Search

This study utilizes a multidisciplinary approach, combining simulation experiments, thermal expansion analysis, XRD, SEM, and physical property assessments to investigate the firing temperature in illitic-kaolinitic porcelain. Our findings indicate that the accuracy of the thermal expansion method depends on both the actual firing temperature and dwell time. When dwell time is uncertain, the method provides a range of possible actual firing temperatures, differing by approximately 100 °C. Remarkably, as the porcelain body nears full vitrification, the determined firing temperature tends to be notably higher. A critical analysis of previous research suggests potential overestimation of ancient kiln temperatures. Additionally, our study highlights the usefulness of bulk density, water absorption, porosity, and mullite content in determining dwell time. Overall, our research offers new insights into ancient porcelain firing processes. [ABSTRACT FROM AUTHOR]

The physicochemical properties of high-molecular weight compounds based on N,N-diallyl-N′-acyllhydrazines were studied. Based on the results of thermal analysis it was established that sorbents are stable up to 160–210 °C; the destruction of the initial N,N-diallyl-N′-acyllhydrazines starts at lower temperatures. The stability of sorbents in various media, the values of static exchange capacities for hydrogen ions and hydroxide ions ( SEC H + and SEC OH − ), and isoelectric points of the surface were determined. Samples for further study of the rare earth metals sorption were selected. [ABSTRACT FROM AUTHOR]

This work evaluates the extraction of anthocyanins from star apple (Chrysophyllum cainito L.) fruit peel as an indicator in smart films that respond to color change at different pH concentrations of 1, 3, 5, 7, and 9. Thermoplastic films (TPS) composed of corn starch and concentrations of 10%, 20%, 30%, 40%, and 50% (w/w) of Chrysophyllum cainito L. peel extract were fabricated for characterization. The FTIR results revealed the characteristic bands of the polymer composed with extract and evidenced the increase of this compound exhibiting an increase in the intensity of the bands. SEM results evidenced the interaction between starch and glycerol, as well as an increase in the growth of clumps as the anthocyanin concentration increased; similar tendency was observed in the thermal analysis. The degradation temperatures and mass loss varied as the amount of anthocyanin contained in the film increased. The evaluation of the response of the films as indicators against various pH's showed saturated color changes as the % anthocyanin contained in the film increased at all pH values evaluated. According to the obtained results, it is concluded that the anthocyanin concentration influences the physicochemical and thermal properties of the films; therefore, TPS/anthocyanin films are potential candidates to be used as pH indicators in the food industry. [ABSTRACT FROM AUTHOR]

This paper reports the synthesis of exfoliated structure of Poly-methylmethacrylate/organomontmorillonite nanocomposites by in situ polymerization of Methylmethacrylate monomer as a cost-effective adsorbent for ultrahigh removal of azo dye pollutant from aqueous media. The obtained nanocomposites with different organoclay loading (1–7 mass%) were characterized by XRD, FTIR, DTA, TGA, TEM and SEM. In the XRD results, the observation of small pick shoulders (d001) and almost no reflection in the X-ray diffractrograms indicated, respectively, the establishment of intercalated/exfoliated structures and major exfoliation of OMMT clay into polymer. This observation was supported by TEM microscopy. TGA results revealed improved thermal properties in comparison with the pure polymer. Adsorption parameters such as pH-value, contact time and initial dye concentration were investigated to assess optimum adsorption activity. The adsorption experiments showed that the equilibrium time of adsorption was reached very rapidly. According to the kinetic study, the adsorption process followed pseudo-second-order model. The adsorption capacity is unaffected by variation of solution pH. The high maximum adsorption capacity of PMMA/OMT nanocomposite toward dye was found to be 309.6 mg g−1. Langmuir isotherm was more suitable model to describe the adsorption of dye than Freundlich and Dubinin–Radushkevich models. Thermodynamic study showed that the removal of the azo dye from aqueous solution by PMMA/OMT nanocomposite is endothermic nature, spontaneous and physisorption process. Under three adsorption–desorption cycles, PMMA/OMT nanocomposite had good re-adsorption effect. Thus, PMMA/OMT nanocomposite can be an efficient and recyclable adsorbent for azo dyes. [ABSTRACT FROM AUTHOR]

Biological methods present a sustainable approach for treating various waste polymers due to green, low-cost, mild condition and simple operation. This study, a novel biological method to process nitrocellulose (NC) to obtain NC with low nitrogen via nitrate ester removal using fungal Chaetomium elatum is proposed. The N% of NC continuously declined during the course of six days, from 13.06% to 11.71%, and the intensity of its energetic groups (O-NO2, -NO2) also weakened. An examination of the thermal properties of NC revealed that the weight-loss ratio decreased after biotreatment from 86.33% (untreated NC) to 66.20% (treated NC).Furthermore, the kinetic parameters of the thermal decomposition reaction with DSC were calculated and the activation energy (Ea) of biotreated NC was higher than that of the original, indicating the thermal stability was enhanced. Hence, this structure exploration and thermal analysis provide new methods for further investigating the mechanism of the biological denitrification process and assessing the safety of biotreated NC. [ABSTRACT FROM AUTHOR]