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The honeycomb structure has superior compressive strength so that it is being utilized in various fields. In addition, the paper honeycomb has excellent economic feasibility because of its low production cost and has an environment-friendly advantage because its recycling is possible. Securing of flame retardant performance is essential to use it as interior materials of buildings and fireproof doors using the advantage like this. The present research has evaluated combustion and thermal properties according to flame retardant treatment in terms of two kinds of specimens when flame retardant film is attached to paper honeycomb, and when paper honeycomb is impregnated to flame retardant agents. As a result of evaluating flame retardant performance utilizing a cone calorimeter, the case impregnated into flame retardant agents showed the most superior flame retardant performance. Through this result, it was confirmed that the paper honeycomb can be utilized as interior materials of buildings though improvement of flame retardant performance. [ABSTRACT FROM AUTHOR]

The paper deals with the study of thermal degradation of some new and old paper supports. The experimental data allows the prediction of the dependence between the half time and the temperature at which the paper support must to be kept. [ABSTRACT FROM AUTHOR]

In this paper, a new designed silicon-containing nitrogen and phosphorus flame-retardant system containing ammonium polyphosphate, modified molecular sieve and methylcellulose was used to prepare the flame-retardant corrugated cardboards (FRCCB). The samples before and after treatment were tested for combustion and thermal stability using vertical burning test (VBT), limiting oxygen index (LOI), cone calorimetric test (CCT) and thermogravimetry (TG). To further analyze the flame-retardant properties of the flame-retardant system, the microstructure, surface elements and functional groups of the materials were characterized by the scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). The mechanical properties of the samples were tested to analyze the effect of flame-retardant treatment on the strength. The VBT and LOI tests showed that the samples after the flame-retardant treatment were able to self-extinguish after ignition, achieving the flame-retardant B-1 grade. The CCT tests showed that the total heat release of treated samples was reduced by 49.90%, and the total smoke production was decreased by 27.64%. TG tests showed that the thermal decomposition temperature of FRCCB decreased but the residual carbon content increased largely. FTIR tests showed that the functional group changed at different temperatures. After flame-retardant treatment, a dense carbon layer was formed on the surface of the treated sample, including N, P, Si and Cu, measured by SEM and EDS. Combining with various characterization methods, the flame-retardant system can retard flame by releasing nonflammable gases, forming covers and catalyzing char formation. [ABSTRACT FROM AUTHOR]

The hyphenated thermal analysis-mass spectrometry technique (TA-MS) was applied for the investigation of the thermal behavior of reference and aged parchment samples. The kinetic parameters of the process were calculated independently from all recorded TA and MS signals. The kinetic analysis showed the distinct dependence of the activation energy on the reaction progress. Such behavior is characteristic for the multistage mechanism of the reaction. The comparison of the kinetic parameters calculated from the different signals i.e. TG, DSC, MS for H2O, NO and CO2, however, indicated that they were differently dependent on the aging of the sample. For the parchment samples, the aging almost does not change the kinetics of the decomposition calculated from the DSC data: the influence of aging seems to be too negligible to be detected by these techniques. On the other hand, the much more sensitive mass spectrometric technique applied to the kinetic analysis allowed monitoring of visible changes in the thermal behavior of the parchment samples due to the aging process. The influence of aging was especially visible when the MS signals of water and nitric oxide were applied for the determination of the kinetic parameters. The applied method of the kinetic analysis allowed also the prediction of the thermal behaviour of reference and aged parchment samples under isothermal and modulated temperature conditions. Presented results have confirmed the usefulness of thermoanalytical methods for investigating behaviour of such complicated systems as leather or parchment. [ABSTRACT FROM AUTHOR]

The present work reports role of Bi2O3 and Sm2O3 on the thermal properties of phospho-zinc tellurite glasses with composition 47.5 P2O5‒ 45ZnO‒ (5-x) Bi2O3 ‒ 2.5TeO2‒x Sm2O3 (where x = 0, 0.3, 0.5 and 1 mol%) coded as PZBTS glass series system. Thermodynamic parameters such as Gibb's free energy (GFE) ∆G, entropy ∆S, etc., have been reported. This paper presents a comprehensive analysis of glass-forming tendency (GFT) and thermodynamic properties within the PZBTS glass system, elucidating key factors that influence glass stability and formation. The glass-forming tendency (KT) is a pivotal parameter, showing that higher KT values are associated with enhanced glass stability, while lower values indicate a propensity for devitrification, particularly accentuated with the addition of Bi2O3. Significantly, the mol% of Sm2O3 exerts a diminishing effect on KT, emphasizing the interplay between rare earth elements and glass formation. Specific heat capacity (∆Cp) is identified as an essential indicator, as its superiority to crystalline materials underscores favorable glass formation. Bond enthalpy (∆H) emerges as an effective gauge for estimating chemical bond strength in the glass network, reliant on the composition of Bi2O3 and Sm2O3. Meanwhile, the entropy of heat (ΔS) offers insight into disorder variation, a critical facet for successful glass formation. The ratio ΔG/ΔH becomes a crucial metric for assessing glass-forming ability, with values close to 0.2 signifying favorable characteristics. Moreover, molar density and volume exhibit an upward trajectory with increasing Sm2O3 mol%, leading to higher density and reduced molar volume due to the influx of rare earth ions. The density of rare earth ions (N) is calculated based on molar density and Avogadro's number, shedding light on ion distribution within the glass structure. Polaron radius (rp) provides valuable insights into structural features, while oxygen packing density (OPD) elucidates the intricate nature of the glass network. These findings collectively contribute to a deeper understanding of the thermodynamic and physical properties of the studied glasses, elucidating their glass-forming abilities and showcasing their potential applications in the realm of opto-electronic devices. [ABSTRACT FROM AUTHOR]

In this paper, the research findings about the impact of polydopamine and tannic acid coatings on specific thermal properties of polylactide are discussed. The influence of deposited coatings on the resistance to oxidation, heat resistance, and the temperatures of phase transitions was determined. Therefore, the oxidation induction temperature, thermogravimetry, and differential scanning calorimetry studies were carried out. To gain a deeper understanding of the findings, mass measurements for the samples before and after the deposition process were conducted, as well as scanning electron microscopy studies. Studies have shown that the application of coatings can improve the resistance of polylactide against oxidative and thermal degradation. However, these coatings have minimal impact on the intensity and temperature of phase transformations. The polylactide showed increased thermal resistance when coated with polydopamine, whereas tannic acid coating was found to be more effective in increasing oxidation resistance. The differences observed were likely caused by variations in the structure of the coatings applied, impacting the level of oxygen diffusion and heat transfer within the material. [ABSTRACT FROM AUTHOR]

