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Glassy materials form the basis of many modern applications, including nuclear waste immobilization, touch‐screen displays, and optical fibers, and also hold great potential for future medical and environmental applications. However, their structural complexity and large composition space make design and optimization challenging for certain applications. Of particular importance for glass processing and design is an estimate of a given composition's glass‐forming ability (GFA). However, there remain many open questions regarding the underlying physical mechanisms of glass formation, especially in oxide glasses. It is apparent that a proxy for GFA would be highly useful in glass processing and design, but identifying such a surrogate property has proven itself to be difficult. While glass stability (GS) parameters have historically been used as a GFA surrogate, recent research has demonstrated that most of these parameters are not accurate predictors of the GFA of oxide glasses. Here, we explore the application of an open‐source pre‐trained neural network model, GlassNet, that can predict the characteristic temperatures necessary to compute GS with reasonable performance and assess the feasibility of using these physics‐informed machine learning (PIML)‐predicted GS parameters to estimate GFA. In doing so, we track the uncertainties at each step of the computation—from the original ML prediction errors to the compounding of errors during GS estimation, and finally to the final estimation of GFA. While GlassNet exhibits reasonable accuracy on all individual properties, we observe a large compounding of error in the combination of these individual predictions for the PIML prediction of GS, finding that random forest models offer similar accuracy to GlassNet. We also break down the performance of GlassNet on different glass families and find that the error in GS prediction is correlated with the error in crystallization peak temperature prediction. Lastly, we utilize this finding to assess the relationship between top‐performing GS parameters and GFA for two ternary glass systems: sodium borosilicate and sodium iron phosphate glasses. We conclude that to obtain true ML predictive capability of GFA, significantly more data needs to be collected. [ABSTRACT FROM AUTHOR]

We propose that spontaneous folding and molecular evolution of biopolymers are two universal aspects that must concur for life to happen. These aspects are fundamentally related to the chemical composition of biopolymers and crucially depend on the solvent in which they are embedded. We show that molecular information theory and energy landscape theory allow us to explore the limits that solvents impose on biopolymer existence. We consider 54 solvents, including water, alcohols, hydrocarbons, halogenated solvents, aromatic solvents, and low molecular weight substances made up of elements abundant in the universe, which may potentially take part in alternative biochemistries. We find that along with water, there are many solvents for which the liquid regime is compatible with biopolymer folding and evolution. We present a ranking of the solvents in terms of biopolymer compatibility. Many of these solvents have been found in molecular clouds or may be expected to occur in extrasolar planets. [ABSTRACT FROM AUTHOR]

Mounting experimental evidence supports the existence of a liquid--liquid transition (LLT) in high-pressure supercooled water. However, fast crystallization of supercooled water has impeded identification of the LLT line TLL(p) in experiments. While the most accurate all-atom (AA) water models display a LLT, their computational cost limits investigations of its interplay with ice formation. Coarse-grained (CG) models provide over 100-fold computational efficiency gain over AA models, enabling the study of water crystallization, but have not yet shown to have a LLT. Here, we demonstrate that the CG machine-learned water model Machine-Learned Bond-Order Potential (ML-BOP) has a LLT that ends in a critical point at Pc = 170 ± 10 MPa and Tc = 181 ± 3 K. The TLL(p) of ML-BOP is almost identical to the one of TIP4P/2005, adding to the similarity in the equation of state of liquid water in both models. Cooling simulations reveal that ice crystallization is fastest at the LLT and its supercritical continuation of maximum heat capacity, supporting a mechanistic relationship between the structural transformation of water to a low-density liquid (LDL) and ice formation. We find no signature of liquid-liquid criticality in the ice crystallization temperatures. ML-BOP replicates the competition between formation of LDL and ice observed in ultrafast experiments of decompression of the high-density liquid (HDL) into the region of stability of LDL. The simulations reveal that crystallization occurs prior to the coarsening of the HDL and LDL domains, obscuring the distinction between the highly metastable first-order LLT and pronounced structural fluctuations along its supercritical continuation. [ABSTRACT FROM AUTHOR]

Poly lactic acid (PLA) is one of the most commonly used bio-derived thermoplastic polymers in 3D and 4D printing applications. The determination of PLA surface properties is of capital importance in 3D/4D printing technology. The surface thermodynamic properties of PLA polymers were determined using the inverse gas chromatography (IGC) technique at infinite dilution. The determination of the retention volume of polar and non-polar molecules adsorbed on the PLA particles filling the column allowed us to obtain the dispersive, polar, and Lewis's acid–base surface properties at different temperatures from 40 °C to 100 °C. The applied surface method was based on our recent model that used the London dispersion equation, the new chromatographic parameter function of the deformation polarizability, and the harmonic mean of the ionization energies of the PLA polymer and organic molecules. The application of this new method led to the determination of the dispersive and polar free surface energy of the adsorption of molecules on the polymeric material, as well as the glass transition and the Lewis acid–base constants. Four interval temperatures were distinguished, showing four zones of variations in the surface properties of PLA as a function of the temperature before and after the glass transition. The acid–base parameters of PLA strongly depend on the temperature. The accurate determination of the dispersive and polar surface physicochemical properties of PLA led to the work of adhesion of the polar organic solvents adsorbed on PLA. These results can be very useful for achieving reliable and functional 3D and 4D printed components. [ABSTRACT FROM AUTHOR]

A familiar polyalcohol, 1,2-propanediol (12PDO), is among the simple alcoholic solvents with high solubility for lithium tetrafluoroborate (LiBF4), as well as a wide temperature range for liquids. The viscosity of 12PDO solutions containing LiBF4 was measured in the temperature range of 280‒340 K using a vibrational viscometer, and it exhibited non-Arrhenius behavior fitted with the Vogel–Fulcher–Tamman (VFT) equation, which is an empirical model for describing liquid dynamics. The viscosity (η) increased with the increasing mole fraction of LiBF4 (x), and the variation in η was found to be mainly controlled by the pre-exponential factor η0 in the VFT expression. The VFT-fitting parameters, the strength parameter (D), and ideal glass transition temperature (T0), which indicate the Arrhenius behavior and an ideal glass transition temperature, respectively, correlated with the thermal analysis results that were obtained via differential scanning calorimetry. With the increasing x, the value of D decreased rapidly for x < 0.20, whereas it remained approximately unchanged for x > 0.20. The concentration dependence of T0 also differed at approximately x = 0.20. The changes in D and T0 with x indicated that the intrinsic hydrogen-bonding networks between the solvent molecules were rapidly destroyed by the added ions at reduced salt concentrations, while such a structural breaking effect of the added ions weakened owing to ion associations at increased salt concentrations. Thus, it was observed that the solvation structure and dynamics of the solutions strongly depended on the salt concentration. [ABSTRACT FROM AUTHOR]

Kinetic analysis of thermally induced processes was carried out in Cux(As2Se3)100-x glass with high copper content, x = 20 and 25 at.%. Non-isothermal differential scanning calorimetry at different heating rates was used to analyze the glass-transition and crystallization processes. It was shown that the glass-transition temperature increases with the increase in the copper content and that the examined glasses during the glass transition process do not show large configurational changes in the structure. Apparent activation energy of crystallization was determined using Kissinger method. In the composition with 25 at.% of copper the crystallization of three structural units was detected: CuAsSe2, Cu3AsSe4 and Cu2Se. Analysis of the crystallization mechanism and determination of parameters that depend on the morphology of nucleation and growth showed that volume nucleation and three-dimensional growth occur with a constant number of nucleation centers. Isoconversional analysis showed that the activation energy does not change significantly during the crystallization process. [ABSTRACT FROM AUTHOR]

