Synthesis of PE/graphene nanocomposite via in-situ polymerization using a multinuclear catalyst of late transition metals based on cobalt

During the last few decades, polyethylene composites are properly used instead of PE in numerous applications. Various types of additives in different size of particles can be used to preparing these composites [1]. Graphene is a two-dimensional, single-layer hybrid of sp2 carbon atom with a macroscopic dimension but with atomic thickness. The properties of graphene-based polymer composites depend heavily on the dispersion of the graphene plates in a polymer matrix. In-situ polymerization is one of the most effective method to synthesis nanocomposites in presence of nano-materialis [2].Polymerization of ethylene with PE/nanocomposites were carried out using (1E, 1 E)-N,N -(2,3,5,6-tetramethyl-1,4-phenylene)bis(1-(6-((E)-1-((2,6-diisopropylphenyl)imino)pyridine-2-yl)ethan-1- imine) cobalt(ll) chloride prepared catalyst, while methylaluminoxane (MMAO) was used as cocatalyst. The optimum polymerization condition was attained at 50 °C, for 30 minutes, with [Al]:[Co] molar ratio of 1000:1. The PE/graphene nanocomposites (1.7-2 nm with 10-12 layers) were synthesized through in-situ polymerization using the catalyst. The result showed that activity of the catalyst slightly enhanced (from 210 to 350 g PE. mmol (Co)-1. hr-1) with increasing of the graphene (0.22 weight percent) during the polymerization. The obtained polyethylene samples were analyzed with FT-IR technique (Fig. 1). As expected, the resultant products distinguished as high density polyethylene (HDPE), and as indicated, the sample prepared in presence of graphene showed higher vinyl content and lower branching density than the neat PE