In this paper, a novel hydrogen-bonded liquid crystalline binary complex system was synthesized from pure mesogenic 4-(octyloxy)benzoic acid (8OBA) and non-mesogenic n-aminobenzoic acid (nABA, n = 3, 4) chemicals. Differential scanning calorimeter (DSC) experiments were performed to investigate the thermal properties of the synthesized samples, and polarized optical microscopy (POM) experiments were performed to investigate the mesogenic phase textures. The DSC and POM results showed that the phase sequence was Cr ↔ SmA ↔ SmC ↔ N ↔ I during continuous heating and cooling cycle. In addition, the thermal stability factor, phase transition entropy, and phase transition activation energy were calculated using DSC data. According to the calculated values, it was concluded that the mesogenic phases of the synthesized complexes occur regularly and the most stable phase is the SmC phase. Moreover, the optical tilt angle value for the SmC phase was measured and it was seen that the value increased up to 29° and 30° for 8OBA/4ABA and 8OBA/3ABA complexes, respectively. The formation of hydrogen bonds between the mesogenic and non-mesogenic molecules in the synthesized mesogenic structure was confirmed by Fourier-transformed infrared spectroscopy (FTIR). Furthermore, XRD results showed that the molecular ordering of the synthesized hydrogen-bonded 8OBA/4ABA and 8OBA/3ABA binary complexes occur in a monoclinic structure in the solid phase. [ABSTRACT FROM AUTHOR]

Polymers are widely employed in many areas, e.g. transport, packaging, electronic devices, etcetera. Among them, acrylonitrile–butadiene–styrene (ABS) is one of the most employed polymers due to its mechanical properties, its ease to mechanize and recyclability. Nevertheless, according to the fire properties, ABS behaviour is usually worse than other polymers, therefore, they have to be upgraded with flame retardant additives. To characterize the fire behaviour of a certain material is necessary to address several typology of tests, providing relevant properties such as thermal conductivity, flammability and heat released. However, researchers may not always be able to run all tests due to the lack of apparatus or samples. Therefore, it is necessary to seek bibliographic sources. As one might expect, for a given material, the property values should be similar, regardless of who performs the test. However, sometimes slightly different results are obtained, which may be due to different causes, such as differences in test set-up and in material composition/manufacture. These differences in properties may lead researcher to doubt which data to use. This paper presents the results of different types of tests using neat ABS polymer. Additionally, these results are compared with the data from literature, discussing the similarities/differences and offering a more comprehensive characterization of ABS. The laboratory techniques included in this work are: thermogravimetric analysis, differential scanning calorimetry, laser flash analysis, smoke density, cone calorimeter, fire propagation and flammability. [ABSTRACT FROM AUTHOR]

The manufacture of flexible devices is of immense interest due to their eco-friendliness, economic prospects and wide range of applications in biocompatible devices. Therefore, this paper reports the characterization and properties of chlorinated natural rubber (Cl-NR)/polyindole (PIN) blend with different contents of nickel oxide (NiO) nanoparticles. The formation of blend nanocomposites was analysed by FT-IR, UV spectroscopy, XRD, FE-SEM, DSC and TGA. The FT-IR and UV spectra proved the effective interfacial interaction between nanoparticles and the blend matrix, with a shift in UV peak intensity with the attachment of NiO at 433 cm−1. The XRD pattern revealed the regular arrangement of the blend matrix due to the presence of nanofiller, resulting in the semicrystalline structure of the composite system. The SEM micrographs revealed a homogeneous distribution of NiO in the blend matrix. The increased degradation temperature in the TGA demonstrated the enhanced thermal stability of the NiO-filled Cl-NR/PIN blend. DSC results showed that the glass transition temperature of the composite increased with NiO content in the blend matrix. The dielectric properties and AC electrical conductivity increased significantly with increasing temperatures, as well as with the addition of nanoparticles up to 5 mass % loading. The inclusion of NiO improved the tensile strength and hardness while reducing the elongation-at-break of nanocomposites. The blend nanocomposite with enhanced thermal stability, glass transition temperature, tensile strength, AC conductivity and dielectric properties enables them to be used in highly flexible electronic applications where traditional elastomeric materials fall short. [ABSTRACT FROM AUTHOR]

In this work, thermal and mechanical properties of cationic cassava starch-g-poly(butyl acrylate-co-methyl methacrylate) films with different amounts of cationic cassava starch (CCS) were studied. The objective of this work was to substitute a portion the monomers (BA/MMA) by CCS in the copolymer and to investigate the consequent effects on the properties of the polymer latex films (e.g., graft percentage, surface tension, thermal and mechanical properties). The results show that the grafting percentage decreased as the concentration of CCS increased. Thermal and mechanical properties of polymer films showed a direct relationship with respect to the content of CCS used and the grafting percentage. Higher grafting percentage led to improvement of the thermal degradation, which indicated better thermal stability than neat poly(BA/MMA). DSC analysis showed that the Tg of the graft copolymers was a little lower as compared to Tg values of un-grafted copolymers. The addition of CCS increases the tensile, elastic modulus and hardness properties of the polymer film, but the elongation at break decreased dramatically. The optimal CCS contents that maximized not only thermal properties, but also mechanical properties, were 7 and 10 mass%, which are directly related to the grafting percentage and CCS content in the formulation. In addition, these results create a new approach for the application of CCS graft-polymer as an adhesive for wood, paper and shoes insole applications. [ABSTRACT FROM AUTHOR]

The authors of the title paper (J Therm Anal Calorim 2012,110:873-878) report to have grown a dipeptide hydrochloride crystal namely glycyl- l-alanine hydrochloride by the slow evaporation of an aqueous solution containing stoichiometric amounts of l-alanine and glycine and an excess of hydrochloric acid. In this letter, we prove that no such dipeptide hydrochloride can be crystallized simply by mixing two amino acids in aqueous hydrochloric acid. [ABSTRACT FROM AUTHOR]

