Differential Scanning Calorimetry Results Research Articles

Expanding the Frontiers of nail product evaluation: Novel application of differential scanning calorimetry (DSC) for assessing crosslinking density and predicting nail brittleness and flexibility.

While modern industry advancements have expanded nail beautification options, scientific literature primarily focuses on nail biology and medicine, with limited attention on cosmetic treatments. This study aimed to investigate human nail denaturation properties, including gender impact, blending nails to enlarge the sample pool, nail sensitization through bleaching, and active effectiveness testing. The objective was to understand the DSC and bending fatigue relationship, and define the consumer relevance of the DSC test. Nail clippings were collected from adult female and male volunteers. The wet DSC was employed to validate sample preparation, explore the effects of gender, and assess the potential of using blended nails for claims substantiation testing. Nails were sensitized through bleaching using hydrogen peroxide. The effects were confirmed through DSC and nail flexure tests. Furthermore, the ability of actives to address concerns related to nail softness and brittleness was assessed using these techniques. The results confirmed the viability of equilibrating nails in water for up to 14 h as a standardized testing method. The denaturation temperature results were independent of gender and suitable for claims substantiation testing. Blending nails from different sources did not yield significant variations in denaturation properties. A preliminary study suggested that cadaver nails should be used with caution because they exhibited differences in denaturation temperature, influenced by the sampling location. Bending fatigue tests highlighted the significance of humidity, with higher humidity conditions (80%) enhancing nail flexibility and providing better resolution for claims substantiation. Sensitizing the nails with hydrogen peroxide induced alterations in both DSC and bending fatigue results. Proof-of-principle studies demonstrated an elevation in denaturation temperature and a decrease in the number of cycles to break, indicating a nail-hardening effect when formaldehyde was applied. The use of a nail softener led to an enhancement in nail fatigue resistance due to a notable reduction in nail crosslinking density. The measurement of crosslinking density proved to be a sensitive tool for assessing the effects of cosmetic treatments on nails, particularly in predicting outcomes related to nail brittleness and flexibility.

Potential of polyphenols from Ligustrum robustum (Rxob.) Blume on enhancing the quality of starchy food during frying.

The increasing concerns about health have led to a growing demand for high-quality fried foods. The potential uses of Ligustrum robustum (Rxob.) Blume, a traditional tea in China, as natural additives to enhance the quality of starchy food during frying was studied. Results indicated that L. robustum polyphenols extract (LREs) could improve the quality of fried starchy food, according to the tests of color, moisture content, oil content, texture property, and volatile flavor. The in vitro digestion results demonstrated that LRE reduced the final glucose content from 11.35±0.17 to 10.80±0.70mmol/L and increased the phenolic content of fried starch foods from 1.23±0.04 to 3.76±0.14mg/g. The appearance and polarizing microscopy results showed that LRE promoted large starch bulges on the surface of fried starchy foods. Meanwhile, X-ray diffraction results showed that LRE increased the intensity of characteristic diffraction peak of fried starch with a range of 21.8%-28%, and Fourier transform infrared results showed that LRE reduced the damage to short-range order structure of starch caused by the frying process. In addition, LRE increased the aggregation of starch granules according to the SEM observation and decreased the enthalpy of starch gelatinization based on the differential scanning calorimetry results. The present results suggest that LREs have the potential to be utilized as a natural additive for regulating the quality of fried starchy food in food industries. PRACTICAL APPLICATION: The enhancement of L. robustum polyphenols on the quality of starchy food during frying was found, and its mechanisms were also explored. This work indicated that L. robustum might be used as a novel economic natural additive for producing high-quality fried foods.

Terahertz Spectroscopic Insight into the Hydrogelation of Copper Ion-Coordinated Poly(vinyl alcohol).