A dynamic trap well model is developed to describe the complex relaxations of functional segments, and explore the working principles behind the hydrothermal coupling effect in shape memory polymers (SMPs). A constitutive relationship among shape fixity strain, shape recovery strain and relaxation time has been formulated to characterize the hydrothermal coupling effect using geometrical parameters (i.e. width and height) of trap wells. Moreover, effects of temperature and solvent absorption on dynamic relaxation behaviours of SMPs have been formulated based on the Flory-Huggins theory and Fokker-Plank probability equation. The trap well model effectively analyzes the shape fixity ratio and shape recovery ratio within ranges of 50–100% and 0–100%, respectively. Finally, an extended Maxwell model is proposed to formulate the dynamic mechanical behaviours of SMPs with hydrothermal shape-memory effect (SME), and the analytical results have been verified using the experimental results reported in literature. A good agreement between the analytical results obtained from the proposed model and the experimental data is present, where the correlation coefficient (R2) is 95%. The present study firstly introduces the dynamic trap well model for shape memory behaviours and intricate relaxations, and then accurately predicts the dynamic shape recovery of SMP in response to hydrothermal stimulus. [ABSTRACT FROM AUTHOR]

The preparation of 0.58 Li2S + 0.315 SiS2 + 0.105 LiPO3 glass, and the impacts of polysulfide and P1P defect structure impurities on the glass transition temperature (Tg), crystallization temperature (Tc), working range (ΔT≡ Tc ‐ Tg), fragility index, and the Raman spectra were evaluated using statistical analysis. In this study, 33 samples of this glass composition were synthesized through melt‐quenching. Thermal analysis was conducted to determine the glass transition temperature, crystallization temperature, working range, and fragility index through differential scanning calorimetry. The quantity of the impurities described above was determined through Raman spectroscopy peak analysis. Elemental sulfur was doped into a glass to quantify the wt% sulfur content in the glasses. Linear regression analysis was conducted to determine the impact of polysulfide impurities and P1P defect impurities on the thermal properties. Polysulfide impurities were found to decrease the Tg at rate of nearly 12°C per 1 wt% increase in sulfur concentration. The sulfur concentration does not have a statistically significant impact on the other properties (α = 0.05). The P1P defect structure appears to decrease the resistance to crystallization of the glass by measurably decreasing the working range of the glasses, but further study is necessary to fully quantify and determine this. [ABSTRACT FROM AUTHOR]

Modern science and technology demand a low glass transition temperature, yet one tailored to specific thermoset needs and specific to individual hardener applications. Two novel, nonterminal liquid crystalline epoxy resins (LCER) were synthesised, with their structures characterized via nuclear magnetic resonance (NMR), mass spectrometry (MS), and elemental analysis. Their liquid crystalline nature and thermal properties were determined using polarized optical microscopy (POM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). A set of seven aromatic amines serving as curing agents was used to perform curing in fourteen different systems in order to assess the glass transition temperature (Tg) of the obtained polymer networks using DSC. The liquid crystalline elastomers were obtained with vitrification occurring in a low temperature range (−10–40 °C), with a more predictable outcome for amines with two aromatic rings in the structure than with one. Moreover, the resin with a core consisting of four aromatic rings produces networks with higher Tg than the three-aromatic resin. The use of nonterminal LCER allowed the lowering of the glass transition temperature of the polymers to more than 70 °C compared to a terminal analogue. This brings new possibilities of designing highly elastic yet cured polymers with potential for use in smart applications due to the LC nature of the resin. [ABSTRACT FROM AUTHOR]

In this work, electrospun polylactide fibers with new photostabilizing additives, 4-methyl-2,6-diisobornylphenol (DIBP) and N-isocamphylaniline (NICA), have been tested under the influence of UV-C radiation (254 nm). The changes in the polymers' chemical structure under UV-C radiation were revealed through the increase in absorption in the 3600–3100 cm−1 region in regard to the FTIR spectra. In the samples that were irradiated for 1 h, the stabilizing effect of the photoprotectors became most noticeable as the difference in the content of the hydroxyl groups in stabilized and the pure PLA reached a maximum. The TG–DSC method revealed that the most sensitive indicator of the irradiation effect was the glass transition temperature (Tg), which persisted after 2 h of irradiation when using photostabilizers and their combinations. The PLA/DIBP(1) and PLA/NICA(1) samples showed the best results in protecting PLA from UV-C radiation based on the Tg values; although, the mixture of DIBP and NICA was not as effective. The chemical structure of the photostabilized PLA samples was studied using NMR, GPC, and Py–GC/MS analysis. The electrospun polylactide fibers were mechanically tested and the effects of the electrospun samples on cell viability were studied. [ABSTRACT FROM AUTHOR]

An additional crossover of viscous flow in liquids occurs at a temperature Tvm above the known non-Arrhenius to Arrhenius crossover temperature (TA). Tvm is the temperature when the minimum possible viscosity value ηmin is attained, and the flow becomes non-activated with a further increase in temperature. Explicit equations are proposed for the assessments of both Tvm and ηmin, which are shown to provide data that are close to those experimentally measured. Numerical estimations reveal that the new crossover temperature is very high and can barely be achieved in practical uses, although at temperatures close to it, the contribution of the non-activated regime of the flow can be accounted for. [ABSTRACT FROM AUTHOR]

High hot-air temperature can improve the quality of paddy in the process of mixed-flow rice drying, while low hot-air temperature can affect the drying rate of paddy. The variable temperature drying is confined to selecting the node of temperature change, the large fluctuation range of temperature, and the long time to reach the specified temperature. In this study, a drying control system was designed to keep the temperature of paddy in the rubbery region of the glass transition curve. The glass transition curve of the paddy was also determined for the control strategy of variable temperature. The opening size of the valve was adjusted in the hot-air mixing device, in order to change the hot-air temperature. A control model was established between the valve opening of the hot air mixing device and the paddy temperature using Logistic regression. Least square identification was used to identify the parameters of the variable temperature control model. Genetic algorithm (GA) was used to optimize the membership degree of fuzzy PID control. The objective function converged to 0.118 in the process of genetic optimization. The amplitude width was then determined as the optimal membership function. Simulink simulation showed that the response time of fuzzy PID control was 66.43 s, and the overshoot was 3.600% when the temperature was set at 42 ℃. The response time of fuzzy PID control was 37.06 s after GA optimization, and the overshoot was reduced to 0.120%. The external signal interference of 5 s was added in the time of 150 s, in order to test the anti-interference performance of the variable temperature control system. The adjustment time of the fuzzy PID control after GA optimization was 4.19 s less than before, and the overshoot was reduced by 0.050%. Once the temperature signal was input at 42 ℃ and the temperature rose to 47 ℃, the adjustment time of the fuzzy PID control after GA optimization was 16.79 s less, and the overshoot was 0.338% less than before. A test system was self-developed for the mixed-flow variable temperature drying, according to the mixed-flow two-way air inlet dryer. Firstly, the temperature-changing test was carried out on the variable-temperature control system under different temperatures. The temperature was set at 37 ℃, 42 ℃, 47 ℃ and 52 ℃. The average response time of the fuzzy PID control was 32.37 s after GA optimization, which was 69.93 s before optimization. In the response time test of gradient temperature rise, the average response time of fuzzy PID control was 27.00 s after GA optimization, which was 45.63 s before that. Compared with the fuzzy PID control after GA optimization, the adjustment time of the target and gradient temperature was shortened by 37.56 s and 18.63 s, respectively. After that, 800 s was divided into eight intervals at the stable temperature, in order to test the stability performance of the variable temperature control system. When the rice temperature reached 42 ℃ in dynamic stability, the paddy temperature varied from 41.9 ℃ to 42.1 ℃, where the average relative error was less than 0.4%, and the coefficient of variation was less than 0.5%. A performance test of the variable temperature control system was carried out on the dryer of Nongjiang Farm in Jiansanjiang National Agricultural High-tech Demonstration Zone, Heilongjiang Province, China. The response time of the fuzzy PID control system after GA optimization was less than 30 s, where the steady-state temperature error was ±0.15 ℃, and the average relative error was less than 0.5%. The simulation and field test showed that the stable temperature control system with glass transition fully met the drying requirements in paddy production. [ABSTRACT FROM AUTHOR]