The aim of this study was to analyse the thermal properties of glazes from the SiO2-Al2O3-CaO-MgO-Na2O system during the addition of zirconium oxide. The paper describes the effect of the addition of zirconium oxide on characteristic temperatures obtained with a high-temperature microscope and a mechanical dilatometer. Based on these data, the course of the logarithm curves of the viscosity of the glazes was determined on the basis of the Vogel–Tamman–Fulcher model. The analysis of thermal effects during the heating and cooling of glazes was also carried out on the basis of measurements made by means of differential scanning calorimetry and analysis of the phase composition at selected temperatures. The obtained results constitute a comprehensive characteristic of the thermal properties of glazes, in which the amount of zirconium oxide increases—from 0 to 24 mass%. [ABSTRACT FROM AUTHOR]

This paper describes the composites of silane cross-linked polyethylene (PEXb) mixed with four different fillers dedicated to improving thermal conductivity, such as multi-walled carbon nanotubes, graphite, boron nitride, and mineral filler. Using the mathematical modeling, the concentration of each filler was estimated to reach the value of 0.675 W m−1 K−1 suitable for the usage PEXb in the production of geothermal pipes. From tested fillers, all improve the thermal conductivity of pure PEXb; however, above the required value, only 28 mass% of boron nitride (0.937 W m−1 K−1). It was associated with its perfect dispersion and the highest gel content achieved, also resulting in the highest flexural modulus. Graphite at 5 mass% and mineral filler at 35 mass% allowed the thermal conductivity to equal 0.622 W m−1 K−1 and 0.624 W m−1 K−1, respectively, with a simultaneous medium effect on the mechanical properties. Carbon nanotubes increased PEX's conductivity to a small extent, due to their occurrence as agglomerates. [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]

Nanotechnology has emerged to be an essential aspect of science and technology. The growth of this field has been enormous specifically in the development of nanomaterials. Till date, numerous nanomaterials have been developed and designed to suit various applications from mechanical to biomedical. Among the developed nanomaterial, alumina (Al) has been subject of interest due to its notable chemical and physical properties. Specifically, in thermal properties, Al has been shown to have superior thermal conductivity, convective heat transfer coefficient and heat transfer coefficient properties. As such, Al has been utilized in different forms in various fields of applications and verified for its importance, significance and efficiency. Though it had shown outstanding results in the field engineering and sciences, their effect towards the environment and human health is yet to be explored extensively. The present paper aims to review the significance of Al nanoparticle addition in mono- and hybrid nanofluids. Also, this paper intends to provide the reader with an overview of the works that have been carried out using Al nanoparticles and their findings. [ABSTRACT FROM AUTHOR]

In this paper, thermal properties of two titanium-titanium boride composites were processed by spark plasma sintering, hot-iso-static pressing, and vacuum sintering were characterized. The scanning electron microscopy and X-ray diffraction analysis are used to examine the uniform distribution of the secondary particles in the processed composites. Thermal properties of the composites such as thermal conductivity, specific heat, thermal diffusivity and coefficient of thermal expansion were estimated for the temperature range between 50 and 250 °C. The results showed that thermal conductivity, thermal diffusivity, and specific heat were increased with increase in temperature and titanium boride reinforcement. The influence of titanium boride reinforcement and processing technique on thermal properties is also discussed. Thermal properties presented in this paper confirmed that the titanium-titanium composites can be used for thermal, automobile, aerospace, and renewable energy applications. [ABSTRACT FROM AUTHOR]

Conventional surfactants such as CTAB (cetrimonium bromide), SDS (sodium dodecyl sulphate), SDBS (sodium dodecyl sulphonate) are combined with nanofluids to improve the stability and thermal conductivity of nanofluids. These nanofluids are mainly used for heat transfer applications where heating and cooling are usual courses of action which result in surfactants producing foams and polluting the heat transfer media, affecting the total system performance. Besides, the common surfactant molecules that augment the thermal resistance between the nanoparticles and base fluid also affect the thermophysical properties of the nanofluid. In this paper, [Bmim][Cl] (1-butyl-3-methylimidazolium chloride), a high purity ionic liquid (IL) with higher thermal stability was used to provide a comparative study on the stability and thermal properties with that of the conventional surfactants (CTAB, SDS, SDBS) on multiwalled carbon nanotubes (MWCNT)/propylene glycol (PG) nanofluid. The transient hot-wire based KD2-Pro and zeta potential results demonstrated that the inclusion of ionic liquid improved the thermal conductivity and stability of the formulated nanofluid. However, much like the conventional surfactants, the strong electrostatic repulsive force created by the ionic liquid was found to decrease when the temperature is increased. The outcome demonstrated the most extreme thermal conductivity upgrade of 33.7% at 303 K and maximum dispersion stability of more than one month without any aggregation for the nanofluid containing ionic liquid. [ABSTRACT FROM AUTHOR]

The energy stands of fast-growing tree species and crops are a prospective resource of renewable energy to the future. The paper focuses the assessment and comparison of the thermal properties of selected species of fast-growing trees (Paulownia tomentosa, Salix viminalis clone Tora, Populus × euramericana clone MAX 4) and energy crops (Sida Hermaphrodita, Arundo donax, Miscanthus × giganteus), as well as ash content (mass%). The following fire and thermal and properties were tested: spontaneous ignition temperature, gross caloric value, heating value. Besides those parameters, the elemental composition and ash content of the samples tested were analyzed. The results showed the energy crops to be much more effective for energy production than the energy trees. It is mostly due to higher yields harvested in a relatively short time, increased share of fiber, as well as higher energy efficiency. The highest heating value (energy potential) in case of energy crops showed Miscanthus × giganteus (16.29 ± 0.14 MJ kg−1), which had the lowest ash content (2.67 ± 0.08 mass% on average). The highest heating value in case of fast-growing tree species showed Paulownia (16.40 ± 0.18 MJ kg−1), which also had the lowest ash content (0.75 ± 0.05 mass% on average), while the Populus had the highest one (2.58 ± 0.24 mass% on average). [ABSTRACT FROM AUTHOR]

