Glass Solution Research Articles

Reuse of polyester-glass laminate waste in polymer composites

Purpose: of this paper is to develop a new generation of polymer composite materials that would ensure the use of residual and serious environmental problems of polyester-glass laminate waste. Design/methodology/approach: The glass reinforced polyester waste was ground and added to produce new composites. Thermoplastic - high impact polystyrene was selected for the composite matrix. Composites containing 10, 20, 30% by weight of the filler of polyester-glass laminate powder were made. The process of extrusion and subsequent injection was used to prepare the test samples. The influence of the filler on selected properties of composites was evaluated. The physical properties of the filler as well as the processing properties of the mixture as well as the mechanical properties - impact strength and tensile strength of the obtained composites were investigated. Findings: A decrease in tensile strength and impact strength was observed along with an increase in the amount of filler. Research limitations/implications: It would be interesting to carry out further analyzes, in particular with a higher volume fraction of the filler or with a different composite structure, e.g. using PVC as a matrix. The developed research topic is a good material for the preparation of publications of a practical and scientific nature, especially useful in the research and industrial environment. Practical implications: The shredded glass-polyester waste can be used as a filler of polystyrene, however, the resulting composite could be used to produce parts with slightly less responsible functions such as artificial jewelery or toy elements. Originality/value: Obtained results are a new solution a global waste management solution for glass reinforced polyester waste, which may contribute to the sustainable development of the composite materials industry through the partial utilization of waste composites with a duroplastic matrix.

Evaluation on Microstructure Stability and Thermal Resistant Ability at High Temperature of Ternary-Blended Geopolymer

Stability of microstructure and heat resistant ability at high temperature is one of the important properties in ceramics or silicate materials which are normally exposed with fire such as refractories and insulation or other materials used in furnaces. This study used a ternary-blended geopolymer which was synthesized from an optimized mixture of red mud (RM), rice husk ash (RHA), diatomaceous earth (DE), and water glass solution (WGS) with silica modulus of 2.5. The geopolymer samples were tested thermal properties of heat resistance (%), volumetric shrinkage (%), mass loss (%) at 1000°C to evaluate thermal resistant ability. Changes of microstructure of the ternary-blended geopolymer samples were also characterized before and after exposed at high temperature using methods of X-ray diffraction (XRD), Thermogravimetric analysis or thermal gravimetric analysis (DTA-TGA), and Scanning electron microscope (SEM). The experimental results showed the ternary-blended geopolymer has high thermal stability and unchanged microstructure even at high temperatures. Hence, the geopolymer in this study is suggested to apply as an insolation with the upper limit of temperature to work at 1000°C.

Utilization of BOF steel slag aggregate in metakaolin-based geopolymer

Steel slag, an industrial by-product during the steelmaking process, has not been effectively utilized so far. In this paper, the feasibility of using basic oxygen furnace (BOF) steel slag aggregate in metakaolin-based geopolymer was systematically evaluated. Tests results showed the use of steel slag aggregate (SSA) as full replacement of natural limestone aggregate could yield higher volume stability, improved compressive strength, smaller drying shrinkage and enhanced anti-freeze property of geopolymer concrete. Moreover, the activator of water glass was demonstrated to be superior to NaOH because free oxides in steel slag could be consumed in water glass solution. Discussion on the mechanism behind the superiority of BOF SSA in conjunction with alkalis was elaborated from the perspective of chemical reaction. The geopolymer matrix and interfacial transition zone (ITZ) were enhanced due to the diffusion of Ca ions to form the gel and densify the microstructure. Techniques of XRD, TGA, SEM/EDX were utilized for the analysis of the improved geopolymer matrix and strengthened ITZ. This research could facilitate the recycling and upgrading of steel slag for construction.

Scientific Approach of Geopolymer Concrete Composites using Marginal Materials

Geopolymer concrete is a sustainable composite where concrete is supplanted totally by pozzolanic cementitious materials like coal fuel ash, granulated blast furnace slag, rice husk ash, metakioline etc. with binding alkaline solutions in the matrix. Since the geopolymer doesn’t have specific code determination, a study has been made to create mix design to achieve the required workability and fresh density as per the considerable limits. Mix design procedure is proposed for flyash rice husk ash composition considering the quantity and fineness of binder, grading of aggregates. Water glass solution with Na2O = 18.79 %, SiO2 = 34.21 % and H2O = 47 % and solution of sodium hydroxide having 10M and 12M concentration were maintained constant throughout the Design. Fluid to binder ratio of 0.56, sodium silicate-to-sodium hydroxide ratio of 2.5 by mass was fixed on the basis of flowability. Measurement of Workability of geopolymer concrete was done using slump cone apparatus as per IS 1199. The cubes of 100 mm size were casted and cured under sundried condition maintaining a temperature about 40°C. From the observation it is concluded that the brick industrial rice husk ash can be utilized upto 10% in class f flyash to satisfy the Mix design criteria.