The present study was designed to investigate the physical stability of three organic materials with similar chemical structures. The examined compounds revealed completely different crystallization tendencies in their supercooled liquid states and were classified into three distinct classes based on their tendency to crystallize. (S)-4-Benzyl-2-oxazolidinone easily crystallizes during cooling from the melt; (S)-4-Benzylthiazolidine-2-thione does not crystallize during cooling from the melt, but crystallizes easily during subsequent reheating above Tg; and (S)-4-Benzyloxazolidine-2-thione does not crystallize either during cooling from the melt or during reheating. Such different tendencies to crystallize are observed despite the very similar chemical structures of the compounds, which only differ in oxide or sulfur atoms in one of their rings. We also studied the isothermal crystallization kinetics of the materials that were shown to transform into a crystalline state. Molecular dynamics and thermal properties were thoroughly investigated using broadband dielectric spectroscopy, as well as conventional and temperature-modulated differential scanning calorimetry in the wide temperature range. It was found that all three glass formers have the same dynamic fragility (m = 93), calculated directly from dielectric structural relaxation times. This result verifies that dynamic fragility is not related to the tendency to crystallize. In addition, thermodynamic fragility predictions were also made using calorimetric data. It was found that the thermodynamic fragility evaluated based on the width of the glass transition, observed in the temperature dependence of heat capacity, correlates best with the tendency to crystallize. [ABSTRACT FROM AUTHOR]

Our research aimed to develop an amorphous solid dispersion (ASD) of myricetin (MYR) with Polyvinylpyrrolidone K30 (PVP30) to enhance its solubility, dissolution rate, antioxidant, and neuroprotective properties. Employing a combination of solvent evaporation and freeze drying, we successfully formed MYR ASDs. XRPD analysis confirmed complete amorphization in 1:8 and 1:9 MYR-PVP weight ratios. DSC thermograms exhibited a single glass transition (Tg), indicating full miscibility. FT-IR results and molecular modeling confirmed hydrogen bonds stabilizing MYR's amorphous state. HPLC analysis indicated the absence of degradation products, ensuring safe MYR delivery systems. Solubility, dissolution rate (pH 1.2 and 6.8), antioxidant (ABTS, DPPH, CUPRAC, and FRAP assays), and in vitro neuroprotective activities (inhibition of cholinesterases: AChE and BChE) were significantly improved compared to the pure compound. Molecular docking studies revealed that MYR had made several hydrogen, hydrophobic, and π-π stacking interactions, which could explain the compound's potency to inhibit AChE and BChE. MYR-PVP 1:9 w/w ASD has the best solubility, antioxidant, and neuroprotective activity. Stability studies confirmed the physical stability of MYR-PVP 1:9 w/w ASD immediately after dissolution and for two months under ambient conditions. Our study showed that the obtained ASDs are promising systems for the delivery of MYR with the potential for use in alleviating the symptoms of neurodegenerative diseases. [ABSTRACT FROM AUTHOR]

Diffusion of hydrogen (H) in silicate glasses plays a critical role in many applications because already at small concentrations the presence of H and its mobility have significant effects on the physical and chemical properties of materials. Although many of these applications such as weathering and alteration occur at low temperatures (e.g., <600 °C), a quantification of diffusion rates at associated conditions have been hindered due to analytical and experimental difficulties in the past. This is especially problematic because it is not clear whether an extrapolation of high-temperature data across the glass transition to low temperatures based on an Arrhenius law is valid. A recently developed experimental technique has now made it possible to report here diffusion rates of H in anorthite-diopside (50/50 mol%) glass between 150 and 600 °C and pressures of 1 atm and 2 kbar. Numerical modelling was used to extract diffusion rates from nanoscale diffusion profiles measured by Nuclear Resonance Reaction Analysis in our thin-film diffusion couples that were produced by pulsed laser deposition. We considered different boundary conditions that are related to the experimental techniques applied and tested two models (i) a single-diffusant species model with different dependencies on total water concentration (H 2 O t) , (ii) a speciation-diffusion model that considers the coexistence of molecular H 2 O and OH as species withing the glass. An exponential dependency on H 2 O t in model (i) describes the measured profiles adequately. Diffusion coefficients for H 2 O t that we obtained from the single-diffusant, and the speciation-diffusion model show minor differences (∼0.2 log units). Our results include three major findings: (i) The diffusivity-temperature relationship between 150 and 600 °C does not follow an Arrhenius law. Instead, the trend exhibits a marked change in slope between 350 and 450 °C. A change in activation energy of diffusion is likely related to a change from a glass to a supercooled melt, which can be fit by a modified Vogel-Fulcher-Tammann (VFT) equation. (ii) All experiments at higher temperatures (≥450 °C) are better fitted within the scope of a two-species model considering OH to be mobile. (iii) A comparison with published diffusion data reveals that a change in activation energy is much more pronounced in depolymerized melts (e.g., basalt) than in polymerized melts (e.g., rhyolite). [ABSTRACT FROM AUTHOR]

In this study, amorphous solid dispersions (ASDs) of pterostilbene (PTR) with polyvinylpyrrolidone polymers (PVP K30 and VA64) were prepared through milling, affirming the amorphous dispersion of PTR via X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC). Subsequent analysis of DSC thermograms, augmented using mathematical equations such as the Gordon–Taylor and Couchman–Karasz equations, facilitated the determination of predicted values for glass transition (Tg), PTR's miscibility with PVP, and the strength of PTR's interaction with the polymers. Fourier-transform infrared (FTIR) analysis validated interactions maintaining PTR's amorphous state and identified involved functional groups, namely, the 4′–OH and/or –CH groups of PTR and the C=O group of PVP. The study culminated in evaluating the impact of amorphization on water solubility, the release profile in pH 6.8, and in vitro permeability (PAMPA-GIT and BBB methods). In addition, it was determined how improving water solubility affects the increase in antioxidant (ABTS, DPPH, CUPRAC, and FRAP assays) and neuroprotective (inhibition of cholinesterases: AChE and BChE) properties. The apparent solubility of the pure PTR was ~4.0 µg·mL−1 and showed no activity in the considered assays. For obtained ASDs (PTR-PVP30/PTR-PVPVA64, respectively) improvements in apparent solubility (410.8 and 383.2 µg·mL−1), release profile, permeability, antioxidant properties (ABTS: IC50 = 52.37/52.99 μg·mL−1, DPPH: IC50 = 163.43/173.96 μg·mL−1, CUPRAC: IC0.5 = 122.27/129.59 μg·mL−1, FRAP: IC0.5 = 95.69/98.57 μg·mL−1), and neuroprotective effects (AChE: 39.1%/36.2%, BChE: 76.9%/73.2%) were confirmed. [ABSTRACT FROM AUTHOR]

The present study examines the impact of a few additives, i.e., silver (Ag), bismuth (Bi), cadmium (Cd), and zinc (Zn) on the kinetics of glass transition and crystallization in glassy Se78Te20Sn2 alloy. This is accomplished by performing the calorimetric experiment in non-isothermal mode. To perceive the metal-induced consequences of Ag, Bi, Cd, and Zn as foreign atoms on the kinematics of glass transition, the glass transition temperature (Tg), Lasocka's glass transition parameters (i.e., A1 and B1), and the glass transition activation energy (Eg) have been calculated. Similarly, we have determined the crystallization temperatures (on-set value To, and peak value Tc) and melting temperature (Peak value Tm), Lasocka's crystallization parameters (i.e., A2 and B2), crystallization rate constant K, and the corresponding activation energy (Ec). Knowing the values of kinetic temperatures of glass transition/ crystallization, the thermal stability, and the glass-forming tendency of ternary Se78Te20Sn2 and quaternary Se76Te20Sn2M2 (M = Ag, Bi, Cd, and Zn) alloys have been also determined. [ABSTRACT FROM AUTHOR]

