Showing papers on "Differential scanning calorimetry published in 2022"

Cardanol-Derived Epoxy Resins as Biobased Gel Polymer Electrolytes for Potassium-Ion Conduction

Abstract: In this study, biobased gel polymer electrolyte (GPE) membranes were developed via the esterification reaction of a cardanol-based epoxy resin with glutaric anhydride, succinic anhydride, and hexahydro-4-methylphthalic anhydride. Nonisothermal differential scanning calorimetry was used to assess the optimal curing time and temperature of the formulations, evidencing a process activation energy of ∼65–70 kJ mol–1. A rubbery plateau modulus of 0.65–0.78 MPa and a crosslinking density of 2 × 10–4 mol cm–3 were found through dynamic mechanical analysis. Based on these characteristics, such biobased membranes were tested for applicability as GPEs for potassium-ion batteries (KIBs), showing an excellent electrochemical stability toward potassium metal in the −0.2–5 V voltage range and suitable ionic conductivity (10–3 S cm–1) at room temperature. This study demonstrates the practical viability of these biobased materials as efficient GPEs for the fabrication of KIBs, paving the path to increased sustainability in the field of next-generation battery technologies.

Formaldehyde-Free Synthesis of Fully Bio-Based Multifunctional Bisbenzoxazine Resins from Natural Renewable Starting Materials

Abstract: Although bio-based benzoxazines (BZs) have been explored widely as sustainable thermosetting resins, few high-performance BZs have been prepared completely from natural renewable resources. In this study we synthesized a fully bio-based multifunctional bisbenzoxazine (AP-fa-BZ) in high yield and purity from apigenin (AP), furfurylamine (fa), and benzaldehyde by using both solvent and solventless approaches. Fourier transform infrared (FTIR) spectroscopy, high-resolution mass spectrometry, and one- and two-dimensional nuclear magnetic resonance spectroscopy confirmed the chemical structure of AP-fa-BZ. We then used dynamic mechanical analysis, differential scanning calorimetry (DSC), thermogravimetric analysis, and in situ FTIR spectroscopy to examine the thermal characteristics of AP-fa-BZ before and after its ring-opening polymerization (ROP). DSC revealed that the temperature required for the formation of poly(AP-fa-BZ) through ROP (236.3 °C) was significantly lower than that of a typical 4-phenyl-3,4-dihydro-2H-1,3-benzoxazine (Pa-type) monomer due to the positive catalytic effect of the phenolic OH groups in the AP structure. After thermal polymerization at 250 °C, the resulting poly(AP-fa-BZ) possessed a high thermal decomposition temperature (Td10 = 395 °C), a high char yield (52 wt %), and a high glass transition temperature (Tg = 283 °C). Contact angle measurements revealed the tunable surface properties of AP-fa-BZ. Finally, the AP-fa-BZ resin functioned as an antibacterial agent against both Staphylococcus aureus and Escherichia coli.

Exploring the physical properties of PVA/PEG polymeric material upon doping with nano gadolinium oxide

Abstract: Nano gadolinium oxide doped polyvinyl alcohol/polyethylene glycol blend (PVA/PEG) was prepared by sol–gel and casting methods. Rietveld refinement method was used for structural and microstructural investigation. The X-ray diffraction (XRD), scanning electron microscope (SEM) and Fourier transform infrared (FTIR) techniques were applied to study the formation of nano Gd2O3 doped PVA/PEG-blend. Differential scanning calorimetry technique (DSC) was utilized to investigate the glass transition, the melting and degradation temperatures of undoped and doped PVA/PEG blends. The melting temperature was increased slightly while the degradation temperature was reduced upon doping with nano Gd2O3. The behavior of the absorbance and other different optical parameters were studied in detail using UV-spectrophotometer. A variation in the optical bandgap of the PVA/PEG blend was observed while the values of refractive index and extinction coefficient were enhanced as the amount of Gd2O3 increased in the blend. The influence of nano Gd2O3 doping on the different dispersion parameters was examined using Wemple and DiDomenico approximation model. The nature of electronic transitions of different samples was examined by comparing the optical band gap obtained from Tauc’s relation and dielectric loss parameter.

