Nondestructive Modification of Catechol/Polyethyleneimine onto Polyester Fabrics by Mussel‐Inspiration for Improving Interfacial Performance

Co‐deposition of catechol and polyethyleneimine onto polyethylene phthalate (PET) fiber by mussel‐inspiration is conducted and subsequently utilized to prepare polyethyleneimine/catechol modified PET fiber reinforced composites (polyethyleneimine (PEI)/CCh‐m‐PET FRCs). The surface polarity is characterized through the dynamic contact angle. The mechanical performances including tensile, flexural, and short beam shear strength are evaluated. Additionally, the single‐bundle pull‐out tests are carried out with the double‐end method. The analysis reveals that compared to the untreated PET reinforced composite, there are 33.49% and 34.35% increase of the critical load and peak load for PEI‐modified specimens, respectively, meanwhile the critical debonding energy and pull‐out energy calculated increase by 28.46% and 24.47%, respectively. The interlaminar shear strength and interfacial shear strength of modified PET can reach the values of 145.89 and 20.88 MPa, which are significantly improved by 58.01% and 70.94%. Mussel‐inspired method is utilized to endow the polyethylene phthalate woven fabric with CCh‐PEI co‐deposited layers for improving the interfacial adhesion with epoxy resin. The interfacial shear properties are measured by single‐bundle pull‐out test. The introduced layers facilitate the interinfiltration between reinforcement and matrix and greatly enhance the mechanical performances through fabricating persistent cross‐linked covalent bonds in the interphase.