Mechanical Properties of Polyethylene-Carbon Nanotube Composites Synthesized by In Situ Polymerization Using Metallocene Catalysts

Mamdouh A Al-Harthi,Bijal Kottukkal Bahuleyan

doi:10.1155/2018/4057282

Abstract

The influence of multiwalled carbon nanotubes (MWCNTs) on the properties of polyethylene prepared by in situ polymerization using metallocene catalyst (Cp2ZrCl2) in combination with methylaluminoxane has been studied. The MWCNT was incorporated in the polymer matrix adopting a stirring method. Incorporation of MWCNT causes a drop in molecular weight of the polymer along with an increase in number of branches and increase in crystallinity. It was also observed that addition of MWCNT during metallocene-catalyzed polymerization caused a drop in both the dynamic modulus and Young’s modulus of polyethylene. But the drop in tensile strength was minimal, and there was an increase in elongation at break along with consequent increase in energy at break.

Highlights

Incorporation of nanofillers in a polymer matrix can greatly influence the mechanical properties, thermal stability, flame retardance, barrier properties, electrical properties, and scratch resistance of the nanocomposites [1,2,3,4,5,6]. e carbon nanotube (CNT) is a promising filler and has attracted a great research interest in the area of polymer nanocomposites since its discovery because of its unique properties [5, 7]. e hydrophilic nature of most inorganic fillers is not compatible with the hydrophobicity of the polyolefins. is results in a weak interfacial adhesion between the polymer and nanofillers, thereby adversely affecting the final properties
We report polymerization activity and polymer properties adopting the stirring method to make the process much easier. e multiwalled carbon nanotubes (MWCNTs) was vigorously stirred (1500 rpm) rather than sonication, unlike our previous report [20]. e properties of the polymer nanocomposites are compared with the neat PE obtained by using the same catalyst, but in the absence of CNT
On the addition of MWCNT, the catalytic activity did not show any significant change when compared to the control, which indicates that the metal complex does not have any effect on the CNT dispersion in +polymer matrix

Summary

Introduction

Incorporation of nanofillers in a polymer matrix can greatly influence the mechanical properties, thermal stability, flame retardance, barrier properties, electrical properties, and scratch resistance of the nanocomposites [1,2,3,4,5,6]. e carbon nanotube (CNT) is a promising filler and has attracted a great research interest in the area of polymer nanocomposites since its discovery because of its unique properties [5, 7]. e hydrophilic nature of most inorganic fillers is not compatible with the hydrophobicity of the polyolefins. is results in a weak interfacial adhesion between the polymer and nanofillers, thereby adversely affecting the final properties. E dispersion of CNTs and their interfacial interaction between the polymer matrix and Advances in Materials Science and Engineering tubes are the main criteria to improve the mechanical properties [19]. Our aim was to prepare PE-MWCNT nanocomposites by a suitable method and to study the mechanical properties of the obtained nanocomposite using the metallocene (Cp2ZrCl2)-catalyzed olefin polymerization in combination with MAO cocatalyst.

Objectives

Results

Conclusion