Metal-coordinated hydrogels are becoming increasingly popular in the biomedical field due to their unique properties. However, the mechanism behind gel forming involving metal ions is not yet fully understood. In this work, terahertz spectroscopy was used to investigate the role of interfacial water in the gelation process of copper ion-coordinated poly(vinyl alcohol) hydrogels. The results showed that the binding of copper ions could alter the interfacial hydration dynamics of the poly(vinyl alcohol) polymers. Combined with the results of differential scanning calorimetry (DSC), we propose a possible hydration layer-mediated mechanism for the formation of cooper ion-coordinated hydrogel during the freeze-thaw cycle. These results highlight the value of terahertz spectroscopy as a sensor for studying the hydration process in hydrogels and provide an important clue for understanding the mechanism of hydrogelation in ion-coordinated hydrogels.

Synthesis and Rheological Analysis of Non-Isocyanate Polyurethanes Blended with Poly(vinyl alcohol)

This study investigated the blending of non-isocyanate polyurethanes (NIPUs) with poly(vinyl alcohol) (PVA) at various ratios, with specific emphasis on ratios such as 20%, 50%, 80%, and 100% NIPU content. Focus has been made on assessing their rheological behaviour, mechanical performance, and thermal stability. As the NIPU content surpassed 50%, a shear-thickening trend emerged, suggesting a highly interwoven molecular structure. Rheological studies demonstrate viscosity variations dependent on blend composition and shear rate, with pure NIPU solution exhibiting shear thickening behaviour suggestive of network formation facilitated by the application of shear. Dynamic modulus analysis revealed viscoelastic properties in blends containing 50% and 100% NIPU. Thixotropic analysis showcased a remarkable structural recovery of 99% in solutions with over 20% NIPU, emphasizing the resilience of NIPU-rich blends to shear-induced alterations. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) demonstrate thermal stability and crystallinity, with blends exhibiting intermediate behaviour and reduced crystallinity compared to pure PVA due to NIPU incorporation. Blends exceeding 10% PVA displayed reduced consistency and diminished PVA crystallization ability, corroborated by DSC and wide-angle X-ray diffraction (WXRD) results. Thermal stability increased with NIPU integration, and blends demonstrated intermediate thermal behaviour between the pure polymers. Notably, the PU2PVA8 blend demonstrates the highest miscibility and a unique combination of amorphous and crystalline nature, showcasing its potential for tailored material design with enhanced structural and thermal properties.

Thermal annealing gradient tailoring on ammonium nitrate-capped CdS nanospheres synthesized via green precipitation

This study explores the impact of thermal annealing gradients on the physical properties and structural evolution of cadmium sulphide (CdS) nanospheres capped with ammonium nitrate as a modifier, which were fabricated through precipitation and subsequent annealing within 160–480 °C temperature range. The properties were characterized using X-ray diffraction (XRD), ultraviolet–visible (UV–Vis), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) techniques The XRD results show that the present CdS exhibits superior crystallinity compared to pure CdS without capping, transitions from a cubic to a hexagonal phase structure, and increases in crystallite size and crystallinity with increasing temperature. The FTIR spectra postulate that a vibrational band presence evidences ammonium nitrate capping on CdS, with another distinct band that represents CdS in the lower wavenumber region, both intensifying at elevated temperatures. The UV–Vis analysis reveals that CdS exhibits strong ultraviolet (UV) absorption suitable for effective photoreaction under UV light and has a broader band gap compared to bulk CdS. SEM images show an extensive distribution of homogeneous nanospheres over the surface, with increased growth in size when capped with ammonium nitrate and at higher temperatures. As validated by TGA and DSC results, CdS with a smaller crystallite size improves thermal stability and energy transfer, as evidenced by reduced weight loss and a lower endothermic temperature, respectively. Varying the annealing temperature with ammonium nitrate capping can improve the structural and physical properties of CdS, which are beneficial for varied applications such as optoelectronics, energy storage, and photocatalysts.

Stability mechanism of Monascus pigment-soy protein isolate-maltodextrin complex.

