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Abs/polyamide-6 blends, their short glass fiber composites and organoclay based nanocomposites: processing and characterization

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2007
Özkoç, Güralp
The objective of this study is to process and characterize the compatibilized blends of acrylonitrile-butadiene-styrene (ABS) and polyamide-6 (PA6) using olefin based reactive copolymers and subsequently to utilize this blend as a matrix material in short glass fiber (SGF) reinforced composites and organoclay based nanocomposites by applying melt processing technique. In this context, commercially available epoxydized and maleated olefinic copolymers, ethylene-methyl acrylate-glycidyl methacrylate (EMA-GMA) and ethylene-n butyl acrylate-carbon monoxide-maleic anhydride (EnBACO-MAH) were used as compatibilizers at different ratios. Compatibilizing performance of these two olefinic polymers was investigated through blend morphologies, thermal and mechanical properties as a function of blend composition and compatibilizer loading level. Incorporation of compatibilizer resulted in a fine morphology with reduced dispersed particle size. At 5 % EnBACO-MAH, the toughness was observed to be the highest among the blends produced. SGF reinforced ABS and ABS/PA6 blends were prepared with twin screw extrusion. The effects of SGF concentration and extrusion process conditions on the fiber length distribution, mechanical properties and morphologies of the composites were examined. The most compatible organosilane type was designated from interfacial tension and short beam flexural tests, to promote adhesion of SGF to both ABS and PA6. Increasing amount of PA6 in the polymer matrix improved the strength, stiffness and also toughness of the composites. Effects of compatibilizer content and ABS/PA6 ratio on the morphology and mechanical properties of 30% SGF reinforced ABS/PA6 blends were investigated. The most striking result of the study was the improvement in the impact strength of the SGF/ABS/PA6 composite with the additions of compatibilizer. Melt intercalation method was applied to produce ABS/PA6 blends based organoclay nanocomposites. The effects of process conditions and material parameters on the morphology of blends, dispersibility of nanoparticles and mechanical properties were investigated. To improve mixing, the screws of the extruder were modified. Processing with co-rotation yielded finer blend morphology than processing with counter-rotation. Clays were selectively exfoliated in PA6 phase and agglomerated at the interface of ABS/PA6. High level of exfoliation was obtained with increasing PA6 content and with screw speed in co-rotation mode. Screw modification improved the dispersion of clay platelets in the matrix.