Investigation of properties of polyethylene/clay nanocomposites prepared by new in situ ziegler-natta catalyst

Nikkhah, S. J ; Sharif University of Technology | 2009

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  1. Type of Document: Article
  2. DOI: 10.1016/j.matdes.2008.11.019
  3. Publisher: 2009
  4. Abstract:
  5. This paper is devoted to investigation of morphological and physical-mechanical properties of polyethylene (PE)/clay nanocomposites prepared via in situ polymerization method using bi-supported Ziegler-Natta catalyst. Bentonite type clay and MgCl2 (ethoxide type) were used as the support of TiCl4. Catalyst support and polymerization process have been done in slurry phase using Triisobutylaluminum as the co-catalyst. The microstructure of the nanocomposites was examined by X-ray diffraction (XRD) and transmission electron microscopy (TEM). XRD and TEM indicated that almost fully exfoliated PE/clay nanocomposites were produced successfully using this method. According to permeability measurements, it was found that oxygen permeability values of the nanocomposite samples prepared with in situ polymerization method were dropped more than 200% introducing only 1 wt% clay to polymeric matrix. Differential scanning calorimetry (DSC) results indicated that the crystallization temperatures of samples are significantly higher than that of virgin PE. Moderate thermal stability enhancement of in situ polymerized nanocomposites was confirmed using thermogravimetric analysis (TGA).The storage modulus, Young's modulus and tensile strength of prepared samples were increased where the toughness was declined slightly. It seems that good dispersion and exfoliation of clay during polymerization should be responsible to get more effective reinforcing properties for clay in this method comparing to melt blending method for preparation of polyethylene nanocomposites. © 2008 Elsevier Ltd. All rights reserved
  6. Keywords:
  7. Nanocomposite ; Clay nanocomposites ; Co catalysts ; Crystallization temperatures ; Ethoxide ; In situ polymerization ; In-situ ; Mechanical property ; Melt-blending methods ; Nanocomposite samples ; Oxygen permeabilities ; Permeability measurements ; Physical-mechanical properties ; Polyethylene nanocomposites ; Polyethylene/clay nanocomposites ; Polymeric matrices ; Polymerization process ; Slurry phase ; Storage modulus ; Tem ; Thermal stabilities ; Triisobutylaluminum ; X-ray diffractions ; XRD ; Young's modulus ; Ziegler-natta catalysts ; Bentonite ; Blending ; Capillarity ; Catalysis ; Catalyst supports ; Clay ; Clay minerals ; Differential scanning calorimetry ; Elastic moduli ; Mechanical properties ; Monomers ; Nanocomposites ; Oxygen ; Polyethylenes ; Polymer melts ; Polymerization ; Polymers ; Thermogravimetric analysis ; Thermoplastics ; Transmission electron microscopy ; X ray diffraction ; X ray diffraction analysis ; Polymer matrix composites
  8. Source: Materials and Design ; Volume 30, Issue 7 , 2009 , Pages 2309-2315 ; 02641275 (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/pii/S0261306908005529