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Production and characterization of polypropylene/organoclay nanocomposites

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2007
Yayla, Saniye
Polypropylene, PP, based nanocomposites were produced via melt blending method by using twin-screw extrusion in this study. The effects of organoclay type, compatibilizer type, and mixing order of components on the morphology, thermal, mechanical and flow properties of ternary nanocomposites were investigated. Terpolymer of ethylene/butyl acrylate/maleic anhydride, ethylene/methyl acrylate/glycidyl methacrylate, and copolymer of ethylene/glycidyl methacrylate elastomers were used as compatibilizer, whereas Cloisite® 30B, Cloisite® 15A, and Cloisite® 25A were used as organoclay. iv In order to determine the optimum amount of compatibilizer, PP/compatibilizer blends were produced with different compositions. The content of compatibilizer was determined as 5 wt % based on the mechanical tests. Then, ternary nanocomposites were prepared with 5 wt % compatibilizer and 2 wt % organoclay contents. In addition, neat PP and PP/organoclay composites were prepared in order to make comparison. After that, the samples were characterized. According to the XRD analysis, the highest increase in the interlayer spacings of organoclays were observed in the PP/E-MA-GMA/Cloisite® 15A (23%) and PP/E-MA-GMA/ Cloisite® 25A (88.3%) ternary systems. SEM micrograms revealed that compatibilizer E-MA-GMA is the most compatible elastomer with PP. Thus, it was decided to investigate the effect of mixing order on the properties of these nanocomposites with E-MA-GMA. DSC analysis showed that the melting behavior of the nanocomposites does not change significantly with the presence of organoclay and compatibilizer. In addition, compatibilizers and organoclays have no significant nucleation activity in PP. The systems PP/E-MA-GMA/Cloisite® 15A and PP/E-MA-GMA/Cloisite® 25A have the highest improvements according to the results of mechanical tests. The results of mechanical tests showed that the mixing sequence (PEC), in which PP, organoclay and compatibilizer were compounded simultaneously in the first extrusion run, is the best sequence.