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This study aimed to assess the role of the combination of design techniques of the engineered substrates, and the effect of encapsulating Marjoram (Origanum Majorana L.) into the matrix network was studied. To this end, PVA-PEG matrices were designed through 3 techniques of freeze–thaw (FT), the combination of both methods of freeze-drying and freeze-thawing(FT-FD), and ternary technique(freeze-drying,freeze-thawing,cross-linking(FT-FD/CL)), by combining equal volume ratios of both polymers. The results indicated the ternary technique can provide better physicochemical properties(porosity: 96%, lower degradation rate, higher modulus) compared to FT and FT-FD methods. Afterward, encapsulation of Marjoram-extracted bio-actives in the matrix network designed with the ternary technique demonstrated that the increase in the extract concentration up to 3% can increase encapsulation efficiency. The encapsulation also caused a more cohesive network by better bonding between functional groups in herbal biomolecules and polymer chains of the matrix. Mass transport mechanisms and release kinetics of matrix-encapsulated bio-actives indicated a deviation from Fickian diffusion and the release by diffusion and swelling process. Biologically, matrix-loaded herbal carbohydrate(Epi-alpha-Cadinol) improved fibroblast adhesion and distribution on the substrate surface, and led to the better synthesis of collagen fibers, especially in 3% herbal extract, and antibacterial activities owing to the controlled release of sesquiterpenoids and N-Acetyl-l-proline. [ABSTRACT FROM AUTHOR]

Abstract This study aimed to assess the role of the combination of design techniques of the engineered substrates, and the effect of encapsulating Marjoram (Origanum Majorana L.) into the matrix network was studied. To this end, PVA-PEG matrices were designed through 3 techniques of freeze–thaw (FT), the combination of both methods of freeze-drying and freeze-thawing(FT-FD), and ternary technique(freeze-drying,freeze-thawing,cross-linking(FT-FD/CL)), by combining equal volume ratios of both polymers. The results indicated the ternary technique can provide better physicochemical properties(porosity: 96%, lower degradation rate, higher modulus) compared to FT and FT-FD methods. Afterward, encapsulation of Marjoram-extracted bio-actives in the matrix network designed with the ternary technique demonstrated that the increase in the extract concentration up to 3% can increase encapsulation efficiency. The encapsulation also caused a more cohesive network by better bonding between functional groups in herbal biomolecules and polymer chains of the matrix. Mass transport mechanisms and release kinetics of matrix-encapsulated bio-actives indicated a deviation from Fickian diffusion and the release by diffusion and swelling process. Biologically, matrix-loaded herbal carbohydrate(Epi-alpha-Cadinol) improved fibroblast adhesion and distribution on the substrate surface, and led to the better synthesis of collagen fibers, especially in 3% herbal extract, and antibacterial activities owing to the controlled release of sesquiterpenoids and N-Acetyl-l-proline.

Diabetic foot ulcer pose a significant challenge in healthcare, often leading to prolonged healing processes and complications requiring sophisticated and advanced therapeutic interventions. This study focuses on the formulation and development of Doxycycline hyclate loaded chitosan nanoparticles in cross-linked topical hydrogel patches for targeted management of DFU healing. Various characterization techniques, such as FT-IR, Zeta potential, DSC, XRD, and SEM, were employed to confirm and gain insights into the structural and morphological features of the crosslinked topical hydrogel patches. The evaluation parameters encompassed analyzing sol-gel behavior, swelling dynamics, and in vitro drug release studies at pH values of 5.5, 6.5, and 7.4. Drug permeation and deposition was performed utilizing the Franz diffusion cell method. The topical hydrogel patches showed pH-sensitive behavior, with enhanced drug release, swelling, and permeation observed at pH 7.4. The synthesized nanoparticles exhibited a spherical morphology, varying particle sizes ranging from 92.83 nm to 206.2 nm, and a zeta potential measuring -22.4 mV. The patches were produced by incorporating CNPs as carriers for DCH into a polymeric matrix, which required the optimization of free radical polymerization. The ion gelation method was utilized to prepare the CNPs. The solvent evaporation technique was used for grafting the topical hydrogel patches. Among the seven formulations, topical hydrogel patch F6 exhibited the most favorable characteristics, as evidenced by a substantial drug content of 97.21 ± 0.524%. The F6 formulation excelled over other formulations over 72 hours at pH 7.4. Stability testing of the selected F6 formulation over 6 months under accelerated conditions confirmed its viability. Therefore, this polymeric network represents an innovative technology for accelerating the healing process of diabetic foot ulcers through the use of doxycycline hyclate loaded chitosan nanoparticles cross-linked in topical hydrogel patches. [ABSTRACT FROM AUTHOR]

The contemporary focus on lignocellulosic waste valorization has triggered a transformative shift towards the utilization of biocomposite materials. This study endeavours to determine the impact of advanced chemical treatments on the properties (mechanical and physical) of composites based on date palm fibres (DPF). The investigation involves the application of soda (NaOH) and silane coupling agent (SCA) treatments, followed by IR spectroscopy analysis. The experimental framework includes the incorporation of 5 and 25% of treated and untreated fibres into polyvinyl chloride (PVC) composites, which are subsequently subjected to both tensile and 3-point bending deformations. Notably, the findings reveal a substantial improvement in mechanical properties when comparing Young's modulus of untreated fibres with those treated with SCA and NaOH with 7.2%, 75.37% and 37.04% in 5% filler content to the neat matrix. Similarly, in 25% filler content FTS composites showed 156.77%, 141.17% and 96.66% improvement respectively, similar results were found in bending modulus. This outcome confirms the potential of incorporating chemically treated date palm fibres to enhance the mechanical performance of composite materials. The advancements achieved through SCA and NaOH treatments present opportunities for the development of biocomposites with superior mechanical attributes. Such enhanced materials hold promise for a myriad of industrial applications, marking a significant stride towards sustainable and innovative solutions in the realm of lignocellulosic waste valorisation. [ABSTRACT FROM AUTHOR]