Over many years, great efforts have been made to develop new fluids for heat transfer applications. In this paper, the thermal conductivity (TC) and viscosity of SiO2–P25 TiO2 (SiO2–P25) hybrid nanofluids were investigated for different nanoparticle volume concentrations (0.5, 1.0 and 1.5 vol%) at five various temperatures (20, 30, 40, 50 and 60 °C). The mixture ratio (SiO2:P25) in all prepared hybrid nanofluids was 1:1. Besides, pure SiO2, P25 nanofluids were prepared with the same concentrations for comparison with the hybrid nanofluids. The base fluid used for the preparation of nanofluids was a mixture of deionized water and ethylene glycol at a ratio of 5:1. Before preparing the nanofluids, the nanoparticles were analyzed with energy-dispersive X-ray analysis, scanning electron microscope, X-ray powder diffraction, and Fourier transform infrared spectroscopy. The zeta potentials of the prepared nanofluids except SiO2 nanofluids were above 30 mV. These nanofluids were visually observed for stability in many days. The TC enhancement of the hybrid nanofluid was higher than the pure nanofluid. In particular, with 1.0 vol% concentration, the maximum enhancement of SiO2, P25 and SiO2–P25 nanofluids were 7.5%, 9.9% and 10.5%, respectively. The rheology of the nanofluids was Newtonian. The viscosity increment of SiO2, P25 and hybrid nanofluids were 19%, 32% and 24% with 0.5 vol% concentration. A new correlation was developed for the TC and dynamic viscosity of SiO2–P25 hybrid nanofluid. [ABSTRACT FROM AUTHOR]

In this paper, the detailed characterization of mechanical, electrical and thermal properties of Ag nanoparticle-reinforced Al6061 alloy was studied. Four composites with Al6061 alloys and different mass percentages (3%, 6%, 9% and 12%) of Ag nanoparticles were processed by stir casting method. The chemical analysis was used to confirm the elemental composition. The microstructural examination was carried out using optical microscopy. The phase analysis of the samples was studied using X-ray diffraction technique. The density and hardness were measured as per ASTM standards. Four-point probe tester and differential scanning calorimetry were used to measure the electrical conductivity and specific heat. In addition, the thermal conductivity and thermal diffusivity were measured using laser flash method. The results reveal the presence of Ag nanoparticles can significantly enhance the mechanical, electrical and thermal properties. [ABSTRACT FROM AUTHOR]

The hydrolysis of copper(II) chloride is the water splitting process in the copper-chlorine thermochemical hydrogen production cycle. In this paper, a simultaneous differential scanning calorimetry and thermogravimetric analysis (DSC/TG) technique is used to determine the transitional temperature and kinetics of the thermal decomposition of CuCl. Thermodynamic analysis is performed on the decomposition reaction for a comparison with the thermogravimetric analysis results. The CuCl decomposition temperature obtained from thermogravimetric experiments is found to be higher than that predicted from the thermodynamic analysis. This broadens the available operating temperature range of the CuCl hydrolysis step for the Cu-Cl cycle. It is also found that the decomposition product CuCl may completely evaporate if the temperature is higher than its melting point, so the CuCl hydrolysis reaction should be operated below the melting point of CuCl (430 °C) to avoid the undesirable CuCl and Cl byproducts. A preliminary correlation is proposed in this paper for the decomposition kinetics in terms of the extent of converting CuCl to CuCl and Cl. [ABSTRACT FROM AUTHOR]

This paper experiments the trio influence of nanoparticles size (NS), per cent mass ratio (PWR), and temperature (T) on the thermal properties of MgO–ZnO/deionised water (DIW) nanofluids. MgO nanoparticles (20 nm and 100 nm) were hybridised with ZnO nanoparticles (20 nm) and suspended in DIW to formulate 0.1 vol% hybrid nanofluids at PWRs of 20:80, 40:60, 60:40, and 80:20 (MgO/ZnO). The pH, electrical conductivity (σ), viscosity (μ), and thermal conductivity (κ) of the hybrid nanofluids were experimentally determined at temperatures of 20–50 °C. The stability was monitored, while the morphology was examined using standard instruments. Findings showed that the suspension of the hybrid nanoparticles enhanced the pH and thermal properties of DIW. The hybrid nanofluids with 100 nm-MgO nanoparticles were observed to possess slightly higher values of pH, σ, and μ than those with 20 nm-MgO nanoparticles except for κ. An increase in temperature augmented κ and σ of MgO–ZnO/DIW nanofluids, while it detracted pH and μ. Maximum enhancements of 453.70–550.62% (40:60), 14.95–22.33% (40:60), and 8.29–17.46% (60:40) were evaluated for σ, κ, and μ, respectively. The influence of PWR, NS, and temperature on the σ, κ, μ, and pH of the hybrid nanofluids was in the order of PWR > NS > T, NS > PWR > T, T > NS > PWR, and T > NS > PWR, respectively. Subject to the experimental data obtained, correlations were developed for each hybrid nanofluid and thermal property as a function of temperature. The MgO–ZnO/DIW nanofluids with a 40:60 PWR appeared to be the best in terms of heat transfer capability. [ABSTRACT FROM AUTHOR]

In this paper, ultrasonic dispersion and surface chemical modification were used to prepare the modified multi-walled carbon nanotubes (MWNTs)/paraffin composite phase-change materials (PCMs). The surface modification of MWNTs was developed via coating MWNTs with silica dioxide. The modified MWNTs were marked as SiO2@MWNTs. The phase-change properties, thermal stability and chemical functional groups of the MWNTs/paraffin composite PCMs were measured by differential scanning calorimetry, thermogravimetric analysis (TG) and Fourier transform infrared spectroscopy, respectively. The results indicated that paraffin and MWNTs were compound physically. The diameter and content of MWNTs had influence on the phase-change temperature and the latent heat of the MWNTs/paraffin composite PCMs. The smaller the diameter or larger content of the SiO2@MWNTs, the greater the influence was. The reduction degree of PCM1(the diameter of the SiO2@MWNTs is 20–30 nm) in latent heat is about 4.5 times of that of PCM3(the diameter of the SiO2@MWNTs is larger than 50 nm). The thermal stability and the thermal conductivity of the composite PCMs were improved with the addition of the SiO2@MWNTs. When the content of SiO2@MWNTs is 5 mass%, the thermal conductivity of the paraffin PCMs is 0.383 W m−1 K−1). [ABSTRACT FROM AUTHOR]