Machine learning techniques such as local binary pattern algorithm and convolutional neural network were applied to study textures of liquid crystal compound (S)-4'-(1-methyloctyloxycarbonyl) biphenyl-4-yl 4-[7-(2,2,3,3,4,4,4-heptafluorobutoxy) heptyl-1-oxy]-benzoate (3F7HPhH7). This compound exhibits in its polymorphism several smectic phases (smectic A, ferroelectric smectic C and antiferroelectric smectic C) and two glass states of antiferroelectric smectic C phase, which textures are difficult to distinguish. Proof-of-concept evidence is provided, demonstrating the ability of machine learning algorithms to identify transition temperatures and the respective phases involved. The article describes the procedure for preparing a dataset of textures obtained from polarised microscopy for classification using convolutional neural networks, especially in cases where the image dataset is unbalanced. It utilises the feature of their self-similarity and image augmentation, particularly the cropping procedure. A Kolmogorov–Smirnov test was conducted to check if selected images do not carry the same information. [ABSTRACT FROM AUTHOR]

This work examines, first, the non-equilibrium character of the glassy state of polymer systems and its significance in the development of novel materials for important technological applications. Subsequently, it summarizes the essentials of the generalized lattice fluid approach for the description of this highly complex non-equilibrium behavior with an approximate and simple, yet analytically powerful formalism. The working equations are derived in a straightforward and consistent manner by clearly defining the universal and specific variables needed to describe the discussed properties. The role of the non-random distribution of molecular species and free volume in the glassy system is also examined, as is the role of strong specific interactions, such as hydrogen-bonding networks. This work also reports examples of applications in a variety of representative systems, including glass densification, retrograde vitrification, increase in glass-transition temperature in hydrogen-bonded polymer mixtures, and hysteresis phenomena in sorption–desorption from glassy polymer matrices. [ABSTRACT FROM AUTHOR]

Thermo-chemical conversion of cigarette butt filters (CBF) waste was investigated using various thermal analysis techniques (simultaneous TG-DTG-DTA and DSC methods) at different heating rates in an inert atmosphere. Thermo- and thermophysical properties of waste material were discussed, from the point of view of chemical structure and the influence of experimental parameters on the conversion process. It was established that acetyl groups of plasticizer (triacetin) interact with cellulose acetate through dipolar interactions and hydrogen bonding's. Influence of these polar interactions can affect the position of glass transition temperature, Tg, of CBF. Based on estimated value of Tg from DSC analysis, it was found that cellulose acetate present in CBF has degree of substitution equals to 2.8, where the presence of cellulose triacetate was confirmed. It was assumed that an increase of degree of substitution leads to decline in the crystallinity. A decline of crystallinity causes the reduction of hydroxyl groups, leading to less organized chains, and whereby decreasing of inter-molecular interactions through hydrogen bonding. Based on the examination of thermophysical characteristics of the tested material, it was found that both, the heat capacity and the thermal inertia of material linearly increase with temperature, during pyrolysis progression. It was concluded that the type of bio-char produced in this process would have a large capacity to store the heat, which may depend on the formed particles size diameter and porosity. Furthermore, it was inferred that magnitude drops of thermal conductivity, κ, after Tg depends on the material fibrillation. [ABSTRACT FROM AUTHOR]

T‐300 6K carbon fabric fiber‐reinforced epoxy laminated composites are prepared by in‐situ and hot‐compression molding technique. The main emphasis of this study is to examine the impact of the structural deformations on fiber orientations of laminated composites during vibrational damping, stiffness, and electromagnetic interference (EMI) shielding properties. The damping properties of carbon fiber laminated composites are analyzed in terms of natural frequency and logarithmic decrement. The digital image correlation technique has been used to measure the mode shape behavior of carbon fiber reinforced polymer (CFRP) composites. The dynamic behavior of the CFRP laminated composites has significant effect on the fiber orientations in terms of storage, loss modulus, and damping ratio. The value of EMI shielding of CFRP laminated composites of T‐300 6K based CFRP polymer laminated composites has slight variations in the SET and their values are 107.17 (B‐45), 106.33 (B‐30), and 110.0 dB (B‐0). The vibrational and EMI shielding properties are showing a huge potential for these kinds of CFRP laminated composites in military and aircraft applications. Highlights: CFRP laminated epoxy composites were fabricated by hand layup technique.The ply orientation of CFRP composites were affected the mechanical properties.DIC was used to determine the mode shapes of laminated composites.CFRP laminated composite exhibited excellent EMI properties. [ABSTRACT FROM AUTHOR]

Non-isocyanate polyurethane (NIPU) networks physically modified with octa(3-hydroxy-3-methylbutyldimethylsiloxy)POSS (8OHPOSS, 0–10 wt%) were conditioned in environments of different relative humidities (up to 97%) to study water–polymer interactions. The equilibrium sorption isotherms are of Brunauer type III in a water activity range of 0–0.97 and are discussed in terms of the Guggenheim (GAB) sorption model. The study shows that the introduction of 8OHPOSS, even in a large amount (10 wt%), does not hinder the water affinity of the NIPU network despite the hydrophobic nature of POSS; this is attributable to the homogenous dispersion of POSS in the polymer matrix. The shift in the urethane-derived carbonyl bands toward lower wavenumbers with a simultaneous shift in the urethane N-H bending bands toward higher wavenumbers exposes the breakage of polymer–polymer hydrogen bonds upon water uptake due to the formation of stronger water–polymer hydrogen bonds. Upon water absorption, a notable decrease in the glass transition temperature ( T g ) is observed for all studied materials. The progressive reduction in T g with water uptake is driven by plasticization and slaving mechanisms. POSS moieties are thought to impact slaving indirectly by slightly affecting water uptake at very high hydration levels. [ABSTRACT FROM AUTHOR]

Differential scanning calorimetry (DSC) revealed an anti-sigmoidal composition dependence of the glass transition temperature in a binary mixture of dicyclohexylmethanol [ (C 6 H 11) 2 CHOH , DCHM] and tricyclohexylmethanol [ (C 6 H 11) 3 COH , TCHM]. The equimolar mixture, of which state was suggested to be robust by the dependence, was subjected to adiabatic calorimetry. The glass transition occurred around 257 K with a significant enthalpy relaxation. The excess heat capacity beyond the weighted average of heat capacities of neat compounds changes its sign from positive to negative upon the glass transition on cooling. The negative excess implies a denser molecular packing than neat glasses. The excess enthalpy is graphically given relative to T = 298.15 K. [ABSTRACT FROM AUTHOR]

Spray drying of sugar-rich foods causes problems, related mainly to low glass transition temperature, which is manifested by high stickiness, lower drying efficiency, and yield. Thus, a number of research papers have been published recently on this topic. This study summarizes the obtained results and indicates possible future directions. The most popular method to overcome the stickiness problem is still the application of carriers. However, in addition to conventional carriers like maltodextrin and gum Arabic, novel carriers are also being tested. The carriers with additional health-promoting properties are the most interesting group. In the material-science approach the application of proteins as anti-stickiness agents can also be mentioned. Moreover, the raw materials can be modified by membrane techniques to reduce sugar content and increase glass transition temperature. In the process-based approach, the main efforts are mostly focused on decreasing of drying temperature. Currently, the use of dehumidified air has been successfully verified as a possible way to reduce drying temperature. The reduction of stickiness achieved by this method allows to minimize the amounts of carriers added into the feed before spray drying. [ABSTRACT FROM AUTHOR]

This article presents the synthesis and molecular dynamics investigation of three novel cyclic thioethers: 2,3-(4′-methylbenzo)-1,4,7,10-tetrathiacyclododeca-2-ene (compound 1), 2,3,14,15-bis(4′,4″(5″)-methylbenzo)-1,4,7,10,13,16,19,22,25-octathiacyclotetracosa-2,14-diene (compound 2), and 2,3,8,9-bis(4′,4″(5″)-methylbenzo)-1,4,7,10-tetrathiacyclododeca-2,8-diene (compound 3). The compounds exhibit relatively high glass transition temperatures (Tg), which range between 254 and 283 K. This characteristic positions them within the so-far limited category of crown-like glass-formers. We demonstrate that cyclic thioethers may span both the realms of ordinary and sizeable molecular glass-formers, each featuring distinct physical properties. Furthermore, we show that the Tg follows a sublinear power law as a function of the molar mass within this class of compounds. We also reveal multiple dielectric relaxation processes of the novel cyclic thioethers. Above the Tg, their dielectric loss spectra are dominated by a structural relaxation, which originates from the cooperative reorientation of entire molecules and exhibits an excess wing on its high-frequency slope. This feature has been attributed to the Johari–Goldstein (JG) process. Each investigated compound exhibits also at least one intramolecular secondary non-JG relaxation stemming from conformational changes. Their activation energies range from approximately 19 kJ/mol to roughly 40 kJ/mol. Finally, we analyze the high-pressure molecular dynamics of compound 1, revealing a pressure-induced increase in its Tg with a dTg/dp coefficient equal to 197 ± 8 K/GPa. [ABSTRACT FROM AUTHOR]

