Thermal Properties Research Articles

Modified Release 3D-Printed Capsules Containing a Ketoprofen Self-Nanoemulsifying System for Personalized Medical Application.

This study explores the realm of personalized medicine by investigating the utilization of 3D-printed dosage forms, specifically focusing on patient-specific enteric capsules designed for the modified release of ketoprofen, serving as a model drug. The research investigates two distinct scenarios: the modification of drug release from 3D-printed capsules crafted from hydroxypropyl methylcellulose phthalate:polyethylene glycol (HPMCP:PEG) and poly(vinyl alcohol) (PVA), tailored for pH sensitivity and delayed release modes, respectively. Additionally, a novel ketoprofen-loaded self-nanoemulsifying drug delivery system (SNEDDS) based on pomegranate seed oil (PSO) was developed, characterized, and employed as a fill material for the capsules. Through the preparation and characterization of the HPMCP:PEG based filament via the hot-melt extrusion method, the study thoroughly investigated its thermal and mechanical properties. Notably, the in vitro drug release analysis unveiled the intricate interplay between ketoprofen release, polymer type, and capsule thickness. Furthermore, the incorporation of ketoprofen into the SNEDDS exhibited an enhancement in its in vitro cylooxygenase-2 (COX-2) inhibitory activity. These findings collectively underscore the potential of 3D printing in shaping tailored drug delivery systems, thereby contributing significantly to the advancement of personalized medicine.

Synthesis, growth, structural, thermal, electrical and optical properties of organic NLO: N’ methyl urea oxalic acid

Synthesis, growth, structural, thermal, electrical and optical properties of organic NLO: N’ methyl urea oxalic acid

Thermal modal analysis of hypersonic composite wing on transient aerodynamic heating

Considering the influence of thermal stress and material property variations, this study employs the Navier–Stokes equations and Fourier heat conduction law to establish a semi-implicit time-domain numerical analysis method for hypersonic aerothermal-structural coupling. Study the temporal variation pattern of different regions of the composite material wing under aerodynamic heating. Using the obtained transient temperature field of the wing, the thermal modal of the wing at different time points is calculated using the finite element method. Additionally, it conducts an analysis and discussion on the factors influencing the thermal modal. Composites can be effectively utilized as thermal protection materials for aircraft. During the aerodynamic heating process, the leading edge temperature reaches thermal equilibrium first, followed by the trailing edge, and the belly plate experiences a slower thermal response. Temperature rise significantly affects higher-order modes, with the change in material properties during the early stages of heating being the dominant factor. This leads to a faster decrease in natural frequency. As heat conduction progresses, the influencing factors of thermal stresses gradually increase, and the natural frequency decreases slowly or even rises.

Thermal and Flow Properties of Jeffrey Fluid Through Prabhakar Fractional Approach: Investigating Heat and Mass Transfer with Emphasis on Special Functions

Thermal and Flow Properties of Jeffrey Fluid Through Prabhakar Fractional Approach: Investigating Heat and Mass Transfer with Emphasis on Special Functions

Structural, Optical, and Thermal Properties of PVA/SrTiO3/CNT Polymer Nanocomposites

Structural, Optical, and Thermal Properties of PVA/SrTiO3/CNT Polymer Nanocomposites

A short banana fiber—PLA filament for 3D printing: Development and characterization

AbstractThis study aims to develop a 3D printable composite filament using short banana fiber and polylactic acid (PLA). The filament was acquired through a single screw extruder, employing various blending techniques. Various fiber loadings were examined, impacting PLA's mechanical, thermal, and printability properties. The results revealed altered mechanical characteristics, with reduced tensile and flexural properties compared with pure PLA. However, these values are at an acceptable level for non‐structural applications. Compared with previous works, the filament developed in the present work is found out to be second strongest among the cellulose fiber‐reinforced PLA filaments. 3D printing with the composite filament encountered no significant issues. A modified mixing method improved mechanical characteristics, although 3D‐printed samples showed deteriorated mechanical characteristics due to poor interfacial bonding. This research introduces an environmentally viable strategy for advancing 3D printing technology by integrating banana fibers into PLA filament. The proposed strategy can be effectively utilized in making cellulose/PLA filaments for 3D printing applications. This innovative approach preserves PLA's natural biodegradability while carefully managing the integration of banana fibers and their potential effects on mechanical properties.Highlights Fiber loading influences mechanical, with minimal impact on thermal properties. Solution casting improved fiber/matrix bonding and filler homogeneity. Plasticizing effect reduces the tensile strength. Modified mixing resulted in even filament diameter and improved tensile properties.

