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Investigation of Production Increasing in In-situ Preparation of Polyolefin/clay Nanocomposites

Javan Nikkhah, Sousa | 2008

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 39198 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Ramazani Saadat Abadi, Ahmad
  7. Abstract:
  8. This project is devoted to experimental investigation of increasing on production of polyethylene/clay nanocomposites (PECNs) and polypropylene/clay nanocomposites (PPCNs) via in-situ polymerization method. First of all we produced bi-supported Ziegler-Natta catalyst to polymerized polyolefins nanocomposites. Bentonite type clay and Magnesiumethoxide (Mg (OEt)2) were used as the support of Tetrachloridetitanium (TiCl4). Catalyst support and polymerization process have been done in slurry phase using Triisobutylaluminum (TiBA) as the co-catalyst. The efficiency of preapared bi-supported Ziegler-Natta was reasonably high (average 200 (gr. Product/mmol Ti. h) for PECNs and 195 (gr. Product/mmol Ti. h) for PPCNs). 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 PECNs and PPCNs 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 50% introducing only 1wt% clay to polymeric matrix. Differential scanning calorimetry (DSC) results indicated that the crystallization temperatures of samples are significantly higher than that of virgin polymers. 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
  9. Keywords:
  10. Nanocomposite ; Clay Soils ; Polyolefins ; Mechanical Properties ; Ziegler-Natta Catalyst ; In-situ Polymerization

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