Biodegradable Films of PLA/PPC and Curcumin as Packaging Materials and Smart Indicators of Food Spoilage

Abstract: Bio-based and biodegradable packaging combined with chemical sensors and indicators has attracted great attention as they can provide protection combined with information on the actual freshness of foodstuffs. In this study, we present an effective, biodegradable, mostly bio-sourced material ideal for sustainable packaging that can also be used as a smart indicator of ammonia (NH3) vapor and food spoilage. The developed material comprises a blend of poly(lactic acid) (PLA) and poly(propylene carbonate) (PPC) loaded with curcumin (CCM), which is fabricated via the scalable techniques of melt extrusion and compression molding. Due to the structural similarity of PLA and PPC, they exhibited good compatibility and formed hydrogen bonds within their blends, as proven by Fourier transform infrared (FTIR) and X-ray diffraction (XRD). Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) analysis confirmed that the blends were thermally stable at the used processing temperature (180 °C) with minimal crystallinity. The rheological and mechanical properties of the PLA/PPC blends were easily tuned by changing the ratio of the biopolymers. Supplementing the PLA/PCC samples with CCM resulted in efficient absorption of UV radiation, yet the transparency of the films was preserved (T700 ∼ 68–84%). The investigation of CCM extract in ethanol with the DPPH• assay demonstrated that the samples could also provide effective antioxidant action, due to the tunable release of the CCM. Analyses for water vapor and oxygen permeability showed that the PPC improved the barrier properties of the PLA/PPC blends, while the presence of CCM did not hinder barrier performance. The capacity for real-time detection of NH3 vapor was quantified using the CIELab color space analysis. A change in color of the sample from a yellowish shade to red was observed by the naked eye. Finally, a film of PLA/PPC/CCM was successfully applied as a sticker indicator to monitor the spoilage of shrimps over time, demonstrating an evident color change from yellow to light orange, particularly for the PPC-containing blend. The developed system, therefore, has the potential to serve as a cost-effective, easy-to-use, nondestructive, smart indicator for food packaging, as well as a means for NH3 gas monitoring in industrial and environmental applications.

Thermal conductivity, reliability, and stability assessment of phase change material (PCM) doped with functionalized multi-wall carbon nanotubes (FMWCNTs)

Abstract: The thermal properties of Phase Change Material (PCM) can be altered by introducing nanoparticles, and composite formed from the addition of nanoparticles are termed Nano-Enhanced Phase Change Materials (NEPCM). In the present study, the enhancement of thermal conductivity and feasibility study of dispersing multi-walled carbon nano tubes (MWCNTs) and functionalized MWCNT (FMWCNTs) in various mass fractions (AFMW-0.1, AFMW-0.3, AFMW-0.5, AFMW-0.7, AFMW-1.0) into the Plusice A70 PCM were examined. Differential scanning calorimetry (DSC) and TEMPOS thermal analyzer measured the latent heat storage, melting temperature, and thermal conductivity of the nano PCM composite. The thermal conductivity measured for the prepared nanocomposite showed a 109.5% enhancement for 1.0 wt% of non-functionalized MWCNT and 150.7% enhancement for 1.0 wt% of functionalized MWCNT compared to pristine PCM's thermal conductivity. This statement concluded that 50% enhancement for a 1.0 wt% of functionalized MWCNT compared to non-functionalize MWCNT immersed in A70 PCM. The nano composite PCM was thermally stable up to 200 °C and no chemical reaction takes place between the base PCM and nanoparticles. The result shows that the microscopic structure remained stable for the nanocomposite while the optical transmittance reduced noticeably for the nanocomposite relative to pristine A70 PCM. It can be concluded, the prepared nano composite PCM may be useful for solar thermal, photovoltaic thermal system, and low concentrated photovoltaic thermal system applications. • Preparation of functionalized MWCNTs • Comparative study between base, non-functionalized, functionalized NEPCM • Thermal conductivity enhancement of 150.7% • Thermal reliability and chemical stability up to 500 thermal cycles

