Compounding and Rheological Characterization af Sepiolite/PP Nanocomposites

TERENZI, ANDREA; LA TÉGOLA, SIMONE; BARBOSA, SILVIA ELENA; KENNY, JOSÉ MARÍA

Salerno, Italia

Congreso; POLYMER PROCESSING SOCIETY - 24TH ANNUAL MEETING - PPS 24; 2008

Polymer Processing Society

The use of nanoclays in polypropylene matrix showed important applications during the last decade. In particular these applications point both to improve functionalities of the matrix and mechanical properties and significant results were obtained in terms of thermal resistance, fire resistance, barrier properties, etc.[1 - 3]. The main nanoclays used till now are layered silicates and in particular MMT. However in the last years sepiolites are being very interesting for the application in polymeric matrices. These nanoparticles have an acicular structure, therefore from a rheological point of view they can be seen as fibres with nanometric dimension. In this work Polypropylene based nanocomposites have been produced by melt intercalation procedure and analysed from a rheological point of view in order to evaluate the effect of the nanofiller on the flow properties and in order to compare with the flow properties of PP filled with short fibres. The analysis of the rheological properties is very important from an industrial point of view because polypropylene is processed in the melt state. Polypropylene HP 500N kindly supplied by BASELL was used as matrix; Sepiolites both compatibilized and pure were used as nanofillers. In particular Sepiolites from TOLSA were used with three different content 0,5; 1 and 1,5 wt%. The materials were processed by melt intercalation by using a twin counter-rotating screw extruder BAUSANO MD30 with different extrusion conditions in order to verify the influence on the final properties. The materials produced were analysed by morphological point of view and an important influence of the processing conditions was observed. Rheological measurements were performed; in particular both dynamic and steady conditions were used in a rotational rheometer with parallel plate configuration. The results show that rheological parameters are significantly affected by the processing conditions and therefore by the morphology of the suspensions In particular the effect can be observed both in viscosity and viscoelastic properties, and also the nanofiller content is an important parameter. A detailed analysis of the normal stress difference have been done, and in general it is possible to assert that the rheology is a useful instrument to analyse the correlation between processing and morphology of the analysed suspensions References: [1]       M. Modesti, A. Lorenzetti, D. Bon, S. Besco “Effect of processing conditions on morphology and mechanical properties of compatibilized polypropylene nanocomposites” Polymer 46 (2005) 10237–10245 [2]       C. Ding, D. Jia, H. He, B. Guo, H. Hong “How organo-montmorillonite truly affects the structure and properties of polypropylene” Polymer Testing 24 (2005) 94–100 [3]       J. Zhang, D. D. Jiang, C. A. Wilkie “Thermal and flame properties of polyethylene and polypropylene nanocomposites based on an oligomerically-modified clay” Polymer Degradation and Stability 91 (2006) 298e304 [4]       S. Xie, S. Zhang, F. Wang, M. Yang, R. Séguéla, J.M. Lefebvre “Preparation, structure and thermomechanical properties of nylon-6 nanocomposites with lamella-type and fiber-type sepiolite” Composites Science and Technology 67 (2007) 2334–2341 [5]       H. Chena, M. Zheng, H. Suna, Q. Jia “Characterization and properties of sepiolite/polyurethane nanocomposites” Materials Science and Engineering A 445–446 (2007) 725–730