An innovative strategy to address recent challenges in the oral administration of poorly soluble drugs is the formulation of amorphous solid dispersions (ASDs), where the drug is dissolved in a highly soluble carrier polymer. Therefore, special knowledge of the drug–polymer phase behavior is essential for an effective product and process design, accelerating the introduction of novel efficacious ASD products. Flory–Huggins theory can be applied to model solubility temperatures of crystalline drugs in carrier polymers over the drug fraction. However, predicted solubility temperatures lack accuracy in cases of strong drug/polymer interactions that are not represented in the Flory–Huggins lattice model. Within this study, a modeling strategy is proposed to improve the predictive power through an extension of the Flory–Huggins interaction parameter by a correlation with the drug fraction. Therefore, the composition dependency of the Flory–Huggins interaction parameter was evaluated experimentally for various drug–polymer formulations that cover a wide variety of drug and polymer characteristics regarding molecular weights, glass transition temperatures and melting temperatures, as well as drug–polymer interactions of different strengths and effects. The extended model was successfully approved for nine exemplary ASD formulations containing the drugs acetaminophen, itraconazole, and griseofulvine, as well as the following polymers: basic butylated methacrylate copolymer, Soluplus®, and vinylpyrrolidone/vinyl acetate copolymer. A high correlation between the predicted solubility temperatures and experimental and literature data was found, particularly at low drug fractions, since the model accounts for composition dependent drug–polymer interactions. [ABSTRACT FROM AUTHOR]

The acrylic-based heat-cured soft denture lining material is the most commonly used in relining dentures. This material has poor thermomechanical properties which is a disadvantage. This research aimed to study the effect of the addition of modified metallic nanoparticles on glass transition, modulus of elasticity, and coefficient of thermal expansion and contraction of the acrylic soft liner. Alumina nanoparticles were first modified by a silane coupling agent and then added to a soft denture liner powder in different weight percentages (0, 0.5, 1, and 1.5 wt%) using a probe ultrasonication machine for mixing. 120 samples of acrylic-based soft liner were constructed and divided into four groups G1-G4 (n = 30). Each group was in turn subdivided into 3 subgroups (n = 10) according to the test performed. The mean value, SD, Kruskal-Wallis test, and Dunn's Multiple Comparison tests were used to analyze the results statistically. Incorporating 0.5% by weight alumina nano-fillers into acrylicbased heat-cured soft denture lining material, increased the glass transition temperature significantly (p ≤ 0.01). Additionally, it significantly reduced the coefficient of thermal expansion and contraction, especially at 30 °C, compared to the control group. The E-modulus was also reduced, especially at 50 °C, compared to the control group. According to the reported results, the polymer nanocomposites possess distinctive material properties that distinguish them from unmodified acrylic-base soft denture lining materials. Nanocomposites have more thermal and mechanical stability than unmodified acrylicbase soft denture lining material especially when incorporating 0.5 wt% Al2O3. [ABSTRACT FROM AUTHOR]

Glass transition can cause the formation of drying cracks in different component of maize (Zea mays) at different drying stages, but the influence of the mechanism is unknown. This work aimed to study the effect of glass transition on crack formation in different components. It was found that the differences in moisture content, temperature distribution, and glass transition temperature of the components can cause different glass transition processes in the components at different drying stages with 55 °C hot air. The temperatures of the pericarp and germ were found to be higher and lower, respectively, than corresponding the glass transition temperature, so remained in a single state, resulting in the absence of cracks. Cracks generated in the hard endosperm and then extended to soft endosperm, which was consistent with the glass transition of the endosperm. At the preheating stage, the endosperm had no cracks. After the main drying stage, the stress crack index (SCI) of hard and soft endosperm were 160.0 and 65.3, respectively. After the cooling stage, the SCI of the hard and soft endosperm increased to 402.3 and 163.3, respectively. Cracks were mainly formed during the main drying and cooling stages, and more cracks formed in the cooling stage. The cracking in the components at different drying stages could be well explained by glass transition. • Crack formation in the components depended on the form and process of glass transition. • Pericarp and germ were in a single state resulted in the absence of cracks. • Occurrence and propagation of cracks in the endosperm consistent with its glass transition. • Glass transition could explain the crack degree in the components at different drying stages. [ABSTRACT FROM AUTHOR]

Purpose: To compare the prediction accuracy of two models used to characterize the complete disordering potential of materials after extensive cryogenic milling. Methods: Elastic shear moduli (μs) were simulated in silico. Comparison with available literature values confirmed that computations were reasonable. Complete disordering potential was predicted using the critical dislocation density (ρcrit) and bivariate empirical models. To compare the prediction accuracy of the models, each material added for dataset expansion was cryomilled for up to 5 hr. Mechanical disordering after comminution was characterized using PXRD and DSC, and pooled with previously published results. Results: Simulated μs enabled predictions using the ρcrit model for 29 materials. This model mischaracterized the complete disordering behavior for 13/29 materials, giving an overall prediction accuracy of 55%. The originally published bivariate empirical model classification boundary correctly grouped the disordering potential for 31/32 materials from the expanded dataset. Recalibration of this model retained a 94% prediction accuracy, with only 2 misclassifications. Conclusions: Prediction accuracy of the ρcrit model decreased with dataset expansion, relative to previously published results. Overall, the ρcrit model was considerably less accurate relative to the bivariate empirical model, which retained very high prediction accuracy for the expanded dataset. Although the empirical model does not imply a mechanism, model robustness suggests the importance of glass transition temperature (Tg) and molar volume (Mv) on formation and persistence of amorphous materials following extensive cryomilling. [ABSTRACT FROM AUTHOR]

The glass transition in polyurethanes is a complicated phenomenon governed by a multitude of factors, including the microphase separation, which in turn depends strongly on the molar mass of the hard and soft segments, as well as the presence of additives. In this work, we study the effects of the segments' length on the microphase separation and consequently on the calorimetric and dynamic glass transition of a polyurethane with aliphatic, "flexible" hard segments. It is found that the dependence of the calorimetric glass transition follows the same principles as those in systems with aromatic hard segments. Strikingly, however, the dynamic glass transition, as studied by dielectric spectroscopy, shows a slowing down of its dynamics despite a decrease in T g . This discrepancy is discussed in terms of the strong dielectric response of the flexible segments, especially those close to the interface between the hard domains and soft phase, as opposed to a weak thermal one. In addition, polyhedral oligomeric silsesquioxanes (POSS) are introduced in the soft phase of the three matrices as crosslinking centres. This modification has no visible effect on the calorimetric glass transition; nevertheless, it affects the microphase separation and the dielectric response in a non-monotonic manner. [ABSTRACT FROM AUTHOR]

We have developed an analytical method to quantitatively analyze differential scanning calorimetry (DSC) experimental data. This method provides accurate determination of thermal properties such as equilibrium melting temperature, latent heat, change of heat capacity which can be performed automatically without intervention of a DSC operator. DSC is one of the best techniques to determine the thermal properties of materials. However, the accuracy of the transition temperature and enthalpy change can be affected by artifacts caused by the instrumentation, sampling, and the DSC analysis methods which are based on graphical constructions. In the present study, an analytical function (DSCN(T)) has been developed based on an assumed Arrhenius crystal size distribution together with instrumental and sample-related peak broadening. The DSCN(T) function was successfully applied to fit the experimental data of a substantial number of calibration and new unknown samples, including samples with an obvious asymmetry of the melting peak, yielding the thermal characteristics such as melting and glass transition temperature, and enthalpy and heat capacity change. It also allows very accurate analysis of binary systems with two distinct but severely overlapping peaks and samples that include a cold crystallization before melting. [ABSTRACT FROM AUTHOR]