Bioplastics reinforced by agricultural waste fibres show promise to provide degradation back into the environment when they are no longer needed. These biocomposites have the potential to replace synthetic polymers from non-renewable resources in some applications and may turn out to be one of the material revolutions of this century. Unlike synthetic composites, biocomposites are renewable, carbon neutral, biodegradable and non-petroleum based and have low environmental, human health and safety risks. In this paper, poly(lactic acid) (PLA)-based biocomposites filled with technical cellulose fibres (CeF) and rice husks (RHs) at 10–30 mass% loading were prepared by twin-screw extrusion and injection moulding to enhance stiffness of resulting biocomposites. Particular attention was given to the enhancement of adhesion between the polymer matrix and natural filler through the physical modification by ozone (O3) and dielectric barrier discharge (DBD) plasma (p) surface treatments. Further than, compatibilizing agent based on PLA-g-MAH was produced and introduced into the PLA systems. The non-isothermal crystallization behaviour and thermal properties were investigated through differential scanning calorimetry (DSC) under various cooling rates (5, 10, 20 and 40 °C min−1). The addition of both fillers increased overall crystallization kinetics of resulted biocomposites, especially at high cooling rates. An increase in crystallinity degree from 2.4 (neat PLA) up to 51% has been observed for PLA/30CeFO3 samples at 40 °C min−1 cooling rate. An increase in crystallinity degree based on mass percentage of filler was noticed especially for PLA/RH. Mass percentage increase in CeF did not notice significant increase in PLA crystallinity. The influence of RH and CeF on transformation behaviours of PLA αʹ-/α-polymorphs was observed. The elimination of imperfect αʹ-crystals was observed with increasing amount of RH and CeF. [ABSTRACT FROM AUTHOR]

The purpose of this study is to investigate the thermal and viscoelastic properties of polylactic acid (PLA) blends with the aim of optimizing properties for fused filament fabrication. Additive manufacturing opens many possible applications for materials in processing and application. Determining the most effective thermal and viscoelastic properties is required for printing. PLA blends can be tailored to suit design specification, printers and printing parameters. Quantified analysis of differential scanning calorimetry and rheology is applied to the qualitative property of "printability", with preferences of thermal stability, melt temperature, shear thinning effects and zero shear viscosities. This paper intends to further bridge this gap between physical properties and material printability. [ABSTRACT FROM AUTHOR]

Silver, silver alloys, and composites with silver matrix are used mainly as electric contacts, circuit-breakers, and slide bearings. Contacts working conditions require as high as possible thermal and electrical conductivity, wear resistance during electric arc work, low susceptibility to tacking, and chemical stability. Unreinforced silver alloys do not meet those expectations, hence increasing interest in metal matrix composites. Reinforcing with ceramic particles improves tribological wear resistance and minimizes formability of silver alloys. At the same time, introduction of ceramic particles decreases thermal and electrical conductivity. In this paper, manufacturing method of silver-based composites reinforced with particles Al2O3, SiC, and glassy carbon was described. Composites were subjected to differential thermal analysis. Furthermore, thermal diffusivity measurements using laser flash method, as well as measurements of linear thermal expansion coefficient using dilatometric method were performed in order to determine heat conductivity of the prepared composites. [ABSTRACT FROM AUTHOR]

Thermal energy storage (TES) has been identified as a breakthrough concept in development of renewable technologies. However, the main challenges are related to the development of competitive heat storage materials. Despite the number of studies on heat storage materials, the determination of new alternatives for next generation technologies is still open. In this regard, this paper presents the results of an experimental study of the physical, thermal and mechanical properties of SiC-doped ceramics as potential materials for TES applications. Two kinds of SiC additives (high and low densities) were incorporated with different percentages into the clay matrix in order to produce ceramics via the extrusion process. The addition of low-density SiC (true density 3.16 g cm−3) led to the increasing of porosity with large pore sizes and the decreasing of bulk density. Therefore, the thermal and mechanical properties are decreased up to − 50% for flexural strength and − 15% for thermal conductivity when 20 mass% of low-density SiC was used. On the other hand, when high-density SiC (true density 3.42 g cm−3) was used, properties of the clay ceramic were strongly improved: i.e., increase in the bulk density, decrease in the porosity, increase in the thermal conductivity and increase in the flexural strength. The best material was found with the addition of 20 mass% of high-density SiC which had a thermal conductivity of 1 W m−1 K−1, a specific heat capacity of 0.62 kJ kg−1 K−1 and a mechanical strength of 19.6 MPa. It also showed a high thermal stability after 20 successive heating/cooling cycles. Hence, this study provided a useful insight into how the SiC modified the microstructure and properties of fired clay ceramics. Thus, the current results suggest that clay ceramics with high-density SiC addition are promising materials for thermal energy storage applications. [ABSTRACT FROM AUTHOR]

In this paper, the results of copper-lead matte investigations are presented. Investigated copper-lead matte is intermediate product of the lead production in TREPCA-Zvečan. In the first part of the paper characterization of starting material is presented, consisting of: chemical composition analysis (XRQ), scanning electron microscopy (SEM) and diffractometry (XRD). Thermal properties of investigated matte were determined using differential thermal analysis (DTA) at characteristic temperatures. Using results of induced analysis, mechanism of matte oxidation process was determined. In the second part of the paper kinetic parameters describing oxidative roasting of copper-lead matte are presented. For activation energy calculations, non-isothermal methods defined by Kissinger and Ozawa were used [1, 2]. Kinetic equation describing oxidation process was determined using Sharps method of reduced half time of reaction [3]. [ABSTRACT FROM AUTHOR]

Phosphate glasses are important materials in many fields. However, their usage can be limited due to water corrosion. Addition of Al2O3 significantly improves the water resistance, and as such, the glass of superior water durability can be obtained. Thus, it may be considered as a matrix for waste immobilization. In the paper, thermal properties of 60P2O5–(40−x)Al2O3–xNa2O glasses are presented. The materials were investigated with the application of DSC/TG method and observations of shape change during heating in a heating microscope. Water durability studies are also presented. It was evidenced that glass of low Na2O content crystallizes during heating, which limits their application in waste vitrification. Nevertheless, the obtained glass–ceramic material is characterized by a superior water resistance. The water durability decreases with sodium content. The obtained results are discussed from a waste immobilization point of view, and the optimal glass composition containing 15 mol% of Na2O is indicated due to it low viscosity, melting temperature and very good water resistance. [ABSTRACT FROM AUTHOR]

