Search

Copyright of Rare Metals is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study chitosan (CS) films were prepared from a deep eutectic solvent (DES) composed of choline chloride and malonic acid by solvent casting, and the influence of DES content on the structure and properties of the CS films was investigated in detail. It was confirmed by the spectral data that hydrogen bonds and ionic bonds were formed between the CS chains and DES. Structural analysis demonstrated that the crystallization of the CS was greatly hampered and the CS chains were stacked disorderly in films with high DES content. Differential scanning calorimetry (DSC) results indicated that DES exerted a significant plasticizing effect. In the case of the plasticized film containing 80 wt% of DES it showed a low glass transition temperature (Tg) of 20 °C. With increasing DES content, the water content of the plasticized films also increased, evidenced by the TGA results. Meanwhile, a structural change from granular to lamellar structure was observed by SEM. In addition, compared with pure CS film, the DES plasticized CS films possessed good fracture toughness and hydrophilicity. These observations suggest that the structure and properties of the CS films can be controlled by changing their DES content. [ABSTRACT FROM AUTHOR]

Currently, there is an environmental problem associated with cleaning the seas and oceans from a large number of dead jellyfish thrown ashore and into the coastal zone, which is urgent and requires solutions. This research aims to study the formation and properties of cement and concrete with added jellyfish mass and to understand the effects of this addition. Tests were carried out on formulations containing dead jellyfish mass in amounts from 0.2% to 1.6%. This study focused on the density, shear stress, workability, water separation, strength, and water absorption of cement and concrete, which are the main properties that characterize cement and concrete in construction. Adding 0.6% dead jellyfish to this composition resulted in greater effectiveness compared to the control composition. With this dosage, the normal density of the cement paste decreased by 16.3%, there was a 32% decrease in ultimate shear stress, the workability expressed in the cone slump increased by 60.8%, the water separation of cement decreased by 19.7%, the increase in compressive strength was 10.6%, and water absorption decreased by 15.5%. An analysis of the structure showed that the modification of concrete with dead jellyfish mass reduces the defectiveness of a concrete structure compared to the composition of the control structure. [ABSTRACT FROM AUTHOR]

Purpose: The present work was intended to develop the ibuprofen-Kollicoat® MAE 100P delayed-release pellets using hot-melt extrusion technology, which exhibits pH-dependent solubility. Ibuprofen irritates the gastric lining, so its release in the gastric environment is not desired. Conventionally, Kollicoat® MAE 100P has been used as an enteric coating polymer, and we have explored its application using hot-melt extrusion technology in our work. Methods: Three different drug loadings were processed at various extrusion temperatures using HME to produce pellets of uniform size. DSC was performed to study the drug's state, the polymer's thermal behavior, and drug-polymer miscibility. An in vitro drug release study was performed in 0.1N HCl followed by pH 6.8 phosphate buffer to understand the ability of the polymer to impede the release of ibuprofen in the stomach. Furthermore, the lead batch was characterized by DSC, FTIR, HS-PLM, and optical microscopy to study the interaction between the drug and polymer. Results: The thermogram of the pellets indicated no drug-polymer immiscibility. This work also demonstrates proof of the plasticizing ability of ibuprofen. Drug release studies showed less than 1.5% drug release in 0.1N HCl in 2 h, and complete drug release was obtained in the next 2 h in pH 6.8 phosphate buffer, indicating the delayed-release characteristics of the pellets. Conclusion: This work proves that Kollicoat® MAE 100P could be used in modified-release dosage forms to attain the delayed-release pellets. Schematic representation of development of ibuprofen delayed release pellets [ABSTRACT FROM AUTHOR]

ABSTRACT: Introduction. To create concrete with a set of physical and mechanical characteristics, a rational selection of the components of the concrete mix is required, including the use of finely dispersed fillers, including those based on recyclable materials, and a highly effective chemical additive of a certain nature and reactive action, which has a complex effect on concrete system. Methods and materials. The effectiveness of the components in used additive was assessed by changing the indicators of compressive strength, tensile strength in bending, the assessment of which was carried out according to GOST 10180-2012 “Concrete. Methods for determining the strength of control samples. For carrying out scientific and experimental studies, the following materials were used: Portland cement CEM I 42.5N; natural sand; fine microsilica; complex chemical additive with increased plasticizing and reactive effects. Results. The combination of polycarboxylate polymers and nanodispersions of silicon hydroxide enhances the effectiveness of each component, which is reflected in a significant increase in the coefficient of crack resistance of concrete at high compressive strength. It has been established that when using a complex nanopolymer chemical additive, the increase in tensile strength in bending is 67% and it exceeds the increase in compressive strength by more than 30%. Discussion. An increase in hydration activity in the presence of a nanopolymer additive has a positive effect on the compaction of the emerging concrete structure. Confirmation of the formation of a dense and strong structure during the hardening of nanomodified concrete is an increase in the water resistance of concrete by 2.5 times and its frost resistance by more than 2.5 times. Conclusion. The advantage of nanomodified concrete is its increased chemical resistance to carbon dioxide and magnesia corrosion and, in accordance with the index of chemical resistance coefficient, CCSт> 0.8, and GOST R 58895-2020, the developed nanomodified concrete belongs to chemically highly resistant concretes. It is advisable to recommend nanopolymer concrete with high physical and mechanical properties for the manufacture of structures for overhead power transmission lines (OPL).

