(A) study on preparation and properties of polypropylene nanocomposites using modified PP and HMDA

Abstract

Researches on PP/Clay nanocomposite have recently focused on the uniform dispersion of modified clay particles. Because, the uniform dispersion correlates with their mechanical and physical properties. To study the effect of HMDA on PP nanocomposite, three different types of organic clay were prepared. Cloisite®20A was just simply mixed with HMDA under shearing condition in Brabender mixer. HMDA group was successfully penetrated into silicate layers. As a results, d-spacing of obtained nanocomposites was increased. Polypropylene/Clay nanocomposites were prepared by compounding with modified PP and amine-treated clay. Nanocomposites were made in two different method. One method is non-equimolar relation between amine content in silicate layers and maleic-anhydride group on modified PP, the other is equimolar relation between them. From the FT-IR spectra, reaction between amine group and maleic-anhydride group was confirmed. In non-equimolar method, the characteristic peak of maleic-anhydride group was disappeared appearing the new peak of amide and imide linkage. On the other hands, equimolar method shows an appreciable characteristic peak of maleic-anhydride group, amide and imide linkage. It means the reaction was not completed. Because, non-equimolar method has an enough amine content on silicate surface, but equimolar method has a lack of amine on their surface. The effects of organoclays on the properties of the nanocomposites such as the morphology, dynamic mechanical properties, crystal structure and crystallization behavior, glass transition temperature, thermal stability and tensile properties were investigated and analyzed. Whether the reaction between them is completed or not, nanocomposites with amine-treated clays shows an enhanced properties compared to those with non amine-treated clays(Cloisite®20A). From the TEM analysis, nanocomposites with amine-treated clays shows a better dispersibility compared to those in same method with Cloisite®20A.