Conjugated polymers have gained considerable interest due to their unique structures and promising applications in areas such as optoelectronics, photovoltaics, and flexible electronics. This review focuses on the structure–property relationship, glass transition, and crystallization behaviors of conjugated polymers. Understanding the relationship between the molecular structure of conjugated polymers and their properties is essential for optimizing their performance. The glass transition temperature (Tg) plays a key role in determining the processability and application of conjugated polymers. We discuss the mechanisms underlying the glass transition phenomenon and explore how side-chain interaction affects Tg. The crystallization behavior of conjugated polymers significantly impacts their mechanical and electrical properties. We investigate the nucleation and growth processes, as well as the factors that influence the crystallization process. The development of the three generations of conjugated polymers in controlling the crystalline structure and enhancing polymer ordering is also discussed. This review highlights advanced characterization techniques such as X-ray diffraction, atomic force microscopy, and thermal analysis, which provide insights into molecular ordering and polymer–crystal interfaces. This review provides an insight of the structure–property relationship, glass transition, and crystallization behaviors of conjugated polymers. It serves as a foundation for further research and development of conjugated polymer-based materials with enhanced properties and performance. [ABSTRACT FROM AUTHOR]

The results of investigation of the phase behavior of a crude oil sample from the Kalchinsk oilfield at pressure up to 1.43 GPa in the temperature range of 140-336 K are presented. It is shown that crystallization occurs in the sample with increasing pressure (decreasing temperature) in a wide range of thermobaric parameters, after which the glass transition process is observed. Based on the experimental data, a phase diagram for the studied sample was constructed. [ABSTRACT FROM AUTHOR]

The use of thermoplastic-based composites for applications in high temperature aeronautical parts is often considered contradictory with respect to the softening of the matrix and the subsequent degradation of their mechanical properties, especially when service temperature T exceeds glass transition temperature. This paper examines the fatigue performance of unidirectional (UD) carbon fibers reinforced PolyArylEtherKetone (PAEK) laminates subjected to tension-tension fatigue at different testing temperatures (Room Temperature, 120°C and 170°C). Laminates consisting of different portions of plies in 0°/+45°/−45°/90° orientations have been investigated to evaluate the contribution of each ply orientation to the fatigue performance in terms of S-N diagrams. From the evolution of life span as a function of applied stress, it appears that the influence of temperature on fatigue behaviour of C/PAEK composites depends on the temperature conditions. 0° plies behaviour is known to be temperature-independent as is dominated by the mechanical behaviour of UD carbon fibers. It is expected to reflect on the fatigue behaviour at high temperature. From the obtained results, one may conclude that the 0° plies primarily bear the tensile load in fatigue (47-67-91% in SOFT, QI and HARD laminates, respectively) and therefore dominate the fatigue behaviour. The deformation mechanisms in +/−45° plies (localized plastic-viscoplastic dissipative behaviors) favoured at temperatures higher than Tg (e.g. 143°C) are limited by the low deformation of 0° plies. SOFT (12% of 0° plies) and QI (25% of 0° plies) laminates have similar relative fatigue performance. Unexpectedly, the fatigue performance of HARD laminates (about 62% of 0° plies) is improved at T>Tg at high stress levels. A simple temperature-dependent analytical model was used to successfully predict the fatigue life of C/PAEK laminates with different stacking sequences. [ABSTRACT FROM AUTHOR]

The local structure and glass transition of Ge-As-Se, Ge-As-Se-Schalcogenide glasses have been studied by X-ray diffraction and differential scanning calorimetry. By applying the theory of topological constraints and considering chemically ordered network models, it has been determined that Ge10As20S10Se60 (average coordination number ⟨ r ⟩ = 2.4), Ge25As10S25Se40 ( ⟨ r ⟩ = 2.6) are the compositions associated with the more stable glasses. This result is related to the larger differences between the glass transition (Tg) and crystallization-transition (Tcr) temperatures (ΔTg-cr∼ 38 and 43 K) at these compositions. Relatively high values of short-range (d∼5.7–6.34 Å) and medium-range (L∼26.59–33.74 Å) order parameters of the local structure in the glass compositions satisfying the mentioned conditions affect the glass-transition temperature (Tg) and cause its value to increase (Tg∼589–689 K). As a result of comparative analyses of X-ray diffraction and differential scanning calorimetry curves it has been determined that there is a correlation between the glass-transition temperature (Tg) with the short range (d) and medium range order (L) parameters of the local structure. [ABSTRACT FROM AUTHOR]

Self‐pressurised rapid freezing (SPRF) has been proposed as a simple alternative to traditional high‐pressure freezing (HPF) protocols for vitrification of biological samples in electron microscopy and cryopreservation applications. Both methods exploit the circumstance that the melting point of ice reaches a minimum when subjected to pressure of around 210 MPa, however, in SPRF its precise quantity depends on sample properties and hence, is generally unknown. In particular, cryoprotective agents (CPAs) are expected to be a factor; though eschewed by many SPRF experiments, vitrification of larger samples notably cannot be envisaged without them. Thus, in this study, we address the question of how CPA concentration affects pressure inside sealed capillaries, and how to design SPRF experiments accordingly. By embedding a fibre‐optic probe in samples and performing Raman spectroscopy after freezing, we first present a direct assessment of pressure build‐up during SPRF, enabled by the large pressure sensitivity of the Raman shift of hexagonal ice. Choosing dimethyl sulphoxide (DMSO) as a model CPA, this approach allows us to demonstrate that average pressure drops to zero when DMSO concentrations of 15 wt% are exceeded. Since a trade‐off between pressure and DMSO concentration represents an impasse with regard to vitrification of larger samples, we introduce a sample architecture with two chambers, separated by a partition that allows for equilibration of pressure but not DMSO concentrations. We show that pressure and concentration in the fibre‐facing chamber can be tuned independently, and present differential scanning calorimetry (DSC) data supporting the improved vitrification performance of two‐chamber designs. Lay version of abstract for 'Self‐pressurised rapid freezing at arbitrary cryoprotectant concentrations' Anyone is familiar with pipes bursting in winter because the volume of ice is greater than that of liquid water. Less well known is the fact that inside a thick‐walled container, sealed and devoid of air bubbles, this pressure build‐up will allow a fraction of water to remain unfrozen if the sample is also cooled sufficiently rapidly far below the freezing point. This phenomenon has already been harnessed for specimen preparation in microscopy, where low temperatures are useful to immobilise the sample, but harmful if ice formation occurs. However, specimen preparation cannot always rely on this pressure‐based effect alone, but sometimes requires addition of chemicals to inhibit ice formation. Not enough is known directly about how these chemicals affect pressure build‐up: Indeed, rapid cooling below the freezing point is only possible for small sample volumes, typically placed inside sealed capillaries, so that space is generally insufficient to accommodate a pressure sensor. By means of a compact sensor, based on an optical fibre, laser and spectrometer, we present the first direct assessment of pressure inside sealed capillaries. We show that addition of chemicals reduces pressure build‐up and present a two‐chambered capillary to circumvent the resulting trade‐off. Also, we present evidence showing that the two‐chambered capillary design can avoid ice formation more readily than a single‐chambered one. [ABSTRACT FROM AUTHOR]