The growing environmental concern with the inappropriate disposal of conventional plastics has driven the development of eco-friendly food packaging. However, the intrinsic characteristics of polymers of a renewable origin, e.g., poor mechanical properties, continue to render their practical application difficult. For this, the present work studied the influence of ionic strength (IS) from 0 to 500 mM to modulate the physicochemical properties of methylcellulose (MC). Moreover, for protection against biological risks, Nisin-Z was incorporated into MC’s polymeric matrices, providing an active function. The incorporation of salts (LiCl and MgCl2) promoted an increase in the equilibrium moisture content in the polymer matrix, which in turn acted as a plasticizing agent. In this way, films with a hydrophobic surface (98°), high true strain (85%), and low stiffness (1.6 mPa) can be manufactured by addition of salts, modulating the IS to 500 mM. Furthermore, films with an IS of 500 mM, established with LiCl, catalyzed antibacterial activity against E. coli, conferring synergism and extending protection against biological hazards. Therefore, we demonstrated that the IS control of MC dispersion presents a new alternative to achieve films with the synergism of antibacterial activity against Gram-negative bacteria in addition to flexibility, elasticity, and hydrophobicity required in various applications in food packaging.

Thymol, known for its antimicrobial properties, was combined with acetic acid, betaine, and caprylic acid to form hydrophobic natural eutectic solvents (NAES), whose influence on the properties of bovine gelatin films was investigated. Films showed enhanced mechanical performance and a clear plasticizing effect provided by the natural eutectic solvents. At 300 wt% concentration, tensile strength and elongation at break reached 871 ± 78 kPa and 141 ± 10 % for acetic acid, 391 ± 41 kPa and 159 ± 10 % for betaine, and 1209 ± 52 kPa and 198 ± 15 % for caprylic acid. Water vapor permeability and total soluble matter were reduced, and swelling decreased to ~250 %, ~150 %, and ~ 200 % for films with 300 wt% of acetic acid, betaine, and caprylic acid, respectively. Pure thymol exhibited significant volatility, with 17.10 ± 1.50 % weight loss over one week, while the NADES demonstrated dramatically reduced losses (up to 1.15 ± 0.04 %). The films displayed exceptional antibacterial activity, achieving inhibition diameters of 34 mm against Gram-positive and Gram-negative bacteria, and films with caprylic or acetic NAES achieved undetectable CFU levels for major pathogens on chicken breast. These results highlight the antimicrobial potency and enhanced stability of NAES-based gelatin films for active packaging applications. • Thymol was combined with acetic acid, betaine, and caprylic acid to form NAESs. • The addition of NAESs into gelatin matrix was studied for active films development. • The incorporation of NAESs provided a plasticizing effect on the prepared films. • The incorporation of NAESs improved the physicochemical properties of the films. • The films containing thymol-based NAESs showed exceptional antibacterial efficacy. [ABSTRACT FROM AUTHOR]

In this paper, we synthesized a kind of bio-based plasticizer epoxidized linoleic acid cardanol ester (ELCE) from cardanol and linoleic acid. Its chemical structure was characterized with FT-IR and 1H NMR. Polyvinyl chloride (PVC) blends plasticized with ELCE were prepared via thermoplastic blending with torque rheometer. The performance including torque, mechanical property, thermal stability, plasticizing property and migration resistance of plasticized PVC blends were investigated and compared with plasticized PVC blends with commercial plasticizer dioctyl phthalate (DOP). The results showed that ELCE improved thermal stability of PVC blends. ELCE played more excellent plasticizing effect on PVC blends than DOP. The better solvent extraction resistance and volatile resistance of ELCE make it possible to completely replace DOP in PVC products. [ABSTRACT FROM AUTHOR]

The growing environmental concern with the inappropriate disposal of conventional plastics has driven the development of eco-friendly food packaging. However, the intrinsic characteristics of polymers of a renewable origin, e.g., poor mechanical properties, continue to render their practical application difficult. For this, the present work studied the influence of ionic strength (IS) from 0 to 500 mM to modulate the physicochemical properties of methylcellulose (MC). Moreover, for protection against biological risks, Nisin-Z was incorporated into MC's polymeric matrices, providing an active function. The incorporation of salts (LiCl and MgCl2) promoted an increase in the equilibrium moisture content in the polymer matrix, which in turn acted as a plasticizing agent. In this way, films with a hydrophobic surface (98°), high true strain (85%), and low stiffness (1.6 mPa) can be manufactured by addition of salts, modulating the IS to 500 mM. Furthermore, films with an IS of 500 mM, established with LiCl, catalyzed antibacterial activity against E. coli, conferring synergism and extending protection against biological hazards. Therefore, we demonstrated that the IS control of MC dispersion presents a new alternative to achieve films with the synergism of antibacterial activity against Gram-negative bacteria in addition to flexibility, elasticity, and hydrophobicity required in various applications in food packaging. [ABSTRACT FROM AUTHOR]

Background. Surface-active agents (surfactants) are widely used to improve the quality of materials and control technological processes. The urgent problem is the creation of new surfactants and their compositions that improve the rheological and structure-forming properties of dispersed systems and cement slurries. Purpose. Obtaining new surface-active derivatives of maleic acid, the study of their colloid-chemical properties and effectiveness for regulating structure formation in cement suspensions. Methodology. Measurements for the study of plastic strength and structure formation of cement mixtures were carried out on a Geppler consistometer. The density of the cement mixture was characterized by the ratio of the mass of the compacted mixture to its volume. The hydrophilic-lipophilic balance of new surfactants was calculated by group numbers. A refractometer was used to determine the refractive index of aqueous solutions of surfactants. The surface tension of surfactant solutions was determined by Rebinder device. Originality. New surfactants based on maleic acid derivatives with different numbers of ethoxy groups and carbon atoms in the alkyl chain have been obtained. It has been established that they are effective regulators of the structure formation of cement dispersed systems. Findings. It has been established that with an increase in the number of ethoxy groups in the molecule and the length of the carbohydrate chain, the surface activity and foaming ability of surfactants of maleic acid derivatives increase. [ABSTRACT FROM AUTHOR]

