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Polypropylene is a useful and widely consumed thermoplastic with very good properties that can be mixed with a combination of rubber and nanoparticles in order to eliminate its shortcomings. In this paper, the simultaneous combination of both the toughening effect of styrene–butadiene rubber (SBR) and the reinforcing effect of silicon carbide (SiC) nanoparticles were investigated in polypropylene matrix. Mechanical properties (tensile and impact strength [TS and IS]) of compounds were analyzed using the central composite design approach in Design‐Expert software. With two factors for input variables of SBR and SiC weight percentages, and their five levels (5, 10, 15, 20, and 25) and (0, 1.5, 3, 4.5, and 6), respectively, the central composite design approach employs 11 experiments for creation of models and the analysis of variance investigations with two output responses of TS and IS. Statistical results revealed that SBR and SiC contents had a significant effect on TS, IS, and the microstructure of compounds, as confirmed by scanning electron microscopy and energy‐dispersive spectroscopy images. To maximize all mechanical properties simultaneously with desirability functions, TS and IS of the optimum sample were computed to be 21.98 MPa and 8.66 kJ/m2 in amounts of 13.45 and 2.80 weight percentage (wt%) of SBR and SiC, respectively. Highlights: By increasing silicon carbide (SiC) in polypropylene/styrene–butadiene rubber (SBR), tensile strength decreases after a peak due to agglomeration effect.By increasing SiC in polypropylene/SBR, impact strength decreases after a peak due to agglomeration effect.By increasing SiC, the rubber particles' dimensions decrease according to scanning electron microscopy analysis.Simultaneous maximum of tensile strength and impact strength are 21.98 MPa and 8.66 KJ/m2, respectively.Optimum value of SBR and SiC in above maximums are 13.45 and 2.8 wt%, respectively. [ABSTRACT FROM AUTHOR]

The modified atmosphere packaging films based on polyethylene nanocomposites reinforced with perlite nanoparticles were prepared using a blow molding machine. The perlite particles were first reduced to nano dimensions using an abrasive mill, then the porosity of nanoperlite was increased to improve their efficiency in absorbing ethylene gas. For this purpose, 6 normal sodium hydroxide solution at 50°C temperature was used. Finally, perlite nanoparticles were modified by polymethyl hydrogen siloxane silane compound. In each of the stages of grinding and modifying the perlite surface, the necessary tests including dynamic light diffraction test, nitrogen absorption test and ethylene gas absorption test were performed using gas chromatography method. The results showed that the size of perlite particles was reduced to 500 nm by using an abrasive mill, and the surface modification process increased the specific surface area of perlite by 10 times. Based on this, the amount of ethylene gas absorption in perlite nanoparticles with modified surface increased up to 3 times compared to normal perlite. The results of the gas chromatography test showed that the nanocomposite film based on polyethylene reinforced with 6% by weight of modified perlite nanoparticles has several times the efficiency in absorbing ethylene gas compared to the potassium permanganate sachets The results of the mechanical properties tests of nanocomposite film in comparison with pure polyethylene film showed that nanocomposite film has higher properties than pure polyethylene. The results of shelf-life tests of green tomatoes packed in nanocomposite film based on polyethylene reinforced with modified nanoperlite showed that green tomatoes can be stored for two months using the prepared modified atmosphere packaging. [ABSTRACT FROM AUTHOR]

The present research outlines the novel finite element analysis of green tire tread compounds based on solution styrene‐butadiene rubber/butadiene rubber (SSBR/BR) reinforced with a hybrid silica/carbon black filler system. For this purpose, a series of micromodels using representative volume elements (RVEs) were developed. The silica/carbon black ratio with a constant value of the reinforcement and considering periodic boundary conditions (PBCs) were established. The distribution of the reinforcing fillers in the matrix was inspired by transmission electron microscope (TEM) micrographs. A nonlinear hyperviscoelastic model was considered for the matrix and interphase zones and a linear elastic model for the reinforcement phase to predict the dissipation behavior at a moderate to high strain regime. To confirm the accuracy of the proposed model, the RVEs of hybrid systems were simulated and then compared with experimental data. The results showed that the proposed model is capable to predict the mechanical properties of rubber compounds. The presence of agglomerated fillers resulted in an increase in the dissipation behavior. This was confirmed by rubber process analyzer (RPA) and dynamic mechanical thermal analysis (DMTA) results. Highlights: Rubber compounds based on SSBR/BR reinforced with silica and/or carbon black were prepared by the melt mixing method.A multi‐scale finite element analysis of the particulate composites was developed using RVE.The distribution of reinforcing fillers in the matrix was inspired by TEM.The prediction of the stress–strain behavior of the hybrid composites was confirmed by the results of tensile tests.The simulated dissipation behavior of the composites was compared with RPA and DMTA analyses. [ABSTRACT FROM AUTHOR]