Dendrite‐accelerated thermal runaway mechanisms of lithium metal pouch batteries

Abstract: High‐energy‐density lithium metal batteries (LMBs) are widely accepted as promising next‐generation energy storage systems. However, the safety features of practical LMBs are rarely explored quantitatively. Herein, the thermal runaway behaviors of a 3.26 Ah (343 Wh kg−1) Li | LiNi0.5Co0.2Mn0.3O2 pouch cell in the whole life cycle are quantitatively investigated by extended volume‐accelerating rate calorimetry and differential scanning calorimetry. By thermal failure analyses on pristine cell with fresh Li metal, activated cell with once plated dendrites, and 20‐cycled cell with large quantities of dendrites and dead Li, dendrite‐accelerated thermal runaway mechanisms including reaction sequence and heat release contribution are reached. Suppressing dendrite growth and reducing the reactivity between Li metal anode and electrolyte at high temperature are effective strategies to enhance the safety performance of LMBs. These findings can largely enhance the understanding on the thermal runaway behaviors of Li metal pouch cells in practical working conditions.

An Insight into the Gelatinization Properties Influencing the Modified Starches Used in Food Industry: A review

Abstract: Abstract Native starch is subjected to various forms of modification to improve its structural, mechanical, and thermal properties for wider applications in the food industry. Physical, chemical, and dual modifications have a substantial effect on the gelatinization properties of starch. Consequently, this review explores and compares the different methods of starch modification applicable in the food industry and their effect on the gelatinization properties such as onset temperature ( T o ), peak gelatinization temperature ( T p ), end set temperature ( T c ), and gelatinization enthalpy (Δ H ), studied using differential scanning calorimetry (DSC). Chemical modifications including acetylation and acid hydrolysis decrease the gelatinization temperature of starch whereas cross-linking and oxidation result in increased gelatinization temperatures. Common physical modifications such as heat moisture treatment and annealing also increase the gelatinization temperature. The gelatinization properties of modified starch can be applied for the improvement of food products such as ready-to-eat, easily heated or frozen food, or food products with longer shelf life.

Novel Copper-Zinc-Manganese Ternary Metal Oxide Nanocomposite as Heterogeneous Catalyst for Glucose Sensor and Antibacterial Activity

Abstract: A novel copper-zinc-manganese trimetal oxide nanocomposite was synthesized by the simple co-precipitation method for sensing glucose and methylene blue degradation. The absorption maximum was found by ultraviolet–visible spectroscopy (UV-Vis) analysis, and the bandgap was 4.32 eV. The formation of a bond between metal and oxygen was confirmed by Fourier Transform Infrared Spectroscopy (FT-IR) analysis. The average crystallite size was calculated as 17.31 nm by X-ray powder diffraction (XRD) analysis. The morphology was observed as spherical by scanning electron microscope (SEM) and high-resolution transmission electron microscopy (HR-TEM) analysis. The elemental composition was determined by Energy Dispersive X-ray Analysis (EDAX) analysis. The oxidation state of the metals present in the nanocomposites was confirmed by the X-ray photoelectron spectroscopy (XPS) analysis. The hydrodynamic diameter and zeta potential of the nanocomposite were 218 nm and −46.8 eV, respectively. The thermal stability of the nanocomposite was analyzed by thermogravimetry-differential scanning calorimetry (TG-DSC) analysis. The synthesized nanocomposite was evaluated for the electrochemical glucose sensor. The nanocomposite shows 87.47% of degradation ability against methylene blue dye at a 50 µM concentration. The trimetal oxide nanocomposite shows potent activity against Escherichia coli. In addition to that, the prepared nanocomposite shows strong antioxidant application where scavenging activity was observed to be 76.58 ± 0.30, 76.89 ± 0.44, 81.41 ± 30, 82.58 ± 0.32, and 84.36 ± 0.09 % at 31, 62, 125, 250, and 500 µg/mL, respectively. The results confirm the antioxidant potency of nanoparticles (NPs) was concentration dependent.