Background. In construction, there is a growing interest in the use of plasticizing surfactants for cement mixtures. The synthesis of import-substituting polyfunctional surfactants with plasticizing properties of cement suspensions is topical. Purpose. Obtaining surface-active derivatives of benzoic acid, study of their properties and effectiveness for the regulation of cement dispersed systems. Methodology. The determination of the surface tension of surfactant solutions was carried out on a Rebinder device. To determine the setting time of the cement paste, a Vicat device with a needle was used. Originality. New surfactants have been obtained in the series of benzoic acid derivatives. It is shown that they are effective retarders of the setting time of cement dispersed systems. It has been established that with an increase in the length of the carbohydrate radical, the effectiveness of setting delay increases, and at surfactant concentrations above CMC, the efficiency of setting delay increases. Findings. The effect of new surfactants on the technological properties of cement slurries has been studied. It is shown that at low concentrations, the retarding effect of surfactants increases. The formation of surfactant adsorption layers leads to a decrease in the hydration of cement particles. At high concentrations, adsorption of surfactant aggregates on the cement surface occurs, which leads to increased stability of the dispersion and a decrease in the setting rate of the cement mass. [ABSTRACT FROM AUTHOR]

More and more industries demand environmental friendliness. Silkworm pupae oil (SPO), extracted from the desilked silkworm pupae, can serve as a promising substrate alternative to use in plasticization. This study aimed to prepare epoxidized silkworm pupae oil (ESPO) and investigate their effects on the thermal stability and plasticization of polyvinyl chloride (PVC) films. A chemo-enzymatic method of ESPO was developed in the presence of Lipase SMG1-F278N and H2O2 in natural deep eutectic solvents (DESs). Lipase SMG1-F278N could initiate the epoxidation reaction effectively at room temperature with a negligible loss of activities 10 batches. A maximum oxirane value of 6.94% was obtained. The formation of oxirane ring in ESPO was confirmed by FTIR and 13C NMR spectra. Moreover, ESPO showed a better thermal stability and lower freezing point than epoxidized soybean oil (ESO). It was demonstrated that ESPO had a good frost resistance. In addition, ESPO showed a significantly improved plasticizing effect on flexible polyvinyl chloride (PVC). Compared with ESO, ESPO could increase the tensile elongation at break effectively. A significantly lower migration rate of plasticizer was observed in PVC plasticized with ESPO. [ABSTRACT FROM AUTHOR]

Biobased plasticizers for polymers is a necessity to replace conventional phthalates based plasticizers. In the present study, Citrullus lanatusseed oil (ECLO) was epoxidized in a magnetically stirred reactor. Polyvinyl chloride (PVC) films were synthesized using different concentrations of ECLO. At 40% of ECLO, films showed better surface morphology and exhibited maximum strength and elongation at break. Plasticized PVC film shown tensile strength of 18.6 MPa and elongation at break of 136.18%. No migration was observed in water, designating hydrophobic characteristics of the films. In gasoline, acid (Acetic acid) and alkali (Sodium hydroxide), plasticized samples exhibited a low resistance for migration. X-ray diffraction analysis confirmed no change in crystallinity of PVC after addition of ECLO. Thermogravimetric analysis presented the plasticized PVC films are thermally stable. Differential scanning calorimetry established the plasticizing effect of ECLO as a glass transition temperature (Tg) of plasticized films was shifted to a lower temperature.Furthermore, Fourier transform infrared spectroscopy revealed interaction of ECLO with PVC as peaks of C–Cl bond (833 cm−1) and CO stretch (1739 cm−1) were detected. Thus, the present study delivered a better substitute for phthalates as it endorses the application of ECLO in the PVC blend as a plasticizer.

[Display omitted] • Internal plasticizing effect: flexible substituents increase mobility, lowering T g. • Universal theory: the internal plasticizing concept applies to both simple van der Waals liquids and H-bonded systems. • Elemental composition and molar mass: insufficient descriptors to describe the structure - T g relationship. Despite years of intense investigation, calculating glass transition temperature, T g , of non-polymeric molecules remains challenging due to many factors affecting this physical quantity. In this article, we have synthesized and thoroughly analyzed three aromatic esters of 1,2-bis(2-hydroxyethylthio)-4-methylbenzene: 1,2-bis(2-acetoxyethylthio)-4-methylbenzene, 1,2-bis(2-propionyloxyethylthio)-4-methylbenzene, and 1,2-bis(2-butyroxyethylthio)-4-methylbenzene. Utilizing differential scanning calorimetry (DSC) and broadband dielectric spectroscopy (BDS), we reveal that T g of these compounds diminishes gradually as the length of the ester group increases from the two-carbon acetic to four-carbon butyric moiety, contradicting the so-far established structure - T g relationships. We indicate that the primary origin of this unexpected trend lies in the increasing flexibility of the aromatic ring side chains. Consequently, we examine the concept of the internal plasticizing effect among low-molecular-weight glass-formers, defining it as a phenomenon, wherein the presence of a flexible substituent (particularly when attached to a rigid moiety) leads to a decrease in T g of a non-polymeric organic compound due to hindered intermolecular packing and enhanced intramolecular dynamics. We demonstrate the universality of this theory, which goes beyond the studied set of aromatic esters, being applicable to CHN–, CHON–, CHOS-, CHNS-, and CHO-based compounds encompassing both simple van der Waals liquids and H-bonded systems. Finally, we highlight the importance of this effect for models parametrizing the structure- T g relationship of non-polymeric glass-formers. [ABSTRACT FROM AUTHOR]

