The effect of clay on the nucleating behavior of 1,3：2,4-bis（3,4-dimethylbenzylidene） sorbitol （DMDBS） in cryatallization of isotactic polypropylene （iPP） was investigated by means of differential scanning calo...The effect of clay on the nucleating behavior of 1,3：2,4-bis（3,4-dimethylbenzylidene） sorbitol （DMDBS） in cryatallization of isotactic polypropylene （iPP） was investigated by means of differential scanning calorimetry （DSC）, dynamic rheology and polarized light microscopy （PLM）. It is interesting to note that the incorporation of layered clay nanoparticles into DMDBS-nucleated iPP may induce a synergetic nucleation effect while the DMDBS content is below 0.1 wt%, otherwise it restricts the crystallization rate prominently as the DMDBS content increases up to 0.3 wt%, which has exceeded the content threshold to yield a nucleating agent （NA） network. As shown by dynamic rheological investigations, the clay nanoparticles demonstrate an obstructive effect of disturbing the consistency of DMDBS fibrils network. Moreover, to further demonstrate the importance of NA network formation in the crystallization of iPP, we used another NA named HPN-20e, which can not form network structure at all over the concentration studied, for comparison. In this case, the nucleated-crystallization rate is independent on the addition of clay nanoparticles, as the nucleating mechanism is an individual nuclei manner without NA network forming.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.21034005,50903048)
文摘The effect of clay on the nucleating behavior of 1,3：2,4-bis（3,4-dimethylbenzylidene） sorbitol （DMDBS） in cryatallization of isotactic polypropylene （iPP） was investigated by means of differential scanning calorimetry （DSC）, dynamic rheology and polarized light microscopy （PLM）. It is interesting to note that the incorporation of layered clay nanoparticles into DMDBS-nucleated iPP may induce a synergetic nucleation effect while the DMDBS content is below 0.1 wt%, otherwise it restricts the crystallization rate prominently as the DMDBS content increases up to 0.3 wt%, which has exceeded the content threshold to yield a nucleating agent （NA） network. As shown by dynamic rheological investigations, the clay nanoparticles demonstrate an obstructive effect of disturbing the consistency of DMDBS fibrils network. Moreover, to further demonstrate the importance of NA network formation in the crystallization of iPP, we used another NA named HPN-20e, which can not form network structure at all over the concentration studied, for comparison. In this case, the nucleated-crystallization rate is independent on the addition of clay nanoparticles, as the nucleating mechanism is an individual nuclei manner without NA network forming.
