Effect of Light Intensity on Ultraviolet Irradiated Polypropylene and its Compatibilization with CaCO3

Some oxygen-containing groups such as C—O and C=O were introduced onto the molecular chains of polypropylene (PP) by ultraviolet irradiation at different light intensities in air. The rate of introducing oxygen-containing groups was increased with increasing light intensity. After irradiating at different light intensities, there was no gel formation in PP. The crystal shape of irradiated PP at different light intensities kept unchanged, which was still monoclinic crystal, but its melting temperature decreased and the crystallinity increased, and meanwhile their variation extent was increased with increasing light intensity. The melt flow rate and hydrophilicity of irradiated PP at higher light intensity were higher than those of PP irradiated at lower light intensity. A little of irradiated PP at different light intensities was added into PP/CaCO3 composite and the PP/CaCO3 composite compatibilized by the irradiated PP was obtained. Compared with those of PP/CaCO3 composite, the dispersion, interfacial interaction, and mechanical properties of the compatibilized PP/CaCO3 composite were improved. The mechanical properties of PP/CaCO3 composite added with PP irradiated for 40 min at lower light intensity and PP irradiated for 30 min at higher light intensity reached a maximum value.