The requirement of developing energetic binders with suitable energetic plasticizers is to enhance the mechanical properties and to reduce glass transition temperature of propellant and explosive formulations. Compatibility of energetic plasticizer 2,4-dinitro-2,4-diazapentane (DNDA-5) with four different energetic binders viz. poly glycidyl nitrate (PGN), poly(3-nitratomethyl-3-methyloxetane) (PLN), glycidyl azide polymer (GAP) and tetra functional glycidyl azide polymer (t-GAP) was studied by using differential scanning calorimeter (DSC) and density functional theory (DFT) methods. Results obtained for the pure binder was compared with the results obtained for binder/plasticizer blend in the parameters of decomposition temperature and the format of the peak which indicated the compatibility or incompatibility of DNDA-5 with the studied binders. Glass transition temperatures of all these blends were determined by low temperature DSC and showed desirable lowering of glass transition temperature with single peak in the case of PLN. The proposed energetic plasticizer DNDA-5 has displayed its compatibility with three binders PGN, PLN and GAP employing thermal techniques. DNDA-5 has been found as incompatible when it is mixed with t-GAP. The predicted relative trend of interaction energies between plasticizer and binder has provided concurrence to results drawn from thermal studies. [ABSTRACT FROM AUTHOR]

Purpose: The microencapsulation of plasticizing molecules, such as 4-methoxy chalcone (4MC), can raise serious stability issues in microparticle (MP) manufacturing and storage, especially when employing low glassy pseudo-plastic polymers, such as polylactides (PLA) and polylactide-co-glycolides (PLGA). In this work, two distinct steps were undertaken: (1) the study of the effect on manufacturing and storage of 4MC loading in polyester MP and (2) the investigation of a new stabilization strategy based on 4MC intercalation into a stearate-modified hydrotalcite (sHTC). Methods: 4MC was loaded up to 20% w/w in PLA and PLGA MP by a W/O emulsion solvent extraction/evaporation method. Likewise, the 4MC-sHTC intercalation compound was prepared and loaded in the MP in the same conditions using a W/O/W double-emulsion method. All preparations were characterized by spectrophotometry, thermal analysis, x-ray powder diffraction (XRPD), scanning electron microscopy (SEM), and energy-dispersive x-ray spectroscopy (EDX) and for their particle size, in vitro drug release profile and kinetics. Storage stability was assessed over 8 months of incubation at room temperature (rt) and 30% relative humidity (RH). Results: The obtained 4MC-loaded MP showed a non-straightforward loading-dependent change of size, morphology, and release behavior. 4MC loading caused extensive clumping and poor MP recovery. Thermal and XRPD analyses confirmed a strong plasticizing effect of 4MC that, in some cases, segregated as crystals on the particle surface. Plasticization was inversely related to drug release. The loading of 4MC as a sHTC intercalation compound granted increased stability upon manufacturing and SEM-EDX evidenced a loading effect on porosity and the 4MC-sHTC distribution inside the MP. A remarkable stability increase was observed over 8 months storage at rt and 30% RH with no changes in the outer and inner MP morphology and compound distribution. Conclusions: The use of sHTC could be a useful stabilization strategy to improve manufacturing of biodegradable MP, surely worthy of further investigation in order to be extended to other MP drug delivery systems. [ABSTRACT FROM AUTHOR]

Thermoplastic starch(TPS)was prepared with glycerol, formamide and compound plasticizer as plastic modifier for cornstarch by small internal mixer. The influence rules were studied that the properties of TPS and starch plasticization of plasticizer type. Differential FT-IR、XRD and SEM were used to the characterization of plasticizing effect, the mechanical properties and water absorption of TPS were tested. The results showed that the order of plasticizing effect from strong to weak is formamide, compound plasticizer and glycerol under the premise of optimum proportions about single and compound plasticizer. In addition, when the ratio of starch to formamide was 10:4. 5, it can be achieved that good plasticizing effect and resistance of starch to regeneration. Simultaneously, the prepared TPS exhibited good mechanical properties and low water absorption. [ABSTRACT FROM AUTHOR]

Azido‐terminated hyperbranched multi‐arm copolymer (POGA) with hyperbranched polyether core (PEHO‐c) and linear azido‐terminated glycidyl azide polymer arms (GAPA‐a) has been prepared. The structures of the polymers were characterized by FT‐IR, NMR, GPC and elemental analysis. The molecular weight of POGA was up to ca 17000 g mol−1, far higher than that of common plasticizers (200∼1000 g mol−1). The enthalpy of formation and high nitrogen content of POGA demonstrated its remarkable energy level, and low impact and friction sensitivities indicated its good safety performance in mechanical stimuli. The results of the kinetic and thermodynamic parameters, calculated from non‐isothermal DSC, denoted a fine thermal stability of POGA. Furthermore, the plasticizing effect of POGA, evaluated by plasticizer efficiency and viscosity, was superior to A3 but inferior to Bu‐NENA, however, its exudation was much slower than that of small molecular plasticizers, especially Bu‐NENA. Moreover, the plasticizing mechanism of POGA as energetic macromolecular plasticizer was established by analyzing its structure and performance characteristics. [ABSTRACT FROM AUTHOR]

• The change of Tg value of PMMA with the interaction with DBM. • The amount of decrease in Tg is proven by both DSC analysis and DFT calculations. • DFT computations supported the experimental test. • The importance of chemical reactivity in polymer modifications was explained. In this study, the amount of change in the glass transition temperature (Tg) of PMMA was analyzed by DSC by adding different ratios of dibutyl maleate (DBM) plasticizer to polymethyl methacrylate (PMMA), which is used as the main ingredient of prosthetics in dentistry. For this, liquid DBM was added to powdered PMMA at a rate of 2, 5, 8 and 15 % by mass, and polymerization was carried out at 100 °C. Mechanical tests such as impact resistance, transverse resistance and maximum flexion tests were applied to these prepared mixtures. It was observed that there was a significant parallelism between the Tg values calculated from the DSC curves and the mechanical tests. The Tg value of PMMA was reduced by approximately half with the addition of DBM plasticizer. Additionally, the chemical interaction between PMMA and DBM was analyzed in the light of the Density Functional Theory (DFT) calculations. The binding energy for the mentioned interaction was determined as 1.591 eV. After both species interacted with each other, the glass transition temperature of the formed complex system was theoretically also predicted through the quantitative structure-property relationship (QSPR) model. For theoretical prediction of Tg, the molecular traceless quadrupole moment Θ and the molecular average hexadecapole moment Φ, are used. The change determined as experimental in glass transition temperature as a result of the interaction between PMMA and DBM was supported with theoretical calculations. Experimental and theoretical data are in good agreement. [ABSTRACT FROM AUTHOR]