Effects of Curing Time to Engineering Properties of Alkaline Activated Materials Synthesized from Thu Duc Water Plant Waste Sludge, Fly Ash, and Geopolymer Aggregate

Alkaline activated materials (AAM) are products of the reactions among activity oxides in high alkaline condition. AAM has many outstanding properties compared to other groups of similar materials. They are applied in many different fields such as construction materials, thermal insulation materials, refractory materials, catalytic materials, and adsorbents in environmental treatment. More importantly, AAMs are fabricated from raw materials of industrial solid waste such as fly ash, bottom ash, rice husk ash, red sludge, water plant waste sludge, blast furnace slag, and others. There are different synthesis and curing methods used to produce AAM. This study used the waste sludge of Thu Duc water plant mixed with fly ash, sand, geopolymer aggregate in alkaline solution prepared from water glass solution and NaOH to fabricate AAM. AAM products were then tested for engineering properties known as compressive strength, volumetric weight, water absorption, pH value, water content, and softening coefficient during various curing times of 1, 3, 7, 28, and 90 days.

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Preparation of quaternary solution processed chalcogenide thin films using mixtures of separate As40S60 and Ge20Sb5S75 glass solutions

In this work, the chalcogenide glass thin films of As-Ge-Sb-S system were prepared in specular optical quality by spin-coating from mixtures of separate As40S60 and Ge20Sb5S75 glass solutions. The five compositions were studied in total (0, 25, 50, 75 and 100 at.% of As40S60) to examine the possibility of deposition of quaternary chalcogenide glass thin films from mixture of simpler compositions solutions. The composition, organic residual content, structure, thickness, surface roughness, optical properties and chemical resistance of prepared films were studied in dependence on annealing temperature (up to 180°C) and targeted composition. Thermally induced structural changes resulted in thin films with high optical quality and chemically stable polymerized glass structure. Physico-chemical properties of prepared mixed compositions thin films showed nearly linear combination of properties observed on As40S60 and Ge20Sb5S75 thin films.

Obtaining Granules from Waste Tannery Shavings and Mineral Additives by Wet Pulp Granulation.

This paper presents the results of research on the granulation process of leather industry waste, i.e., tanning shavings. It is economically justified to granulate this waste together with mineral additives that are useful in the processes of their further processing. Unfortunately, the granulation of raw, unsorted shavings does not obtain desired results due to their unusual properties. In this study, the possibilities of agglomeration of this waste were examined by a new method consisting of the production and then the granulation of wet pulp. During granulation, no additional binding liquid is added to the granulated bed. As part of this work, the specific surface of granulated shavings, the granulometric composition of the obtained agglomerates, and their strength parameters were determined. The use of a vibrating disc granulator, the addition of a water glass solution (in the pulp), dolomite, and gypsum made it possible to obtain durable, mechanically stable granules.

ВЛИЯНИЕ ГРУБОДИСПЕРСНЫХ КОМПОНЕНТОВ НА СВОЙСТВА КЕРАМИЧЕСКОГО МАТЕРИАЛА

In modern conditions, clay raw materials of fine-grained structure are used for the production of building ceramics. The task of using coarse non-traditional non-plastic components in the compositions of ceramic masses and the choice of rational sizes of their grains is relevant. The exclusion of pre-grinding determines the reduction of energy costs and, as a result, the cost of finished products. The paper offers an optiom of using diopside concentrate of various grain sizes in compositions with minor additions of clay and sodium silicate solution. The problems of stress development at the interface of grain and ligament contact, which in case of a negative outcome do not make it possible to obtain a strong structure of a ceramic shard, are solved. The presence of an insignificant voltage formed as a result of the relationship between the diopside and the forming glass phase is revealed, this does not prevent the consideration of the probability of obtaining a ceramic material. The study of the behavior of ceramic samples containing diopside of different granulometric composition when adding a solution of sodium-silicate glass after molding and firing shows the effectiveness of using diopside concentrate in 100-150 microns. Contacts of this size of diopside are wrapped in liquid glass during molding. A glass phase is formed when fired. In this case, the diopside is partially melted, but it is preserved and exists as an independent unit. A smaller grain size during sintering requires more glass phase, which leads to structural stresses, and with a larger size, not enough glass phase is formed and the strength of the material is significantly reduced. When studying the influence of grain size on the properties of the sample, the results of water absorption indicators of 7 %, mechanical compressive strength – 36 MPa, bending strength-17 MPa are obtained. It is found that the dispersion of diopside in 100–150 microns allows to develop a technology for the use of coarse-grained raw materials in the ceramic mass

