An Investigative Study on the Progress of Nanoclay-Reinforced Polymers: Preparation, Properties, and Applications: A Review

Nanoclay-reinforced polymers have attracted considerable universal attention in academic and industrial research due to their outstanding properties and their ever-expanding utilization in diversified applications. In that regard, in the present review, the structure of layered silicate clay, as well as procedures for clay material modification, are outlined. We also discuss the general characterization techniques, synthesis methods, and various properties of polymer–clay nanocomposites (PCNs), and some examples likewise are depicted from the scientific literature. The study’s primary goal is to provide an up-to-date survey of polymer–clay nanocomposites and their specific applications in industries such as automotive, flame-retardant, and biomedical applications, coating, and packaging.

Supramolecular exfoliation of layer silicate clay by novel cationic pillar[5]arene intercalants

Clays are multi-layered inorganic materials that can be used to prepare nanocomposite fillers. Because the multi-layered structure is thermodynamically stable, it is difficult to change a multi-layered material into single layers to improve its dispersity. Previously, clays were modified with dodecylammonium cations to promote complexation with nylon 6, nylon 66, polypropylene, polyethylene, polystyrene, and polycaprolactone to increase the mechanical strength (and/or thermal stability) of the composite material; however, complete exfoliation could not be achieved in these composites. In this study, pillar[5]arenes are synthesized and functionalized with ten cationic substituents as novel intercalants for modifying bentonite clay, which is a multi-layered metal-cation-containing silicate. The pillar[5]arenes exfoliate the clay by forming polyrotaxanes with poly(ethylene glycol) through host–guest interactions.

Synthesis of bio-based poly limonene oxide with green catalyst

In the present work, the polymerization of limonene oxide (LO) catalyzed by Maghnite H+ (Mag- H+) is investigated. Mag-H+ is Algerian montmorillonite sheet silicate clay exchanged with protons. The poly limonene oxide (PLO) is obtained by cationic ring opening polymerization in bulk and with solvent. The effect of the reaction time, the temperature and the amount of catalyst are studied and discussed in order to find the optimal reactions conditions. The polymerization in solution at 0 °C with 5% by weight of catalyst leads to the best yield 61.34% for a reaction time of 1h. The structure of the obtained products is characterized by XRD, 1H-NMR, 13C-RMN, ATR-FTIR, DSC and TGA.

Spectral Sensitivity of Heavy Metal Concentration in Mine Soils: A case study of Gagok mine, South Korea

<p><span><span> Heavy metal contamination in soils of mining area accompanies contaminations in drainage and vegetation. The traditional soil survey methods for heavy metal contamination requires significant investment of time, labor, and money although the methods can drive accurate assessment. Moreover, the point-based survey is problematic to understand spatial distribution with limited sample numbers. Remote sensing approaches may provide alternative solutions to understand spatial distribution of contamination with minimal investment of time and labor. It is very critical to understand spectral signals associated with heavy metal concentration to apply the phenomenon to remote sensing approaches. This study investigated spectral signals associated with heavy metal concentration in mine soils based on chemical analysis, mineral composition analysis, and spectral analysis. The study site is a Pb-Zn skarn ore deposit located in Gangwon province, South Korea, where the ore was formed by granite intrusion to slate and limestone. The chemical analysis revealed that the soils are contaminated with heavy metals. Mineral composition classified the soils into two time with silicate/clay mineral group and silicate/carbonate/clay mineral groups. Spectral analysis showed that sensitive spectral bands to heavy metal concentration is located in SWIR region for silicate/clay mineral group and VNIR region for silicate/carbonate/clay mineral group. It reveals that mineral composition and geochemical reaction play an important role in spectral signals manifested by heavy metal concentration. </span></span></p><p> </p>

Induction of resistance to Colletotrichum truncatum in lima bean

ABSTRACT: Anthracnose (Colletotrichum truncatum) is one of the major diseases of the lima bean culture, found in production fields, causing decrease in productivity. The objective of this study was to evaluate the effect of abiotic and biotic inducers applied in lima bean plants to reduce anthracnose severity. Lima bean accessions were used and treated with: the abiotic inducers calcium silicate (Agrosilício Plus) and silicate clay (Rocksil), using the 3 g dose.L-1; the biotic inducer citric biomass extract (Ecolife), at the dose of 3 mL.L-1; and distilled water as control. To evaluate the resistance induction, the results of severity and degree of resistance of fava bean at 7, 11, 15, 19 and 23 days after inoculation were considered according to the scale of grades and classes of reactions. The design was a randomized block in a factorial arrangement 4 × 15 (treatments × hits) with four blocks. Resistance inducers Agrosilicon Plus, Ecolife and Rocksil have potential to be used in the management of anthracnose in fava bean. The studied accesses showed degree of resistance, being able to be explored in relation to obtaining anthracnose resistant cultivars in future breeding programs of this crop.