The main purpose of this paper was to evaluate the impact of both high- and low-Tg polymer additives on the physical stability of an amorphous drug, sildenafil (SIL). The molecular mobility of neat amorphous SIL was strongly affected by the polymeric excipients used (Kollidon VA64 (KVA) and poly(vinylacetate) (PVAc)). The addition of KVA slowed down the molecular dynamics of amorphous SIL (antiplasticizing effect), however, the addition of PVAc accelerated the molecular motions of the neat drug (plasticizing effect). Therefore, in order to properly assess the effect of the polymer on the physical stability of SIL, the amorphous samples at both: isothermal (at constant temperature—353 K) and isochronal (at constant relaxation time—τα = 1.5 ms) conditions were compared. Our studies showed that KVA suppressed the recrystallization of amorphous SIL more efficiently than PVAc. KVA improved the physical stability of the amorphous drug, regardless of the chosen concentration. On the other hand, in the case of PVAc, a low polymer content (i.e., 25 wt.%) destabilized amorphous SIL, when stored at 353 K. Nevertheless, at high concentrations of this excipient (i.e., 75 wt.%), its effect on the amorphous pharmaceutical seemed to be the opposite. Therefore, above a certain concentration, the PVAc presence no longer accelerates the SIL recrystallization process, but inhibits it.

Fresh blueberries were processed into three powder forms through freeze drying, namely juice powders containing 8% whey protein isolate (WPI), fruit powders and pomace powders. The water binding behaviors of these blueberry powders were studied through thermodynamic sorption analysis, quantification of water plasticizing effect and characterization of particle properties. The GAB model was successful in fitting the water sorption isotherms of blueberry powders at 20, 35 and 50 °C. Thermodynamic studies revealed that the sorption processes of all the samples were enthalpy-driven and only the sorption process of blueberry juice powders containing WPI was spontaneous (Δ G < 0). Meanwhile, the highest absolute integral entropy values for blueberry juice powders containing 8% WPI, fruit powders and pomace powders were obtained at the moisture contents of 0.011, 0.013 and 0.024 kg H 2 O/kg dried matter, respectively. Furthermore, the plasticizing effect of water on blueberry pomace powders was the weakest, since its k value of Gordon-Taylor model was lower than that of other samples. These results implied that blueberry pomace powders had the weakest affinity with water molecules. Thus, blueberry juice powders containing 8% WPI and fruit powders were suggested to be stored at a lower relative humidity than pomace powders. Besides, it was temporarily found that the difference in water binding capacity among blueberry powders was associated with the distribution of functional groups derived from sugars and acids, as well as the particle size. All the results can be a reference for drying, packaging, storage and distribution of blueberry powders in practical applications. [ABSTRACT FROM AUTHOR]

Sodium gluconate (SG) is usually employed as a supplementary material in polycarboxylate superplasticizer (PCE) system to enhance the dispersion and dispersion retention. In real concrete, this enhancement cannot always be achieved as expected, and sometimes, even a negative effect can be found. This uncertainty is mainly because SG would perturb the dispersion of PCE, while the mechanism behind has not been completely understood. The objective of this study is to investigate the interaction between PCE and SG. The rheology was studied to assess the dispersion ability, and adsorption behavior was characterized with total organic carbon analyzer. The combination between PCE and SG was analyzed with conductivity, X-ray photoelectron spectrometer and dynamic light scattering. The dispersion model was then proposed to explain the main mechanism behind. The results show that two positive effects of SG on dispersion of PCE-SG system can be found: one is the formation of water film caused by adsorption of SG, and the other is more interesting, namely the combination between SG and PCE via the bridging Ca 2+ to enhance the steric hindrance. The negative effect of SG can also be found, mainly because of the hindrance to adsorption of PCE resulting from competitive adsorption. Accordingly, the dispersion of PCE-SG depends on the predominant effect: when the dosage of SG less than 0.10%, the contribution to dispersion predominates; while the competitive adsorption effect predominates when the dosage more than 0.10%, with a decline in dispersion ability. Such results would provide guidance on the design of high efficient dispersant system in real engineering practice. [ABSTRACT FROM AUTHOR]

The creep behavior of an E-glass-polyester matrix composite was evaluated as a function of time of immersion in water and lubricant oil. The effect of the test temperature was also evaluated. It was observed that, after 6 and 14 months of exposure to the aging fluids, the Young’s modulus of the composite was reduced by 20% regardless the aging fluid when the test was performed at room temperature. For the tests performed at 60 °C, the effects of immersion in lubricant oil were more severe than those after immersion in water. Variation of the creep behavior due to exposure to water was associated only to physical aging, because the properties’ variation was correlated to the amount of absorbed water, decreasing only while the amount of water increased. The test temperature was shown to be the main parameter influencing the creep behavior of the composite. The action of the plasticizing effect of water and reduction of oil viscosity with temperature influenced the results of the steady creep rate when the tests were performed at 60 °C. Micromechanics approach was used to qualitatively explain the experimental results obtained. [ABSTRACT FROM AUTHOR]