The effect of Na+ and H2O on structural and mechanical properties of coal gangue-based geopolymer: Molecular dynamics simulation and experimental study

The aim of this work is to study the impacts of Na+ and H2O on structural and mechanical properties of coal gangue-based geopolymer by experiment and molecular dynamics. Geopolymers were prepared by coal gangue and mixed solution of NaOH and water glass. Then X-ray fluorescence (XRF) and X-ray diffraction (XRD) were utilized to characterize the main chemical composition and crystalline phase of geopolymer after 28d curing. Moreover, Na2Si2O5 glass was firstly proposed to establish the molecular structure of geopolymers with different Na/Al and H2O/Al. Structural optimization and molecular dynamics simulation were implemented under the specific force field. Simulated XRD pattern, energy and temperature curves, radial distribution function (RDF), hydrogen bond, bond angle distribution, mean square displacement (MSD) and elastic modulus of geopolymer were calculated and analyzed. Results indicated that with the increase of Na+ and H2O content, structure of geopolymer became more stable and mechanical properties were improved significantly.

RESEARCH OF CONDITIONS OF APPLICATION OF TUNGSTEN ON OXIDE-CERAMIC CARRIERS

Atmospheric pollution by the waste generated by the combustion of organic fuel is an important environmental problem. With the development and introduction of new environmental standards, increasing attention is being paid to the creation of effective catalysts for the elimination of car fuel gases. The active components of the catalysts are applied to ceramic materials and metal surfaces in various ways.Using the experimental design, the efficiency of plasma electrolytic oxidation (PEO) and extraction-pyrolytic methods for the introduction of anionic metals into the catalyst surface was compared and the optimal technological parameters of the processes of deposition of catalytically active coatings were established. With the help of a central composite rotatable plan, response functions were found that show the dependence of the thickness Yδ, the porosity Yp, and the content of tungsten YW in the coating, depending on the technological conditions of plasma PEO. The substance with the active ingredient W (Na2WO4 2H2O) was added directly to the electrolyte or used for further impregnation of the coatings. In the first case, the content of the active component in the coating is found to be on average 50 times greater than after the impregnation of the previously obtained coatings. In addition, the concentration of Na2WO4 2H2O in the electrolyte should be much lower than in the solution for impregnation. It is shown that when conducting PEO in a liquid glass solution, the porosity of the coating increases directly in proportion with the glass concentration in the electrolyte. When added to the electrolyte of sodium tungsten porosity depends only on the time of the process and has an extreme dependence with a maximum at 25 min. It was found that the thickness of the coating when conducting PEO in solutions of liquid glass increases more with the lengthening of the process time than with increasing the concentration of glass in the electrolyte 1.7 times. When added to the electrolyte, the tungsten coating does not increase over time with a glass concentration of up to 5 g·l-1.

Bioavailability Enhancement of Olmesartan Medoxomil Using Hot-Melt Extrusion: In-Silico, In-Vitro, and In-Vivo Evaluation.

Olmesartan medoxomil (OLM) an antihypertensive molecule with poor solubility and poor bioavailability (26% when taken orally) was selected as a model drug. Herein, rationale development of amorphous solid dispersion with hot-melt extrusion of poorly bioavailable OLM was carried out with the aid of quality by design (QbD), in-silico, in-vitro, and in-vivo evaluations. Polymer selection commenced with the selection of thermoplastic water-soluble polymers with the compatible processing temperature window as per the thermal behavior of OLM. Molecular dynamics (MD) simulations as well assisted in the selection of a carrier. Promising dissolution enhancement was observed with the help of Kollidon VA-64 (VA-64) as a carrier. Optimization of the formulation was executed using the QbD approach with design of experiment as a statistical optimization tool. Interactions between VA-64 and OLM on the atomic level were studied with the help of atomistic MD simulations. Characterization of the optimized extrudates were carried out with scanning electron microscopy, atomic force microscopy, differential scanning calorimetry, thermogravimetric analysis, Fourier transforms infrared spectroscopy, powder X-ray diffraction, in-vitro dissolution study, and in-vivo pharmacokinetic studies. Molecular-level mixing of OLM with VA-64 resulted into glass solution formation which rapidly dissolves (28 times in-vitro dissolution enhancement) in GI tract fluids and instantly gets absorbed into blood circulation. In-vivo pharmacokinetic studies performed in Sprague-Dawley rats reflected superior bioavailability (201.60%) with a significant increase in the Cmax with short Tmax through amorphization of OLM. The in-silico results were in agreement with the observed results of in-vitro dissolution studies and in-vivo pharmacokinetic study.