The Brazilian mining industry plays a significant role in the country's economy; however, it also generates large volumes of tailings during the ore beneficiation process, resulting in severe environmental impacts. Recent research has explored the potential of iron ore tailings as a raw material in the manufacture of construction materials, with the aim of promoting environmental impact reduction. The characteristic coloring acquired by the materials produced can contribute to their application in some segments, where the aesthetic factor is relevant. In this study, we sought to evaluate the applicability of iron ore tailings, from the dam-breaking disaster that occurred in Mariana-MG, as a pigment for polypropylene, widely used as a polymeric matrix for composites, especially plastic wood. Samples were developed with different contents of polypropylene and iron ore tailings, the latter varying from 1 to 10% in mass, from the processes of thermokinetic mixing, milling, extrusion, pelletization and hot compression. The produced specimens were analyzed as to their appearance, and evaluated as to their mechanical performance. The results obtained show that the tailings have a high pigmentation power when incorporated into the polypropylene, besides not compromising its performance in terms of mechanical properties, even providing flexural strength gains.

The construction of coatings on the surface of materials to avoid contamination is a common means of antifouling that has been extensively and systematically studied. Currently, adding biocide components to the coating to kill bacteria and other adherent microorganisms on the material's surface is the most effective way. However, the loss of effective bactericidal components can cause the coating to lose its long-lasting antimicrobial performance. To solve this problem, the use of organic polymeric antimicrobial agent quaternary ammonium salts came into being. The quaternary ammonium salt component can be chemically bonded to the polymer matrix in the coating, effectively avoiding the loss of the active ingredient. Quaternary ammonium salts mainly achieve bactericidal purposes through interaction with cell membranes, and their antimicrobial activity is closely related to the molecular structure. This article mainly summarizes the relevant research progress of quaternary ammonium salt compounds and divides their application in antifouling coatings into two major categories: quaternary ammonium salt grafted polymer matrix and quaternary ammonium salt compounded with inorganic particles through different doping methods of quaternary ammonium salt in antifouling coatings, summarizing the relevant research in recent years. [ABSTRACT FROM AUTHOR]

A series of homogeneous hybrid BPA.DA-NVP@Eu2L3 materials were obtained through an in situ approach where the luminescent dopant was formed at the molecular level with different contents (0.1; 0.2; 0.5; 1; and 2% by weight). A Europium(III) complex (Eu2L3) with quinoline-2,4-dicarboxylic acid was applied as a luminescence additive while a polymer matrix consisted of a combination of bisphenol A diacrylate (BPA.DA) and N-vinylpyrrolidone (NVP) monomers. Synthesis steps and the final materials were monitored by NMR and Fourier transform infrared spectroscopy (FTIR). The emission, excitation spectra, lifetime, and quantum yield measurements were applied for the determination of the photophysical characteristics. The thermal and mechanical properties of the obtained materials were tested via thermal analysis methods (TG/DTG/DSC and TG-FTIR) in air and nitrogen atmospheres, dynamic mechanical analysis (DMA), and hardness and bending measurements. Generally, even a small addition of the metal complex component causes changes in the thermal, mechanical, and luminescent properties. Hybrid materials with a greater europium complex content are characterized by a lower stiffness and hardness while the heterogeneity and the flexibility of the samples increase. A very small amount of an Eu2L3 admixture (0.1% wt.) in a hybrid material causes an emission in the red spectral range and the luminescence intensity was reached for the BPA-DA-NVP@1%Eu2L3 material. These materials may be potentially used in chemical sensing, security systems, and protective coatings against UV. [ABSTRACT FROM AUTHOR]

The production of renewable energy or biochemicals is gaining more attention to minimize the emissions of greenhouse gases such as methane (CH4) and carbon dioxide for sustainable development. In the present study, the influence of copper (Cu)- and iron (Fe)-based nanoparticles (NPs), such as Cu, Fe3O4, and CuFe2O4, was evaluated during the growth of methanotrophs for inoculum preparation and on the development of a polymeric-matrix-based encapsulation system to enhance methanol production from simulated biogas (CH4 and CO2). The use of simulated biogas feed and the presence of NP-derived inoculums produce a remarkable enhancement in methanol production up to 149% and 167% for Methyloferula stellata and Methylocystis bryophila free-cells-based bioconversion, respectively, compared with the use of pure CH4 as a control feed during the growth stage. Furthermore, these methanotrophs encapsulated within a polymeric matrix and NPs-based systems exhibited high methanol production of up to 156%, with a maximum methanol accumulation of 12.8 mmol/L over free cells. Furthermore, after encapsulation, the methanotrophs improved the stability of residual methanol production and retained up to 62.5-fold higher production potential than free cells under repeated batch reusability of 10 cycles. In the presence of CH4 vectors, methanol production by M. bryophila improved up to 16.4 mmol/L and retained 20% higher recycling stability for methanol production in paraffin oil. These findings suggest that Cu and Fe NPs can be beneficially employed with a polymeric matrix to encapsulate methanotrophs and improve methanol production. [ABSTRACT FROM AUTHOR]

