In situ hydrothermal synthesis of MWCNT/MIL-100(Fe) composites can combine all the attributes required of a commercial adsorbent into a single material designed for high-performance adsorption chillers.
There is an increasing demand for sustainable and safe packaging technologies to improve consumer satisfaction, reduce food loss during storage and transportation, and track the quality status of food throughout its distribution. This study reports the fabrication of colorimetric pH-indicative and flame-retardant nanocomposite films (NCFs) based on polyvinyl alcohol (PVA) and nanoclays for smart and safe food packaging applications. Tough, flexible, and transparent NCFs were obtained using 15% nanoclay loading (PVA-15) with superior properties, including low solubility/swelling in water and high thermal stability with flame-retardant behavior. The NCFs showed average mechanical properties that are comparable to commercial films for packaging applications. The color parameters were recorded at different pH values and the prepared NCFs showed distinctive colorimetric pH-responsive behavior during the transition from acidic to alkaline medium with high values for the calculated color difference (∆E ≈ 50). The prepared NCFs provided an effective way to detect the spoilage of the shrimp samples via monitoring the color change of the NCFs during the storage period. The current study proposes the prepared NCFs as renewable candidates for smart food packaging featuring colorimetric pH-sensing for monitoring food freshness as well as a safer alternative choice for applications that demand films with fire-retardant properties.
1 March 2018 in Journal of Natural Gas Science and Engineering
An improved instrumented impact test method is used to correlate the impact resistance of low-density polyethylene and linear low-density polyethylene blown films to their solid-state deformation process during impact test. The two materials, low-density polyethylene and linear low-density polyethylene, showed different deformation behaviors under the same impact testing conditions. The region before the peak force in the load versus deformation plot for low-density polyethylene was linear, whereas for linear low-density polyethylene two different slopes were observed. The average peak force values of linear low-density polyethylene film is about 14% greater than that of low-density polyethylene film. Furthermore, the measured deflection at the peak force is about 50% higher in the case of linear low-density polyethylene film. In addition, the energy to peak force of linear low-density polyethylene is more than twice higher than that of low-density polyethylene. In the region after the peak point, the low-density polyethylene exhibited another peak before failing and no such peak was observed for linear low-density polyethylene. Tensile test results with low strain rate of deformation have also been compared. The tensile stress–strain in machine direction (MD) and transverse direction (TD) direction play an important role during the biaxial deformation during the impact test. The crystallographic deformations were explained using the scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) techniques for lamellar structure and orientation. The low-density polyethylene film has developed columnar clusters of lamellae, which are aligned parallel to the TD direction. On the other hand, the linear low-density polyethylene film structure shows more randomly orientated and thicker lamellae than that of the low-density polyethylene film. The result of this structure is a more balanced toughness in both MD and TD directions.
A novel composite composed of exfoliated graphene nanoplatelets (Ex-GNPs) incorporated in a MIL-100(Fe) framework has been synthesized using an in situ molecular-level interaction approach. The resulting Ex-GNP/MIL-100(Fe) composite, with varying Ex-GNP contents, has been characterized for microstructure, degree of crystallinity, thermal stability, water sorption behavior, and hydrothermal cyclic stability.