Thermal Stability Properties Research Articles

Development of an eco-friendly geopolymer mortar using slag and fly ash with high bentonite content for thermal and environmental applications

The construction industry is exploring the use of low-cost waste materials to create eco-friendly geopolymer mortar binders. Our study aims to develop various environmentally friendly geopolymer mortar mixes for thermal and adsorption applications using natural materials like bentonite and industrial by-products such as ground-granulated blast furnace slag and fly ash. Ternary geopolymer mortar pastes are prepared using equimolar amounts of slag (GBFS) and fly ash (FA), with 6%, 8%, 10%, and 12% weight of bentonite (BC) from the total geopolymer weight to study the bentonite replacement effect. The prepared mortar are tested for their physico-chemical, mechanical, adsorption, and thermal stability properties (300 °C to 900 °C). The adsorption behavior of eco-friendly geopolymer mortar mixes against crystal violet dye in aqueous solutions is also identified. The study found that adding 6% bentonite to the slag/fly ash-based geopolymer mortar mix yielded the highest mechanical characteristics. Moreover, all the ternary geopolymer mortar mixes exhibited excellent thermal stability up to 900 °C. In adsorption study, the results indicated that the mortar mixes had excellent capacities and adhered well to the Freundlich isotherm model, suggesting potential applications in treating wastewater. Using bentonite in slag/fly ash geopolymer mortar offers a sustainable, cost-effective, and heat-resistant alternative to traditional cement binders.

A novel phosphorus/boron-containing flame retardant for improving the flame retardancy of ramie fiber reinforced epoxy composites

As a kind of plant fiber, ramie fibers (RFs) are widely used in fiber reinforced resin matrix composites, however, both of RFs and resin matrix are flammable. Enhancing the flame retardancy of ramie fiber reinforced epoxy composites is important. In this study, a highly efficient flame retardant, PBXY, was synthesized from phytic acid, boric acid, and xylitol to improve the flame retardancy of ramie fibers, and flame-retardant ramie fiber reinforced epoxy composites (EP/RF-PBXYs) with different weight gain were prepared by coating PBXY on the surface of ramie fibers. The effects of different weight gain of PBXY on the thermal stability, flame retardancy, and mechanical properties of EP/RF-PBXYs were investigated. Compared with that of EP/RF, the limiting oxygen index value of EP/RF-PBXY2 was increased from 23.0% to 31.4% and a UL-94 V-0 rating was obtained, the total heat release and total smoke production were reduced by 33.2% and 31.0%. However, the presence of PBXY had a negative effect on the mechanical properties of EP/RF when the weight gain of PBXY was more than 10wt% (related to RFs). This study offers a promising avenue to improve the flame-retardant resistance of EP/RF.

Flexible and lightweight carbon fiber/silicone resin composites with the “soft-rigid” structural interface for thermostable and antistatic applications

To avoid a large difference in modulus between carbon fiber (CF) and silicone resin (SR) and unstable thermal properties, the “soft-rigid” structural interface is constructed by coating polydopamine-polyethyleneimine@octaphenyl-silsesquioxane (PDA-PEI@octaphenyl-POSS) on the fiber surface. The tensile strength of the CF-AE@3P/SR composite was 24.35 % higher than that of the unmodified CF/SR. The mechanism of mechanical enhancement revealed that the rigid layer with nanoparticles effectively deflected the crack and prolonged the path, and the hydrogen bonds and van der Waals forces helped disperse the stress concentration at the interface. The defects in the soft–rigid structural interface were reduced, and the decomposition of the fibers and composites was effectively inhibited, thereby increasing the heat transmission in the composites. After heating for 20 s on the heating plate at 200 °C, the surface temperature of the CF-AE@3P/SR composite was 155.4 °C, which is higher than that of the unmodified CF/SR (131.4 °C). Therefore, the thermal stability of the CF-AE@3P/SR composites was significantly improved compared to that of unmodified CF/SR after holding at 350 °C for 3 h. Surface resistance analysis showed that the soft–rigid modification maintained the antistatic properties of the composites at room and high temperatures. It was also found that the CF-AE@P/SR composites exhibited good flexibility, lightweight, and hardness for application in sealing and electronic components. This work provides ideas for forming a seamless transition and effective bonding between high-modulus carbon fibers and a low-modulus elastomer matrix, increasing the thermal stability and mechanical properties, and maintaining the flexibility, stiffness, lightweight, and antistatic properties of composites at high temperatures

