Good Miscibility Research Articles

Fatty acid-derived ionic liquids as renewable lubricant additives: Effect of chain length and unsaturation

Fatty acid-derived ionic liquids (FAILs) are synthesized and then demonstrated as the environmentally-friendly additive to mineral lube base oil for enhancement of lubrication properties. Unlike most of the conventional ionic liquids, FAILs exhibited good miscibility with non-polar mineral lube base oil. The quaternary structure of tetrabutylammonium (TBA) cation, diffused positive charge on the cationic center due to +I effect of alkyl chains, and the alkyl chain of fatty acid anion collectively facilitates the miscibility of FAILs in the mineral lube base oil. Experimental results revealed that 1% FAILs could significantly reduce the friction (16–27%) and wear (9–15%) of lube base oil. The viscosity of these ionic liquids is found to be governed by alkyl chain-length and unsaturation of fatty acid anions, and it exhibited a linear correlation with the coefficient of friction. The elemental mapping of worn surfaces on aluminium disc suggested the formation of ionic liquids-derived tribochemical film, which is accounted for protection of tribo-interfaces to reduce the wear and friction. The FAILs being halogen-free, environment-friendly, having an excellent affinity towards engineering surfaces, and good miscibility with non-polar hydrocarbon lubricants, promised the immense potential for tribological applications.

Evaluation of thermal and mechanical properties of crumb/natural rubber nanocomposites

Although crumb rubber or waste tires are not classified as hazardous waste, they can cause environmental pollution if disposed incorrectly or irresponsibly. Waste tires can be put to many beneficial uses from one side and to protect the environment via limitting its accumulation when reaching their end of life from the other side. Shredded tires can be added to rubbers to be used in making school playgrounds, equine bedding and football pitches. This may result in the reduction of the mechanical properties of the composites which can be kept by the use of higher levels of other fillers in addition to crumb and hence keeping and even more enhancing these mechanical properties. The crumb rubber was added to natural rubber in the ratio of 10:100 by weight with the partial removal of the carbon black, from 60 to 20 phr, by montmorillonite (organo-modified nanoclay). The modified nanoclay was added in different loadings; 0, 2.5, 5, 7.5, and 10 phr to the rubber mix formulations. Results of morphological analysis revealed the good miscibility and homogeneity between crumb and Natural rubber in one hand and all other ingredients in the other hand.The mechanical, thermal measurements the role of OMMT in enhancing the mechanical and thermal properties of the crumb/NR nanocomposites. The addition of crumb rubber reduces the hazardous working environments for personnel, lower the production cost by making a good use of waste tires and presents a green solution for getting rid of an environmental problem.

Compatibility and thermal decomposition behavior of acrylic block copolymer modified epoxy resin

A series of epoxy modified with acrylic amphiphilic block copolymer (BCP) were prepared with different BCP contents. The compatibility between BCP and epoxy matrix was characterized by differential scanning calorimetry (DSC). The nanostructures in the thermosets were investigated by means of atomic force microscopy (AFM). The thermal stability and degradation kinetics of BCP/epoxy blends were investigated that by thermogravimetric analysis (TGA) in N2 atmosphere. The ‘model free method (Vyazovkin’ method) and ‘model fitting’ methods (Coats-Redfern method, Malek method and ABS differential method) were applied to analyze the decomposition of cured neat epoxy and BCP/epoxy blends. The glass transition temperature (Tg) of the BCP/epoxy blends was found almost not affected by the incorporation of BCP. The miscibility of acrylic BCP in the epoxy matrix was verified by comparing the theoretical calculation with experimental results. AFM further confirmed the good miscibility of the blends. The thermal stability of the BCP/epoxy blends remained unchanged and the main decompose reaction was slightly accelerated from the perspective of transition state theory. The relationship between pre-exponential factor and reaction activation energy was established by utilizing the kinetic compensation parameter method. The degradation kinetics of both neat epoxy and BCP/epoxy blend were found abide to the Fn (n > 3/2) reaction mechanism.