Mechanical recycling process: An alternative for a viable disposal of carbon fiber‐reinforced thermoplastic waste

AbstractConcern for the environment has increased the interest of the automotive and aerospace industries in evaluating the feasibility of mechanical recycling of waste carbon‐fiber‐reinforced polymer composites (CFRP) and waste from protective films used during the transport and storage of thermosetting composites, which are removed and discarded during manufacturing. Therefore, this work aimed to develop a recyclable composite from protective film waste by incorporating carbon fiber/poly(aryl ether ketone) (CF/PAEK) composite particles obtained through grinding in knife mills, followed by an analysis of the particle size distribution. Protective film residues (PEres) were cut to facilitate processing. A mixture of low‐density polyethylene and PEres (50/50) was used as the composite matrix, and 5, 10, 15, and 20 wt% CF/PAEK composite particles were added as the reinforcing agents. Then, these recycled composites were prepared by melt mixing using a twin‐screw extruder and injection molding to obtain standardized samples. Mechanical, thermal, electrical, and electromagnetic properties were evaluated. It was possible to observe that the increase in the addition of CF/PAEK composite particles contributed to a 290% increase in elastic modulus values and a 9.1% increase in Shore D hardness, electrical conductivity, and attenuation of the electromagnetic wave. Furthermore, satisfactory adhesion between filler and matrix contributed to a good interface and reinforcement of the final material.Highlights Mechanical recycling by extrusion of waste from the automotive and aerospace sectors Grinding of carbon fiber/poly(aryl ether ketone) composite waste to be used as filler Protective film waste used as matrix Composites developed with waste with good electrical and electromagnetic properties The addition of thermoplastic composite residues does not affect thermal and mechanical properties

A new nano-sachet manufactured by solution blow spinning to retard ripening of bananas using biodegradable nanostructured polymeric mats emitting 1-methylcyclopropene

The aim of this study was to produce nanostructured poly (lactic acid) (PLA) mats incorporated with the 1-MCP/α-CD complex (F1-MCP) by the solution blow spinning (SBS) technique and to apply them as a nano-sachet emitting 1-MCP in a banana packaging system. The nanofibers that comprise the mats presented uniform morphology with diameters between 157 and 184 nm. Scanning electron microscopy showed that crystals of 1-MCP/α-CD were encapsulated and found on the nanofibers' surface, changing their thermal properties and contact angles. The release of 1-MCP gas from the nano-sachet of nanostructured PLA mats with encapsulated 1-MCP/α-CD was proven based on the delay of banana ripening during storage (21 °C and 90 % RH). Therefore, the nanostructured PLA mats with encapsulated MCP/α-CD, produced by SBS, proved viable and applicable in packaging systems that aim to delay ripening and increase the postharvest shelf life of climacteric fruit, such as bananas.

Purely Ionically Bonded Cation Paving the Way to Ultralow Thermal Conductivity and Large Thermoelectric Figure of Merit in Ruddlesden-Popper Perovskite Cs2SnI2Br2.

Lower dimensional materials have gained quite a bit of popularity in the last few decades. Perovskite materials have been studied extensively for their photovoltaic properties. But for large scale application of photovoltaic materials, the thermal properties need to be studied. In this work, using first principles calculations, we have studied the thermal conductivity and thermoelectric performance of quasi two-dimensional (2D) Ruddlesden-Popper phase of perovskite, Cs2SnI2Br2. The Cs atoms are found to be ionically bonded to the halogens leading to low elastic constants and hence give rise to weak bonding. The large anharmonicity in this material causes the lattice thermal conductivity to be ultralow having a value of 0.30 W.m-1.K-1 at 300 K and therefore the thermoelectric figure of merit has been found to be high with a maximum value of 2.08 at 600 K. This lead-free 2D perovskite can be the precursor to a wide variety of similar materials with ultralow thermal conductivity.

