Propylene Polymerization Catalyzed by Metallocene /Methylaluminoxane Systems on Rice Husk Ash
Molecules (Basel, Switzerland)
|April 25, 2019
Summary
Rice husk ash silica supports zirconcene catalysts for efficient propylene polymerization, yielding polypropylene with controlled molecular weight and unique morphologies. This eco-friendly approach offers a cost-effective alternative to traditional methods.
Area of Science:
- Materials Science
- Polymer Chemistry
- Catalysis
Background:
- Agricultural waste valorization offers sustainable alternatives to conventional industrial processes.
- Rice husk ash (RHA) is a promising source for silica nanoparticle synthesis.
- Zirconocene complexes are effective catalysts for olefin polymerization.
Purpose of the Study:
- To synthesize spherical silica nanoparticles from RHA for catalyst support.
- To investigate the catalytic activity of RHA-supported zirconcene complexes in propylene polymerization.
- To analyze the effect of reaction conditions and catalyst structure on polypropylene properties.
Main Methods:
- Spherical silica nanoparticles (approx. 120 nm) were synthesized from RHA.
- Two bridged zirconcene complexes, Me2Si(Ind)2ZrCl2 (I) and C2H4(Ind)2ZrCl2 (II), were supported on RHA.
- Propylene polymerization was conducted at 40-70°C with methylaluminoxane (MAO) co-catalyst (0.1-0.6 wt%).
Main Results:
- RHA-supported catalysts showed significantly higher activity than commercial silica-supported catalysts due to smaller particle size.
- Polymer yield and molecular weight increased with MAO concentration at 55°C.
- Catalyst (II) produced more polymer chains but with shorter lengths compared to (I).
- Increasing polymerization temperature decreased molecular weight and altered polypropylene morphology.
Conclusions:
- RHA-derived silica is a cost-effective and eco-friendly support for high-activity polymerization catalysts.
- Catalyst structure and reaction conditions critically influence polypropylene molecular weight and morphology.
- The study demonstrates a sustainable route for producing tailored polypropylene using agricultural waste-derived materials.
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