Influence of P and C co-alloying on soft magnetic properties and crystallization behavior of FeSiBPCCu nanocrystalline alloys

In this study, multicomponent synergistic effects were adopted to enhance the glass-forming ability (GFA), processing window (PW), thermal stability, and soft magnetic properties (SMPs) of FeCuSiB nanocrystalline alloys (NAs) with high Fe and Cu contents via P and C co-alloying. The co-addition of P and C is beneficial for enhancing the GFA, expanding the PW, and increasing the crystallization resistance of the compound phases in present FeCuSiBPC alloys. Consequently, the Fe81.5Cu1.7Si3.8B9P3C1 alloy exhibited a large optimum TA window of up to 100 °C and a large tA window of 40 min for nanocrystallization. Crystallization kinetic analysis showed that the co-addition of P and C led to a high-frequency factor (v) in the precipitation of α-Fe crystals, which was related to the high nanocrystal density (Nd) of α-Fe. This result may be attributed to the nucleation of α-Fe by Cu and CuP clusters. Additionally, the co-addition of P and C increased the growth active energy (Ep) of the α-Fe crystals because of their larger atomic diffusion resistance. The high Nd and Ep values led to the formation of fine nanostructures and excellent SMPs in FeCuSiBPC alloys. Therefore, the Fe81.5Cu1.7Si3.8B9P3C1 NA obtained by annealing at 420 °C for 30 min exhibited excellent SMPs with a Bs of up to 1.78 T, a low Hc of 7.5 A/m, and a high μe of 9863 (@1kHz). This study provides technical and theoretical guidance for optimizing the composition and processability of NAs with high Fe and Cu contents, paving the way for mass production of high-performance soft magnetic NAs.

Fast production of highly sensitive nanotextured nonwovens for detection of volatile amines, bacterial growth, and pH monitoring

An efficient manufacturing of colorimetric nonwoven indicators represents a promising alternative to enable applications of such materials in food quality monitoring. The objective of this study is to use the solution blow spinning technique (SBS) to rapidly produce colorimetric nonwoven indicators based on polycaprolactone, incorporating natural or synthetic pH indicators to detect volatile amines, bacterial growth and monitor pH. Produced via the SBS method, these indicators were characterized aiming their physical, mechanical, thermal, and spectroscopic properties, evaluating their efficacy in detecting amines, monitoring bacterial growth, and pH, as well as assessing color stability during storage. The thermal stability and mechanical properties of the nonwovens practically always increased with the incorporation of natural and synthetic indicators. When exposed to volatile amines, the nonwoven indicators, particularly those embedded with bromophenol blue, displayed remarkable color change abilities in the presence of five volatile amines. These smart nonwovens in direct contact with E. coli K-12 or its volatiles in 24 h changed their color perceptible to the naked eye. The nanofiber nonwovens displayed visible color changes (ΔE ≥ 3) in response to buffer solutions (pH between 3 and 10). The smart nonwovens rapidly produced by the solution blow spinning method prove to be a promising tool for real-time monitoring of food freshness.

The Flammability and Thermal Stability of Filling Epoxy Foam Plastics for Construction Purposes