CAPE (caffeic acid phenethyl ester) incorporated microspheres formulate and evaluate these microspheres for topical application. In order to achieve the objective firstly various batches of CAPE loaded microspheres were formulated using varying concentrations of ethyl cellulose as the polymeric matrix and solvent evaporation method. All the microsphere formulations were characterized for yield, entrapment efficiency, In-vitro drug release particle size and FTIR studies were also performed to confirm the non-interference of the drug and excipients. The maximum drug release of CAPE over a period of 12 h was obtained in F2 with 71.02 ± 0.64 % drug concentration found in the dissolution medium whereas the minimum release was witnessed for F5 with 56.89 ± 0.47 drug concentration. The formulation F2 was found to be the most appropriate microspheric formulation loaded with CAPE with good yield, drug encapsulation as well as in vitro drug release. It was therefore considered for formulation in the form of gel. All formulation was achieved employing 22 factorial approaches using both the polymer (carbopol 934) and polypropylene glycol at two concentration levels. All formulations loaded with F2 were found to be white and transparent with good homogeneity with pH ranging from 4.92 to 6.1 confirming that the formulations will be compatible to the skin for topical application. On the basis of the results obtained from the study it can be concluded that Carbopol 934 1% w/v and propylene glycol 20% w/v form an excellent combination for development of gel loaded with microsphere of CAPE. [ABSTRACT FROM AUTHOR]

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The abaca also known as cañamo of manila, produces a natural fiber that is known as the most resistant worldwide natural fiber, that has properties like resistance to salinity, mechanical strength, flexibility, and durability. The unique characteristics of fiber have caused an increase in its use in many industries. However, the cultivation of abaca is threatened by the presence of Fusarium oxysporum f. sp. cubense, one of the most important diseases which has been considered the most lethal, due to the scarcity of existing control methods. The article aims to highlight recent data about the characteristics of the plant and its fiber, crop management, productivity, and the market as an approach updating the current knowledge regarding the abaca. It was found that some characteristics of abaca fiber such as strength and physical properties depend on the position of its leaves, on the maturity of the plant, and also on the fiber extraction system. Regarding fiber extraction, it is mentioned that there are two types of methods (stripping and decortication). Concerning productivity, there exists a considerable difference between the ways of bundle extraction, for instance, the hand stripping technique produces about 20 kg of fiber bundles per day. It is concluded that abaca has great potential as a crop that could boost the markets of various countries. Though the information available on this crop is scarce, it is necessary to increase research about its production and management to promote greater use. [ABSTRACT FROM AUTHOR]

A series of homogeneous hybrid BPA.DA-NVP@Eu2L3 materials were obtained through an in situ approach where the luminescent dopant was formed at the molecular level with different contents (0.1; 0.2; 0.5; 1; and 2% by weight). A Europium(III) complex (Eu2L3) with quinoline-2,4-dicarboxylic acid was applied as a luminescence additive while a polymer matrix consisted of a combination of bisphenol A diacrylate (BPA.DA) and N-vinylpyrrolidone (NVP) monomers. Synthesis steps and the final materials were monitored by NMR and Fourier transform infrared spectroscopy (FTIR). The emission, excitation spectra, lifetime, and quantum yield measurements were applied for the determination of the photophysical characteristics. The thermal and mechanical properties of the obtained materials were tested via thermal analysis methods (TG/DTG/DSC and TG-FTIR) in air and nitrogen atmospheres, dynamic mechanical analysis (DMA), and hardness and bending measurements. Generally, even a small addition of the metal complex component causes changes in the thermal, mechanical, and luminescent properties. Hybrid materials with a greater europium complex content are characterized by a lower stiffness and hardness while the heterogeneity and the flexibility of the samples increase. A very small amount of an Eu2L3 admixture (0.1% wt.) in a hybrid material causes an emission in the red spectral range and the luminescence intensity was reached for the BPA-DA-NVP@1%Eu2L3 material. These materials may be potentially used in chemical sensing, security systems, and protective coatings against UV.

The production of renewable energy or biochemicals is gaining more attention to minimize the emissions of greenhouse gases such as methane (CH4) and carbon dioxide for sustainable development. In the present study, the influence of copper (Cu)- and iron (Fe)-based nanoparticles (NPs), such as Cu, Fe3O4, and CuFe2O4, was evaluated during the growth of methanotrophs for inoculum preparation and on the development of a polymeric-matrix-based encapsulation system to enhance methanol production from simulated biogas (CH4 and CO2). The use of simulated biogas feed and the presence of NP-derived inoculums produce a remarkable enhancement in methanol production up to 149% and 167% for Methyloferula stellata and Methylocystis bryophila free-cells-based bioconversion, respectively, compared with the use of pure CH4 as a control feed during the growth stage. Furthermore, these methanotrophs encapsulated within a polymeric matrix and NPs-based systems exhibited high methanol production of up to 156%, with a maximum methanol accumulation of 12.8 mmol/L over free cells. Furthermore, after encapsulation, the methanotrophs improved the stability of residual methanol production and retained up to 62.5-fold higher production potential than free cells under repeated batch reusability of 10 cycles. In the presence of CH4 vectors, methanol production by M. bryophila improved up to 16.4 mmol/L and retained 20% higher recycling stability for methanol production in paraffin oil. These findings suggest that Cu and Fe NPs can be beneficially employed with a polymeric matrix to encapsulate methanotrophs and improve methanol production.