Cellulose nanofiber grafting and aluminum nitride deposition on the surface of expanded graphite to improve the thermal conductivity and mechanical properties of phase change material composites

Abstract: Phase change material (PCM) composites have attracted much attention as thermal energy storage devices for thermal management because of their high latent heat. However, the intrinsically low thermal conductivity of PCMs hinders the efficient thermal management of these devices. In this study, novel cellulose nanofibers (CNFs) grafting onto an expanded graphite (EG) and aluminum nitride (AlN) covering were carried out to prepare novel thermally conductive PCM composites, analyzed in detail using Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), Raman spectra, X-ray diffraction (XRD) patterns, field-emission scanning electron microscopy (FE–SEM), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The composites exhibited ultra-high through-plane thermal conductivity of 3.39 W/mK and latent heat of 136 J/g, and the tensile strength increased by 402% compared with pure erythritol. The resulting erythritol/EG–CNF/AlN composites enable efficient thermal management because they save and dissipate heat due to the high latent heat and thermal conductivity. Moreover, the composite was insulated by nano-size AlN covered on the surface and pores of the EG structure. The proposed PCM composites are promising candidates for developing superior thermally conductive PCM composites and advanced electronic packaging.

Cellulose nanofiber grafting and aluminum nitride deposition on the surface of expanded graphite to improve the thermal conductivity and mechanical properties of phase change material composites

Abstract: Phase change material (PCM) composites have attracted much attention as thermal energy storage devices for thermal management because of their high latent heat. However, the intrinsically low thermal conductivity of PCMs hinders the efficient thermal management of these devices. In this study, novel cellulose nanofibers (CNFs) grafting onto an expanded graphite (EG) and aluminum nitride (AlN) covering were carried out to prepare novel thermally conductive PCM composites, analyzed in detail using Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), Raman spectra, X-ray diffraction (XRD) patterns, field-emission scanning electron microscopy (FE–SEM), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The composites exhibited ultra-high through-plane thermal conductivity of 3.39 W/mK and latent heat of 136 J/g, and the tensile strength increased by 402% compared with pure erythritol. The resulting erythritol/EG–CNF/AlN composites enable efficient thermal management because they save and dissipate heat due to the high latent heat and thermal conductivity. Moreover, the composite was insulated by nano-size AlN covered on the surface and pores of the EG structure. The proposed PCM composites are promising candidates for developing superior thermally conductive PCM composites and advanced electronic packaging.

Thermal hazards analysis for benzoyl peroxide in the presence of hexanoic acid

Abstract: Benzoyl peroxide (BPO) is a common cross-linking agent and initiator that is widely used in the chemical industry. The instability of a substance may be influenced by the presence of impurities; therefore, the thermal hazard of organic peroxides under contamination has always been a topic of interest. In this study, the effects of hexanoic acid (HAA) on the thermal decomposition of BPO were investigated using differential scanning calorimetry (DSC; 2.0, 4.0, 6.0, 8.0, and 10.0 °C/min) experiments. By using the Kissinger-Akahira-Sunose and Flynn-Wall-Ozawa kinetic models, the progress of the obtained DSC curve was fitted linearly, and the thermokinetic parameters of BPO in the presence of HAA were further calculated. The two apparent activation energy calculations consistently indicated that HAA increased the thermal hazard of BPO. In addition, the Coats-Redfern model was adopted to compute the decomposition mechanism function of each phase of the material, and Gaussian 16 was used to determine the atomic bonding levels between the molecules to discover the thermal decomposition reaction path of BPO under the effect of HAA. The study results can be used as a reference for the loss prevention and control of BPO in practical engineering applications.