Cyanate esters are preferred resins for space composites based on excellent mechanical, thermal and dimensional properties. Yet, they are sensitive to co‐reactions with secondary constituents making compatibility a processing challenge. Anodized aluminum mandrels are commonly used for composite manufacturing but deleterious interactions with cyanate ester is not well understood. We investigate here the interaction of anodized aluminum mandrels with surrounding environments and its impact on cure, thermal stability and mechanical properties of M55J/RS3C composites. The uptake and diffusivity of environmental moisture in mandrels was determined gravimetrically and fit to a predictive Fickian model. Cured composite properties were evaluated and correlated with glass transition temperatures (Tg) by dynamic mechanical analysis (DMA), thermal stability by thermal gravimetric analysis (TGA), mechanical properties by flatwise tensile test, and the degradation depth profile by atomic force microscopy (AFM). Parallel to previous results for RS3C but more severe, the degradation penetrated up to 500 μm with reductions of 90°C in Tg, 100°C in thermal stability and 33% mass loss. The inorganic oxide surprisingly absorbs 10× more water at 10× higher rate than composite mandrel materials. The reported results show the anodization presents a unique hydrolysis risk when manufacturing cyanate ester composites so disciplined use and environmental conditioning should be considered when developing space structures. Highlights: Cyanate ester composites degraded by anodized mandrels for all conditions.Thermogram signals correlate to composite mechanical degradation.Composite degradation depth gradient determined by atomic force microscopy. [ABSTRACT FROM AUTHOR]

The electrical and mechanical properties of carbon fiber-reinforced polymer (CFRP) composites have a close dependence on the use of modifiers like polyvinylpyrrolidone (PVP), as well as on the processing techniques to disperse functional charges such as graphene-related materials into the epoxy base. In the present work, reduced graphene oxide (RGO), prepared by a natural antioxidant agent, astaxanthin, was used as a filler material in the epoxy matrix of the carbon fiber composites. The astaxanthin reduction leads to an increase in the sp2 ordering in RGO; some residual epoxy and C-O groups that enhance the interaction with the epoxy matrix remain after reduction. The effects of RGO and PVP-modified RGO (PVP-RGO) fillers with different contents (0.05, 0.1, and 0.15% wt.) on the electrical conductivity, bending properties, and dynamic mechanical properties of CFRP were investigated. The incorporation of 0.15 wt.% RGO with and without PVP-modification, leads to through-the-thickness (Z-direction testing) conductivity values 7.4 and 9.6 times higher than those of the neat composite, respectively. The conductivity tests indicate that the RGO/epoxy composite behaves as a continuous conductor due to the formation of agglomerates of RGO within the matrix, while at the added contents of the PVP-RGO filler, the composite is below the percolation threshold, then conducting by electron tunneling, due to a better dispersion of the PVP-RGO filler within the epoxy matrix. The dynamic mechanical analysis shows that the glass transition temperature is indicative of the interactions among the filler, the epoxy matrix, and the carbon fiber, that is, the PVP-RGO filler increases the chain mobility due to its higher dispersion in the matrix. While Tg of the neat epoxy/CFRP composite is 92.5°C, a minimum Tg of 88.5°C was achieved with a 0.10 % wt. PVP-RGO filler contents, and a maximum Tg of 94.5°C with a 0.15 % wt. of RGO filler amount. For constant filler content (0.15 wt.%), CFRP composite containing RGO and PVP-modified RGO exhibited 9.73% and 13.87% increase in flexural strength values, respectively, compared to the neat composite. The bending test revealed that PVP modification to RGO is beneficial to improve flexural strength of CFRP composites. Graphical Abstract [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons play a critical role in the development of organic semiconductors. This study unravels the impact of alkyl substitution position on the molecular energy level, glass transition temperature, diffusion of external species, and hole transport of a pyrrole‐rich, helical polycyclic heteroaromatic, that is TBPC. Compared to terminal substitution, internal hexyl substitution results in steric repulsion with TBPC, weakening π─π stacking and therefore improving thin film morphology. Internal substitution also reduces energy disorder, lowers reorganization energy, and increases intermolecular transfer integrals, leading to enhanced hole mobility. Notably, the organic semiconductor with internal hexyl substitution (TBPC‐611) exhibits a higher molecular packing density, resulting in a markedly higher glass transition temperature and slower diffusion of external species. Using TBPC‐611 as the hole transport material, this work successfully fabricates perovskite solar cells with an average power conversion efficiency above 24%, showing good photostability and thermostability. These findings contribute new insights to the development of high‐performance organic semiconductors. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: As one of the three types of polymeric materials, rubber has played an irreplaceable role in various fields such as industrial production, aerospace, military, and national defense. Improving the cold resistance of rubbers and extending their service temperature range have always been one of the main focuses in rubber research. However, there have been few detailed public reports or literatures on the progress or summary of cold‐resistant rubbers, creating an invisible barrier for new researchers wishing to enter this field of research. Therefore, starting from the basis of polymer physics, this review introduces the research difficulties in this field and systematically summarizes the research progress in constructing cold‐resistant rubbers based on three different types of flexible polymer chains in recent years. In addition, several important properties of cold‐resistant rubbers including mechanical performance, oil resistance, and self‐healing ability are also discussed along with the summary of recent progresses. Finally, the future challenges and prospects of cold‐resistant rubbers are discussed. It is hoped that this review will attract more attentions from polymer or material scientists, thus activating the fundamental research in the field of cold‐resistant rubber and promoting its practical application. [ABSTRACT FROM AUTHOR]

Strontium phosphate glasses containing bismuth oxide were prepared using conventional melt-quenching technique. X-ray diffraction and differential scanning calorimetry (DSC) analysis suggests that stable ternary glasses of composition 70 P2O5-(30-x)SrO-xBi2O3 can be obtained for x = 5–25 mol%. This study examines such physical properties as the density, molar volume (Vm), glass transition temperature (Tg), and structural properties in the interest of explaining the effect on these glasses of Bi-Sr substitution. An almost linear increase in the density when the concentration of bismuth increases between x = 5 and x = 10 mol% followed by monotonic decreasing is noted. However, the calculated molar volume (Vm) behaves in exactly the opposite way. DSC curves showed that the glass transition temperature (Tg) decreases by 555 °C down to 490 °C as the concentration of Bi2O3 increases, due to the increase in the number of bridging oxygens. Structural investigations performed using IR spectroscopy revealed that the structure of the phosphate network contains predominately meta-phosphate (Q2) units, with contributions from pyrophosphate (Q1) and orthophosphate (Q0). The infrared spectra also revealed depolymerization of the phosphate chains in the glass system, with increased Bi2O3 concentration and the formation of P–O–Bi bonds. The study of the gamma ray shielding parameters showed that the prepared glasses can be used for shielding radiation applications. [ABSTRACT FROM AUTHOR]

Nowadays, the glass transition kinetics is most commonly described in terms of the Tool–Narayanaswamy–Moynihan (TNM) model. Evaluation of one of the most prominent features of the structural relaxation motions—the relaxation nonlinearity—was traditionally done using the peak‐shift (PS) method. This paper introduces, for the first time, extensive testing of the PS method by means of theoretical simulations for all practically observable types of structural relaxation behavior and all types of glassy/amorphous materials (tested range of the glass transition temperatures: −55 to 1000°C; tested range of the relaxation activation energies: 300–1300 kJ⋅mol−1). For the majority of types of structural relaxation behavior, the PS method tends to slightly overestimate the value of the TNM nonlinearity parameter x (by ∼ 0.05–0.10). In the specific cases of the highly linear behavior (↑ x) combined with a broad distribution of relaxation times, the PS method systematically vastly underestimates the value of x. A new, improved temperature program was proposed for the PS method, eliminating the major intrinsic drawback of the originally proposed version of the PS methodology. In addition, based on the comparison between the theoretically simulated and real‐life experimental data, a new approach (based on the characteristic PS dependence shape) was introduced to estimate the width of the relaxation times distribution. [ABSTRACT FROM AUTHOR]