An effective type of polymer heat-insulating material (foams) based on reactive oligomers is casting epoxy foams with high technological and operational parameters. However, polyepoxide foams are highly flammable, which significantly restrains their application in the construction industry. The aim of this work was to develop effective methods for reducing the flammability of filling epoxy foams. In order to achieve the objective, the following objectives were addressed: determining the influence of the chemical nature and content of additive and reactive bromine- and phosphorus-containing compounds on the thermal stability, flammability and operational properties of filling epoxy foams, and the development of polyepoxy foams of reduced flammability with high-quality physical and mechanical characteristics. When estimating the flammability of epoxy foams, we used both state-approved methods and the methods described in scientific and technical literature. The thermal properties of epoxy foams were studied with the help of multimodular thermoanalytical complex DuPont-9900. The data on the influence of the apparent density of foams and oxygen concentration in the oxidant flow on the flame propagation speed on the horizontal surface of polyepoxy foams are presented. It was revealed that the chemical nature of amine hardeners does not affect the thermal stability and flammability of epoxy foams. It was established that phosphate plasticizers are ineffective flame retardants of foamed epoxy resin, and the chemical structure of additive organobromic flame retardants insignificantly affects their efficiency. It was shown that microencapsulated flame retardants are inferior in flame retardant efficiency to additive flame retardants. It was found that effective flame retardants for casting polyepoxy foams are phosphorus-containing oligoether methacrylate and epoxidized waste from the production of tetrabromodiphenylpropane. The results of this research will form the basis for the production of an experimental industrial batch of samples of pouring epoxy foams of reduced flammability.

Effects of Kimchi-Derived Lactic Acid Bacteria on Reducing Biological Hazards in Kimchi.

This study was performed to investigate the use of plant-based lactic acid bacteria (LAB) to reduce microbiological hazards in kimchi. Cell-free supernatants (CFS) from four LAB strains isolated from kimchi were tested for antimicrobial activity against five foodborne pathogens and two soft-rot pathogens. Each CFS showed antimicrobial activity against both foodborne and soft-rot pathogens. Washing salted kimchi cabbages inoculated with B. cereus with 5% CFS inhibited B. cereus to a greater extent than NaClO. The CFS from WiKim 83 and WiKim 87 exhibits inhibition rates of 25.09% and 24.21%, respectively, compared to the 19.19% rate of NaClO. Additionally, the CFS from WiKim 116 and WiKim 117 showed inhibition rates of 18.74% and 20.03%, respectively. Direct treatment of kimchi cabbage with soft-rot pathogens and CFS for five days inhibited the pathogens with similar efficacy to that of NaClO. To elucidate the antimicrobial activity mechanisms, pH neutralization, heat treatment, and organic acid analyses were performed. pH neutralization reduced the antimicrobial activity, whereas heat treatment did not, indicating that lactic, acetic, citric, and phenyllactic acids contribute to the thermal stability and antimicrobial properties of CFS. This study suggests that the four kimchi-derived LAB, which maintain a low pH through organic acid production, could be viable food preservatives capable of reducing biological hazards in kimchi.

Electricallymodified bacterial cellulose tailored with plant based green materials for infected wound healing applications

Effective treatment of infected wounds remains a challenge due to the rise of antibiotic-resistant microorganisms. The development of advanced materials with strong antimicrobial properties is necessary to address this issue. In this study, a unique composite of electrically modified bacterial cellulose (EBC) with allantoin (ABC) and zein was developed by dipping diffusion method. Morphological structural analysis revealed a uniform distribution of zein and aligned fibers, confirming the synthesis of the ABC-Zein composite. The formation of ABC-Zein was further confirmed by attenuated total reflection-Fourier transform infrared (ATR-FTIR), which displayed additional peaks corresponding to EBC, indicating the incorporation of zein into ABC. X-ray diffraction (XRD) analysis of ABC-Zein demonstrated a similar crystalline structure with EBC. The ABC-Zein showed mechanical integrity (tensile strength: 1.15 ± 0.21 MPa), thermal stability (degradation temperature: 290 °C), porous structure (porosity: 40.23 ± 0.21 %), and hydrophilic (water contact angle: 53.3 ± 5.3°) properties. Furthermore, the antimicrobial agent terpinen-4-ol (T4O), derived from tea tree oil, was incorporated into the ABC-Zein composite. Biological studies confirmed the antimicrobial efficacy (Staphylococcus aureus inhibition: 88.5 ± 7.19 %) and biocompatible (cell viability: 84.95 ± 5.6 %, hemolysis: 4.479 ± 0.39 %) nature of the T4O-ABC-Zein composite. The combined effects of the aligned fiber structure, zein protein, and antimicrobial T4O significantly enhanced infected wound healing by day 7, promoting inflammatory response, granular tissue formation, cell proliferation, and angiogenesis. By day 14, T4O-ABC-Zein facilitated complete wound healing, with reepithelization, collagen I deposition, and downregulation of CD 31, Ki67, and α-SMA. Overall, the innovative T4O-ABC-Zein composite, with an aligned fiber structure, improved biocompatibility, and antimicrobial properties, holds significant potential for the treatment of infected wounds.