The unique properties of graphene make it a very attractive application, although there are still no commercial products in which graphene would play a key role. Good thermal conductivity is undoubtedly one of the attributes which can be easily used both in materials involving large monoatomic layers, that are very difficult to obtain, as well as multilayer graphene flakes, which have been commercially available on the market for several years. The article presents the results of tests on the characteristic thermal properties of composites with the addition of 2–15% of multilayer graphene (MLG) crystals. The motivation of the study was literature reports showing the possibility of increasing the thermal conductivity of composites with MLG participation in the copper matrix. Since the production of composites with increased properties is associated with obtaining a strong orientation of the flakes in the structure, composites with hBN flakes exhibiting significantly worse but also directional thermal properties were produced for comparison. The paper showed a strong influence of flake morphology on the possibility of creating a directional structure. The obtained Cu/MLG composites with the addition of only 2% MLG were characterized by an increase in the thermal conductivity coefficient of about 30% in relation to sinters without the participation of MLG. [ABSTRACT FROM AUTHOR]

This paper presents the thermal properties of highly crosslinked di(methacryloyloxymethyl)naphthalene–divinylbenzene (DMN–DVB) copolymeric microspheres containing polar groups in the structure and their alkyl-bonded derivatives. C8 and C18 alkyl chains were introduced into the aromatic rings of the DMN–DVB porous copolymer by means of the Friedel–Crafts reaction. As a source of C8 and C18 alkyl chains, octyl and octadecyl chlorides were used. It was necessary to check whether the introduction of alkyl chains into the structure of polymeric packing had an impact on its thermal properties. The studies were carried out by thermogravimetry coupled online with FTIR spectroscopy and differential scanning calorimetry in inert atmosphere (helium). It was stated that the modified materials showed 20 and 50% mass losses at higher temperatures than the non-modified one while 1% mass loss was observed at lower temperatures. Moreover, an analysis of volatile decomposition products was performed. [ABSTRACT FROM AUTHOR]

Fly ash recycling reduces the amount of waste to be treated or disposed in landfills, allowing both to decrease the environmental damage and to save the costs of transport and disposal of waste. Systems with different percentages in mass of fly ash (20, 50 and 70 mass%) and the remaining part of pure metakaolin were synthesized. The effect of fly ash on the mechanical and thermal properties of a new geopolymer has been investigated in this paper. Fourier transform infrared spectroscopy has allowed us to verify the bonds formation between the geopolymeric matrix and the fly ash. The consolidation of the materials has been confirmed by pH and conductivity at up to 28 days of hardening. Dynamic mechanical analysis, differential scanning calorimetry and thermogravimetric analysis were performed in order to evaluate the thermo-mechanical performance of this new geopolymer in comparison with its counterpart pure geopolymer. [ABSTRACT FROM AUTHOR]

This paper presents a simple theoretical model of a nondestructive electropyroelectric technique in front configuration to easily determine all static and dynamic thermal parameters of semiconductors sulfides thin films. The suitability of the method was demonstrated with investigations on several binary and sulfides (NiS and Sb2S3) and ternary ones (ZnIn2S4 and CuInS2). The validity of our theoretical approaches was investigated by determining all the thermal properties of the antimony(III) sulfide (Sb2S3) thin film and comparing them with published results. The thermal conductivity and the thermal diffusivity of nickel sulfide NiS have been investigated yielding unprecedented values of k = 5.8 W m−1 K−1 and D = 2.01 × 10−6 m2 s−1. In addition, to the authors' knowledge, this study is the first attempt at defining thermal diffusivity, thermal effusivity, and heat capacity of copper–indium sulfide CuInS2. Finally, it was found that ZnIn2S4 compound has a higher thermal conductivity and diffusivity values which lead us to conclude that it is the most suitable alloy for optoelectronic, solar cells and photovoltaic applications. [ABSTRACT FROM AUTHOR]

Many papers have been published concerning the influence of different steric properties of metylamine, dimethylamine and trimethylamine on the type of interactions with different exchanged montmorillonite and their properties. The most effective active sites in montmorillonite are placed between two silicate layers, where the naturally occurring cations can easily be replaced by heavy metals and organic groups. Mercury is one of the most serious contaminants in environment. All forms of mercury are poisonous; however, organic mercury species are the most dangerous. It is harmful even in very small amount and presents a significant environmental threat. The results of thermogravimetry, differential thermogravimetry, X-ray powder diffraction and IR spectroscopy analysis show that methyl, dimethyl and trimethylamines are intercalated into the interlayer space of Hg-MMT. The effect of different steric properties of studied alkylamines is evident. [ABSTRACT FROM AUTHOR]

The paper is focused on the ability of using two complementary photothermal techniques for the measurement of all thermal parameters of some porous and/or semi-transparent solid samples whose composition, structure, and geometry do not allow a complete thermal characterization using a single technique. In this work, we combine a contact technique, photopyroelectric (PPE) calorimetry, with a non-contact one, infrared lock-in IR thermography (IRT), in order to investigate some solid samples such as dental composites, building materials, drugs, and semiconductors. The composition and the geometry of the investigated samples make the PPE method (in 'front' detection configuration together with thermal-wave resonator cavity (TWRC) technique as scanning procedure) suitable for thermal effusivity measurements and IRT for thermal diffusivity investigations. In such a way, this combination of methods leads to a complete thermal characterization of the investigated materials. [ABSTRACT FROM AUTHOR]

Preparation of nanofluid is of prime importance to obtain better thermal and physical properties. Different preparation parameters used in nanofluid preparation sometimes perform contrarily even if prepared with same nanoparticles and base fluid. Stability, thermal conductivity, and viscosity of the nanofluid are significantly affected by the cluster (agglomerate) size of nanoparticles in the base fluid which deteriorate thermal performance. In order to break the agglomerates and improve the dispersion of nanoparticles, ultrasonication is a more prevalent method. Nanofluids react differently for different sonication time and the reaction of the nanofluid with the change in sonication time varies for different nanofluids, which is dependent on various factors. In this regard, research works pertinent to the effect of ultrasonication on different properties of nanofluids are confined. In this paper, review of investigations carried out on experimentally evaluated ultrasonication effects on thermal properties and various physical properties of nanofluid. It is found that with an increased sonication time/energy, reduces the particle size and thus aids in obtaining a better dispersion leading to enhancement of stability, thermal conductivity and reducing viscosity. However, the longer ultrasonication duration was not found to be better in all cases where best performance was obtained for an optimum duration of ultrasonication. [ABSTRACT FROM AUTHOR]

