Effect of benzofuranone on degradation and mechanical properties of polypropylene in processing

Melt flow index, polydistribution index, Fourier-transform infrared spectroscopy, and differential scanning calorimetry have been used for the assessment of the degradation of virgin polypropylene (PP) and PP stabilized with benzofuranone derivatives. When PP samples were subjected to five extrusion cycles, the melt flow index and polydistribution index values of virgin PP sharply increased with the number of extrusion cycles, but the corresponding changes of PP stabilized with benzofuranone derivatives were not as great as those of virgin PP. Furthermore, the results of Fourier-transform infrared spectroscopy and differential scanning calorimetry showed that benzofuranone prevented the increasing of double bonds and the moving of crystal peak temperature to the higher temperature. All those changes indicate that the degradation of PP is inhibited efficiently by benzofuranone derivatives, and the stabilization with benzofuranone derivative in PP is beneficial to the maintenance of mechanical properties of PP. J. VINYL ADDIT. TECHNOL., 24:124-129, 2018. (c) 2016 Society of Plastics Engineers