Thermochromic smart windows have been extensively investigated due to two main benefits: first, the comfort for people in a room through avoiding high temperatures resulting from solar heating while taking advantage of the visible light, and second, the energy efficiency saving offered by using those systems. Vanadium dioxide (VO2) is one of the most used materials in the development of thermochromic devices. The countries located in the tropics show little use of these technologies, although studies indicate that due to their characteristics of solar illumination and temperature, they could benefit greatly. To optimize and achieve maximum benefit, it is necessary to design a window that adjusts to tropical conditions and at the same time remains affordable for extensive implementation. VO2 nanoparticles embedded in polymeric matrices are an option, but improvements are required by means of studying different particle sizes, dopants and polymeric matrices. The purpose of this review is to analyze what has been regarding toward the fabrication of smart windows based on VO2 embedded in polymeric matrices for tropical areas and provide a proposal for what this device must comply with to contribute to these specific climatic needs. [ABSTRACT FROM AUTHOR]

A new series of composite materials (PLMTPA) based on tungstophosphoric acid (TPA) included in a polymeric matrix of polyacrylamide (PLM), with a TPA:PLM ratio of 20/80, 40/60, and 60/40, were synthesized and well characterized by FT-IR, XRD, 31P MAS-NMR, TGA-DSC, and SEM-EDAX. Their acidic and textural properties were determined by potentiometric titration and nitrogen adsorption–desorption isotherms, respectively. Considering 31P MAS-NMR and FT-IR analyses, the main species present in the samples is the [PW12O40]3− anion that, according to XRD results, is highly dispersed in the polymeric matrix or appears as a noncrystalline phase. The thermogravimetric analysis revealed that PLMTPA materials did not undergo any remarkable chemical changes up to 200 °C. Additionally, the PLMTPA materials showed strong acid sites whose number increased with the increment of their TPA content. Finally, PLMTPA materials were used as efficient and recyclable noncorrosive catalysts for the synthesis of 2-benzazepines and related compounds. Good yields (55–88%) and high purity were achieved by a Pictet-Spengler variant reaction between N-aralkylsulfonamides and s-trioxane in soft reaction conditions: low toluene volume, at 70 °C, for 3 h. The described protocol results in a useful and environmentally friendly alternative with operative simplicity. The best catalyst in the optimized reaction conditions, PLMTPA60/40100, was reused six times without appreciable loss of activity. [ABSTRACT FROM AUTHOR]

In past one-decade, significant studies have been reported on metallic/non-metallic, organic/in-organic reinforcements (both at micro/nano-level) in thermoplastic/thermosetting matrix for preparation of feed stock filaments for possible three-dimensional printing (3DP) platform. But hitherto very less has been reported on the decision-making of reinforcement proportions in thermoplastic matrix based upon rheological properties. This paper highlights the use of rheological measurements (melt flow index (MFI) and viscosity) of thermoplastic matrix composite for controlling mechanical, thermal and wear properties, before going for 3D printing on commercial open-source fused deposition modelling (FDM) system as a comprehensive review. The rheological data have been taken for the previous reported work, which has been interpreted mathematically, graphically for developing a decision-making tool in the selection of reinforced composition/proportion in the thermoplastic matrix. As a benchmark, MFI of commercial acrylonitrile butadiene styrene (ABS) was taken and a case study of Nylon 6+ Al+Al2O3 proportions has been evaluated mathematically and graphically in order to predict the composite material properties (such as mechanical, thermal and wear properties), from the rheological measurements. The results highlighted that the intersection point of MFI and viscosity curve plays a crucial role in the selection of composition, that is, reinforcement in polymeric matrix. [ABSTRACT FROM AUTHOR]

Plant biomass-based composites have emerged as a sustainable alternative to synthetic fillers in the maritime industry. They have gained significant attention due to their unique advantages compared to traditional synthetic fillers. These advantages include greater flexibility, environmental friendliness, biodegradability, renewability, and low density. This study provides a comprehensive evaluation of plant biomass-based composites (PBCs) within the maritime sector, focusing on their composition, treatment methods, properties, and diverse applications. It highlights the extensive use of various plant biomass components, such as stems, leaves, seeds, grass, and wood, as effective fillers for PBCs. To enhance their performance, a variety of modification techniques, both physical and chemical, have been successfully employed. Polymer-based matrices are the most commonly chosen for PBC synthesis, although metals and ceramics are also utilized. The study examines the mechanical, chemical, water absorption, thermal, electrical, and morphological properties of PBCs relevant to the maritime industry. Applications of these composites are broad and encompass the production of boats, hulls, decks, canoes, surfboards, shipping ropes, paddles, and more. The adaptability and versatility of PBCs across these applications hold the potential to enhance structural integrity, reduce maintenance costs, and improve environmental performance in the maritime industry. This research contributes to a better understanding of plant biomass-based composites' potential in the maritime sector, addressing global concerns related to climate change and resource conservation. It underscores the pivotal role of PBCs in fostering a more eco-friendly and resilient maritime industry while promoting technological advancements and operational efficiency. [Display omitted] • The feasibility and impact of plant biomass-based composites in the maritime sector. • Composition, treatment, properties of plant biomass-based composites. • Versatile applications of plant biomass-based composites in maritime. [ABSTRACT FROM AUTHOR]

The galactomannan-based gel from Cassia grandis seeds was used to incorporate Penicillium sp. UCP 1286 and commercial collagenases. Experiments were carried out according to a 23-full factorial design to identify the most significant parameters for the incorporation process. The pH of the incorporation solution (pH i), stirring time (t), and initial protein concentration in the crude extract (PC i) were selected as the three independent variables, and the efficiency of collagenase incorporation (E) and collagenolytic activity (CA) after 360 min as the responses. pH i and PC i showed positive statistically significant effects on E , while CA was positively influenced by pH i and t , but negatively by PC i. The fungi collagenase was released from the gel following a pseudo-Fickian behavior. Additionally, no <76 % of collagenase was efficiently incorporated into the gel retaining a high CA (32.5–69.8 U/mL). The obtained results for the commercial collagenase (E = 93.88 %, CA = 65.8 U/mL, and n = 0.10) demonstrated a pseudo-Fickian behavior similar to the fungi-collagenase. The results confirm the biotechnological potential of the gel as an efficient matrix for the incorporation of catalytic compounds; additionally, the incorporation of collagenases was achieved by retaining the proteases CA and releasing them in a controlled manner. [Display omitted] [ABSTRACT FROM AUTHOR]

