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In this research, the tensile properties of polypropylene/natural rubber composite reinforced with perlite nanoparticles produced using a biaxial internal mixer were studied. The mathematical modeling of analysis of variance using the surface response method was used to confirm the experimental results. The role of each materials variable and the weight percentage of natural rubber and pearlite nanoparticles on the tensile properties of the new nanocomposite samples was investigated. It was observed that the values of tensile strength and elongation at break by increasing the amount of natural rubber from 20 wt.% to 40 wt.% and the constant amount of perlite nanoparticles at 3 wt.%, decreased by 14.68% (from 8.92 to 7.61 MPa) and increased by 72% (from 51.05% to 87.81%), respectively. The results obtained from the parameters optimization showed that the maximum values of tensile strength and elongation at break are 8.332 MPa and 74.38% was obtained in the sample with 3.268 wt.% of natural rubber and 4.046 wt.% of perlite nanoparticles, respectively. The scanning electron microscope images showed the positive effect of adding nanoparticles to the polypropylene/natural rubber composite due to the reduction in the size of the elastomeric phase and as a result, the increase in the tensile strength of the composite samples. Also, the proper dispersion of nanoparticles in the polymer matrix phase occurred in the sample with 5 wt.% of perlite nanoparticles and 30 wt.% of natural rubber. However, with increasing the weight percentages of nanoparticles up to 9 wt.%, some agglomerations of pearlite nanoparticles were observed in the thermoplastic phase. [ABSTRACT FROM AUTHOR]

In this article, response surface methodology (RSM) has been applied to simultaneously optimize the tensile and impact strength of polypropylene (PP)/nitrile butadiene rubber (NBR)/halloysite nanotubes (HNTs)/maleic anhydride (MA)‐grafted‐PP nanocomposites. Three levels of material parameters, including NBR (10, 20, and 30 wt%), HNTs (1, 3, and 5 wt%), and PP‐g‐MA (3, 9, and 15 wt%) as compatibilizers were used to design the experiments according to Box‐Behnken design. In order to investigate the morphology of nanocomposite samples, a scanning electron microscope was used. The model predicted that both the tensile strength and impact strength of nanocomposite were peaked between middle and high levels of HNTs content. There was also a peak for NBR loading in the main effect plot of impact strength. Two‐way interactions of all parameters were significantly affecting both responses. Based on RSM models using the desirability function, the optimum values of input parameters leading to optimized tensile strength and impact strength were predicted to be 17.87, 4.35, and 15 wt% for NBR, HNT, and PP‐g‐MA, respectively. Confirmation experiments were in good agreement with the predicted values. [ABSTRACT FROM AUTHOR]

Thermoplastic elastomeric nanocomposites due to their excellent mechanical, thermal, and chemical properties have a wide application in airplane, shipbuilding, and automotive industries and medical apparatus. Friction stir processing (FSP) is a novel technique for the fabrication of composites, nanocomposites and microstructural modifications. In this paper, polypropylene/ethylene–propylene–diene monomer (PP/EPDM) nanocomposite with 5 wt% nanoclay are fabricated by FSP to determine the effect of process parameters such as tool rotational speed, traverse speed, shoulder temperature, and number of passes on total work of fracture of this nanocomposite. Response surface methodology (RSM) and Box–Behnken design were used to develop a mathematical model relating the process parameters to the total work of fracture. The results show that the total work of fracture increased with increasing the rotational speed and number of passes and decreasing the shoulder temperature. A maximum total work of fracture of 50.3 N/mm was obtained at traverse speed of 42 mm/min when other parameters were at their center level. The maximum total work of fracture of 61.8 N/mm is achieved at rotational speed of 1,200 rpm, traverse speed of 40 mm/min, shoulder temperature of 100°C, and number of passes of 3. POLYM. COMPOS., 39:2336–2346, 2018. © 2016 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

In this article, effects of friction stir processing parameters such as tool rotational speed, traverse speed, shoulder temperature, and number of passes on tensile modulus and impact strength of polypropylene/ethylene-propylene diene monomer/clay nanocomposite has been investigated. The Box-Behnken design with four factors at three levels was used for design of experiments. The response surface methodology was employed to develop models capable of predicting the effect of input variable on responses. A multi-layer artificial neural network with back propagation algorithm and 4 - 8 - 10 - 2 topology was also selected for modeling. A set of data on friction stir parameters and experimental results of the mechanical properties were used to train and test the artificial neural network. POLYM. COMPOS., 38:E421-E432, 2017. © 2016 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]