Bonding characteristics of recycled polyethylene terephthalate (PET) fibers coated with maleic anhydride grafted polypropylene in cement-based composites

In this study, we sought to enhance the bond performance between recycled polyethylene terephthalate(PET) fibers and cement‐based composites using a hydrophilization treatment with hydrophilic maleic anhydride grafted polypropylene (mPP). The bond performance was evaluated with bone‐shaped specimens after the hydrophilization treatment. The effects of the concentration of mPP in the solution in which the PET fibers were immersed (0, 5, 10, 15, and 20%) and the three types of shapes on the surface energy of the recycled PET fibers were evaluated. The pullout behavior, bond strength, and interfacial energy all increased with the concentration of mPP to 15% but decreased at 20%. This occurred because 15% mPP coated the recycled PET fiber thoroughly, whereas a 20% mPP coating resulted in partial cracks, which led to fractures on application of a pullout load. Of the fiber shapes, the embossed fibers demonstrated the best bond behavior. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011