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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]

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]

Abstract Super-crosslinked epoxy nanocomposites containing N-octadecyl-N'-octadecyl imidazolium iodide (IM)-functionalized montmorillonite (MMT-IM) nanoplatelets were developed and examined for cure kinetics, viscoelastic behavior and thermal degradation kinetics. The structure and morphology of [...]

This work reports on nonisothermal degradation kinetics of polyurethane (PU)‐based powder coatings containing 1, 3, and 5%wt% vinyltrimethoxysilane functionalized Al2O3 (V‐Al2O3) nanoparticles. Thermogravimetric analysis of PU/V‐Al2O3 powder coatings with different V‐Al2O3 contents has been performed at different heating rates. Variation of activation energy (Ea) of PU/V‐Al2O3 powder coatings was modeled as a function of partial mass loss by using Kissinger–Akahira–Sunose, Ozawa–Wall–Flynn and modified Coats–Redfern isoconversional approaches. The results revealed hindered decomposition process of PU/V‐Al2O3 nanocomposite powder coatings, featured by an increase in activation energy of degradation from ∼158 for blank PU to 225, 183, and 229 kJ/mol for nanocomposites filled with 1, 3, and 5 wt% of V‐Al2O3, respectively. Likewise, pre‐exponential factor values increased for samples containing V‐Al2O3 nanoparticles compared to that of blank sample. Sestak–Berggren kinetic model appropriately captured thermal degradation behavior of PU/V‐Al2O3 nanocomposites than that of nth order decomposition kinetic reaction models. [ABSTRACT FROM AUTHOR]

Carbon nanotube (CNT)/Natural rubber (NR)/ ethylene–propylene diene monomer (EPDM) nanocomposites were prepared via a traditional mixing method using a two‐roll mixer and cured by a conventional vulcanization system. The nanocomposites were characterized with respect to their curing characteristics and mechanical properties. The cure characteristic investigations showed that the introduction of CNTs into the rubber blend leads to a decrease in scorch and cure times. The minimum and maximum torque values of the cured nanocomposites rise with respect to CNTs loading. Tensile strength of NR/EPDM (75/25 wt/wt) blends containing 0.5 wt% of CNTs showed an increase compared to the NR/EPDM blends. The moduli of the nanocomposites at 100% and 300% elongations revealed that the CNTs can increase these parameters with no significant effect on the elongation at break. The stress–strain behavior of the nanocomposites was analyzed by some proper phenomenological hyperelastic models and the effect of CNTs loading on their material parameters was investigated. The introduction of CNTs into the NR/EPDM matrix leads to a significant change in material parameters of hyperelastic models. The results suggested that various CNTs loadings have a significant effect on the dispersion state of nanotubes and ultimate mechanical properties of CNT/NR/EPDM nanocomposites. POLYM. COMPOS., 39:4071–4079, 2018. © 2017 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]