Synthesis Of Magnesium Dichloride/Montmorillonite Composite Supported Catalyst And Its Ethylene Polymerization

PE/OMMT nanocomposites were prepared by in-situ polymerization using supported TiCl₄/MgCl₂/OMMT/ED catalyst, where OMMT is modified by organic modification agent. The catalyst was prepared by immobilization of TiCl₄ on complex support of MgCl₂/OMMT. The structures and properties of the support and polyethylene nanocomposite were characterized by XRD,TEM,SEM,DSC,IR analysis.MMT was modified by three kinds of organic modifiers: dimethyldi octadecyl ammonium bromide, octadecyl-ammonium chloride and octadecylamine. The result showed that a maximum expansion of interlayer distance from 1.25nm to 2.63nm can be reached by modification with dimethyldi octadecyl ammonium bromide with a folded chain. IR spectrum indicated that hydroxyl and structural -C-H stretching vibration increased after organic long-chain is diffused into MMT.The effects of the amount of ethanol and other factors on the performance the prepared catalyst and the bulk density of polyethylene product were investigated in the article. It was observed that the performance of the catalysts deteriorate as the amount of ethanol increases. Compared with one time, two time immobilization of TiCl₄ can effectively enhance the performance of the catalyst. Introduction of MgCl₂ to MMT can considerably improve the performance of the catalyst. The addition of TMOS can increase the bulk density of the nanocomposites.Polyethylene(PE)/Organic Montmorillonite(OMMT) nanocomposites were prepared by in-situ polymerization of ethylene TiCl₄/OMMT and TiCl₄/MgCl₂/OMMT intercalated catalyst. TEM results indicated that the clay is exfoliated into nanometer size and disorderedly dispersed in the PE matrix and exfoliated clay nanocomposites are formed. SEM results showed that the polymer composites with a better distribution of MMT and polymer morphology can be obtained by using TiCl₄/MgCl₂/OMMT catalyst. The addition of TMOS as inner the donor of TiCl₄/MgCl₂/OMMT catalyst resulted in the formation of more homogeneously distributed spherical PE/OMMT nanoparticles.The effects of the content of MMT in PE/OMMT nanocomposite on the properties of nanocomposites were discussed in the article. It was found that crystallization properties of the nanocomposites improved with increasing content of MMT, achieving optimal results with MMT content of 1.7%. Thermally stable properties increase firstly and then minish with increasing content of MMT, further, that reaches top with the content of MMT equal to 1.1%,the decomposition temperature of which is 436.7℃. Mechanical properties such as tensile strength, elongation and yield strength of the nanocomposites were significantly reduced with increasing content of MMT.Comparision of the properties of PE/OMMT nanocomposites prepared by using MMT/TiCl₄, TiCl₄/MgCl₂/OMMT, TiCl₄/MgCl₂/OMMT/ED and mixed of TiCl₄/OMMT and JM-1 supported catalyst revealed that PE/MMT nanocoposites prepared by TiCl₄/MgCl₂/OMMT composite supported catalyst exhibit superior heat stability and the decomposition temperature is 448.9℃.PE/OMMT nanocomposites demonstrate an enhanced crystallization properties prepared by the composite TiCl₄/MgCl₂/OMMT/ED supported catalyst, the crystallinity is 79.1%. Elongation and yield strength of the PE/OMMT nanocomposites which synthesized by TiCl₄/OMMT supported catalyst displayed a higher elongation and yield strength. Molecular weight of PE/OMMT nanocomposition is above 105, the molecular weight distribution index approximately 7.