Mechanical Properties of Thermoplastics Corn Starch (TPCS) Reinforced Pineapple Leaf Fibre (PALF) Composite

The aim of this study is to investigate the mechanical characterization of bio-composites on thermoplastic corn starch (TPCS) reinforced with 2 mm length of pineapple leaf fibre (PALF). The selection of different weight percentages of fibres (20, 30, 40, 50 and 60) weight percentage (wt.%) of PALF contents were applied in this study. The mixtures of TPCS with different wt.% of PALF were made by using a hot compression moulding at 165 °C for 15 minutes. The mechanical testing that has been performed are tensile, flexural and impact testing to determine the effect of fibre loading on bio-composites characteristics. The results show that by incorporating 40 wt.% loading of PALF, the tensile strength and tensile modulus has increased to the maximum. However, the flexural testing result shows that 50 wt.% loading of PALF show the highest strength and modulus. Meanwhile, the impact testing result shows decrement when the loadings of PALF increases. Scanning electron microscopy (SEM) show that the TPCS with 40 wt.% of PALF have a good miscibility between matrix/fibre in the bio-composites. Overall, the TPCS/PALF composites enhance the properties of the bio-composites for short-life application: that is, plate, container, disposable tray, packaging etc.

The Preparation of Curcumin Sustained-Release Solid Dispersion by Hot-Melt Extrusion—Ⅱ. Optimization of Preparation Process and Evaluation In Vitro and In Vivo

The purpose of this study was to optimize hot-melt extrusion (HME) preparation process and evaluate in vitro and in vivo for developing curcumin (CUR) sustained-release solid dispersion, to explore the possibility of HME for one-step preparation of insoluble drug sustained-release solid dispersion. The effect of 3 process parameters—barrel temperature, screw speed, and cooling rate—was systematically studied. Physical state of CUR sustained-release solid dispersion was characterized by differential scanning calorimetry, X-ray powder diffraction, and Fourier transform infrared spectroscopy. It was found that CUR–Eudragit RS/RL system exhibited a good miscibility. Curcumin in the solid dispersion existed in an amorphous state and had molecular interactions with carriers. Stability studies showed no apparent difference of physical state of solid dispersion after 6 months. The mechanism of the CUR release in sustained-release solid dispersion was a diffusion and dissolution coexisting action. Pharmacokinetics study showed the relative bioavailability of the CUR in sustained-release solid dispersion to CUR was 223.44%. The CUR sustained-release solid dispersion have been successfully prepared by HME, significantly extending the half-life, ensuring a stable and effective blood concentration, and improving the bioavailability of CUR. In conclusion, HME can be used to prepared sustained-release solid dispersion of a poorly water-soluble drug as a promising method.

Energetic Disorder and Activation Energy in Efficient Ternary Organic Solar Cells with Nonfullerene Acceptor Eh‐IDTBR as the Third Component

Solution‐processed ternary organic solar cells (OSCs) contain a third component in the active layer in addition to the donor/acceptor materials. Two main avenues are considered to fabricate ternary OSCs: 1) to improve the short‐circuit current density by the selected third component that broadens and/or enhances the absorption of the host films and 2) to increase the fill factor by adding materials with diverse crystallinity to tune the film morphology. However, little work is reported for the improvement of open‐circuit voltage (VOC), energetic disorder, charge transfer state energy (ECT), and activation energy in ternary OSCs. Herein, ternary OSCs with active layer composed of PCE10:F8IC:Eh‐IDTBR as the model to examine these parameters in addition to the morphology are used. In the ternary device, the additional Eh‐IDTBR improves the crystallinity of the acceptor phase in the ternary mixture; the VOC is 58 mV higher than that of the reference caused by the reduced energetic disorder; due to the good miscibility of Eh‐IDTBR with both PCE10 and F8IC, only 50 meV in ECT is observed; and the zero‐field activation energy is lower than that for the reference. The findings provide an alternative way to understand the complex ternary OSC structural–electrical properties’ correlations.