The objective of this study was the preparation and characterization of a sustained-release matrix tablet containing a high-dose hydrophobic drug and its comparison with marketed products. In the present study, HPMC was applied as the matrix-forming polymer for the sustained release of clarithromycin (500 mg). The compatibility of clarithromycin and excipients was studied using a binary mixture approach and compatible excipients were selected. Matrix tablets were prepared using the high-shear wet granulation technique. Tablets were compressed using oblong (19 mm), shallow concave punches, under a compression weight of 900 mg/tablet. The flow of granules was evaluated by determining their bulk density, tapped density, angle of repose, Hausner ratio, and Car's index. Compressed tablets were tested for their physical parameters, mechanical characteristics, drug content, and in vitro drug release, as per United States Pharmacopeia (USP). Clarithromycin is a drug having poor water solubility and showed compatibility with all the excipients used in the formulation of polymeric matrix tablets. FTIR spectra of clarithromycin, before and after being subjected to the stress conditions, confirmed the compatibility of clarithromycin and other ingredients of the matrix tablets. All the formulations exhibited good rheological characteristics and all the parameters related to flow showed results in the acceptable range. Physically, matrix tablets were smooth and shiny, without any surface defects. Weight variation (±5%) and drug content of the tablets (95–102%) were within the pharmacopeial limits. HPMC successfully sustained the drug release for 24 h. It is concluded from the study that dissolution rate of clarithromycin can be sustained using hydrophilic polymer (HPMC) as a release-controlling agent. [ABSTRACT FROM AUTHOR]

The presence of phenol in wastewater poses a risk to ecosystems and human health. The traditional processes to remove phenol from wastewater, although effective, have several drawbacks. The best alternative is the application of ecological biotechnology tools since they involve biological systems (enzymes and microorganisms) with moderate economic and environmental impact. However, these systems have a high sensitivity to environmental factors and high substrate concentrations that reduce their effectiveness in phenol removal. This can be overcome by immobilization-based technology to increase the performance of enzymes and bacteria. A key component to ensure successful immobilization is the material (polymeric matrices) used as support for the biological system. In addition, by incorporating magnetic nanoparticles into conventional immobilized systems, a low-cost process is achieved but, most importantly, the magnetically immobilized system can be recovered, recycled, and reused. In this review, we study the existing alternatives for treating wastewater with phenol, from physical and chemical to biological techniques. The latter focus on the immobilization of enzymes and microorganisms. The characteristics of the support materials that ensure the viability of the immobilization are compared. In addition, the challenges and opportunities that arise from incorporating magnetic nanoparticles in immobilized systems are addressed. [ABSTRACT FROM AUTHOR]

A matrix of galactopyranose, tetraethylorthosilicate xerogels were used to synthesize glass ionomer gels. The purpose was to produce gels of glass ionomer cement in the presence of a polysaccharide by means of the sol-gel method. The gels were characterized by scanning electron microscope, analysis for fractal dimension, energy dispersive X-ray and watershed segmentation method. According to the results, the gels were successfully synthesized with TEOS xerogels in the presence of a polymeric network in solution. Among other things, the peaks/Î?m² count corresponding to the surface properties of the characterized gels have a normal distribution with ranges between 17 and 22 nm. Also, the analysis of fractal dimension that represents the similarity of the roughness of the surface of the gels has a value of 2.508. [ABSTRACT FROM AUTHOR]

A new series of composite materials (PLMTPA) based on tungstophosphoric acid (TPA) included in a polymeric matrix of polyacrylamide (PLM), with a TPA:PLM ratio of 20/80, 40/60, and 60/40, were synthesized and well characterized by FT-IR, XRD, 31P MAS-NMR, TGA-DSC, and SEM-EDAX. Their acidic and textural properties were determined by potentiometric titration and nitrogen adsorption–desorption isotherms, respectively. Considering 31P MAS-NMR and FT-IR analyses, the main species present in the samples is the [PW12O40]3− anion that, according to XRD results, is highly dispersed in the polymeric matrix or appears as a noncrystalline phase. The thermogravimetric analysis revealed that PLMTPA materials did not undergo any remarkable chemical changes up to 200 °C. Additionally, the PLMTPA materials showed strong acid sites whose number increased with the increment of their TPA content. Finally, PLMTPA materials were used as efficient and recyclable noncorrosive catalysts for the synthesis of 2-benzazepines and related compounds. Good yields (55–88%) and high purity were achieved by a Pictet-Spengler variant reaction between N-aralkylsulfonamides and s-trioxane in soft reaction conditions: low toluene volume, at 70 °C, for 3 h. The described protocol results in a useful and environmentally friendly alternative with operative simplicity. The best catalyst in the optimized reaction conditions, PLMTPA60/40100, was reused six times without appreciable loss of activity.

Thermochromic smart windows have been extensively investigated due to two main benefits: first, the comfort for people in a room through avoiding high temperatures resulting from solar heating while taking advantage of the visible light, and second, the energy efficiency saving offered by using those systems. Vanadium dioxide (VO2) is one of the most used materials in the development of thermochromic devices. The countries located in the tropics show little use of these technologies, although studies indicate that due to their characteristics of solar illumination and temperature, they could benefit greatly. To optimize and achieve maximum benefit, it is necessary to design a window that adjusts to tropical conditions and at the same time remains affordable for extensive implementation. VO2 nanoparticles embedded in polymeric matrices are an option, but improvements are required by means of studying different particle sizes, dopants and polymeric matrices. The purpose of this review is to analyze what has been regarding toward the fabrication of smart windows based on VO2 embedded in polymeric matrices for tropical areas and provide a proposal for what this device must comply with to contribute to these specific climatic needs.

