High-density polyethylene-graphene nanocomposites and methods thereof

Abstract

Methods of preparing high-density polyethylene (HDPE) nanocomposites by in situ polymerization with a metallocene catalyst and a methylaluminoxane co-catalyst in a solvent. The HDPE nanocomposites contain graphene nanofillers that promote the polymerization process, and are found to enhance the molecular weight, molecular weight distribution and flame retardency of the HDPE nanocomposites produced.

1 . A method of producing a high-density polyethylene nanocomposite, comprising:
 polymerizing ethylene in a polymerization mixture comprising a metallocene catalyst, a methylaluminoxane co-catalyst and a graphene nanofiller to form the polyethylene;   wherein the graphene nanofiller is dispersed in the polyethylene during the polymerizing to form the high-density polyethylene nanocomposite.   
     
     
         2 . The method of  claim 1 , wherein the graphene nanofiller is not chemically modified. 
     
     
         3 . The method of  claim 1 , wherein the amount of graphene nanofillers present during the polymerizing is 0.14-0.85 wt. % based on the total weight of the high-density polyethylene nanocomposite produced. 
     
     
         4 . The method of  claim 1 , wherein the metallocene catalyst comprises zirconium. 
     
     
         5 . The method of  claim 1 , wherein the polymerizing is carried out in a solvent. 
     
     
         6 . The method of  claim 1 , wherein the polymerizing is carried out in gas phase. 
     
     
         7 . The method of  claim 1 , wherein the polymerizing forms a high-density polyethylene nanocomposite having a molecular weight of 30-120 kDa. 
     
     
         8 . The method of  claim 1 , wherein the polymerizing forms a high-density polyethylene nanocomposite having a polydispersity index of 3-12. 
     
     
         9 . The method of  claim 1 , wherein the polymerizing forms a high-density polyethylene nanocomposite that is non-flammable. 
     
     
         10 . The method of  claim 1 , wherein the polymerizing is carried out at atmospheric pressure. 
     
     
         11 . A high-density polyethylene nanocomposite, comprising:
 a polyethylene matrix and a graphene nanofiller dispersed therein;   wherein the polyethylene polymer of the polyethylene matrix has a molecular weight of 30-120 kDa and a polydispersity index of 3-12.   
     
     
         12 . The high-density polyethylene nanocomposite of  claim 11 , wherein the graphene nanofiller is not chemically modified. 
     
     
         13 . The high-density polyethylene nanocomposite of  claim 11 , wherein the graphene nanofiller is present in an amount of 0.14-0.85 wt. % based on the total weight of the high-density polyethylene nanocomposite. 
     
     
         14 . The high-density polyethylene nanocomposite of  claim 11 , wherein the polyethylene nanocomposite further comprises zirconium. 
     
     
         15 . The high-density polyethylene nanocomposite of  claim 11 , wherein the high-density polyethylene nanocomposite is non-flammable.