Monascus pigment (MP) is a natural food coloring with vital physiological functions but prone to degradation and color fading under light conditions. This study investigated the effect of complex formation of soybean protein isolate (SPI), maltodextrin (MD), and MP on the photostability of MP. Light stability was assessed through retention rate and color difference. Fluorescence spectroscopy (FS), circular dichroism (CD), Fourier-transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD) explored MP, SPI, and MD interactions, clarifying the MP-SPI-MD complex mechanism on the light stability of MP. Microstructure and differential scanning calorimetry (DSC) analyzed the morphology and thermal properties. The retention rate of MP increased to approximately 80%, and minimal color difference was observed when adding SPI and MD simultaneously. FS revealed hydrophobic interaction between MP and SPI. FTIR analysis showed intensity changes and peak shifts in amide I band and amide II band, which proved the hydrophobic interaction. CD showed a decrease in α-helix content and an increase in β-sheet content after complex formation, indicating strengthened hydrogen bonding interactions. Scanning electron microscopy (SEM) analysis demonstrated that MP was attached to the surface and interior of complexes. XRD showed MP as crystalline, while SPI and MD were amorphous, complexes exhibited weakened or absent peaks, suggesting MP encapsulation. The results of DSC were consistent with XRD. SPI and MD enveloped MP through hydrogen bonding and hydrophobic interaction, ultimately enhancing its light stability and providing insights for pigment-protein-polysaccharide interactions and improving pigment stability in the food industry. © 2024 Society of Chemical Industry.

Development of Monoethanolamine Chloride-Ethylene Diamine Deep Eutectic Solvent for Ffficient Carbon Dioxide Capture

Deep eutectic solvents (DES) emerge as a compelling class of ionic liquids, with distinct advantages over traditional solvents, particularly in the realm of CO2 capture. In the present study, [MEACl][EDA] is synthesized across various molar ratios (1:3 to 1:10) and combined with the results of Differential Scanning Calorimetry (DSC) to identify DESs. The DESs are further characterized using Fourier Transform Infrared Spectroscopy (FTIR), and the properties and performance of the DESs with diverse water contents (30–60 wt%) are systematically studied for CO2 capture. The optimal aqueous solution is identified based on the CO2 uptake and viscosity, followed by the evaluation of the cyclic absorption experiments. Results demonstrate that 40 wt% of [MEACl][EDA] DES with (1:5) molar ratio exhibits higher CO2 uptake (22.09 wt%) and comparable viscosity (4.401 mPa·s before and 13.330 mPa·s after CO2 capture at 25 °C) compared to aqueous 40 wt% MEA (15.74 wt% CO2 capture capacity, viscosity of 3.318 mPa·s before and 8.413 mPa·s after CO2 capture), and its absorption rate is also more favorable than the aqueous MEA. Furthermore, recycling studies reveal ∼ 88 % regeneration of the aqueous DES solution at 100 °C.

Optimizing clozapine-loaded nanostructured lipid carriers through central composite design for enhance bioavailability in antipsychotic therapy

Clozapine (CLZ), a tricyclic dibenzodiazepine antipsychotic drug employed for the treatment of Schizophrenia. However, CLZ's significant first-pass effect, poor water solubility, and low oral bioavailability (27%) limit its potential for therapeutic use. The present investigation aimed to prepare CLZ-loaded nanostructured lipid carriers (NLCs) to improve its solubility, bioavailability, and therapeutic efficacy. The NLCs were prepared using an ultrasonic probe sonication technique using selected solid lipids (Gelucire 44/14), liquid lipids (Labrafil M 1944), and surfactants (Monoemul 80). A central composite design approach was adopted to optimize the NLCs. The optimized CLZ-loaded NLCs were evaluated in terms of particle size, zeta potential, surface morphology, crystallinity, drug loading, and in-vitro CLZ release studies. The optimized CLZ-loaded NLCs showed a particle size, zeta potential, and entrapment efficiency of 115.1 ± 2.48 nm, −17 mV and 96.74 ±1.82%, respectively. The morphology revealed the coarsely spherical shape of NLCs. Fourier transform infrared spectroscopy indicated the physical interaction between the CLZ and lipids rather than chemical interaction. The results of powder X-ray diffraction and differential scanning calorimetry showed the conversion of crystalline to amorphous form of CLZ and distributed molecular level in lipid matrix. In the in-vitro release study, pure CLZ showed 14±1.86% release, whereas CLZ-loaded NLC showed initial burst release (20.0±0.56%) followed by sustained release (69.0±1.03%) up to 24 hours. Collectively, results revealed that the developed novel CLZ-loaded NLCs could be a potential formulation to improve efficacy by increasing solubility and prolonging CLZ release and bioavailability with enhanced patient compliance and reduced side effects.