Heat seal and mechanical properties of 1‐octene grafted low density polyethylene films containing various concentrations of Dicumyl peroxide as the initiator and 1‐octene grafting agent is investigated through using experimental measurements. The results of differential scanning calorimeter (DSC) measurements revealed that the melting temperature shifts to higher values and the peak of the DSC curve becomes wider with the increase of 1‐octene concentrations. Thermogravimetric analysis (TGA) revealed a higher thermal stability up to 20 °C for 1‐octene grafted PE compared with neat LDPE alloy. The results of stress–strain measurements revealed that the 1‐octene grafted PE alloys has higher tensile strength in comparison with neat PE alloy and samples containing only DCP initiator. The results of heat seal analysis indicated that both DCP initiator and 1‐octene tended to offer a moderate increase peel strength of PE alloy. DMTA measurements for various grafted PE alloys show a higher damping factor in comparison with neat LDPE alloy. Rheological measurements indicated a higher storage modulus up to 25% and higher complex viscosity for grafted PE samples containing 1‐octene comonomer. [ABSTRACT FROM AUTHOR]

Polypropylene/polycarbonate (PP/PC) nanocomposites containing various proportions of the organically modified montmorillonite were prepared by extrusion and injection molding process. The morphology of PP/PC nanocomposites was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The nanocomposites with 3 or 5 wt% of nanoclay (NC) show a uniform dispersion of the NC as pointed out by two different methods, TEM and XRD. It was shown that the morphology of dispersed phase (PC) is highly dependent on the content of minor phase, which was correlated with the balance of drop breakup and coalescence. The mechanical properties have been investigated by tensile test and Izod impact test. The virgin PP/PC samples showed a reduction in impact strength and elongation at break and up to 50% increase in Young’s modulus by increase in PP content comparing with the pure PP. Investigating the effect of NC and PC content on the mechanical behavior of PP/PC nanocomposites showed increased Young’s modulus and decreased impact strength with increasing PC and NC loading. An obvious ductile to brittle behavior transition at a high content of PC or NC was supported by notched Izod impact strength experiments and SEM results.

Ternary blends based on polyamide 6 (PA6)/acrylonitrile-butadiene rubber (NBR)/polycarbonate (PC) were prepared by melt compounding via extrusion process. The effect of organoclay (OC), compatibilizer, and blend ratio was investigated on structural and mechanical properties of the blend. The effect of OC and compatibilizer studied on crystallization temperature, melting temperature, and crystallinity of PA6/NBR/PC ternary blends was studied by differential scanning calorimetry. Improvement in the crystal structure of compatibilized blend compared to unfilled blend was observed by polarized optical microscope. Dispersion of OC into PA6/NBR/PC ternary blends was done by X-ray diffraction, transmission electron microscopy, and scanning electron microscopy (SEM)/energy-dispersive X-ray. The results confirmed the exfoliation of OC particles into the polymer matrix. The improvement in yield stress and tensile modulus of the ternary blend was observed in the presence of OC. The impact strength showed an increase using NBR-glycidyl methacrylate-grafted (g-GMA) to prepare compatibilized PA6/NBR/PC ternary blend.

In this study, the various properties of hybrid nanocomposite based on solution styrene butadiene rubber (SSBR)/butadiene rubber (BR) have been investigated. For this purpose, SSBR/BR rubber blend with nano‐silica and carbon black (CB) in constant filler content (60 phr) with and without Bis (triethoxysilylpropyl) tetrasulfide (TESPT) silane coupling agent was fabricated. The various properties, including curing behavior, morphology, dynamic–mechanical, and dissipation characteristics, were studied. For this objective, rheometry, field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM), tensile test, and Dynamic mechanical thermal analysis (DMTA) were used. The results of rheometry illustrated that the addition of nano‐silica increased the optimum cure time (t90) and declined the cure rate index (CRI). However, the addition of surface‐modified silica improved the t90 and CRI. Replacing nano‐silica with CB also reduced the scorch and optimum cure time. TEM and SEM micrographs showed the good dispersion state of nano‐silica in the SSBR/BR/nano‐silica/TESPT matrix. According to the mechanical test data, including tensile, hardness, and abrasion, the addition of hybrid filler containing 40 phr modified nano‐silica and 20 phr CB improved properties. The results of DMTA illustrated the appropriate compatibility between blend phases, also an increase in the glass transition temperature (Tg) and storage modulus (E′) for the samples containing higher amounts of CB. Considering the importance of the damping factor at temperatures of −20, 0, and 60°C, which is related to ice grip, wet grip, and rolling resistance, respectively, the TSi40CB20 sample showed the essential properties of the magic triangle better than other samples. Dissipative properties also revealed that by increasing the filler content and replacing nano‐silica with CB, the dissipation of the compound increases significantly. According to the results, the optimum amount of nano‐silica and CB in the SSBR/BR/TESPT was 40 and 20 phr, respectively. [ABSTRACT FROM AUTHOR]