Abstract This study investigates the effect of hydrothermal aging on the properties of glass fiber reinforced polymer (GFRP) rebars manufactured with isophthalic polyester or vinylester resin and glass fiber type E. The GFRP rebars were immersed in an alkaline solution (pH 12.6) for 1000 h at different temperatures (23 and 60 ºC), and their deterioration was evaluated based on microstructural and chemical changes (using SEM, DSC, XRF, and FTIR techniques), moisture absorption, and variation in mechanical properties. The results indicated an increase in the presence of voids and water absorption of the rebars with accelerated aging, with a reduction in the glass transition temperature of the resin and alteration of the chemical composition of the glass fiber. The comparison between the experimental results indicates that the rebars with matrix in vinylester resin present greater chemical resistance than the rebars with a polyester matrix. The degradation of the rebar also resulted in a reduction of approximately 6% in the tensile strength of the rebar and 2% in the modulus of elasticity. Using the damage model, it was possible to identify that the reduction in mechanical strength was associated with the simultaneous degradation of the resin and glass fiber due to the alkaline attack.

Sodium alginate membranes filled with iron oxide nanoparticles consist of a mixture of organic and inorganic phases. This design offers the possibility to combine the polymer’s easy processability and superior separation performance. For a better understanding of the mechanisms of mixture separation, we analyze the diffusion motion of a particle in the hybrid membrane environment. We model structures of two-dimensional heterogenic membranes, which resemble real membrane structures, and then we simulate a random walk on them. We investigate how the additional action of drift changes the motion properties of the diffusing particles through the polymeric membrane filled with inorganic powder. We test the effect of two parameters: the distribution of obstacles (filling) in the membrane and the value of drift on the nature of diffusion. It appears that the synergy between drift, the diffusion, and the membrane structure affect the occurrence of the superdiffusive and subdiffusive character of particle motion as measured by the time-averaged mean square displacement. An important point is the observation that the strong drift supports subdiffusive motion as it increases the chances of particle trapping. Moreover, there exists the optimal value of drift, for which the transport through a membrane speeds up and does not cause trapping.

The objective of this study was the preparation and characterization of a sustained-release matrix tablet containing a high-dose hydrophobic drug and its comparison with marketed products. In the present study, HPMC was applied as the matrix-forming polymer for the sustained release of clarithromycin (500 mg). The compatibility of clarithromycin and excipients was studied using a binary mixture approach and compatible excipients were selected. Matrix tablets were prepared using the high-shear wet granulation technique. Tablets were compressed using oblong (19 mm), shallow concave punches, under a compression weight of 900 mg/tablet. The flow of granules was evaluated by determining their bulk density, tapped density, angle of repose, Hausner ratio, and Car’s index. Compressed tablets were tested for their physical parameters, mechanical characteristics, drug content, and in vitro drug release, as per United States Pharmacopeia (USP). Clarithromycin is a drug having poor water solubility and showed compatibility with all the excipients used in the formulation of polymeric matrix tablets. FTIR spectra of clarithromycin, before and after being subjected to the stress conditions, confirmed the compatibility of clarithromycin and other ingredients of the matrix tablets. All the formulations exhibited good rheological characteristics and all the parameters related to flow showed results in the acceptable range. Physically, matrix tablets were smooth and shiny, without any surface defects. Weight variation (±5%) and drug content of the tablets (95–102%) were within the pharmacopeial limits. HPMC successfully sustained the drug release for 24 h. It is concluded from the study that dissolution rate of clarithromycin can be sustained using hydrophilic polymer (HPMC) as a release-controlling agent.

Micromechanical analyses of transversely loaded fiber-reinforced composites are conducted to gain a better understanding of the damage behavior and to predict the composite behavior from known parameters of the fibers and the matrix. Currently, purely elastic material models for the epoxy-based polymeric matrix do not capture the nonlinearity and the tension/compression-asymmetry of the resin’s material behavior. In the present contribution, a purely elastic material model is presented that captures these effects. To this end, a nonlinear-elastic orthotropic material modeling is proposed. Using this matrix material model, finite element-based simulations are performed to predict the composite behavior under transverse tension, transverse compression and shear. Therefore, the composite’s cross-section is modeled by a representative volume element. To evaluate the matrix modeling approach, the simulation results are compared to experimental data and the prediction error is computed. Furthermore, the accuracy of the prediction is compared to that of selected literature models. Compared to both experimental and literature data, the proposed modeling approach gives a good prediction of the composite behavior under matrix-dominated load cases. [ABSTRACT FROM AUTHOR]

A new 18 karat light gold, composed of gold single crystals, amyloids, and a polymer latex matrix is developed. It is similar to a glassy plastic, yet lighter than aluminum and of use in watches, jewelry, radiation shielding, catalysis, and electronics. The material is prepared via a hydrogel precursor dried into an aerogel. Annealing of the polystyrene matrix under vacuum gives rise to a homogeneous template. The final apparent density and porosity of the material depend directly on the volumetric concentration of the starting solution used for hydrogel formation. After annealing, a homogeneous microstructure is obtained in which the shining gold single crystal platelets are evenly embedded in a polystyrene matrix. The material has a glass transition temperature of ≈105 °C which allows for annealing and molding above this temperature. A general scaling behavior is found for the Young's modulus of the material with the density. The Young's modulus of the material with a density of 1.7 g cm−3 is ≈50 MPa. The density and stiffness, as well as the color, of the material can be tuned depending on the final application. [ABSTRACT FROM AUTHOR]