Preparation and characterization of double-shell phase change material microcapsules with flame retardancy and temperature regulation capability as low-emission building fillers

The building application of phase change materials (PCMs) has attracted widespread attention due to energy conservation and emission reduction. In this study, designed and prepared by two-step polymerization poly melamine tetramethylene phosphonium sulfate (PMTMPS) coating the raw phase change materials microcapsules (MPCMs), which were novel double-shell microcapsules (D-MPCMs). D-MPCMs further achieved low smoke and low toxicity in the fire based on enhancing the temperature regulation performance of MPCMs. The chemical structure of D-MPCMs was characterized by Fourier transform infrared (FTIR) spectroscopy, and 13C solid-state nuclear magnetic resonance (NMR). Transmission electron microscope (TEM) confirmed that D-MPCMs were successfully prepared, whose shapes were regular spherical. The results of differential scanning calorimetry (DSC) showed that D-MPCMs revealed excellent phase transition enthalpy (80.51 J/g). Then, the resultant D-MPCMs had good thermal reliability and stability from the thermogravimetric analysis (TGA), characterized by a residual mass of D-MPCMs was 17 % more than that of MPCMs. In the cone calorimeter test (CCT), we confirmed that the coated PMTMPS significantly reduced the fire risk parameters of the rigid polyurethane foam (RPUF) containing D-MPCMs (D-MPCM/RPUF) referring to the heat release rate (HRR), total heat release (THR), and total smoke production (TSP). D-MPCM/RPUF exhibited the lowest peak values of HRR and TSP, which were 400.115 kW/m2 and 10.512 m2, respectively. In addition, the PMTMPS shell significantly enhanced the solar photo-thermal conversion performance of the D-MPCMs. To sum up, D-MPCMs have great potential to improve flame retardancy, environmental protection, and temperature regulation capability for building thermal insulation materials.

Synthesis of shape memory bio-based crosslinked polymer: Poly(arbutin)-co-poly(tosyl arbutin)-co-poly(ethylene glycol)

Oxidative copolymerization of arbutin (Arb) with 6-O-tosyl-Arb (TArb) was performed in water media in the presence of a di-μ-hydroxo-bis[(N,N,N′,N′-tetramethylethylenediamine)copper(II)] chloride (Cu[tmeda]) catalyst under oxygen to produce the corresponding copolymer PArbxPTArby (where, x and y indicate the molar ratio) with a number-average molecular weight (Mn) ranging from 4.2 to 9.3 kDa depending on the polymerization temperature and the time. This copolymer was further reacted with poly(ethylene glycol) (PEG) with amino groups at the terminals (Mn = 8.0 kDa) (PEG8.0k2NH2) in a silicone mould at 100 °C for 24 h to give the bio-based PArbxPTArbyPEGz crosslinked copolymer (z indicates the molar equivalent of the NH2 functions in the PEG to TArb units). The results of differential scanning calorimetry, wide-angle X-ray analysis and polarizing optical microscope image measurements determined that the PEG domain was homogeneously dispersed within the film. The degree of crystallization of the PEG domain was calculated to be 59%–78% and the film swelled over 2100 vol% after immersion in water for 12 h. This bio-based film showed good shape memory after being moulded at 80 °C, maintaining its shape at 20 °C and quickly recovering its original shape upon reheating.