Preparation of porous chitosan/reduced graphene oxide microspheres supported Pd nanoparticles catalysts for Heck coupling reactions

Novel porous chitosan/reduced graphene oxide microspheres supported Pd nanoparticles catalysts (Pd@CS/RGO) were prepared by a combination of silica nanoparticles etching and freeze-drying treatments of CS/RGO/silica/PdCl2 composite microspheres. The microstructure of the Pd@CS/RGO microspheres catalysts have been investigated by X-ray photo electron spectroscopy (XPS), Raman spectroscopy, high resolution transmission electron microscopy (HR-TEM), thermo-gravimetric analysis (TGA), and X-ray diffraction (XRD), etc. The results revealed that: the novel catalysts showed open porous structure; CS had good miscibility with RGO nanosheets; Pd nanoparticles were well incorporated within CS/RGO matrix; the thermal stabilities of the catalysts were improved significantly over CS. Meanwhile, the Pd@CS/RGO catalysts have been demonstrated as highly active and easily recyclable catalysts for Heck reactions. The preparation process is simple, and the structure and performance of the catalytic material can be governed by changing the mass ratios of CS/RGO/silica/PdCl2 and the pore-forming process conditions.

Rheology of Cellulose/Alginic Acid Blends with 1‐Allyl‐3‐Methylimidazolium Chloride as Solvent

In this study, cellulose/alginic acid blend solutions were prepared with 1‐allyl‐3‐methylimidazolium chloride as solvent. The effect of cellulose/alginic acid blend ratios on the rheological properties was studied. It was found that the viscosity and dynamic modulus decreased with the increase of alginic acid ratio. And the calculated viscosity values, which were obtained from the log‐additivity rule, are less than the experimental viscosity values. This may be caused by the hydrogen bonding interaction between cellulose and alginic acid, which is beneficial to the miscibility of the blends. In order to prove the rheological result, cellulose/calcium alginate films were prepared from the solution, the hydrogen bonding between cellulose and alginate were investigated, which was related to the good miscibility of the blend solutions. POLYM. ENG. SCI., 60: 243–249, 2019. © 2019 Society of Plastics Engineers

Thermodynamic characterization of solder Au–Ga alloys

Differential thermal analysis, Oelsen calorimetry as well as optical microscopy are used for thermodynamic characterization of Au–Ga solder alloys. Mechanical and electrical characteristic of the investigated alloys is done by measuring of hardness, micro hardness and electro conductivity. Obtained activities and activity coefficients at 873K are smaller than the unit, which means there is a negative deviation of the gallium activity from the Raoult law. Partial mixing and excess Gibbs's energy of gallium is negative for all investigated alloys and do not reach −1800 J/mol for the excess energy and −4400 J/mol for the mixing energy which indicates good miscibility regardless of the existence of an intermetallic compound (AuGa2) in the alloy that microstructural analysis is shown. The obtained good miscibility is excellent for solder characteristics of the investigated alloys.

Thermodynamic properties of the Pb-Sb-Bi ternary system

The paper presents the results of the Pb-Sb-Bi ternary system thermodynamic study. Experimental data were obtained using the EMF method in the temperature range from 873 to 973 K. The alloys compositions related to the concentration triangle projections with ratios of antimony and bismuth mole fractions (NSb/NBi) equal to 1/3, 1 and 3, were studied. The values of partial molar Gibbs energy (ΔG¯Pb), entropy (ΔS¯Pb), enthalpy (ΔH¯Pb) and the corresponding excess characteristics (ΔG¯Pbex and ΔS¯Pbex) of lead in the binary and ternary liquid metal alloys were found using the optimized experimental dependencies of EMF (Ep) on lead mole fraction (NPb). The integral thermodynamic quantities were calculated using the Darken method. Isolines of integral excess Gibbs energy and entropy (ΔGex and ΔSex), integral Gibbs energy, entropy and enthalpy (ΔG, ΔS and ΔH) for the Pb-Sb-Bi system are illustrated graphically. It is determined that ΔGex and ΔSex values in the Pb-Bi-Sb ternary system at 973 K are small, which indicates a good miscibility of the studied system and the absence of a strong chemical interaction of the components.

Growth of Nb-Doped Monolayer WS2 by Liquid-Phase Precursor Mixing.

Controlled substitutional doping of two-dimensional transition-metal dichalcogenides (TMDs) is of fundamental importance for their applications in electronics and optoelectronics. However, achieving p-type conductivity in MoS2 and WS2 is challenging because of their natural tendency to form n-type vacancy defects. Here, we report versatile growth of p-type monolayer WS2 by liquid-phase mixing of a host tungsten source and niobium dopant. We show that crystallites of WS2 with different concentrations of substitutionally doped Nb up to 1014 cm-2 can be grown by reacting solution-deposited precursor film with sulfur vapor at 850 °C, reflecting the good miscibility of the precursors in the liquid phase. Atomic-resolution characterization with aberration-corrected scanning transmission electron microscopy reveals that the Nb concentration along the outer edge region of the flakes increases consistently with the molar concentration of Nb in the precursor solution. We further demonstrate that ambipolar field-effect transistors can be fabricated based on Nb-doped monolayer WS2.

