Effect of pimelic acid treatments on the crystal structures, crystallization behaviors, morphologies and mechanical properties of polypropylene composites pp.647-680
Authors: (Qiang Dou, College of Materials Science and Engineering, Nanjing University of Technology, Nanjing, China)
Abstract: Pimelic acid was used as a new surface modifier for calcium carbonate, wollastonite and mica, respectively. The crystal structures, crystallization behaviors, morphologies and mechanical properties of the PP composites were characterized by means of wide angle X-ray diffraction, differential scanning calorimetry, polarized light microscopy, scanning electron microscopy and mechanical tests. The chemical reactions between pimelic acid and the fillers were analyzed by means of Fourier transform infrared spectroscopy. The results of wide angle X-ray diffraction, differential scanning calorimetry and polarized light microscopy proved that pimelic acid treated fillers induced a large amount of β crystalline form PP and decreased the spherulitic size of PP. The results of scanning electron microscopy showed that pimelic acid treatment enhanced the interfacial adhesion between the fillers and the matrix, indicating the improvement of the compatibility between PP and the fillers. It was revealed by energy dispersive spectrum and Fourier transform infrared spectroscopy that pimelic acid reacted with the fillers and effective β nucleating agents were formed. The toughness of the composites was markedly improved by the more ductile β-form spherulites.