Formulation and optimization of electrospun nanofiber films for ultrafast delivery of domperidone: In vitro and in-vivo characterization

Nanotechnology has significantly transformed drug delivery approaches by providing precise control of drug release kinetics and enhancing therapeutic effectiveness. Electrospun nanofiber films have unique features, including a significant surface-to-volume ratio and substantial porosity, resulting in enhanced patient adherence. The study was aimed at developing electrospun nanofiber films of domperidone for ultrafast release using polyvinyl alcohol (PVA). The nanofibers were prepared by electrospinning method and optimized using 32 factorial design. Electrospinning process parameters like feed rate, applied electric voltage, and tip-to-collector distance were optimized. The prepared nanofiber film was characterized using scanning electron microscopy, differential scanning calorimetry (DSC), Fourier transform infrared microscopy (FTIR), X ray diffraction (XRD), in-vitro diffusion, and permeation studies. The resultant domperidone-loaded nanofibers (diameters 280–565 nm) exhibited a uniform and highly porous structure. With an increase in applied voltage from 11 to 13 kV, entrapment efficiency increased, and fiber diameter decreased. DSC and XRD results confirmed the amorphous nature of the domperidone. The FTIR study confirmed the compatibility between domperidone and PVA. The wetting and disintegration times of nanofibers were 8 and 4 s, respectively. Due to their nanosize, small particles with an increased surface area resulted in improved drug delivery through nanofibers (93.36% release within 10 min). The nanofiber film had a higher Cmax (398.8 ng/mL) and AUC (2078.593 ± 17.71 ng/mL.h) than the commercial tablet formulation (186.6 ng/mL and 1875.619 ± 10.38). Thus, domperidone nanofibers would be a promising approach for enhancing therapeutic and biopharmaceutical properties by providing ultra-fast delivery.

Enhanced antichemobrain activity of amino acid assisted ferulic acid solid dispersion in adult zebrafish (Danio rerio).

Chemotherapy-induced cognitive impairment (CICI), also known as "chemobrain," is a common side effect of breast cancer therapy which causes oxidative stress and generation of reactive oxygen species (ROS). Ferulic acid (FA), a natural polyphenol, belongs to BCS class II is confirmed to have nootropic, neuroprotective and antioxidant effects. Here, we have developed FA solid dispersion (SD) in order to enhance its therapeutic potential against chemobrain. An amorphous ferulic acid loaded leucin solid dispersion (FA-Leu SD) was prepared by utilizing amino acid through spray-drying technique. The solid-state characterization was carried out via Fourier-transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and field emission scanning electron microscopy (FE-SEM). Additionally, in-vitro release studies and antioxidant assay were also performed along with in-vivo locomotor, biochemical and histopathological analysis. The physical properties showed that FA-Leu SD so formed exhibited spherical, irregular surface hollow cavity of along with broad melting endotherm as observed from FE-SEM and DSC results. The XRD spectra demonstrated absence of sharp and intense peaks in FA-Leu SD which evidenced for complete encapsulation of drug into carrier. Moreover, in-vitro drug release studies over a period of 5h in PBS (pH 7.4) displayed a significant enhanced release in the first hr (68. 49 ± 5.39%) and in-vitro DPPH assay displayed greater antioxidant potential of FA in FA-Leu SD. Furthermore, the in-vivo behavioral findings of FA-Leu SD (equivalent to 150mg/kg of free FA) exhibited positive results accompanied by in-vivo biochemical and molecular TNF-α showed a significant difference (p < 0.001) vis-à-vis DOX treated group upon DOX + FA-Leu SD. Additionally, histopathological analysis revealed neuroprotective effects of FA-Leu SD together with declined oxidative stress due to antioxidant potential of FA which was induced by anticancer drug doxorubicin (DOX). Overall, the above findings concluded that spray-dried FA-Leu SD could be useful for the treatment of chemotherapy induced cognitive impairment.