Use of DMA-material pocket to determine the glass transition temperature of nitrocellulose blends in film form

This work describes an unexploited use of DMA-material pocket to determine the glass transition temperature of blends composed by nitrocellulose and poly(Ɛ-caprolactone) in film form. A total of eight blends were prepared increasing the poly(Ɛ-caprolactone) content and changes in the mechanical properties of the blends were determined by DMA-material pocket. Storage modulus, loss modulus, and tan δ were analyzed as a function of temperature. The blends and each former polymer were also analyzed by FTIR-ATR. By the spectroscopy measurements, the intermolecular interactions between poly(Ɛ-caprolactone) and nitrocellulose in the blend is observed, been an evidence of miscibility. Tg of nitrocellulose and poly(Ɛ-caprolactone), 68 and −52 °C respectively, agree with reported values. Tg of the blends shows a single peak of tan δ between the Tg values of isolated former polymers, reinforcing the good miscibility between them. Finally, Tg of the blends exhibits a logarithmic dependence of PCL content, decreasing as poly(Ɛ-caprolactone) content increases.

Effect of sugar palm nanofibrillated cellulose concentrations on morphological, mechanical and physical properties of biodegradable films based on agro-waste sugar palm (Arenga pinnata (Wurmb.) Merr) starch

Sugar palm (Arenga pinnata) fibres and starches are considered as agro-industrial residue in the agricultural industry. This paper aims to investigate the effect of different concentrations (0–1.0wt%) of sugar palm nanofibrillated cellulose (SPNFCs) reinforced sugar palm starch (SPS) on morphological, mechanical and physical properties of the bionanocomposites film. The SPNFCs, having a diameter of 5.5±0.99nm and length of several micrometres, were prepared from sugar palm fibres via a high-pressure homogenisation process. FESEM investigation of casting solution displayed good miscibility between SPS and SPNFCs. The FTIR analysis revealed good compatibility between the SPS and SPNFCs, and there were existence of intermolecular hydrogen bonds between them. The SPS/sPNFCs with 1.0wt% had undergone an increment in both the tensile strength and Young’s modulus when compared with the SPS film, from 4.80MPa to 10.68MPa and 53.97MPa to 121.26MPa, respectively. The enhancement in water barrier resistance was led by reinforcing SPNFCs into the matrix, which resulted in bionanocomposites. The properties of bionanocomposites will be enhanced for short-life applications, such as recyclable container and plastic packaging through the incorporation of SPNFCs within the SPS bionanocomposites.

Efficient Nonhalogenated Solvent-Processed Ternary All-Polymer Solar Cells with a Favorable Morphology Enabled by Two Well-Compatible Donors.

The rational design of the morphology of ternary all-polymer solar cells (all-PSCs) having broadened photon harvesting is crucial to achieve high device performance. However, multicomponent blends often illustrated an unfavorable morphology such as large-sized phase separation due to their complicated interaction. Herein, we proposed to solve these problems by employing two donors with good miscibility (J51 and PTB7-Th), which also have similar compatibility with the acceptor (N2200). The resultant ternary blend films of J51:PTB7-Th:N2200 feature a uniform phase separation morphology due to the reduced competitive effect of intermolecular interactions. As an additional polymer donor, PTB7-Th could not only enhance the absorption of the binary blend but also act as a crystallization regulator to boost the face-on orientation in ternary blends. Accordingly, the J51:PTB7-Th:N2200 ternary blends exhibited improved sunlight absorption and higher and well-balanced carrier mobility accompanied by enhanced carrier extraction. With the nonhalogenated cyclopentyl methyl ether as the processing solvent, the ternary all-PSCs showed outstanding power conversion efficiency (PCE) higher than 9% when varying the PTB7-Th weight ratio in donors from 20 to 50%. Due to the PTB7-Th content holding a 30% weight ratio in donors, the ternary all-PSCs demonstrated the optimal PCE of 9.60%, which perform better than those of binary all-PSCs (PCE = 7.58 or 5.63%).