A method for the synthesis of polymeric film based on a copolymer of styrene and maleic anhydride (stiromal) and oligodiol was suggested. Block copolymer of ethylene glycol and propylene glycol was used as oligodiol. It was shown that synthesized materials have moderate water swelling capacity in and ion-exchange properties. Static exchange capacity in 0.1 mol/L NaOH aqueous solution is within the interval of 1.44–1.76 mmol/g. At air-dry state films have a tensile strength of 4–6.6 MPa and an elongation at break tensile 38–61 %. The effect of stiromal molecular weight and oligodiol type, and conditions of film formation on ion-exchange and physical-mechanical properties of the films was studied. The synthesized material appeared to be able to sorb Cu2+-ions from neutral and acidic solutions. The distribution coefficient in case of sorption from slightly acidic solution with Cu2+ concentration of 50 mg/L was 48–50. Composite material with a metal submicroparticles uniformly distributed in the polymeric matrix was obtained by chemical reduction of copper ions sorbed. It was found that the film acquires electric conductivity, as a result of filling of metal particles, which allows copper electrodeposition on the film surface.

Transition to renewable and sustainable energy from fossil fuels (natural gas, coal, and oil) has dominated the research cycle. The shift is as a result of increasing population growth, industrialisation, decreasing oil reserves and hazardous environmental impact of energy generation from fossil fuels. The new methods of energy generation demand functional materials that are smart and strong for generation and storage of energy. Polymeric composite materials have been widely used. With the recent material performance demand, there is a need to improve the properties of the composite. The improvement can be achieved by reinforcing with fibres and/or nanoparticles as the matrix alone does not possess the required properties. The influence of incorporating fibres and/or fillers into the polymeric matrix has been largely reported in many studies. Recent advancement in the development and use of polymeric composites and nanocomposites is discussed for energy applications. The discussion includes material property improvements, processing methods and improving interface adhesion that may arise when compounding the materials. Various areas, in the energy sector where these materials, can be used are equally highlighted.

The curcumin degradation represents a significant limitation for its applications. The stability of free curcumin (FC) and immobilized curcumin in complex particles (ComPs) based on different polysaccharides was studied under the action of several factors. Ultraviolet-visible (UV-VIS) and Fourier-transform infrared (FTIR) spectroscopy proved the FC photodegradation and its role as a metal chelator: 82% of FC and between 26% and 39.79% of curcumin within the ComPs degraded after exposure for 28 days to natural light. The degradation half-life (t1/2) decreases for FC when the pH increases, from 6.8 h at pH = 3 to 2.1 h at pH = 9. For curcumin extracted from ComPs, t1/2 was constant (between 10 and 13 h) and depended on the sample’s composition. The total phenol (TPC) and total flavonoids (TFC) content values increased by 16% and 13%, respectively, for FC exposed to ultraviolet light at λ = 365 nm (UVA), whereas no significant change was observed for immobilized curcumin. Antioxidant activity expressed by IC50 (µmoles/mL) for FC exposed to UVA decreased by 29%, but curcumin within ComPs was not affected by the UVA. The bovine serum albumin (BSA) adsorption efficiency on the ComPs surface depends on the pH value and the cross-linking degree. ComPs have a protective role for the immobilized curcumin.

For maintaining good health, one needs a proper balance and composition of intestinal microflora which can be achieved by supplementing probiotics. A noteworthy issue in creating helpful and valuable probiotic food items is bacterial survival, amid capacity and ingestion. Several gastrointestinal diseases can be reduced by colonizing Probiotic supplement as the appropriate barrier in the small intestine. Probiotic is characterized as a suitable microorganism with several medical advantages to the consumer when administrated in a satisfactory amount. The poor survival and steadiness of the probiotic microorganisms as revealed from the earlier reports is an essential question to that impact. Diverse natural components like oxygen toxicity, an intolerant condition of acidity and travel through the gastrointestinal tract offers a variety of extreme conditions to the probiotic microorganisms. Therefore, the current review is more emphasized upon the microencapsulation of the probiotics that enhance their viability against different parameters like oxidation, light, moisture, and temperature. Recent advancements in ensuring microorganism survival rate and their colonization in the gut as gut microflora using microencapsulation enhance probiotic supplements for better health. Hence, the present review also emphasis on the methodological systems used for probiotic alive by the encapsulation process advance technologies used to stabilize their viability during storage including the selection of biomaterial and decision for proper innovation. [ABSTRACT FROM AUTHOR]

The polymeric composites on the base of the PA+PAI filled by glass fibres are usually used in automotive industry and also exposed to natural atmosphere. The research is focused on resistance study of the mentioned composites in simulated atmospheric conditions. The tested specimens contented 10, 20 and 30 % of the glass fibres and they were exposed in UV box with defined time and intensity of UV radiation and temperature. The mentioned factors have a considerable influence on utility and lifetime of product made of the polymeric composite. The effect of the exposition on the composites behaviour was evaluated microscopically, by rheological measurements and impact tests. By the rheological measurements the changes of visco-elastic parameters (complex viscosity, moduli of elasticity and plasticity) were studied after different times of exposition in the UV box as well as chosen mechanical properties. [ABSTRACT FROM AUTHOR]