Form-stable oleic acid based polyHIPE/nanoclay framework supported composite phase change materials for low‐temperature latent heat storage

Latent heat storage, one of the promising methods in energy storage, is an important option for the sustainable use of energy and is attracting more attention day by day. Phase change materials (PCMs) produced for this purpose allow the storage/release of latent heat due to the temperature of the medium and can be obtained using various methods. In this work, the preparation of a new fatty acid based composite phase change material was accomplished by applying simple two-step approach. Here, oleic acid (OA) was employed as PCM, and emulsion templated macroporous polymers (polyHIPEs) as supporting matrices. Furthermore, macroporous supports were also fabricated in the presence of surface modified montmorillonite nanoclay to enhance thermal properties of the targeted composite PCMs. In this respect, a neat macroporous support and surface modified nanoclay enhanced macroporous support were synthesized. Then, the composite PCMs were prepared by filling the macropores of the obtained polymer foams with OA via a solvent-assisted impregnation approach for cold energy storage. The examinations on the thermal characteristics of the composite PCMs were performed through Differential Scanning Calorimetry (DSC), while the chemical structure was analyzed with FT-IR. Besides, polarizing optical microscopy (POM) was used to monitor the loading of OA to macroporous polymer supports. Additionally, the thermal behaviors of composite PCMs were investigated by the temperature-history (T-history) method and the findings were also found to be compatible with DSC. Furthermore, thermal stability of the composite PCMs was investigated through thermogravimetric analysis (TGA). According to DSC results, the prepared composite PCMs are candidates for utilizing cold thermal energy storage such as building cooling, cold protection and cold chain transportation applications with their proper melting temperatures (7.08 °C and 7.40 °C) and moderate latent heat capacities.

Identification and isolation of a novel antifreeze peptide from crayfish shells

In this study, a novel antifreeze peptide was isolated from crayfish shells and its antifreeze mechanism and activity were investigated. Firstly, the crayfish shells peptides (CSPs) were prepared by Enzymatic Hydrolysis Technology (alkaline protease and trypsin) and the CSPs could significantly enhance the survival rate of Saccharomyces cerevisiae from 12.5% to 88.5% after 24h freeze-thaw cycle. Then, a total 1004 peptides were identified from CSPs by liquid chromatography/tandem mass spectrometry (LC-MS/MS), among those peptides, two peptide sequences YWDHPIRDGFAPH (AFP1) and GPPGKPGIPDIVDW (AFP1) were selected as potential antifreeze polypeptides (AFPs) according the physicochemical properties: instability index, hydrophilicity, and confidence level. Furthermore, the antifreeze activity and mechanism of AFP1 and AFP2 were studied through molecular dynamics simulation, revealing that the AFP1 and AFP2 could adsorb to ice surface with 7 and 14 hydrogen bonds, respectively. Moreover, AFP2 has a more stable binding capacity and could interact with 33 water molecules. At last, the results of differential scanning calorimetry (DSC) and cold-stage polarization microscope indicated that the thermal hysteresis (TH) values of AFP2 were 1.62–2.09 °C and could inhibit ice recrystallization. Therefore, this study provides a theoretical basis for developing safe peptide-based cryoprotectants which will improve the quality of frozen foods.