Although gypsum belongs to the low-energy environmentally friendly binders, its wider applications in building constructions are limited due to the negative effect of moisture on its mechanical properties. When calcined gypsum (CaSO4·1/2H2O) transforms into its hydrated form (CaSO4·2H2O), it is partially soluble in water and it has a relatively low strength. This problem can be resolved when gypsum is used as a part of binary or ternary binders. In this paper, a system consisting of calcined gypsum, lime, and silica fume is presented as a functional solution for a wider utilization of gypsum in wet environments. For this purpose, the newly designed materials were stored in different environments (laboratory conditions in air or water) up to 182 days. The effect of silica fume on the hydration process and the growth of the main products is evaluated by using differential scanning calorimetry and thermogravimetry in the temperature range from 25 to 1000 °C with a heating rate of 5 °C min−1 in an argon atmosphere. The carbonation level of studied materials is also evaluated. Besides this, the information about the thermal stability of studied materials is provided. These results are supported by evolved gas analysis, X-ray diffraction, and scanning electron microscopy. The basic physical and mechanical properties are determined to provide more detailed information about the behavior of the designed materials under various conditions at selected days of hydration. The addition of silica fume to the gypsum-lime system activates the pozzolanic reaction of the analyzed pastes, which is proved by the presence of the CSH phase and by the consumption of portlandite in the mixtures. Wet environment speeds up the hydration processes and prevents samples from carbonation. [ABSTRACT FROM AUTHOR]

Insights within thermal expansion, conductivity, and decomposition dependencies with temperature on symmetrical and unsymmetrical layered carbon (CF) or basalt (BF) fabrics in combination with flax fibers (FF) were approached. Driven by commercial application and environmental concerns, the paper draws attention on a modified formula of cyanate ester with a common epoxy resin under an optimized ratio of 70:30 (vol%) as well as on the hybrid reinforcements stacking sequences. Synergetic effects were debated in terms of the CF and BF stacking sequences and corresponding volume fraction followed by comparisons with values predicted by the deployment of hybrid mixtures rules (RoHM/iRoHM). CF hybrid architectures revealed enhanced effective thermophysical properties over their BF counterparts and both over the FF-reinforced polymer composite considered as a reference. Thermal conductivities spread between 0.116 and 0.299 W m−1 K−1 from room temperature up to 250 °C on all hybrid specimens, giving rise to an insulator character. Concerning the coefficient of thermal expansion, CF hybrid architectures disclosed values of 1.236 10−6 K−1 and 3.102 10−6 K−1 compared with BF affine exhibiting 4.794 10−6 K−1 and 6.245 10−6 K−1, respectively, with an increase in their volume fraction. [ABSTRACT FROM AUTHOR]

Abstract: In this paper we demonstrate a facile and efficient synthesis of monoalkenylsubstituted POSS compounds, i.e., R7(Si8O12)-alkenyl and R7(Si8O12)(OSiMe2)-alkenyl with a functional alkenyl group of chain length (from vinyl to dec-9-enyl, with or without additional -OSiMe2- spacer between the silsesquioxane core and alkenyl moiety) and with five types of inert groups (Et, iBu, iOc, Cy, Ph) at the POSS core. These compounds constitute a library of monosubstituted POSS systems, including thorough spectroscopic and thermal characteristics. These findings could be especially useful for material chemists applying the compounds as modifiers or comonomers for copolymerization reaction, e.g., with olefins.Graphical Abstract: [ABSTRACT FROM AUTHOR]

New materials and structures are applied in order to maintain the engineering products more and more efficient. Different types of thermal analysis/modelling of such materials and structures are also needed for the proper planning or design. The thermal analysis/modelling processes are supported by many commercial codes but in some cases, the experts might have applied a self-developed method also. The success of the analysis/modelling depends on many factors, but the basis is the correct application of the heat conduction theory which is more important in case of transient thermal processes. As the used tools are more and more powerful, the users pay less attention to the theory background, according to the author experience. It seems that the long tradition of the inconsistent application of the temperature-dependent thermal diffusivity is continuing, even strengthened by the increased availability of data of the temperature-dependent thermal properties. Regarding the origination of the thermal diffusivity, this might lead to the misinterpretation or misunderstanding of the nonlinear heat conduction problem solution procedures. This paper calls attention to avoid this, shows what kind of mistakes might occur related to this widely observable practice, summarizes the proper application and interprets where and how one could find room for the temperature-dependent thermal diffusivity. [ABSTRACT FROM AUTHOR]

The main objective of this paper was to study the influence of the diesters derivatives of naturally occurring alcohol: 3-phenylprop-2-en-1-ol, on the thermal, viscoelastic and mechanical properties of bulk poly(trimethylolpropane trimethacrylate) [poly(TRIM)]. The bulk poly(TRIM) networks were obtained by mixing trimethylolpropane trimethacrylate with 0.5, 1, 2, 3, 5, 10 and 20 mass% of diesters and polymerized in the presence of 1.5 mass% of benzoyl peroxide in the temperature range from 50 to 80 °C. Generally, bulk poly(TRIM) modified with esters derivatives of 3-phenylprop-2-en-1-ol was characterized by lower stiffness, lower glass transition temperature, lower thermal stability, lower hardness and heat deflection temperature values, and higher tensile strength and percentage elongation, especially for compositions containing higher diester content as compared to pure, bulk poly(TRIM). [ABSTRACT FROM AUTHOR]

The objects for the studies of this paper are iron sulfates where the iron has second or third valences and where coordination between iron, sulfur and oxygen is different. DSC technique is used to investigate thermal stability and enthalpy changes when iron compounds are treated in different gas medium. The main objective is to compare thermal stability and enthalpy of iron oxy-sulphate, often detected as an intermediate, with commonly known iron sulphates. DSC curves of samples with equal mass under different gas medium, determining different partial pressure of oxygen in the gas phase, are the base for comparative study of the sample’s thermal properties. Obtained different values of the enthalpy and mass losses and kinetic parameters demonstrate that the stability of oxy-sulphate strongly depended on the value of oxygen partial pressure in the gas phase. The new evidences from the experimental study help to propose the mechanism of the decomposition and to compare some of the iron sulphates properties. [ABSTRACT FROM AUTHOR]

