Application of Nano‐Titania Co‐Grafted With Lactic Acid and Chitosan in Poly(Lactic Acid)/poly(ε‐Caprolactone) Blend Fiber

ABSTRACT Lactic acid and chitosan co‐grafted nano‐titania (LA‐g‐TiO 2 ‐g‐CS) is prepared by chemical grafting in solution and added as an antibacterial agent to poly(lactic acid)/poly(ε‐caprolactone) blend fiber (PLA/PCL blend fiber) to prepare LA‐g‐TiO 2 ‐g‐CS/PLA/PCL blend fiber by melt extrusion‐hot stretching technology in order to promote the wide application of PLA fiber in the fields of biomedicine, clothing and home textiles. The results indicate that LA‐g‐TiO 2 ‐g‐CS is prone to uniform dispersion in PLA/PCL blend fiber because of its lactic acid oligomer. Under the heterogeneous nucleation of nano‐titania (nano‐TiO 2 ), physical crosslinking of chitosan (CS) and synergistic antibacterial effect of nano‐TiO 2 and CS, LA‐g‐TiO 2 ‐g‐CS/PLA/PCL blend fiber exhibits good crystallization and thermal stability, excellent mechanical properties and outstanding antibacterial activity. When the LA‐g‐TiO 2 ‐g‐CS addition amount is 1.5 phr, the crystallinity, temperature at 5% weight loss, tensile strength, elongation at break and antibacterial activity against E scherichia coli and S taphylococcus aureus of LA‐g‐TiO 2 ‐g‐CS/PLA/PCL blend fiber are 12.78%, 338.7°C, 203.7 ± 4.6 MPa, 52.7% ± 2.5%, 92.4% and 95.5%, respectively. In addition, LA‐g‐TiO 2 ‐g‐CS/PLA/PCL blend fiber shows moderate degradability in PBS solutions with different pH values and alkaline PBS solutions have a greater impact on its weight loss rate and mechanical properties than acidic PBS solutions.