Comparative Investigation of Thermal Properties Improvement of Nano-Enhanced Organic Phase Change Materials

Thermal energy storage (TES) using phase change materials (PCMs) is one of the potential solutions for stockpiling thermal energy and utilizing it for different applications, which results in effective energy usage. The main drawback of organic PCMs in practical applications is poor heat transfer due to low thermal conductivity (TC). Therefore, investigations into nano-enhanced PCMs are being explored to improve their thermophysical properties. In this work, the various thermophysical characteristics of nano-enhanced lauryl alcohol as a PCM were investigated using carbon-based and metallic nanoparticles. The results indicated that the addition of nanoparticles improved its thermal properties and affected other physical properties, such as viscosity. The latent heat was degraded with the addition of nanoparticles. The results revealed that by adding MWCNTs and CuO nanoparticles, a maximum of 82.6% and 49.6% improvement in TC was achieved, respectively. The maximum drop in latent heat during melting and freezing for the PCM with MWCNTs was about 10.1% and 9.3%, respectively, whereas for the PCM with CuO, they were about 11% and 10.3%, respectively. The lowest supercooling for the PCM with MWCNTs and CuO nanoparticles was 8.6 and 8.3 °C, respectively. The present work confirms that nano-enhanced PCMs can be a potential material for storing thermal energy for various applications.

Enhancing performance: insights into the augmentation potential of acrylonitrile butadiene styrene/boron nitride composites

Abstract This work aims to investigate the morphological, mechanical and thermal characteristics of boron nitride (BN)-reinforced acrylonitrile-butadiene styrene (ABS) composites. ABS and ABS/BN composites with a maximum BN loading up to 8 wt% were developed using two-roll mill followed by compression molding. Scanning electron microscopy (SEM) images presented interlinking of BN flakes in the dimple texture of ABS. A modest decrease in tensile properties was observed for the composites. The tensile strength and impact strength for the ABS/BN8 specimen were lowered by 4.7 and 81.7 %, respectively. On the other hand, hardness increased by 3.39 % for ABS/BN8 composite. The interaction effect of BN in the ABS matrix on the thermal properties was assessed using thermo-gravimetric analysis (TGA). An enhancement in the thermal-stability was observed for BN incorporated ABS. There is a modest shift in glass transition (T g) temperature to a higher value for the ABS/BN composites.

Mechanical and thermal characterization of elastomer modified polypropylene hybrid composites reinforced with hazelnut shell and wollastonite fillers

AbstractThe demand for sustainable and recyclable materials in industrial applications has led to a surge in interest in green composites, particularly those incorporating natural fillers derived from agro‐food industry waste. This study investigates the mechanical and thermal properties of polypropylene (PP) hybrid composites filled with hazelnut shell and wollastonite, along with the effect of styrene‐ethylene/butylene‐styrene (SEBS) and SEBS‐g‐maleic anhydride (SEBS‐g‐MA) compatibilizers. Various characterization techniques, including tensile, flexural, and impact tests, as well as differential scanning calorimetry (DSC), thermogravimetry (TGA), and scanning electron microscopy (SEM) analyses, were employed to evaluate the composites. Results demonstrate that the addition of wollastonite significantly improves mechanical properties, while hazelnut shell filler affects thermal behavior and stability. SEBS and SEBS‐g‐MA compatibilizers enhance impact resistance; however, they lead to a decrease in other mechanical properties. DSC and TGA analyses demonstrate changes in crystallization behavior and thermal stability due to filler and compatibilizer incorporation. SEM microstructure images show the distribution of SEBS and SEBS‐g‐MA within the composite structure, affecting mechanical and thermal properties. Overall, this study highlights the importance of filler selection, compatibilizer addition, and their distribution in attaining desired properties for industrial applications. Future research should focus on optimizing formulations for specific uses and assessing long‐term performance under real‐world conditions.

Relationship between Chalkiness and the Structural and Physicochemical Properties of Rice Starch at Different Nighttime Temperatures during the Early Grain-Filling Stage

The chalkiness, starch fine structure, and physiochemical properties of rice starch were analyzed and their correlations were investigated under different nighttime temperatures during the early grain-filling stage. Compared to MT, medium temperature (MT) and low (LNT) and high (HNT) nighttime temperatures resulted in an increased chalky grain rate (CGR) and chalkiness degree (CD). LNT mainly affected the chalkiness by increasing peak1 (short branch chains of amylopectin), the branching degree, and the proportion of small starch granules but decreasing peak2 (long branch chains of amylopectin) and peak3 (amylose branches). This altered the pasting properties, such as by increasing the peak viscosity and final viscosity. However, HNT mainly affected the chalkiness by increasing peak2 and the crystallinity degree but decreasing peak1 and peak3. Regarding the thermal properties, HNT also elevated peak and conclusion temperatures. The CGR and CD were significantly and positively correlated with the proportions of small and medium starch granules, peak1, branching degree, gelatinization enthalpy, setback viscosity, and pasting time but markedly and negatively correlated with the proportion of large starch granules, amylose content, peak3, peak viscosity, and breakdown viscosity. These findings suggest that LNT and HNT disrupted the starch structure, resulting in increased chalkiness. However, their mechanisms of action differ.

