Sonochemical activation calcium sulfate whisker with enhanced beta-nucleating ability for isotactic polypropylene

The crystalline morphology, structure, and the beta-nucleating ability of ultrasound-activated calcium sulfate whisker (CSW)-filled isotactic polypropylene were investigated via X-ray diffraction (XRD), polar light microscopy (PLM), and differential scanning calorimetry (DSC). The XRD results revealed that ultrasound treated CSW (UCSW) could improve the beta-nucleated ability, and resulted in enhancing the content of beta-crystal form. The ultrasonic time was conducive to the improvement of the contents of beta-crystal and reached the maximum value at ultrasonic 120 min. PLM and DSC results verified the enhanced nucleating ability of UCSW supported as beta-nucleating agent. The scanning electron microscopy, energy dispersive spectroscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy indicated the surface of CSW treated by ultrasound had been changed. The activity of the calcium ion was improved and the sulfuric acid layer appeared on the whisker surface had a significant effect on the iPP beta-heterogeneous nucleation, and resulted in enhancing the content of beta-crystal form.