the structure and mechanical properties of Poly (Arylene Ether Sulfone) (PAES)/Cellulose Nanocrystal (CNC) composite fiber

Abstract

Cellulose nanocrystal (CNC) is one of the most abundant biopolymers that can be easily obtained from natural resources. Since it consists of only crystalline parts and has a high stiffness structure, it can be utilized as reinforcing fillers for nanocomposite materials. In addition, because of many hydroxyl groups on the surface, it is easy to functionalize. Poly (Arylene Ether Sulfone) (PAES) is an amorphous polymer and can be classified into super engineering plastic (EP). Due to its rigid backbone, it has good mechanical and chemical properties, and its glass transition temperature is high. In order to manufacture the eco-friendly super EP composite fiber, CNC was added to PAES as a filler, and the effect of CNC contents and draw ratio on PAES fiber was observed during this experiment. PAES solution mixed with CNC (CNC content: 0 to 15 wt%) was spun in the dry-jet wet spinning method and then the post-drawing process was conducted to manufacture the composite fibers. Through the tensile property analysis, it was confirmed that the strength and modulus of PAES/CNC nanocomposite fibers increased with the draw ratio due to the well-aligned CNC. On the other hand, as the CNC content increased, the tensile strength tended to decrease because the agglomeration of CNC itself had an adverse effect on the alignment of PAES polymer chains and CNC. For the crystallinity analysis of PAES composite fiber, it was found that the polymer chain arrangement was well-aligned in the axial direction of the fibers as the draw ratio increased at the same CNC content. However when the CNC content was 15 wt%, the draw ratio of the composite fiber was lower than others, which resulted in the low orientation of the polymer chains. This was because the degree of CNC aggregation was maximized due to many hydroxyl groups on the surface of CNC. From these results, it was possible to understand the correlation between the CNC content and draw ratio and the mechanical properties of PAES/CNC composite fiber.