Coamorphous formation in binary systems of valsartan (Val) with 4,4′-bipyridine (Bipy) and trimethoprim (Tri) was investigated for mixtures with a mole fraction of 0.16~0.86 of valsartan and evaluated in terms of the glass transition temperature. The glass transition of the systems had a behavior outside the values predicted by the Gordon–Taylor equation, showing that Val-Bipy (hydrogen bonding between the components) had a lower deviation and Val-Tri (ionic bonding between the components) had a higher deviation. Mixtures of compositions 2:1 Val-Bipy and 1:1 Val-Tri were selected for further investigation and verified to be stable, as no crystallization was observed during subsequent heating and cooling programs. For these systems, the effective activation energy during glass transition was evaluated. Compared to pure valsartan, the system with the lower glass transition temperature (Val-Bipy) presented the highest effective activation energy, and the system with the higher glass transition temperature (Val-Tri) presented a lower effective activation energy. The results presented a good correlation between the data obtained from two different techniques to determine the fragility and effective activation energy: non-isothermal kinetic analysis by DSC and TSDC. [ABSTRACT FROM AUTHOR]

InSe is a III-VI semiconducting layered compound having potential applications in memories, solar cells, infrared sensors, switching devices and optical fibers. In this article various physical parameters of In0.1Se0.9-xSbx (x = 0, 0.04, 0.08, 0.12) chalcogenide alloy depending on the varying composition of Se and Sb are discussed. The physical parameters include the theoretical calculations of average coordination number, number of constraints, floppy modes, number of lone pair electrons, deviation of stoichiometry, average heat of atomization, mean bond energy, density, molar volume, compactness, cohesive energy, electronegativity, energy band gap, conduction and valance band energy and glass transition temperature. The number of lone pair electrons and floppy modes is found to decrease, whereas the average coordination number, mean bond energy, average heat of atomization and density are found to increase with increasing Sb content. The theoretical values of glass transition temperature are calculated using the Tichy-Ticha and Lankhorst approach. [ABSTRACT FROM AUTHOR]

The temperature and chemical dependence of the melt viscosity are ubiquitous in the model development of the volcanic dynamics, as well as in the glass production and design. We focussed on the yet-explored relationship between the bulk and shear moduli ratio and boson peak with the melt fragility of their parental glasses. Here, we explored the extension of the observed trend by testing the conventional binary system Na2O-SiO2, thus providing new evidence supporting the link between the flow of melts and supercooled liquids and the vibrational dynamics of their parental glasses. This was accomplished by integrating new low-frequency Raman measurements and integrating data from the literature on Brillouin light scattering and viscometry. This approach allows us to feed the MYEGA equation with reliable input parameters to quantitatively predict the viscosity of the Na2O-SiO2 system from the liquid up to the glass transition. [ABSTRACT FROM AUTHOR]

Glass sintering involves the densification of packs of particles and the expulsion of the interparticle pore gas. The pore space begins as a convolute interconnected interparticle network, and ends as distributed isolated bubbles; two configurations that are separated by the percolation threshold. Here, we perform experiments in which (i) the particles are initially saturated in H2O at 871 K, and (ii) they are then heated non‐isothermally at different rates to temperatures in excess of 871 K. In step (ii), H2O becomes supersaturated and the particles diffusively lose mass as they sinter together. We use thermogravimetry to track the loss of mass with time. We find that the mass loss is initially well predicted by solutions to Fick's second law in spherical coordinates with the appropriate material and boundary conditions. However, as the sintering pack crosses the percolation threshold at a time predicted by sintering theory, we find that the mass loss deviates from simple diffusional solutions. We interpret this to be the result of an increase in the diffusion distance from the particle‐scale to the scale of the sintering pack itself. Therefore, we conclude that the open‐ to closed‐system transition that occurs at the percolation threshold is a continuous, but rapid jump for diffusive and other transport properties. We use a capillary Peclet number Pc to parameterize for this transition, such that at low Pc diffusive equilibrium is achieved before the sintering‐induced transition to closed system, whereas at high Pcthere is a "diffusion crisis" and disequilibrium may be maintained for longer relative timescales that depend on the system size. [ABSTRACT FROM AUTHOR]

Recent discovery and investigation of the flow of glasses under the electron beams of transmission electron microscopes raised the question of eventual occurrence of such type effects in the vitrified highly radioactive nuclear waste (HLW). In connection to this, we analyse here the flow of glasses and glass–liquid transition in conditions of continuous electron irradiation such as under the e-beam of transmission electron microscopes (TEM) utilising the configuron (broken chemical bond) concept and configuron percolation theory (CPT) methods. It is shown that in such conditions, the fluidity of glasses always increases with a substantial decrease in activation energy of flow at low temperatures and that the main parameter that controls this behaviour is the dose rate of absorbed radiation in the glass. It is revealed that at high dose rates, the temperature of glass–liquid transition sharply drops, and the glass is fully fluidised. Numerical estimations show that the dose rates of TEM e-beams where the silicate glasses were fluidised are many orders of magnitude higher compared to the dose rates characteristic for currently vitrified HLW. [ABSTRACT FROM AUTHOR]

In the present paper, the study of amorphous-crystalline transformation in (Se80Te20)94−x Ge6Bix (x = 0, 1, 2, 4, 6, 8, 10 and 12 at.%) chalcogenide alloys has been done using non-isothermal differential scanning calorimetry (DSC). Characteristic temperatures indicate that the samples with x = 1 at.% and x = 6 at.% can be considered as a critical configurations at which the system becomes a chemically ordered alloy. Kissinger and Moynihan approaches which utilized dependence of glass transition temperature (Tg) on heating rate (α) are used to deduce activation energy of glass transition (Eg). Crystallization process is characterized by various kinetic parameters such as activation energy and frequency factor deduced using different methods. Dietzel, Hruby, Saad and Poulin criteria are employed to assess glass forming ability and thermal stability of investigated alloys. The alloy with x = 12 at.% of Bi content has highest ∆T confirms maximum thermal stability, further validated from the values of Hruby parameter (Kgl) and thermal stability parameter (S). The fragility index infers that the composition studied in the present study is made from strong glass forming liquids. [ABSTRACT FROM AUTHOR]

Miscibility of poly(butylene terephthalate, PBT) with a PVC plasticizer (PN-250) has been characterized by modulated temperature DSC measurements. The glass transition parameters were measured by total heat flow measurements as the midpoint of the heat capacity increase (for the PBT rich areas) and by creating an endothermic hysteresis peak at the glass transition of the plasticizer, because there was no low temperature baseline due to the low Tg of PN-250. The disadvantage of this method is that it does not allow determination of the heat capacity jump at the glass transition. Partial miscibility was determined between these two components. It was observed that crystallinity of PBT in the blends was much higher than in neat PBT because of the higher segmental mobility of the polymer segments in the blends. The hysteresis peak at the PBT glass transition in the blends is much narrower and more intense than for neat PBT since the mobile amorphous fraction of PBT is higher in the blends. Together with the lower rigid amorphous fraction, this means sharper boundary between the mobile amorphous fraction and the PBT crystallites. [ABSTRACT FROM AUTHOR]

The application of low-temperature, dehumidified air-assisted spray drying was evaluated as a method to produce carrierfree powders of selected sugar-rich and acid-rich food materials: blackcurrant juice concentrate, mango puree, purple carrot juice concentrate, sauerkraut juice, kiwiberry pulp, and tomato pulp. As a consequence of decreased drying air humidity, inlet/outlet air temperature was lowered to 80/55°C. In order to validate this new approach, the conventional spray drying was conducted as well at 180/80°C inlet/outlet air temperature. The powder recovery, physical properties and color parameters of powders were determined. For blackcurrant juice concentrate, mango puree, purple carrot juice concentrate and sauerkraut juice it was possible to obtain carrier-free powders only by low-temperature drying, while for kiwiberry pulp and tomato pulp both variants of spray drying were effective. Decreased drying temperature positively influenced some properties of powders; i.e., median particle size diameter and hygroscopicity of the powders obtained by spray drying with dehumidified air were lower compared to those of the powders dried by conventional spray drying. Carrier-free powders of some raw materials (blackcurrant juice concentrate, mango puree, purple carrot juice concentrate, sauerkraut juice) were spray dried solely with dehumidified air, underlining its importance in the production of "clean label" products. [ABSTRACT FROM AUTHOR]