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Composites Science and Technology, Volume 84, 29 July 2013, Pages 1-7.
Marcéo A. Milani, Darío González, Raúl Quijada, Nara R.S. Basso, Maria L. Cerrada, Denise S. Azambuja, Griselda B. Galland.
Instituto de Química, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, 91501-970 Porto Alegre, Brazil &
Departamento de Ingeniería Química y Biotecnología, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Casilla 2777, Santiago, Chile &
Faculdade de Química, Pontifícia Universidade Católica do Rio Grande do Sul-Brasil, Av. Ipiranga 6681, 90619-900 Porto Alegre, Brazil &
Instituto de Ciencia y Tecnología de Polímeros (ICTP-CSIC), Juan de la Cierva 3, 28006 Madrid, Spain
Abstract
This study investigates the synthesis, characterization and properties of isotactic polypropylene/graphene nanosheet nanocomposites (iPP/GNS). These nanocomposites were prepared by in situ polymerization using the metallocene complex rac-Me2Si(Ind)2ZrCl2 and methylaluminoxane (MAO) as cocatalyst. Homogeneous graphene nanosheet dispersions within the polymeric matrix were observed by TEM and XRD. The molecular characteristics of iPP, such as molecular weight, polydispersity and tacticity, were not affected by the presence of nanoparticles. The thermal properties investigated by DSC and TGA showed that graphene nanosheets significantly improved the matrix, increasing the crystallization and the degradation temperatures. From a mechanical perspective, there was an excellent balance between a significant increase in Young’s modulus and a slight reduction in the elongation at break. The reinforcing effect of graphene incorporation was confirmed by the increase of the storage modulus with nanosheet content. An enhancement of dimensional stability was also detected, and deformability was significantly smaller in the nanocomposites than in the homopolymer. Impedance measurements showed that the electrical conductivity increased by a factor of 108 compared to that of neat iPP.