Al-Doped ZnO/SiO2 Nano-glass Ceramic System: A New Composite System for Improvement in Thermal Stability and Mechanical Properties of Dental Resins

AbstractThis study aims to enhance dental resins' mechanical and thermal properties by reinforcing them with Al-doped ZnO/SiO2 nano-glass ceramic. The synthesis of the nano-glass ceramic involved the addition of Al-doped ZnO nano-powders to a diluted aqueous solution of liquid glass (25 mL) in ethanol (50 mL) at room temperature. The synthesized samples were characterized using TEM, EDS, FE-SEM, and XRD techniques. Various concentrations of the nano-glass ceramic (2, 5, 8, 10, and 15 wt.%) were then integrated with Bis-GMA and TEGDMA. The mechanical properties, including flexural strength (FS), compressive strength (CS), diameter tensile strength (DTS), and flexural modulus (FM), were evaluated. Thermal stability was assessed through TGA analysis, which indicated polymer degradation occurring between 300 and 450 °C. An increase in filler content correlated with enhanced thermal stability. The optimal mechanical properties were observed at a 7.5 wt.% filler content, showing significant improvements in FS (124.652 MPa), FM (9.87GPa), DTS (33.87 MPa), and CS (178.47 MPa).

Synthesis of a gallic acid-based self-healing waterborne polyurethane with a thermo-responsive dynamic phenol-carbamate network for enhanced mechanical strength, antimicrobial activity, and shape memory properties

To expedite the advancement of multifunctional next-generation smart materials, it is imperative to create polymers derived from renewable, green bio-based resources. This paper presents a direct synthesis of thermo-responsive aqueous polyurethanes by combining gallic acid (GA) with isocyanate groups to form a dynamic phenol-carbamate crosslinked network and the incorporation of the metal-organic framework Cu-MOF-2 for synergistic effects. The resulting GA-based polyurethane (MOF-GWPU) exhibits excellent thermal stability and mechanical properties, achieving an ideal balance between mechanical strength and self-healing efficiency. The MOF-GWPU film demonstrates strong antimicrobial efficacy against Escherichia coli and Staphylococcus aureus, highlighting its exceptional antibacterial performance. The thermo-responsive dynamic covalent bonds enable the MOF-GWPU film to rapidly revert from a temporary shape back to its original form. Post-processing experiments further indicate that the crosslinked GA-PU polymer can be efficiently recycled through solution casting and hot-pressing techniques. This design offers a novel approach and valuable insights for advancing the development of multifunctional smart polymers derived from bio-based resources.

Passivator materials based on the benzothiazole-sulfonamide hybrid: Synthesis, optical, electrochemical properties, and molecular modeling for perovskite solar cells

This study presents the synthesis of N-(4-(N-carbamimidoylsulfamoyl)phenyl)benzo[d]thiazole-2-carbohydrazonoyl cyanide (NCSBC), a novel passivator material for perovskite solar cells (PSCs). The structure was confirmed by FTIR, ¹H NMR, and ¹³C NMR, while Hall-effect measurements revealed a hole mobility of 1.15 × 10³ cm²/Vs. UV–Vis analysis showed absorption peaks at 295 and 422 nm, corresponding to transitions related to azo groups and aromatic rings in NCSBC. The compound exhibited an optical energy gap of 2.47 eV, consistent with DFT-based molecular modeling. Thermal stability and electrochemical properties further validated its suitability for photovoltaic applications. Incorporating NCSBC into PSCs with an FTO/c-TiO2/MAPbI3/NCSBC/spiroMeOTAD/Ag device configuration resulted in a power conversion efficiency (PCE) of 16.21 %, compared to 14.47 % for the control. This work highlights NCSBC's potential for cost-effective, high-efficiency defect passivation in PSCs.