This study deals on the supercritical impregnation of thymol in polylactic acid (PLA) in order to obtain biodegradable antimicrobial films by means of a procedure, which is in agreement with the principles of green chemistry, reducing the environmental impact of products and of its preparation processes. The impregnation tests were carried out in a high-pressure cell using supercritical carbon dioxide as impregnation medium at different operational conditions. These assays were implemented at pressures of 9 and 12 MPa, a constant temperature equal to 40 °C and different values of depressurization rates: 0.1, 1.0 and 10 MPa min −1 . Depending on the impregnation process conditions, thymol was incorporated into the films at concentrations from 13.5 to 20.5 %w/w. FTIR analyses confirmed the presence of thymol on the surface of the films. Furthermore, the supercritical impregnation process at the conditions used in this work produced a strong modification of the thermal and mechanical properties of the PLA films. On the other hand, release kinetic assays were carried out on the all prepared films. From these experimental results, it can be observed that the highest amounts of released thymol at the slowest depressurization rate were obtained. Meanwhile, the use of a previously reported mass transfer model shows that there is no significant effect of the supercritical impregnation process on the transport properties of PLA. From the experimental and theoretical results obtained in this work, it could be suggested that the impregnation of thymol in PLA using dense carbon dioxide is a promising technique to prepare active biodegradable materials for a wide range of applications. [ABSTRACT FROM AUTHOR]

The development of energetic binders with suitable energetic plasticizers is required to enhance the mechanical properties and to reduce the glass transition temperature of propellant and explosive formulations. The compatibility of the energetic binder poly(3-nitratomethyl-3-methyloxetane) (polyNIMMO) with five different energetic plasticizers viz. bis(2,2-dinitro propyl)acetal (BDNPA), dinitro-diaza-alkanes (DNDA-57), 1,2,4-butanetriol trinitrate (BTTN), N- N-butyl- N'(2-nitroxy-ethyl) nitramine (BuNENA) and diethyleneglycoldinitrate (DEGDN) was studied by differential scanning calorimetry (DSC), rheology, and DFT methods. The results obtained for the pure binder were compared with the results obtained for the binder/plasticizer blend in regard of the decomposition temperature and the format of the peak indicated the compatibility of polyNIMMO with the plasticizers. The glass transition temperatures of the blends were determined by low temperature DSC and showed desirable lowering of glass transition temperature with single peak. The rheological evaluation revealed that the viscosity of the binder is considerably lowered by means of flow behavior upon addition of 20 % (w/w) plasticizer. The addition of BuNENA and DEGDN has maximum effect on the lowering of viscosity of polyNIMMO. The predicted relative trend of interaction energies between plasticizer and binder is well correlated with the corresponding trend of viscosity of binder/plasticizer blends. These experimental studies verified by theoretical methods are valuable to design practical blends of new plasticizers and binders. [ABSTRACT FROM AUTHOR]

Glass transition phenomena applied to powdered amorphous food carbohydrates. During these last fifteen years, some food technologists and scientists have become aware of the importance of the glass transition, a thermal property of glassy or amorphous material, in food preparation processes. Recent studies have successfully correlated this fundamental notion to technofunctional changes within the powder. The aim of this paper is to present in a non exhaustive manner the relationship between glass transition characteristics and applications in food technology (caking, alterations, etc.).

Although bacteriophage (phage) has great potential use as an antimicrobial material, its application is limited due to its high susceptibility to physical stress in a liquid state. In this study, phage T4 was spray-dried into fine dry powders to improve its usability as an antimicrobial agent. In specific, phage T4 was co-encapsulated with maltodextrin and trehalose, and the effects of the two miscible systems on phage lytic activity were investigated to identify the optimal formulation. The changes in physicochemical properties of the microcapsules were evaluated relative to differences in phage lytic activity after spray-drying. The formulation of 11% (w/w) maltodextrin and 4% (w/w) trehalose miscible system (MD11/TR4) was the best, with high phage lytic activity and strong antimicrobial activity. Because the two materials are hygroscopic, both water sorption isotherms with a Guggenheim-Anderson-de Boer model fitting and changes in thermal and structural properties were investigated. When the MD11/TR4 microcapsules were stored at various relative humidity conditions, the water-plasticizing effect affected the lytic activity of encapsulated phages. The MD11/TR4 formulation efficiently maintained the phage lytic activity at 22.6% RH, even when stored at 25 °C. The phage microcapsules were applied to control bacterial growth in foods, suggesting the utilization as alternative antimicrobial agents. [Display omitted] • Maltodextrin (MD) and trehalose (TR) effectively encapsulate the phage T4. • The stability of phage microcapsules depends on the storage relative humidity (RH). • The MD 11%/TR 4% microcapsules maintain phage viability for 6 weeks at 22.6% RH. • The MD 11%/TR 4% microcapsules showed strong antibacterial activity on food samples. • Potent antimicrobial activity is still found at low and room temperatures. [ABSTRACT FROM AUTHOR]

Biodegradable and edible cassava starch-glycerol based films with different concentrations of yerba mate extract (0, 5 and 20 wt.%) were prepared by casting. The plasticizing effect of yerba mate extract when it was incorporated into the matrix as an antioxidant was investigated. Thermal degradation and biodegradability of the obtained biofilms were also studied. Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), attenuated total reflectance Fourier transform infrared spectroscopy (ATR/FTIR), X-ray diffraction analysis (XRD), water absorbance, stability in different solutions and biodegradability studies were performed. The clear correlation among the results obtained from the different analysis confirmed the plasticizing effect of yerba mate extract on the starch-glycerol matrix. Also, the extract led to a decrease in the degradation time of the films in soil ensuring their complete biodegradability before two weeks and to films stability in acidic and alkaline media. The plasticizing effect of yerba mate extract makes it an attractive additive for starch films which will be used as packaging or coating; and its contribution to an earlier biodegradability will contribute to waste reduction. [ABSTRACT FROM AUTHOR]

