科研之友
微信
新浪微博
Facebook
分享链接
摘要
In order to promote better understanding of the structure-mechanical properties relationships of filled thermoplastic compounds, the molecular orientation and the degree of crystallinity of injection molded talc-filled isotactic polypropylene (PP) composites were investigated by X-ray pole figures and wide-angle X-ray diffraction (WAXD). The usual orientation of the filler particles, where the plate planes of talc particles are oriented parallel to the surface of injection molding and influence the orientation of the alpha-PP crystallites was observed. The PP crystallites show bimodal orientation in which the c- and a*-axes are mixed oriented to the longitudinal direction (LD) and the b-axis is oriented to the normal direction (ND). It was found that the preferential b-axis orientation of PP crystallites increases significantly in the presence of talc particles up to 20 wt% in the composites and then levels-off at higher filler content. WAXD measurements of the degree of crystallinity through the thickness of injection molded PP/talc composites indicated an increasing gradient of PP matrix crystallinity content from the core to the skin layers of the molded plaques. Also, the bulk PP crystallinity content of the composites, as determined by DSC measurements, increased with talc filler concentration. The bulk crystallinity content of PP matrix and the orientation behavior of the matrix PP crystallites and that of the talc particles in composites are influenced by the presence of the filler content and these three composite's microstructure modification factors influence significantly the flexural moduli and the mechanical stiffness anisotropy data (E(LD)/E(TD)) of the analyzed PP/talc composites.
- 出版日期2010-5