Fire risk assessment of cypress wood coated with metal oxide and metal silicate flame retardant using cone calorimeter

This study investigated the fire risk properties of cypress wood for the construction of interiors, especially focusing on heat and smoke hazard properties in fire scenarios. Fire risk characteristics were measured using a cone calorimeter (ISO 5660-1). The external heat flux was maintained at 50 kW/m2. The flame retardants used were metal oxide and metal silicate; they were mixed with a water glass solution. Flame retardants and the silicon compound were dispersed in a concentration of 20 wt% versus 80 wt%, respectively, during 24 h using a magnetic stirrer. The fire performance indexes of the specimens increased by 3–16 times, compared with uncoated specimen and the fire growth index of the specimens increased by 70%–92%. The smoke performance index of the specimens increased by 9–66 times, compared with uncoated specimens. The smoke risk as shown by the smoke performance index increased in the following order: SnO < mica < Co3O4 < ZrSiO4 < cypress. The smoke growth index decreased from 93% to 98%, compared with uncoated wood. The smoke risk due to smoke growth index increased in the following order: SnO < mica < ZrSiO4≈ Co3O4 < cypress. The smoke intensity decreased from a minimum of 85% to a maximum of 99%, compared with uncoated wood. The concentration of CO gas generated after combustion was decreased by 24%–67%. They increased in the following order: mica ≈ ZrSiO4 < SnO < Co3O4 < cypress. A comprehensive assessment of fire performance shows that flame retardants decreased heat hazards, smoke hazards, and CO toxicity.

Artificial neural network model to predict the compressive strength of eco-friendly geopolymer concrete incorporating silica fume and natural zeolite

The growing concern about global climate change and its adverse impacts on societies is putting severe pressure on the construction industry as one of the largest producers of greenhouse gases. Given the environmental issues associated with cement production, Geopolymer Concrete (GPC) has emerged as a sustainable construction material. This research experimentally studied the effect of partially substituting ground granulated blast-furnace slag (GGBS) with silica fume (SF) and natural zeolite (NZ) (by 0–30% with 5% increments) in the GPC activated by sodium hydroxide (NaOH) solution with different concentrations (4, 6 and 8 M) and sodium silicate (water glass) solution on the compressive strength. Obtained results revealed that increasing the NaOH concentration reduced the concrete strength, while adding SF and NZ to the concrete yielded an improvement in the compressive strength. Moreover, this study proposed an Artificial Neural Network (ANN) to predict the compressive strength of pozzolanic GPC based on GGBS (i.e., at the ages of 7, 28, and 90 days). The compressive strength of GGBS-based GPC (i.e., 117 concrete specimens manufactured out of 39 various mixtures) obtained by experimental tests was used to develop the model. The specimen age, NaOH concentration, contents of NZ, SF, and GGBS were considered as inputs variables for developing the ANN model. The predicted results establish the accuracy and high prediction ability of the proposed model. The findings of this study can bring significant benefits for the range of organizations involved.

Stability against the aqueous corrosion and nanofilamentation of chalcogenide glass

Chalcogenide photonic devices are widely used in the detection of harmful substances in solutions; thus, their stability in aqueous solutions is very critical. In this work, the aqueous corrosion behaviors of commonly used chalcogenide glasses (ChGs) were studied at different temperatures and duration. Optical transmission spectra show that the durability of ChGs is greatly affected by glass composition corrosion, solution temperature, and corrosion time. In addition, Se-based glasses are less stable in aqueous solution and will form nanoparticles of pure Se component on the outer surface of samples, which will contribute to the loss of optical transparency. However, Se-nanostructured materials, such as nanowires, can be obtained by carefully controlling the corrosion process and used for the self-assembly of multi-scale devices. The results show that water is a good solvent for the growth of Se nanowires in the liquid phase. This study provides a new way for the production of Se nanowires.

