Composite materials based on graphene nanoplatelets and polypropylene derived via in situ polymerization

Abstract

Nanocomposites of polypropylene and graphene nanoplatelets were synthesized by in situ polymerization in liquid monomer in the presence of highly effective isospecific homogeneous metallocene catalyst. Microstructure, mechanical, dielectric, and thermal properties of composites are presented. X-ray phase analysis data indicate that graphene nanoplatelets are present in composites as thin flaky particles aggregates, with aspect ratio affected by sonication of reaction mixture. Crystallization temperature of polypropylene increases in composites. Nanocomposites are characterized by high rigidity, thermal stability, and crystallization temperature, low conductivity, and high dielectric losses in the microwave range. V C 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 127: 904-911, 2013

The electrical conductive behaviours of polymer-based three-phase composites prepared by spatial confining forced network assembly

“…Sun 1 , X. Gao 1 , X. He 1 , X. Zheng 1 , I. Skopincev 2 , N. Memetov 3 , A. Tkachev 4 , Z. Zhi 5 of these structures would be observed if the fillers have a large contact surface and aspect ratio, see examples in the previous studies, carbon fiber [10,21], CNTs [17,22] and graphene [19,23]. For example, in work [22] a wide review of works aimed at studying the relationship between the geometric shape of the filler and the structure of the polymer composites was presented.…”

“…The most effective way to improve the electrical conductivity behavior of CPCs is increasing the concentration of the filler, which leads to a denser arrangement of filler particles in the matrix and simplifies the mechanism of conductivity between them. However, in a certain case, the higher concentration would lead to a critical decrease in the physical and mechanical properties of composite [9,23]. Recently the research studies demonstrated the emergence of new effective methods for organizing filler networks to improve the conductive properties of CPCs.…”

In-situ polymerization of isotactic polypropylene-nanographite nanocomposites

“…Solution processing has shown success in other GNP-nanocomposite systems [12,13], however this technique is not applicable to polyolefin-GNP nanocomposites due to the general insolubility of polyolefins. Other fabrication techniques include, nanoparticle surface coating [11], polymerization filling technique [14], Solid State Shear Pulverization [15][16][17], Solid State Ball Milling [18], and in-situ polymerization [19][20][21][22][23].…”

“…Polyolefin-GNP nanocomposites have recently been prepared via in-situ polymerization, and demonstrated modest increases in linear mechanical properties [19][20][21]23,29]. However, the non-linear mechanical properties of the PNCs in these studies were limited by their relatively low molecular weight (M w < 80,000 g/mol).…”

“…Through rational metallocene catalyst design, features of the polyolefin microstructure can be controlled, such as molecular weight, co-monomer incorporation, regio-selectivity, and stereo-selectivity [25,26]. In principle, any single site catalyst or combination of catalysts can be applied to an in-situ polymerization, enabling control of the morphology and properties of synthesized PNCs [27,28].Polyolefin-GNP nanocomposites have recently been prepared via in-situ polymerization, and demonstrated modest increases in linear mechanical properties [19][20][21]23,29]. However, the non-linear mechanical properties of the PNCs in these studies were limited by their relatively low molecular weight (M w < 80,000 g/mol).…”