In this paper, a systematic analysis of the errors involved in the determination of the kinetic parameters (including the activation energy and frequency factor) from five integral methods has been carried out. The integral methods analyzed here are Coats-Redfern, Gorbachev, Wanjun-Yuwen-Hen-Zhiyong-Cunxin, Junmeng-Fusheng-Weiming-Fang, Junmeng-Fang and Junmeng-Fang-Weiming-Fusheng method. The results have shown that the precision of the kinetic parameters calculated by the different integral methods is dependent on u ( E/ RT), that is, on the activation energy and the average temperature of the process. [ABSTRACT FROM AUTHOR]

Extensive thermal analysis has shown that DMSO-containing reaction mixtures can be more energetic and decompose at lower temperatures than pure DMSO. Several processes at Merck using DMSO as a solvent were found to have the onset temperatures of decompositions reduced to the point where it became a thermal and operational hazard. The onset temperature depended on the reagents in the reaction mixture and the thermal history of the mixture. The case studies presented in this paper will include discussion on what process hazards were identified, how the process hazards differ from the pure DMSO hazards, and how to scale up these processes safely. [ABSTRACT FROM AUTHOR]

This paper reports the investigation of the thermal stability of a series of new complexes with azo and azomethinic chromophores of the type [Er(HL)2(H2O)2](HO); (( B) H2L: o,o’-dihydroxy-azobenzene ( A); ( D) H2L: N-(2-hydroxy-1-naphthalidene)aminophenol ( C); ( F) H2L: N-(2-hydroxy-1-naphthalidene)anthranilic acid ( E)). The complexes thermal behaviour steps were investigated and comparatively presented with those of corresponding ligand. The thermal transformations are complex processes according to TG and DTG curves including phenol elimination, oxidative condensation and thermolysis processes. The final product of complexes decomposition is Er2O3. [ABSTRACT FROM AUTHOR]

This paper reports an investigation of thermal and spectral properties of the complexes Cu2(3,5-Cl2sal)4·H2O (I), Cu(3,5-Br2sal)2·2H2O (II), Cu(3,5-I2sal)2·2H2O (III) and Cu(5-Isal)2·2H2O (IV), (where sal=salicylate). TG, DTG, DTA, IR, EPR and electronic spectra have been applied to investigate thermal and spectral properties of these complexes. The chemical composition of the complexes has been identified by means of elemental analysis and complexometric titration. Schemes of destruction of these complexes are suggested. Heating of these compounds first resulted in a release of water molecules. The thermal stability of these complexes can be ordered in the sequence: IV=I

This paper presents a recent implementation of the radial heat flow method, a classical technique used to measure the thermal conductivity of materials, including the hardware designed to this end, as well as the theoretical formalism used to analyse the data. The novelty is in its application to high-aspect-ratio hollow cylindrical samples, more specifically sections of nuclear cladding tube, whereby samples representative of full length fuel clads can be measured instead of platelets, like in usual laser-flash measurements. The apparatus designed and built to this end can accommodate tubular samples of varying length, diameter and wall thicknesses made of most materials, with the specific goal of determining the through-thickness thermal conductivity of silicon carbide composites, a highly anisotropic material under consideration as a fuel cladding material. [ABSTRACT FROM AUTHOR]

In this paper, ionic liquid treatment was applied to produce nanometric cellulose particles of two polymorphic forms. A complex characterization of nanofillers including wide-angle X-ray scattering, Fourier transform infrared spectroscopy, and particle size determination was performed. The evaluated ionic liquid treatment was effective in terms of nanocrystalline cellulose production, leaving chemical and supermolecular structure of the materials intact. However, nanocrystalline cellulose II was found to be more prone to ionic liquid hydrolysis leading to formation larger amount of small particles. Each nanocrystalline cellulose was subsequently mixed with a solution of chitosan, so that composite films containing 1, 3, and 5% mass/mass of nanometric filler were obtained. Reference samples of chitosan and chitosan with micrometric celluloses were also solvent casted. Thermal, mechanical, and morphological properties of films were tested and correlated with properties of filler used. The results of both, tensile tests and thermogravimetric analysis showed a significant discrepancy between composites filled with nanocrystalline cellulose I and nanocrystalline cellulose II. [ABSTRACT FROM AUTHOR]

Adamantan-2-one is an adamantane derivative used as a precursor for different adamantane-based pharmacologically active compounds. Adamantan-2-one and memantine hydrochloride were investigated in other of our previous published papers, as pure compounds and in binary mixtures with various excipients. The aim of our study is to determine the thermal behavior of adamantan-2-one, as well as the kinetic parameters that characterize the degradation process of this precursor. The employed analytical techniques were thermal analysis (TG/DTG/HF) and FTIR spectroscopy. The TG/DTG/HF curves were recorded in air at different heating rates: β = 5, 7, 10, 12 and 15 °C min, in respect of the ICTAC 2000 protocol regarding the kinetic analysis. The methods used for kinetic analysis of the thermal degradation process were isoconversional methods: Friedman and Flynn-Wall-Ozawa. Modified NPK method was used for determination of kinetic parameters. [ABSTRACT FROM AUTHOR]

In this paper, the glass-ceramic materials from SiO-AlO-NaO-KO-CaO system were examined. The zirconium oxide was added to this composition in three different amounts (1.5; 3; 6 mass%). In addition, the sample without zirconium oxide as the reference sample was prepared. To determine the effect of zirconium oxide on the thermal parameters, the characteristic temperatures, by using hot stage microscopy (HSM-Misura) and mechanical dilatometry (DL-Netsch), were measured. Based on these results, the viscosity curves were calculated (by the equation of Vogel-Fulcher-Tammann). Furthermore, for the description of the phenomena which occur during the heating-cooling cycle differential scanning calorimetry (DSC) was used. These data were linked with the results from X-ray diffraction and scanning electron microscopy with microanalyzer (EDS). Two crystalline phases in zirconium glazes were identified: zirconium oxide and zirconium silicate. The presence of crystalline phases (zirconium oxide, zirconium silicate) caused a nonlinear increase in the characteristic temperatures obtained by HSM. On DSC curves, the effect probably associated with crystallisation of zirconium silicate was registered. The addition of zirconium oxide to the tested glazes results in an increase in high-temperature viscosity, and the increasing ratio is proportional to the amount of zirconium oxide. The change in the value of this parameter is proportional to the amount of introduced zirconium oxide. [ABSTRACT FROM AUTHOR]