Exfoliation of boron nitride nanosheets by liquid phase method based on deep eutectic solvents and their thermal management application

AbstractBoron nitride had emerged as an innovative thermally conductive filler, garnering increasing attention from researchers. However, there was a need to create new methods for efficiently producing functionalized boron nitride nanosheets with enhanced thermal conductivity and dispersion. In this study, a novel approach was introduced to utilize deep eutectic solvents as additives to facilitate the exfoliation of boron nitride nanosheets. This method offered significant advantages in terms of cost‐effectiveness (low additives level) and high yield (about 60%). Furthermore, the resulting epoxy resin composite material exhibited outstanding thermal conductivity and thermal management properties. The thermal conductivity of EP/d‐BNNS composites reached 1.02 W/mK at 20 wt% d‐BNNS loading. Additionally, the composite material demonstrated good thermal stability and low dielectric properties. This work demonstrated that this proposed approach represents an effective means for the scalable production of boron nitride nanosheets.Highlights The boron nitride nanosheets were obtained by deep eutectic solvents (DES) ball milling method. The exfoliated boron nitride exhibits superior dispersion stability. The thermal conductivity of EP composites is significantly improved.

Effect of radiation-induced graft polymerization onto pineapple nonwoven fabric reinforced polymer composite

Natural fiber-reinforced polymer composites are gaining attention for their environmental benefits, such as biodegradability and reduced carbon footprint, as well as the potential of the natural fibers to replace or partially substitute synthetic fibers in various applications. However, challenges, such as poor interfacial adhesion and moisture absorption, limit the effectiveness of natural fibers, such as pineapple nonwoven fabric (PNWF) as reinforcement materials in polymer composites. To address these challenges, this study aims to enhance the properties of PNWF through glycidyl methacrylate grafting via radiation-induced graft polymerization. A 22 factorial design was employed to assess the effects of absorbed dosage and monomer concentration on the properties of the grafted PNWF. Infrared spectroscopy and electron microscopy analyses confirmed successful grafting. The grafted PNWF exhibited improved thermal stability and mechanical properties. The resulting composites showed significant enhancements in tensile and flexural strength, specifically, with tensile strength increase ranging from 23.32 to 34.49 MPa and flexural strength from 39.14 to 54.59 MPa. Additionally, the tensile modulus ranged from 0.77 to 1.29 GPa, while the flexural modulus varied from 1.17 to 2.06 GPa. These findings highlight the potential of PNWF grafted with polyglycidyl methacrylate (PNWF-g-PGMA) as an effective reinforcement material for various applications.

Flexible and antistatic carbon fiber/silicone rubber composite coating with improved thermal stability, mechanical and wave-transmission properties

The properties of the interface have a significant impact on the application of silicone rubber (SR) composite coating fillers with carbon fiber (CF). The one-step growth of silica nanoparticles on the fiber surface was investigated in terms of the mechanical, electrical, and thermal properties of the CF/SR composite coatings. The results showed that the tensile strength and elongation of the composite with modified fibers were 7.13 ± 0.44 MPa and 690.40 ± 37.04 %, which were 20.44 % and 23.22 % higher than those with unmodified CFs, respectively. The improvement in interfacial adhesion by silica modification effectively disperses stress and avoids stress concentration. Additionally, the introduction of the low-dielectric material SiO2 and the reduction of the interfacial polarization enhanced the wave-transmission properties and weakened the electromagnetic wave-shielding properties of the composites. Meanwhile, the silica modification maintained the antistatic properties of the coatings at room and high temperatures, as well as before and after bending. The weight loss of the composites with modified fibers was lower than that of the composites with unmodified fibers, while the thermal conductivity was higher because of the stable structure of the Si-O-Si bonds and interfacial adhesion. This work provides a simple way to enhance the thermal resistance, thermal conductivity, mechanical and wave-transmission properties, and preserve the antistatic properties as well as the flexibility of CF/SR composite coatings.