Effect of electron beam irradiation on hole structure of cellulose acetate membrane

Cellulose acetate (CA) is one of the most popular biomaterials used for filtration membranes in water treatment.In this study, the CA membranes immersing in water were irradiated by electron beam, and the hole structure of CA membranes at different irradiation doses was investigated. The SEM pictures show the combination of micro-meter sized pores in CA membrane during the irradiation process. The electrochemical impedance spectroscopy(EIS) results reveal the membrane resistance decreases with the irradiation dose, which implies easier ion permeation. The positron annihilation lifetime measurement (PAL) results indicate the mean free-volume hole size becomes smaller with increasing irradiation dose. The above results demonstrate that electron beam irradiation would lead to chain scission of CA, and then the formation of new pores and pores combination, which provides more channels for ion permeation. FTIR results suggest stronger hydrogen bonding in CA after the irradiation in water. The differential scanning calorimetry (DSC)results indicate that the crystallinity has been enhanced with the irradiation dose up to 10 kGy and reduces in the range from 10 kGy to 80 kGy. The results could provide the clues explaining the performance deterioration of CA membrane during treating radioactive waste water.

Effects of sanxan on water and ice crystal status of salt free frozen cooked noodles during freeze-thaw cycles

This study compared four biocolloids (sanxan, xanthan gum, curdlan, and guar gum) in different concentrations to replace NaCl in improving the recooking quality of salt free frozen cooked noodles (SF-FCNs). Sanxan outperformed NaCl and other biocolloids significantly improving the firmness (21.0%), chewiness (63.5%), and toughness (15.4%) of SF-FCNs after 10 freeze-thaw (FT) cycles. The results of the freezing-thawing curves showed SF-FCNs had prior FT stability when sanxan was added at 1.2%. Subsequently, the result of differential scanning calorimetry and nuclear magnetic resonance revealed sanxan reduced the content and mobility of freezable water while increasing the content of bound water. The scanning electron microscope, mercury intrusion, and optical microscopy analyses indicated that sanxan reduced the size and volume of ice crystals and the structural damage of SF-FCNs by controlling the water. The work contributes to a theoretical framework for enhancing SF-FCNs quality through precise water and ice crystal control.

Redox-sensitive self-assembling polymer micelles based on oleanolic modified hydroxyethyl starch: Synthesis, characterisation, and oleanolic release

Our study aimed at developing polymer micelles that possess redox sensitivity and excellent controlled release properties. 3,3′-dithiodipropionic acid (DTDPA, Abbreviation in synthetic polymers: SS) was introduced as ROS (Reactive oxygen species)response bond and connecting arm to couple hydroxyethyl starch (HES) with oleanolic acid (OA), resulting in the synthesis of four distinct grafting ratios of HES-SS-OA. FTIR (Fourier Transform infrared spectroscopy) and 1H NMR (1H Nuclear magnetic resonance spectra) were used to verify the triumphant combination of HES-SS-OA. Polymer micelles were found to encapsulate OA in an amorphous form, as indicated by the results of XRD (X-ray diffraction) and DSC (Differential scanning calorimetry). When the OA grafting rate on HES increased from 7.72 % to 11.75 %, the particle size decreased from 297.79 nm to 201.39 nm as the polymer micelles became compact due to enhanced hydrophobicity. In addition, the zeta potential changed from −16.42 mv to −25.78 mv, the PDI (polydispersity index) decreased from 0.3649 to 0.2435, and the critical micelle concentration (CMC) decreased from 0.0955 mg/mL to 0.0123 mg/mL. Results of erythrocyte hemolysis, cytotoxicity and cellular uptake illustrated that HES-SS-OA had excellent biocompatibility and minimal cytotoxicity for AML-12 cells. Disulfide bond breakage of HES-SS-OA in the presence of H2O2 and GSH confirmed the redox sensitivity of the HES-SS-OA micelles and their excellent controlled release properties for OA. These findings suggest that HES-SS-OA can be potentially used in the future as a healthcare drug and medicine for the prevention or adjuvant treatment of inflammation.

