The effects of sonication time and frequencies on degradation, crystallization behavior, and mechanical properties of polypropylene

摘要: The effects of ultrasound with different frequencies on the degradation, crystallization behavior, and mechanical properties polypropylene were investigated by means intrinsic viscosity, gel permeation chromatography, dynamic rheological measurements, X-ray diffraction, differential scanning calorimetry, polarized optical microscopy, tensile impact measurements. results demonstrated that degradation extent (PP) increased increasing sonication time, especially for samples treated in more than 5 min. Meanwhile, PP at 20 KHz was easily degraded other two frequencies. On hand, β-form could be induced ultrasonic irradiation, its amount as time to 3 min then decreased further due PP. Likewise, β-phase formed when KHz. showed toughness enhanced formation β−phase, while would weakened substantial under irradiation higher intensity. Therefore, it believed both frequency should account balance between toughening POLYM. ENG. SCI., 55:2566–2575, 2015. © 2015 Society Plastics Engineers