Recycled polypropylene/crystalline cellulose composites obtained using polypropylene functionalized with maleinized hyperbranched polyol polyester as compatibilizing and plasticizing agent

AbstractRecycled polypropylene (rPP)/crystalline cellulose (rPP/CC) composites are promising alternatives for reducing the detrimental environmental consequences of virgin PP. However, the incompatibility of the rPP/CC composites hinders their widespread application. In this study, PP functionalized with maleinized hyperbranched polyol polyester (PP‐g‐MHBP) was used as a compatibilizing and plasticizing agent for the rPP/CC composites. Furthermore, the effect of PP‐g‐MHBP content on the rheological, thermal, morphological, and mechanical properties of the rPP/CC composites was evaluated. The composites were prepared at a mixing speed of 50 rpm for 7 min and the PP‐g‐MHBP content was varied between 0 and 20 wt%. The torque stabilization time was less than 1 min. The activation energy of flow () decreased with increasing PP‐g‐MHBP content, with its values ranging from 0.78 × 102 to 1.42 × 102 kcal.mol−1. The flow index () followed the opposite trend with values ranging from 0.55 ± 0.0030 to 0.85 ± 0.0010. PP‐g‐MHBP enhanced the processability, thermal stability and conductivity. The crystallinity, interactions between rPP and CC, and tensile modulus of the rPP/CC composites were also enhanced. Furthermore, it reduced the agglomeration of CC particles.Highlights The torque stabilization was lowest for all composites. The composites displayed low activation energy of flow. Recycled polypropylene and crystalline cellulose exhibited good interaction. The plasticizing effect was higher than that of compatibilization. The thermal stability and mechanical properties of the composites improved.

Exploring Thermal Stability, Vibrational Properties, and Biological Assessments of Dichloro(l-histidine)copper(II): A Combined Theoretical and Experimental Study.

Dichloro(l-histidine)copper(II) crystal ([Cu(l-His)Cl2] complex) was obtained by the slow evaporation method and characterized concerning its thermal stability, phase transformations, and electronic and vibrational properties. X-ray diffraction (XRPD) confirmed that this complex crystallizes with an orthorhombic structure (P212121 space group). Thermal analyses (TG and DTA) demonstrate stability from ambient temperature up to 460 K, followed by a phase transition from the orthorhombic structure to the amorphous form around 465 K, as confirmed by temperature-dependent XRPD studies. The active modes in Fourier transform infrared (FT-IR) and Raman spectroscopy spectra were suitably assigned via density functional theory (DFT) calculations. Additionally, Hirshfeld surface analysis uncovered the prominence of Cl···H, O···H, and H···H interactions as the primary intermolecular forces within the crystal structure. The antimicrobial activity of the [Cu(l-His)Cl2] complex was investigated, demonstrating significant efficacy against Gram-positive bacteria (Staphylococcus aureus), Gram-negative bacteria (Pseudomonas aeruginosa), and fungi (Candida albicans). The minimum inhibitory concentration and cell viability tests showed that the complex inhibits the growth of S. aureus bacteria at a concentration of 1.5 μM without causing damage to the human cell line. The pharmacokinetic parameters corroborate the other tested parameters and highlight the [Cu(l-His)Cl2] complex as a promising alternative for future clinical trials and medicinal applications. The alignment of the pharmacokinetic parameters with other tested criteria highlights the potential of the [Cu(l-His)Cl2] complex as a promising candidate for future clinical studies.

Alicyclic Polyimide With Multiple Breakdown Self-Healing Based on Gas-Condensation Phase Validation for High Temperature Capacitive Energy Storage.

Polymer dielectrics with combined thermal stability and self-healing properties are specifically desired for high-temperature film capacitors. The high thermal stability of conventional polymers benefits from the abundance of aromatic rings in the molecule backbone, but the high carbon content sacrifices their self-healing properties. Here, analicyclic polyimide with a high glass transition temperature (256°C) and wide energy bandgap (4.58eV) is designed, which exhibits electric conductivity more than an order of magnitude lower than that of classical polyimide at high electric fields and high temperatures. As a result, alicyclic polyimide achieves a discharged energy density of 4.54 Jcm-3 and a charge-discharge efficiency of above 90% at 200°C, which is superior to existing dielectric polymers and composites. The alicyclic polyimide benefits from a low pyrolytic residual carbon rate, retaining 93% of the dielectric breakdown strength after four electrical breakdown cycles. Distinguishing from the current condensed-phase self-healing concept, for the first time, exploring the self-healing capability of high-temperature polyimide dielectric is presented based on dual self-healing mechanisms of gas-phase and condensed-phase. The high energy density at high temperatures and the superior self-healing capability of alicyclic polyimide further indicate the promise of polyimide dielectric film capacitors for extreme conditions.