Insight into the Dissolution Molecular Mechanism of Ternary Solid Dispersions by Combined Experiments and Molecular Simulations.

With the increase concern of solubilization for insoluble drug, ternary solid dispersion (SD) formulations developed more rapidly than binary systems. However, rational formulation design of ternary systems and their dissolution molecular mechanism were still under development. Current research aimed to develop the effective ternary formulations and investigate their molecular mechanism by integrated experimental and modeling techniques. Glipizide (GLI) was selected as the model drug and PEG was used as the solubilizing polymer, while surfactants (e.g., SDS or Tween80) were the third components. SD samples were prepared at different weight ratio by melting method. In the dissolution tests, the solubilization effect of ternary system with very small amount of surfactant (drug/PEG/surfactant 1/1/0.02) was similar with that of binary systems with high polymer ratios (drug/PEG 1/3 and 1/9). The molecular structure of ternary systems was characterized by differential scanning calorimetry (DSC), infrared absorption spectroscopy (IR), X-ray diffraction (XRD), and scanning electron microscope (SEM). Moreover, molecular dynamic (MD) simulations mimicked the preparation process of SDs, and molecular motion in solvent revealed the dissolution mechanism of SD. As the Gordon-Taylor equation described, the experimental and calculated values of Tg were compared for ternary and binary systems, which confirmed good miscibility of GLI with other components. In summary, ternary SD systems could significantly decrease the usage of polymers than binary system. Molecular mechanism of dissolution for both binary and ternary solid dispersions was revealed by combined experiments and molecular modeling techniques. Our research provides a novel pathway for the further research of ternary solid dispersion formulations.

Development and characterization of novel composite glycerol-plasticized films based on sodium caseinate and lipid fraction of tomato pomace by-product

Tomato processing industries generate many byproducts that are mainly unexploited or underutilized. In order to convert tomato byproducts into added-value products, composite films made of sodium caseinate (NaCas), glycerol (25 wt%), and lipidic fraction of tomato pomace (LFTP) at different contents (0–40 wt%) were produced and characterized in terms of thermal stability, antioxidant activities, mechanical, hydrodynamic and optical properties. Our results showed that increasing LFTP concentration beyond 20 wt% increased the flexibility of NaCas films within the range of 17–25%. Moreover, LFTP incorporation at the highest content improved thermal stability of NaCas films and reduced their water absorption by >72%. Furthermore, increasing LFTP content led to a significant decrease in the light transmission of NaCas/LFTP composite films. Such improvement in functional and physical properties can be attributed not only to the establishment of specific interactions between NaCas and LFTP but also to their good miscibility in the blend along with the homogeneous dispersion of the incorporated LFTP in the polymeric matrix, as confirmed by FTIR and SEM analysis. On the other hand, the antioxidant capacity of NaCas/LFTP composite films was enhanced by increasing LFTP content most likely due to LFTP's high total phenolics content.

Hindered phenol-mediated damping of polyacrylate rubber: effect of hydrogen bonding strength on the damping properties

Abstract The loss factor (tanδ) and glass transition temperature (T g) are two important parameters for evaluating damping properties. Hydrogen bonds (H bonds) play an important role in improving damping properties. In this work, the effect of the hydrogen bond strength and number on the damping properties was studied. Four hindered phenols with different steric hindrances were used to form hydrogen bonds with different strengths to mediate tanδ and T g. Dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) showed that hindered phenol content lower than 38 wt% led to a linear increase in tanδ and T g because of the formation of H bonds. The Kwei equation was used to explain the relationship between H bonds and tanδ. When the content was higher than 38 wt%, the small molecule-hindered phenols can be divided into two categories: those that can maintain a good miscibility, thus continuously increasing the tanδ, and those that make tanδ increase slowly or decrease because of poor miscibility. These results demonstrated that tanδ is closely related to both hydrogen bond strength and number. The degree of hindrance of the hydroxyl group determines the hydrogen bond strength, whereas the miscibility determines the number.