Understanding the microstructure evolution of carbon-doped Sb2Te3 phase change material for high thermal stability memory application

The Sb2Te3 phase change material shows a growth-dominated crystallization mechanism with fast phase transition but poor thermal stability of the amorphous state. This work investigated the effects of carbon doping on the thermal stability, microstructure, and electrical properties of the Sb2Te3 material. The 10-year data retention temperature of the material increased to ∼147.3 °C and the size of the grains was limited to ∼10 nm by carbon doping. The formation of the C cluster upon crystallization was found at the grain boundaries, which was accelerated as the temperature increased due to the break of the Sb–C bonds. The memory device based on the carbon-doped Sb2Te3 material exhibited a switching speed of 15 ns and an endurance of ∼105 cycles with a resistance ratio of more than two orders of magnitude. This work suggests that the carbon-doped Sb2Te3 material is a promising candidate for memory applications that require high thermal stability, fast speed, and high endurance.

Evaluation of Energy Density in Hexadecane Phase Change Emulsions in Comparison to Water

The development of energy-dense, thermomechanically stable, and low-viscous phase change emulsions (PCMEs) is proposed as an alternative thermal energy storage solution for building air conditioning. A set of oil-in-water (O/W) nanoemulsions with hexadecane concentration varied between 10, 20, 25, 30, 35, and 40 wt. % is prepared and characterized with respect to their physical, thermal, and rheological properties. The storage characteristics are evaluated in terms of storage density, phase transition behaviour, supercooling, and dynamic viscosity. A systematic comparison in terms of energy density between the PCMEs and water is carried out at different temperature conditions. For this purpose, the storage break-even temperature TBE is proposed as a novel parameter to determine suitable operating temperature ranges and cycling conditions. The cycle stability is evaluated by rheological measurements, applying thermomechanical loads to the samples for a high number of cycles. According to the results, the energy density of the PCMEs is always higher than that of water, when the minimum temperature used for the cycling is below the storage break-even temperature. The emulsion with 30 wt. % hexadecane fraction is considered particularly promising, thanks to its high stability when exposed to thermomechanical stress, relatively low viscosity between 10 and 22 mPa s (0–30°C), and a storage density of 98 MJ/m3 within a cycling temperature range of 12 K.

Electron-electron scattering limits thermal conductivity of metals underextremely high electron temperatures.

We report on the thermal transport properties of noble metals (gold, silver and copper) under conditions
of extremely high electron temperatures (that are on the order of the Fermi energy). We perform parameterfree
density functional theory calculations of the electron temperature-dependent electron-phonon coupling,
electronic heat capacities, and thermal conductivities to elucidate the strong role played by the excitation of
the low lying d-bands on the transport properties of the noble metals. Our calculations show that, although
the three metals have similar electronic band structures, the changes in their electron-phonon coupling at
elevated electron temperatures are drastically different; while electron-phonon coupling decreases in gold,
it increases in copper and, it remains relatively unperturbed for silver with increasing electron temperatures
of up to ∼60,000 K (or 5 eV). We attribute this to the varying contributions from acoustic and longitudinal
phonon modes to the electron-phonon coupling in the three metals. Although their electron-phonon
coupling changes with electron temperature, the thermal conductivity trends with electron temperature are
similar for all three metals. For instance, the thermal conductivities for all three metals reach their maximum
values (on par with the room-temperature values of some of the most thermally conductive semiconductors)
at electron temperatures of ∼6,000 K, and thereafter monotonically decrease due to the enhanced effect of
electron-electron scattering for electronic states that are further away from the Fermi energy. As such, only
accounting for electron-phonon coupling and neglecting electron-electron scattering can lead to large overpredictions
of the thermal conductivities at extremely high electron temperatures. Our results shed light
on the microscopic understanding of the electronic scattering mechanisms and thermal transport in noble
metals under conditions of extremely high electron temperatures and, as such, are significant for a plethora
of applications such as in plasmonic devices that routinely leverage hot electron transport.