Improvement of the properties of poly (L-lactide)/ethylene-ethyl acrylate-glyceryl methacrylate terpolymer (EGA) by the introduction of stereocomplex polylactide crystals

Ternary blends comprising poly(L-lactide) (PLLA), ethylene-ethyl acrylate-glyceryl methacrylate terpolymer (EGA), and poly(D-lactide) (PDLA) were melt blended using low-temperature method to obtain blends with balanced properties. The formation of stereocomplex polylactide (SC-PLA) crystals was verified by torque changes and differential scanning calorimetry (DSC) results. The SC-PLA crystals formed a percolating network in the PLLA matrix at a concentration of 2 wt% PDLA, and blend melt presented solid-like rheological behavior. Attributing to the increased viscosity ratio between PLLA and EGA, the size of dispersed EGA phase increased. The crystallization of PLLA was significantly promoted because of the nucleation effect of SC-PLA crystals. The PLLA/EGA/2 %PDLA ternary blends with elongation at break of 138 % and impact strength of 72.3 kJ/m2 exhibited excellent toughness. These ternary blends demonstrated exceptional crystallization ability and tailored rheological and mechanical properties, opening a new path for developing high-performance PLLA-based materials in packaging industry.

Fabrication and evaluation of cross-linked nanogels of Dexibuprofen

The objective of this study was to design and develop an Agarose-based polymeric nanogel network system for solubility enhancement of a lipophilic drug, Dexibuprofen. Polymeric nanogels were synthesized through free radical polymerization where Agarose was cross-linked with 2-Acrylamido-2-methylpropane sulfonic acid (AMPS) in the presence of ammonium persulfate (APS) as an initiator and N, N’-Methylenebisacrylamide (MBA) as crosslinking agent. The resulting polymeric nanogels underwent a comprehensive characterization process including Fourier transform infrared (FTIR), particle size analysis, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), powder X-ray diffraction (PXRD), and swelling studies to confirm the preparation of a stable polymeric nanogel system. FTIR spectral findings revealed that Agarose was chemically cross-linked with AMPS and confirmed the successful insertion of AMPS chains on the Agarose backbone. Particle size analysis revealed a diameter of 168 nm with a zeta potential of −9.91 mV, providing assurance of a stable polymeric nanogel system. SEM images depicted a highly porous surface. DSC and TGA results showed a more thermally stable network system than individual ingredients. Swelling studies revealed an increased swelling ratio of polymeric nanogels at phosphate buffer of pH 6.8 than acidic buffer of pH 1.2. Dexibuprofen was efficiently loaded into a polymeric nanogel system with a high entrapment efficiency of up to 80%. The solubility of the drug was enhanced when introduced to a polymeric nanogel formulation when compared to pure drug. The system reproducibility was evaluated through in vitro drug release and kinetic modeling of drug release. Toxicity studies confirmed the formulation’s effectiveness, showcasing the developed polymeric nanogels as a promising option for delivering lipophilic drugs, with outstanding physicochemical properties, improved solubility, and minimal oral toxicity.

The Crystallization Morphology and Conformational Changes of Polypropylene Random Copolymer Induced by a Novel β-Nucleating Agent.

The crystal morphology and conformational changes during crystallization of a polypropylene random copolymer (PPR) are the basis for understanding its crystallization process. In this work, novel rare-earth β-nucleating agent WBN-28 was directly added into PPR to induce β-crystallization. The results of differential scanning calorimetry (DSC) showed that it has an excellent β-crystal-induced effect. The β-crystal content could surpass 85%, calculated from wide-angle X-ray diffraction (WAXD) data. The morphology of the β-crystal and α-crystal was intuitively observed via a polarizing optical microscope (POM). The β-crystallites were interconnected to naturally develop plate-like crystalline regions possessing a certain size, and the α-crystallites with sufficient thicknesses possessed a cross-hatched phenomenon. The bundle-like supramolecular structure of the β-crystal induced by WBN-28 was further observed via a scanning electron microscope (SEM). The conformational changes in the crystallization process of PPR were resolved via high-resolution infrared spectroscopy to understand its β-crystallization in depth. The conformational changes during the crystallization of PPR were found to be different from those of the isotactic polypropylene homopolymer (PPH); they had their own characteristics. This will provide guidance for understanding the β-crystallization of PPR in depth.