Preparation and Characterization of Novel α-Naphthol Luminophors for Optoelectronic Devices.

Luminophors of α-Naphthol doped with varying concentrations of anthracene and perylene were prepared by conventional solid state reaction method to explore its fluorescence characteristics. The fluorescence spectra of bicomponent and tricomponent luminophors reveals the fluorescence excitation energy transfer (FRET) process. The prepared bi and tri component luminophors were excited at 290nm which corresponds to host excitation wavelength. The weak violet fluorescence of host, α-Naphthol, gets quenched and give anthracene like emission in bicomponent luminophor systems. Further doping with second host, perylene, in anthracene containing α-Naphthol luminophors, red shifted emission was observed at 605nm. The structural parameters, thermal stability and electrical properties of doped luminophors were studied by using X-ray diffraction, TGA-DSC and Cyclic Voltammetry respectively. The particle size of the prepared luminophors was confirmed by scanning electron microscopy (SEM).

Studies on Nitrogen Rich Benzoxazines Containing Schiff Base for Optical, Aggregation Induced Emission and Anti-Microbial Applications

ABSTRACT Dihydroxy derivative of vanillin-based diaminotriazole core monomer (DTV) has been synthesized using sustainable vanillin (V) and 3,5-diamino-1,2,4-triazole (DT) under appropriate experimental conditions and characterized with a view to develop Schiff base core nitrogen-rich benzoxazines capable of exhibiting excellent optical and anti-microbial properties. The monomer DTV has been subsequently converted into benzoxazines separately using six structurally varied amino compounds, viz. aniline (a), 1-(−2-aminoethyl)piperazine (aep), furfurylamine (ffa), 4-H-1,2,4-triazoal-4-amine (ta), 3-aminopyrazol (apy) and 1-(3-aminopropyl)imidazole (api) with paraformaldehyde through Mannich condensation. The corresponding Schiff base based benzoxazines, viz. DTV-a, DTV-aep, DTV-ffa, DTV-ta, DTV-apy and DTV-api were synthesized and characterized for their molecular structure, thermal stability, optical, hydrophobic and anti-microbial properties using different analytical techniques and methods. Data obtained from different analyses for DTV based benzoxazines can be used for wide range of industrial and engineering applications.

Structural design and characterization of a new type of organic nonlinear optical flavanone crystal

Two new crystals were designed and obtained: the chalcone derivative HMMP (1-(2‑hydroxy-4-methoxyphenyl)-3-(4-(methylthio)phenyl)prop‑2-en-1-one) and the flavanone derivative 7M4MC (7‑methoxy-2-(4-(methylthio)phenyl)chroman-4-one). Yellow bulk 7M4MC single crystal with dimensions of 3 × 2 × 1 mm3 and orange-yellow needle-like HMMP single crystal were grown by solution evaporation. 7M4MC crystal belongs to the P21 space group of the monoclinic structure, which has a non-centrosymmetric structure. HMMP crystal monoclinic, belongs to the P21/m space group with a centrosymmetric structure. In the 7M4MC molecule, the methoxy and methylthio groups act as electron donors (D) and the carbonyl group acts as an electron acceptor (A), forming a d-π-A-π-D structure with an electron gradient. 7M4MC exhibits a high degree of second-harmonic generation intensity (11 × KDP), a broad transmission range (600–1600 nm, >88 %), an elevated optical energy bandgap (Eg = 2.57 eV), high thermal stability (Tm = 105 °C) and excellent dielectric properties (εr ≈ 2.1). This work not only provides two new crystals but also offers a viable molecular design option by changing the degree of intramolecular distortion by altering the backbone structure.