Effects of nano graphene oxide as support on the product properties and performance of Ziegler–Natta catalyst in production of UHMWPE

Abstract

The synthesis of mono-and bi-supported Ziegler-Natta catalysts using magnesium etoxide Mg(OEt) 2 and graphene oxide (GO) as catalyst support for production of Ultra High Molecular Weight Polyethylene (UHMWPE) is reported in this investigation. Nano-graphene oxide was prepared by the modified Hummer's method and its structure was analyzed by XRD and FTIR indicating the presence of hydroxyl groups on graphene oxide and the formation of an exfoliated structure. The activity of TiCl 4 /Mg(OEt) 2 , TiCl 4 /Mg(OEt) 2 -GO, and TiCl 4 /GO catalysts in terms of grams of PE produced per mmol of Ti per hour was experimentally obtained for catalysts with different ratios of co-catalyst (triisobutylaluminium) to TiCl 4 . For all three series of catalysts, the activity curve showed an optimum point at a specific Al/Ti molar ratio. Catalyst activity was highest for TiCl 4 /Mg(OEt) 2 and lowest for TiCl 4 /GO. The characterization of UHMWPE products indicated that the viscosity average molecular weight (Mv) was highest for the polymer produced by TiCl 4 /Mg(OEt) 2 and lowest for the polymer produced by TiCl 4 /GO. Furthermore, thermogravimetric analysis (TGA), dynamic mechanical thermal analysis (DMTA), and mechanical tensile testing were conducted on the prepared polymers indicating that the polymer produced by TiCl 4 /GO had the highest thermal and mechanical properties, while these properties were at their minimum for polymers produced by TiCl 4 /Mg(OEt) 2 .

SiO2‐covered graphene oxide nanohybrids for in situ preparation of UHMWPE/GO(SiO2) nanocomposites with superior mechanical and tribological properties

“…In fact, placement of GO(SiO 2 ) nanosheets through the growing PE chains could increase the steric hindrance between the chain and restrict the chain mobility and growth of PE chains during the polymerization process. In addition, it seems that addition of GO(SiO 2 ) into the catalyst may change the termination reactions of the polymerization and affect the activity of the Ziegler–Natta catalyst …”

“…Nevertheless, a challenging task for this field is fabrication of UHMWPE nanocomposites with uniformly dispersed fillers . Polyolefin nanocomposites can be conceptually fabricated by solution compounding, melt blending, and in situ polymerization . However, UHMWPE, due to a lack of flowability and an appropriate solvent, can be produced by two former methods.…”

Recent advances in graphene/polyamide 6 composites: a review

“…In situ polymerization is the most often method for preparation graphene/PA6 and other graphene-filled polymer composites including epoxy [84][85][86][87][88] , PS 89 , PMMA 90,91 , PU 92,93 , PE 94 , PANI [95][96][97] , PI 98-101 , etc. This method consist two main steps: 7,8,55,57 1. Graphene or its derivative is mixed pure monomers (or multiple monomers, a solution of monomers).…”

Preparation of Polyethylene/Graphene Nanocomposites with Octadecylamine‐Modified Graphene Oxide‐MgCl‐Supported Ziegler–Natta Catalyst

“…Using the same method, our group studied the effects of degree of oxidation of GO on the ethylene polymerization behavior and PE properties . Ramazani and co‐workers also reported PE/GO nanocomposites using Mg(OEt) 2 and a GO bi‐supported titanium‐based Ziegler–Natta catalyst. In our previous work, PE/GO nanocomposites were also prepared by using a GO‐supported VOCl 3 catalyst .…”