Response surface method of experimental design was applied to optimize the mechanical properties of polypropylene (PP)/nanoclay/CaCO 3 hybrid ternary nanocomposite using three different levels of melt flow index (MFI) of PP, nanoclay, and CaCO 3 contents. The samples were prepared by melt mixing in a lab scale corotating twin screw extruder. The main effect of each parameter on the tensile modulus, tensile strength, and impact strength was extensively discussed. The structure of obtained nanocomposite was studied using X-ray diffraction (XRD), atomic force microscopy (AFM), and scanning electron microscopy (SEM) techniques. Tensile modulus and impact resistance of prepared ternary nanocomposite were correlated to considered parameters using a second-order polynomial model. Also, the optimum values of studied variables were determined using contour plots. The obtained results show that increasing the nanoclay and CaCO 3 contents improve the tensile modulus up to 45%, whereas the optimum value of impact strength, about 54%, is achieved at low concentrations of nanoclay (2 wt %) and CaCO 3 (8 wt %).

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The tensile modulus of PP/nanoclay/ CaCO 3 hybrid ternary nanocomposite was analyzed using composite models. Rule of mixtures, inverse rule of mixtures, modified rule of mixtures (MROM), Guth, Paul, Counto, Hirsch, Halpin-Tsai, Takayanagi, and KernerNielsen models were developed for three-phase system containing two nanofillers. Among the studied models, inverse rule of mixtures, Hirsch, Halpin-Tsai, and KernerNielsen models calculated the tensile modulus of PP/ nanoclay/CaCO 3 ternary nanocomposite successfully compared with others. Furthermore, the Kerner-Nielsen model was simplified to predict the tensile modulus by volume fractions of nanofillers. Also, Takayanagi model was modified for the current ternary system. The developed Takayanagi model can predict the tensile modulus using Young's modulus and volume fractions of matrix and nanofillers.

Nanocomposites of LDPE/LLDPE/nanoclay have been prepared using a lab-scale co-rotating twin screw extruder. Using XRD, tensile testing, AFM, TGA, effects of some material properties and one processing parameter on mechanical and thermal properties of the prepared nanocomposites were evaluated. Tensile properties indicated that all the prepared nanocomposites exhibited a significant improvement in elastic modulus and toughness compared to pristine LDPE/LLDPE blends of the same composition. Thermal stability of nanocomposites in the air and nitrogen atmosphere was improved. XRD patterns and AFM micrographs showed semi-exfoliated and intercalated microstructures for the prepared nanocomposites with different orders of mixing.On a préparé des nanocomposites de polyéthylène basse densité/polyéthylène basse densité linéaire/nanoargileà l'aide d'une extrudeuseà deux visà co-rotationà l'échelle laboratoire.À l'aide de la diffraction des rayons X, de l'essai de traction, de la microscopieà force atomique et de l'analyse gravimétrique par procédé thermique, on aévalué les effets de certaines propriétés de matériaux et d'un paramètre de traitement sur les propriétés mécaniques et thermiques des nanocomposites préparés. Les propriétés de traction ont indiqué que l'ensemble des nanocomposites préparés ont affiché une amélioration importante du module d'élasticité et de la ténacité comparativement au mélange polyéthylène basse densité/polyéthylène basse densité linéaire original de même composition. La stabilité thermique des nanocomposites dans l'air et de l'atmosphère d'azote aété améliorée. Les modèles de diffraction des rayons X et les micrographies de microscopieà force atomique ont démontré des microstructures semi-exfoliées et intercalaires pour les nanocomposites préparés avec différents ordres de mélange.

Studies of the microstructure and permeability of extruded ribbons of polypropylene (PP)/ethylene vinyl alcohol copolymer (EVOH) and polyethylene (PE)/polyamide‐6 (PA‐6) blends have shown that it is possible to control the flow‐induced morphology to generate discontinuous overlapping platelets of EVOH or PA‐6 dispersed phase in a PP or HDPE matrix phase. The effects of the following factors on morphology development and blend properties were considered: blending sequence, melt temperature, composition, compatibilizer level, die design, screw type, and cooling conditions. The impact properties and interfacial adhesion of laminar blends of PP and EVOH were improved without diminishing the barrier properties. The oxygen and toluene permeability of extruded samples with EVOH content of 25 vol% resembled values obtained with multilayer systems. Processing conditions had a major influence on the morphology of blends of high density polyethylene and polyamide‐6 (HDPE/PA‐6), and, under special processing conditions, laminar morphology was obtained in this system. The toluene permeability of extruded ribbons of HDPE/PA‐6 blends was in the range obtained with multilayer systems.

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Wood-plastic composites (WPCs) and natural fiber composites (NFCs) are increasingly used in decking applications, where exterior exposure can lead to photodegradation and fungal deterioration. Since the fire retardancy is another proficiency concern of these composites, bagasse/polypropylene composites were produced by incorporation of commercially available additives including flame retardants, ultraviolet (UV) stabilizer, antifungal agent and color masterbatches. The addition of the flame retardant which decomposed at high temperature could result in NFC with significant decrease in burning rate (up to 98%) compared to the composite without flame retardant. Simultaneous effects of antifungal agent and green masterbatch lead to complete suppression of the fungal growth and reproduction on composites exposed to either Lentinus edodes, Pleurotus eryngii strain or each of them accompanied by Trichoderma sp. fungus. Durability performance followed by discoloration, mechanical properties loss and surface chemistry variation depended on all additives used. The results indicated that darker color pigment improved color stability and caused much lower fading for UV-stabilized NFC in comparison to the nonstabilized unpigmented composite.

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