In this study, mechanical properties were computed for polyurethane (PU)/ Cloisite20A (C20A) coatings. These coatings material were synthesized by three processing methods at variable clay weight percentages (0–3 wt%). Dispersion of C20A platelets in pre-polymer suspension were assessed by the transmission electron microscopy (TEM). In order to scrutinize the conformational changes in the functional groups at the molecular level, deconvolution of Fourier transform infrared spectroscopy – attenuated total reflectance (FTIR-ATR) spectrum was employed. An enhancement in elongation at break with the reduction in stiffness for the nanocomposites was quantified from dynamic tensile testing. For instance, 3 wt% C20A PU nanocomposites processed by sonication and subsequent homogenization showed a decrease of Young's modulus by 53% but exhibits an increase in both elongation at break and toughness by 97% and 93% respectively. The amount of shear force exerted during the processing protocols played a crucial role w.r.t dispersion of C20A. Even at low wt% (1–2) nanocomposite samples exhibit better mechanical properties in simultaneous processing using sonication and homogenization. To quantify the relationship between theoretical and experimental observations, three conventional mathematical models have been applied. Deviations in model behavior was observed, due to the high sensitivity of the nanocomposites to processing schemes, even with same chemical formulations. • Polyurethane-Cloisite 20A (C20A) nanocomposites subjected to differential processing schemes. • Mechanical properties were determined and assessed by Nicolais and Narkis, Callister and Pukanszky models. • Plasticizing (tactoidal) and Velcro effect (exfoliated) observed for C20A nanoclay platelets in their interface with PU chains. • Enhancement in elongation at break of approximately 14% to 97% is observed with the reinforcement of C20A in PU matrix. [ABSTRACT FROM AUTHOR]

Copyright of Jianzhu Cailiao Xuebao: Journal of Building Materials is the property of Journal of Building Materials and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A new polymeric ionic liquid (PIL), poly(1-vinyl-3-methylimidazolium) bis(fluorosulfonyl)imide (PVyMIM-FSI), has been prepared by polymerization of the monomer of ionic liquids, 1-vinyl-3-methylimidazolium bis(fluorosulfonyl)imide (VyMIM-FSI). Its structure and composition have been characterized by 1H and 19F NMR, and viscosity-average molecular weight (M v). For comparison, the corresponding PIL, poly(1-vinyl-3-methylimidazolium) bis(trifluoromethanesulfonyl)imide (PVyMIM-TFSI), is also prepared and characterized. The physicochemical properties of the binary composite electrolytes of lithium bis(fluorosulfonyl)imide (LiFSI)/PVyMIM-FSI with various concentrations of LiFSI have been comparatively studied with those of the corresponding lithium bis(trifluoromethylsulfonyl)imide (LiTFSI)/PVyMIM-TFSI system, in terms of DSC, TGA, ionic conductivity, and lithium ion transference number (t Li +). Both the FSI−- and TFSI−-based PILs are thermally stable up to 250°C. While both types of the prepared PILs show a significant decrease in glass transition temperature (T g) upon addition of lithium salt, the values of T g for the composite electrolytes of LiFSI/PVyMIM-FSI are all significantly lower by 20–60°C in magnitude than those of the corresponding LiTFSI/PVyMIM-TFSI composite ones, indicating much better plasticizing effect for FSI− vs. TFSI−. The ionic conductivities of LiFSI/PVyMIM-FSI are all higher by about 2 orders in magnitude than those of the corresponding LiTFSI/PVyMIM-TFSI with the same concentration of lithium ions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Effective utilization of glycerol is crucial to avoid environmental burden. • Glycerol is an emerging additive for polymer industry. • Glycerol affects mechanical, barrier, and thermal properties of bio-based polymers. • A lack or excess of glycerol would compromise the film's integrity. Glycerol is the major by-product of the biodiesel production line. Every cycle of processing, yields ∼10% (w/w) of waste glycerol, and therefore, creates a glut in the glycerol market. The underutilized glycerol has undoubtedly increased the environmental liability. There are plenty of research focusing on discovering the effective glycerol utilization to produce value-added chemical commodity to ensure sustainable consumption and production patterns. This paper portrays the existing connection between glycerol and the polymer industry, particularly as a feedstock for polymer synthesis and its role as a plasticizer in the starch polymer. Glycerol is a potential bio-based material to afford prominent biocompatible yet biodegradable polymers for a variety of applications through direct polymerization, fermentation, and chemical conversion. Besides, glycerol plays a critical role in the food packaging industry to perform a plasticizing effect; it improves the ductility of the bio-derived packaging. The native unplasticized starch film is too brittle for handling, while the glycerol-plasticized starch film has adequate flexibility and processability, but with compromised water and gaseous barrier properties. Nevertheless, more established works should be published to exploit the use of this versatile base chemical in diverse fields to good advantages, yet reducing the adverse environmental impact. [ABSTRACT FROM AUTHOR]

Features of the formation of the epoxy-allyl polymers are considered during simultaneous and consecutive curing of epoxy and allyl polymers. Study of their molecular mobility and relaxation properties shows the high interpenetration degree of the epoxy-allyl interpenetrating polymer networks. [ABSTRACT FROM AUTHOR]

Abstract: The degree of gelatinization (DG) of potato starch after treatment with scCO2 was investigated. A broad range of experimental conditions were applied, including variations in temperature (50–90°C), pressure (0.1–25MPa), and the starch water content (16.2–40%wt/wt). Changes in the DG were observed by in situ FT-IR measurements, DSC and confirmed by the XRD analysis. The DG increases at higher temperatures and pressures. A maximum DG of about 14% was achieved at the highest pressure (25MPa) and temperature in the range (90°C). A series of experiments under N2 pressure confirms that scCO2 plays a special role in the gelatinization process. [Copyright &y& Elsevier]

