Influence of cooling conditions on the crystal structures of PP composites reinforced by knitted GF

In this paper, the crystal structure of the polypropylene (PP) matrix in four groups of knitted glass fabric reinforced polypropylene (GF/PP) composites with different cooling conditions was studied using wide angle X-ray diffraction and optical microscope. It was found that the various cooling conditions had no effect on the crystal phase of the PP matrix. However, the crystal degree and sizes of crystallite and spherulite varied with cooling conditions. They increased with the decrease of the cooling speed and the prolongation of the cooling time.