Experimental investigations of temperature-sensitive shape memory polymer composites for 4D printing

Shape memory polymers (SMPs) and their composites (SMPCs) have emerged as popular materials in a variety of industries due to their unique properties of shape-changing behavior in response to external stimuli. The inclusion of reinforcement may modify the SMPs to enhance their thermal and shape memory properties. Different types of bio ceramics have already been used to alter the thermal and shape memory behavior of SMPs. However, using bioactive glass (BG) as filler to modify these properties has not yet been explored. Despite the significant advantages that shape-memory polymers (SMPs) offer when combined with 3D/4D printing technology, their potential in 3D printing has been explored only to a limited extent. This work created a solvent-based 4D-printed temperature-sensitive shape memory polymer composites (SMPCs) system using polylactic acid (PLA) and bioactive glass (BG). The influence of BG on the thermal as well as shape-memory capabilities of composites was further examined. An increase in the degree of crystallinity and viscoelastic characteristics of PLA/BG composites led to improved shape memory properties, like shape fixity and shape recovery. These findings suggest the potential for using the developed SMPC printed through 4D printing technology, to develop complex shapes for self-foldable structures and smart biomedical devices in the future.

Aging-Induced Changes in Popping, Structural, Functional, Thermal, and Crystalline Properties of Roasted Makhana Seeds

Aging-Induced Changes in Popping, Structural, Functional, Thermal, and Crystalline Properties of Roasted Makhana Seeds

Synthesis, optical characterization and electrical behavior of chitosan/MgO/Cr2O3 nanocomposite for electrical applications

Magnesium oxide nanoparticles (MgO NPs) are straightforward, cheap, biocompatible, and biodegradable, making them one of the most popular inexpensive and non-toxic nanoparticles. In addition, Nanosized chromic oxide (Cr2O3) is a significant transition metal oxide due to its numerous exceptional attributes, it finds application in several domains. It has good electrical conductivity, excellent thermal and chemical stability. It is utilized in several industries for its ability to resist oxidation at high temperatures, as well as its application in refractory materials and catalysts. In this study, we utilized a laser ablation approach to synthesize a ternary nanocomposite composed of MgO and Cr2O3 nanoparticles as it is considered a clean method for the preparation of nanoparticles. Subsequently, these nanoparticles were integrated into Chitosan (CS) solution to create polymer nanocomposite via casting route. XRD confirmed the formation of Cr2O3 nanocrystals with size of 61 nm dispersed in chitosan/MgO matrix. FTIR verified the interactions between chitosan, MgO, and Cr2O3 nanoparticles. The broadening and shifting of the OH and NH bands with increasing Cr2O3 content confirms the interaction and complexation between Cr2O3 and Chitosan/MgO. UV–Vis analysis revealed that incorporating 7 wt% Cr2O3 reduced optical band gap from 5.59 eV for chitosan to 3.91 eV. The band gap values decreased with increasing Cr2O3 content due to polaronic defects. TGA showed improved thermal stability, with the 7 wt% Cr2O3 nanocomposite exhibiting a residual mass of 47 % at 700 °C compared to 28 % for chitosan. Dielectric studies demonstrated high dielectric constant and conductivity (10−5 S/cm at 10 Hz) values for the 7 wt% Cr2O3 nanocomposite, attributed to interfacial polarization effects and nanocapacitor formation by the conductive nanofillers. The ternary chitosan/MgO/Cr2O3 nanocomposites with tunable optical, thermal and electrical properties show promising potential for electronic applications.

Performance of bioresorbable peptide incorporated polymers produced for fused deposition modelling (FDM)

The use of biomaterials in additive manufacturing (AM) of medical devices has gained significant attention over the years, especially in areas such as wound care and orthopedics. This study aims to investigate the performance of bioresorbable peptide-incorporated polymers produced for fused deposition modelling (FDM) process. Herein, we report FDM 3D Printing process of bioactive polymers comprising polycaprolactone (PCL), poly(lactic-co-glycolic acid) (PLGA) or polylactic acid (PLA) or blended with peptide–containing brush copolymers bearing similar synthetic polymer side chains. Mechanical, thermal and rheological properties of the materials were carried out and we report that the incorporation of bioactive polymers into these biodegradable polymers does not result in significant changes to glass transition temperature, melt temperature, tensile properties of the base polymers. However, it was observed that flexural and rheological properties altered significantly. This study provides an insight into the thermomechanical performance of bioresorbable peptide-incorporated polymers for FDM utilization which allows for their use potential in medical device fabrication.