Water dynamics and thermal properties of tyramine-modified hyaluronic acid - Gelatin hydrogels

A new family of injectable hydrogels, enzymatically crosslinked from mixtures of tyramine conjugates of hyaluronic acid (HA) and gelatin (Gel) are characterized in terms of their molecular morphology, miscibility and water sorption ability by employing Field Emission Scanning Electron Microscopy, water sorption/desorption measurements and differential scanning calorimetry technique. The hydrogels were chemically crosslinked by reaction of the phenol groups of the tyramine in the presence of the enzyme horseradish peroxidase and a small amount of hydrogen peroxide. The water fraction in the microporous hydrogels, hw, was up to 0.68 being achieved by equilibration in environment of saturated water vapor. Our measurements reveal good miscibility between HA and Gel components in the whole hydration range studied and that the HA/Gel mixtures exhibit glass transition characteristics, water diffusion dynamics and equilibrium water contents that are independent of the composition. The intermolecular interactions have been found to be dependent on the hydration level and the mixtures behave like the Gel component for hw < 0.20 and like the HA for higher hydration levels. On the other hand, the appearance of gel-sol like transition in all mixtures, like in neat Gel component, points to nanoscale heterogeneities in the hydrogels and the existence of Gel-rich nanodomains. Calorimetric measurements on hydrogels at high hydration levels (hw > 0.40) show that they become partially crystallized at subzero temperatures and reveal that absorbed water molecules form, at least, two discrete forms of ice crystals. In the phase separated hydrogels, next to ice phase, a second phase of polymer/water homogeneous mixture with constant water fraction about 0.25 has been identified.

Investigation of Controlled Release Molecular Mechanism of Oil Phase in Spilanthol Emulsion: Development and In Vitro, In Vivo Characterization.

The aim of the present study was to develop a spilanthol emulsion and investigate the effect of oil and drug physicochemical properties on drug release and skin retention at molecular level. Formulation factors including oil, emulsifier, and humectant were investigated by in vitro skin retention/permeation study and the optimized formulation was evaluated in vitro and in vivo. In addition, the controlled release effect of oil was characterized using drug emulsion distribution study, drug release study, FT-IR, and molecular modeling. The optimized emulsion (squalane as oil phase) obtained the maximum skin retention (118.71 ± 10.30μg/g), which significantly restored skin hydroxyproline content (23.99 ± 2.21μg/g), compared with the positive group (14.75 ± 1.84μg/g) and the negative group (15.55 ± 2.03μg/g). It was caused by high drug release of squalene and good drug-skin miscibility. FT-IR and molecular modeling showed that spilanthol (SPI) interacted with squalene through Van der Waals force, which was weaker than a hydrogen bond formed with other oils, thus exhibited good drug release properties. And the released drug was stored in the skin due to good drug-skin miscibility, which was proved by miscibility calculation and molecular modeling. In conclusion, an effective emulsion was developed and the controlled release effect of oil phase was proved through drug-excipient interaction.

Alginate-Graphene Oxide Biocomposite Sorbent for Rapid and Selective Extraction of Non-Steroidal Anti-Inflammatory Drugs Using Micro-Solid Phase Extraction

In this work, a bio-composite sorbent, alginate incorporated graphene oxide (Alg/GO) is prepared for the micro solid phase extraction of non-steroidal anti-inflammatory drugs (NSAIDs) from water samples. The sorbent was prepared in a suspended solution form at a ratio of 0.3:1 (w/v %) of graphene oxide (GO) and alginate (Alg). The chemical structure, morphology and surface area of the composite beads were characterized using Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM) and Brunauer–Emmett–Teller (BET). GO showed good miscibility and well dispersion through intermolecular hydrogen bonds and electrostatic interactions within the Alg matrix. The synthesized sorbent was applied for the determination of the selected drugs in a tap water sample using micro-solid phase extraction technique and was analyzed by high-performance liquid chromatography-ultraviolet detector (HPLC-UV). The results showed good linearity in the range of 10–1000 µg L–1 with correlation coefficients (r ≥ 0.9979), low detection limits (LOD) between 3.1–4.6 µg L–1, excellent relative recoveries in the range of 99.6–102.1% and good reproducibility (RSD ≤ 3.9%). Thus, these validated results showed that Alg/GO could be potential and useful as a bio-composite sorbent for micro-solid phase extraction for the analysis of targeted drugs from aqueous matrices.