Keratin modified and functionalized as a reinforcement and nucleation agent of β-polypropylene composites

Abstract

A new green β nucleating agent has been obtained from industrial waste. This way, pimelic acid (PA) was chemically supported on treated keratin fibers to promote the β polymorph into a polypropylene matrix using several percentages of reinforcement (0.5, 1.0, and 5.0% w/w). IR spectra suggest a successful functionalization showing the presence of a new band at 1571 cm−1, indicating a bond between PA and the keratin surface. According to the scanning electron spectroscopy, the nucleating agent was homogeneously distributed on the keratin surface. Wide angle X-ray diffraction (WAXD) patterns and differential scanning calorimetry (DSC) curves demonstrate that the functionalized keratin fibers were able to promote a high percentage of β-crystal into the polypropylene matrix (79% and 60%, respectively). The thermomechanical properties were characterized by dynamic mechanical analysis (DMA). At −30°C, the new reinforcement provides an important increase of 25% in the storage modulus compared with the raw polypropylene. The new reinforcement seems to strongly influence the mobility of the amorphous phase, shifting the Tg to higher temperatures.