Study On The Preparation And Properties Of PVC/OMMT And PVC/CaCO₃ Nanocomposites

In this paper,nano-CaCO₃ and nanomontmorillonite were modified,then they were mixed with PVC(polyvinyl chloride) respectively by melt blending method to prepare the PVC/nano-CaCO₃ and PVC/nanomontmorillonite composites.The properties of PVC nanocomposite were studied.Na-MMT was intercalated by CATB ion,and then was modified with MMA.The PVC/org-MMT nanocomposite was prepared by melt blending method.The structure of nanomontmorillonite and nanocomposites were characterized using XRD and TEM. By the measure of mechanical properties,we find that the impact strength and tensile strength of PVC/org-MMT nanocpmposite declined than PVC.The measure result of DSC, TGA and vicat softening point indicated that the addition of org-MMT enhanced the thermal stability of nanocomposite, but the change extent of Tg was minor.The acquired result of rheology testing showed that the rheological curves of the nanocomposites exhibited power-law relationship, nanocomposites had more overpowering behavior of shear thining compared with the polymer matrix.The flow behavior index n augmented when temperature increased.Under invariant temperature,flow behavior index decreased with the content of org-MMT increased at a constant temperature,apparent viscosity increased slightly . The dependence of apparent viscosity on temperature in accord with Arrhenius-Eyring expression.Silane coupling agent(KH-570) was used for the treatment on nano-CaCO₃ particles in this article.PVC/ nano-CaCO₃ composite was prepared by melt mixing method.The dispersion condition of nano-CaCO₃ in PVC matrix was observed by TEM. The impact strength of composite,vicat softening temperature and relict of weightlessness enhanced with the augmente of nano-CaCO₃ usage.However,the variation of decomposition temperature was in a small range.Tg declined at first,then increased as the increase of nano-CaCO₃.The impact strength reached the maximum when nano-CaCO₃ loading reached 8wt% and the loading of CPE reached 8-10wt%.The adding of ACR had little effect on impact strength largely.With increase of CaCO₃loading the experiment curve of tensile strength descend at first,then ascended abruptly when the loading of CaCO₃ reached 8wt%,later the curve declined again.It indicated that the adding of CaCO₃could improve tensile properties of composites.From the flow cure of composite we can see that these materials all belong to pseudoplastic fluid.Moreover,with the increase of temperature the apparent viscosity descend.When the loading of CaCO₃ was very low,it's affect on apparent viscosity was slight.But when the loading of CaCO₃ was high,apparent viscosity had outstanding accretion at a fixed shear rate.