Block copolymers are widely applied to toughen epoxy thermosets but usually imparts plasticizing effect. Herein, SEBS-g-PEG copolymers (BCPs) were synthesized by grafting short and miscible branches of polyethylene glycol (PEG-350) on polystyrene- block -poly(ethylene- co -butylene)- block -polystyrene (SEBS) and were applied to toughen epoxy thermosets. The effect of BCPs loading level on epoxy thermosets' properties were studied. Surprisingly, both the toughness and glass transition temperature (T g) of epoxy composites were increased with increase in BCPs loading level in the range of 4–15 wt%. Morphology analysis revealed that the immiscible poly (ethylene-butylene) blocks (PEB) formed a soft spherical micro-domains surrounded by rigid PS/PEG/epoxy composites. The epoxy miscible PEG, grafted with the PS, created a homogeneous dispersion of the BCP particles in the epoxy matrix and the PS phases were expanded into the epoxy phases. As BCPs loading level increased, the particle density increased but the particle size decreased, subsequently the cross-linking density increased among the rubbery particles, which restricted the movement of segments in the neighboring chains. The fracture toughness of modified epoxy exhibited significant increment by 87% without compromising its T g. [Display omitted] • Epoxy miscible PEG chains created homogeneous dispersion of the SEBS-g-PEG in the epoxy phase, due to its bonding with the PS phase and miscibility in the epoxy phase. • As the loading levels increased, the PS phases expanded in the epoxy due to the miscible PEG branches. • Fracture toughness (K IC) and critical strain energy release rate (G IC) were increased 87% and 196% respectively without sacrificing its T g. [ABSTRACT FROM AUTHOR]

A series of polymer blends of poly(vinyl chloride) (PVC) and epoxidized liquid natural rubber (ELNR) were prepared and characterized. The aim of the work was to study the plasticizing effect of ELNR on the PVC/ELNR blend systems. Thermal properties of the samples were studied by differential scanning calorimetry (DSC). The glass transition temperature of the samples decreased with both degree of epoxidation and the percentage of composition of the samples. The scanning electron microscope (SEM) studies point to the two phase morphology. Tensile test results for the blend samples have been compared. From tensile tests, it was found that elongation of the materials increased with degree of epoxidation. On the other hand, tensile strength and modulus of the material decreased with the epoxide content. A good plasticization effect was observed for samples of ELNR with wt. 50% of epoxidation. [ABSTRACT FROM AUTHOR]

The influence of styrene content on styrene added vinylester resin (VER) is investigated. The network structure and its thermal properties is investigated by differential scanning calorimetry (DSC) and the combination of thermal gravimetric analysis (TGA) and Fourier transform infrared spectrometry (FTIR) (TGA-FTIR). The glass transition temperatures (Tgs) of the resins are found to decrease systematically with increasing styrene content, which decreases the cross-link density of the cured materials. The Tg of VER samples cured 97-98% is significantly lower, by as much as 25°C, than the Tg of a fully cured (100%) sample. This is due to the plasticizing effect of unreacted styrene in the network. The combination of TGA and FTIR confirm the evolution of gaseous styrene moieties at the degradation temperature of vinylester groups, the relative amount of styrene emitted being higher with increasing styrene content. A good correlation is found between the thermal properties by DSC and the results obtained from the TGA-FTIR system. [ABSTRACT FROM AUTHOR]

: The aim of the present study was to determine whether an increased water content during thermal cycling of hot water-treated acrylic was associated with a reduction in surface hardness and an increased opacity or whitening of the surface. : Ten acrylic samples were treated with 30 soak cycles (cycle duration, 24 hours), using warm water (40°C) and an alkaline peroxide tablet (Efferdent® control group); a further ten samples were treated with boiling water (100°C) and one Efferdent® tablet (experimental group). Indentation hardness of the acrylic specimens was measured prior to and immediately following the completion of the warm and hot water treatments, using an automated micro-indentation system. The hydrated acrylic specimens were then allowed to air dry at room temperature (20°C) and were weighed weekly until they had obtained a constant dry weight. The loss in weight of the acrylic specimens represented the maximum water absorption. : The hot water-treated specimens were much whiter than the warm water-treated specimens. The mean reduction in hardness ( HIT) of the acrylic specimens following the treatment with hot water and alkaline peroxide tablet was 12.9%. Treatment with warm water and alkaline peroxide resulted in a slight increase in mean hardness (2.63%). There was a significant correlation between the water content of the acrylic specimens after treatment and the percentage of change in indentation hardness ( r= 0.495, p= 0.026). : The hot water treatment of the acrylic was associated with a significant reduction in hardness. We attribute the whitening and reduction in the hardness of the hot water-treated specimens to absorption of water and a disruption of the acrylic surface structure. [ABSTRACT FROM AUTHOR]

Dielectric properties of P-toluene sulphonic acid (PTSA) doped poly(4-vinylpyridine) have been studied in the frequency range 50 Hz–100 KHz and temperature range 300–430 K. Dielectric constant (&epsiv;′) decreases with increasing frequency and remains almost constant at higher frequencies. There is an increase in constant value at temperatures especially near Tg of the complexes and pure polymer. With increase in the concentration of PTSA, dielectric constant increases and then decreases at higher concentration. The dissipation factor (&epsiv;″) decreases in the medium frequency range and increases at higher frequencies. With respect to temperature the dissipation factor (&epsiv;″) is very high near the Tg values of the complexes and pure polymer. For increasing concentration of dopant &epsiv;″ decreases and increases at higher concentration. The results are interpreted considering the dipole orientation, relaxation of functional groups and polymer chain segments. Effect of further doping with iodine is also studied. AC conductivity values are calculated from dielectric data and effect of temperature and frequency has been studied. [Copyright &y& Elsevier]