• A novel design for polymeric matrixes, containing dispersed solute, has been suggested for providing zero-order release. • Mathematical modeling and simulation have been carried out to evaluate the performance of the suggested system. • The effect of coating degradation rate on the release profile has been assessed through the mathematical simulation. • The effect of solute loading level on the release profile has been assessed through the mathematical simulation. • The suggested system is able to eliminate burst release at initial time and provide approximate zero-order behavior. In the context of controlled release drug delivery approaches, the systems providing zero-order release kinetics have special advantages. Through employing these systems, drug concentration could be maintained within the therapeutic window over release time; thus maximum effectiveness alongside minimized side effects of the drug are achieved. However, obtaining zero-order drug release is extremely challenging. One of the main obstacles is the fact that implemented devices should be designed to overcome the decreasing mass transfer driving force, especially, in polymeric systems in which diffusion mechanism is dominant. In this study, we developed a new configuration of a polymeric matrix containing dispersed solute which provides sustained zero-order release. A combination of two innovative approaches including separating baffles and a two-layer coating was proposed to be incorporated into the conventional cylindrical polymeric matrix to induce zero-order release behavior. Then, an approximate mathematical model was developed to investigate the performance of the system under different conditions. The simulated results showed the potential of proposed configuration to be used as a carrier for sustained zero-order release. [ABSTRACT FROM AUTHOR]

In this paper, a mathematical model of drug release from polymeric matrix and consequent intracellular drug transport is proposed and analyzed. Modeling of drug release is done through solubilization dynamics of drug particles, diffusion of the solubilized drug through the polymeric matrix in addition to reversible dissociation/recrystallization process. The interaction between drug-receptor, drug-plasma proteins along with other intracellular endosomal events is modeled. This leads to a mixed system of partial and ordinary differential equations with associated pertinent set of initial and boundary conditions. Furthermore, besides the stability of the proposed model, several sub-models are also studied for their stability criteria. Prominence is provided to the reduced model system having requisite relevance to the original system where quasi steady state approximation (QSSA) theory is utilized. For the model to be potent enough to generate appropriate predictive results for drug delivery, the stability properties of equilibrium in the mathematical model are analyzed both analytically and numerically. Numerical simulation in the embodiment of graphical representations speaks about various vital characteristics of the underlying physical phenomena along with the importance and sensitized impact of the model parameters controlling significant biological functions. Probed new therapies and clinical procedures could be assessed considering the present mathematical model and its analysis as the basis framework in order to effectively enhance therapeutic efficacy and improved patient compliance. The present study confirms the necessity of stability analysis study so that advocated mathematical model can effectively complement the real physiological behavior of pharmacokinetics. [ABSTRACT FROM AUTHOR]

Microwave absorption has attracted considerable attention in the last decade. Absorbing materials are an essential component for the reduction of incident microwave by absorption or by the use of destructive interference. Various factors such as permittivity and permeability affect the attenuation of microwaves by absorbers. From this observation, in this research an absorbing material has been developed to improve these properties using multiwall carbon nanotubes (MWCNTs) as a conductive polymer and Zn0.25Co0.75Fe2O4 as magnetic nanoparticles. For better dispersion in the reaction medium, consequently enhancing the interfacial polarization, MWCNTs were functionalized with carboxylic acid groups. The functionalized MWCNTs were then decorated with Zn0.25Co0.75Fe2O4 magnetic nanoparticles through sonochemical and solvothermal complementary methods in ethylene glycol as solvent. Zn0.25Co0.75Fe2O4 nanoparticles and MWCNT/Zn0.25Co0.75Fe2O4 nanocomposite were identified by diffuse reflection spectroscopy (DRS), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray diffraction (XRD) and vibrating sample magnetometer (VSM). Investigation of microwave absorption properties was performed by vector network analyzer (VNA). Finally, MWCNT/Zn0.25Co0.75Fe2O4 nanocomposite was blended in silicone rubber as a polymeric matrix to investigate its microwave absorption properties. The MWCNT/Zn0.25Co0.75Fe2O4/silicone rubber nanocomposite absorbed 79.08 dB at 10.5 GHz with a thickness of 2.4 mm, having effective bandwidth (RL < −20 dB) more than 2.7 GHz. [ABSTRACT FROM AUTHOR]

The controlled release of a compound entrapped in a biocompatible formulation is a sought-after goal in modern pharmaceutical technology. Zein is a hydrophobic protein which has several advantageous properties that make it suitable for use as a biocompatible and degradable material under physiological conditions. It is, therefore, proposed for different biomedical and pharmaceutical applications. In particular, due to its gelling properties, it can be used to form a polymeric network able to preserve biomolecules from harsh environments. The current study was designed to investigate the influence of different probes on the rheological properties of gels made up of zein, in order to characterize the systems as a function of the polymer concentration. Four model compounds characterized by different physico-chemical properties were entrapped in zein gels, and different behaviors (viscoelastic or pronounced solid-like characteristics) of the systems were observed. Zein-based gels showed various release profiles of the encapsulated compounds, suggesting that there are different interaction rates between the probes and the polymeric matrix.

Micromechanical analyses of transversely loaded fiber-reinforced composites are conducted to gain a better understanding of the damage behavior and to predict the composite behavior from known parameters of the fibers and the matrix. Currently, purely elastic material models for the epoxy-based polymeric matrix do not capture the nonlinearity and the tension/compression-asymmetry of the resin’s material behavior. In the present contribution, a purely elastic material model is presented that captures these effects. To this end, a nonlinear-elastic orthotropic material modeling is proposed. Using this matrix material model, finite element-based simulations are performed to predict the composite behavior under transverse tension, transverse compression and shear. Therefore, the composite’s cross-section is modeled by a representative volume element. To evaluate the matrix modeling approach, the simulation results are compared to experimental data and the prediction error is computed. Furthermore, the accuracy of the prediction is compared to that of selected literature models. Compared to both experimental and literature data, the proposed modeling approach gives a good prediction of the composite behavior under matrix-dominated load cases.