A strategy for effective improvement the dispersion of cellulose nanocrystals and adhesive properties of starch-matrix sizing agent on polyester roving via dopamine self-polymerization

Starch sizing agent has poor mechanical property, strong hygroscopicity and weak adhesion to polyester yarns. In this study, cellulose nanocrystals embellished by dopamine (CNC-DA) as the filler of starch is used for sizing polyester roving. The structure of CNC-DA is characterized, and the structure and properties of starch-matrix nanocomposite (CS/CNC-DA) are studied. The results show that DA self-polymerizes on the surface of CNC to form polydopamine. With the increase of CNC-DA amount, tensile strength, elongation at break, fracture work, the initial degradation temperature, water contact angle of CS/CNC-DA film, and adhesion of CS/CNC-DA to polyester roving increase first, and then decrease, while moisture uptake of CS/CNC-DA film shows the opposite trend. When the addition amount of CNC-DA is 5 wt%, the corresponding tensile strength, elongation at break and fracture work reach maximum that are 53.82 MPa, 4.87% and 1.69 MJ/m3, respectively. Breaking force, elongation at break and work-to-break of sizing polyester roving by CS/5CNC-DA are 143.47 N, 15.49% and 550.95 N·mm, respectively. These are attributed to the better dispersion of CNC-DA in starch-matrix nanocomposite film and the stronger interfacial interaction between CNC-DA and starch.