Experimental study of one-part geopolymer using different alkali sources

This paper investigates the feasibility of combining different solid alkali materials as activator to prepare one-part geopolymer mortars. The effects of different composite solid activators on aluminosilicate materials were studied and compared with the traditional water glass and sodium hydroxide composite solution activator through the measurement of fresh and harden properties and microstructural analysis. The results showed that sodium metasilicate pentahydrate was more suitable than quick-dissolving sodium silicate for preparation of geopolymer. The addition of sodium carbonate and calcium hydroxide in solid activator enhanced the compressive strength and decreased the setting time and flowability of the mixes. The highest compressive strength (47.4 MPa, 28 d) was obtained with the activators consisting of sodium metasilicate pentahydrate and sodium carbonate. While scanning electron microscope (SEM) analysis indicated that micro-pores left by the dissolution of metasilicate particles might have an adverse effect on the mechanical properties of mortar samples.

Mechanical and microscopic properties of alkali-activated fly-ash-stabilised construction and demolition waste

The geotechnical properties, chemical reaction mechanisms, and microstructure evolution of alkali-activated fly-ash-stabilised construction and demolition waste (C&D) and the main components recycled concrete aggregate (RCA) and clay brick (CB) were investigated in this study. The alkali activator was a composite solution of sodium hydroxide and water glass. XRD, FTIR, SEM, and UCS testing methods were used to analyse the properties and mechanisms of the alkali-activated fly-ash-stabilised C&D and main single-component RCA and CB. The test results demonstrate that using alkali-activated fly ash in stabilising C&D improves the UCS of the material significantly. When C&D is mixed with fly ash at a mass ratio of 60/40, its UCS reaches 37 MPa at 28 days, which is much higher than the strength requirement of cement-stabilised soil mixture and meets the strength requirements of inorganic binder stable materials for road base and sub-base layers. C-A-S-H and N-A-S-H (where N = Na2O, A = Al2O3, C = CaO, S = SiO2, and H = H2O) generated by the alkaline activation have several similarities with cement hydration products and also show high cementing ability. Alkali-activated fly ash improves the strength and stability of C&D as a roadbed filler and has prospective applications in road engineering.

Disperse-Reinforced Polystyrene Concrete Modified by Silica-Containing Additive

The composition of disperse-reinforced polystyrene concrete for the manufacture of small-pieces load-bearing structural insulating wall products is developed. Its properties and microstructure are studied. It is composed of Portland cement, granular foamed polystyrene, basalt fibre, water and silica-containing modifier obtained by mixing condensed silica, superplasticizer S-3 and an aqueous solution of sodium water glass. The developed disperse-reinforced polystyrene concrete modified by silica-containing additive is characterized by higher values of adhesive strength (0.231 MPa), class by bending tension strength (Btb4), class by compressive strength (B5), cracking resistance coefficient (0.77), grade by frost-resistance (F1150) with a slight increase in the average density and thermal conductivity coefficient. The increase of physical and mechanical properties and frost resistance of polystyrene concrete of the developed composition is achieved by compaction and hardening of cement stone, improving its adhesion to granular foamed polystyrene due to the synergistic effect of a silica-containing modifier acting as an adhesive and structure-forming additive, and basalt fibre as a disperse-reinforcing component.

Soft tooling process chain for the manufacturing of micro-functional features on molds used for molding of paper bottles

Paper-based packaging products, due to their excellent sustainable properties are preferred over the glass, plastic, and metal-based packaging solutions. The paper bottle molding process is very new in this category, and the tooling aspect is not well explored. Existing tooling solutions offer certain limitations in the molding process such as clogging of channels, low open-area fraction, low fatigue life, and longer cycle times. With the utilization of additive manufacturing techniques, the tooling can not only be made more economical and produced in shorter time duration but also more efficient. VAT photopolymerization based soft tooling process chain is highlighted and discussed in this work. Design of micro-features and their fabrication is carried out using UV light mask projection method. A characterization approach for precision manufacturing of micro-features using X-ray Computed Tomography is also discussed. Validation of the soft tooling process chain and its effectiveness against the conventional tools is presented and discussed in this work. It is shown that the proposed soft tooling process chain for the manufacturing of molds for paper bottle production is a better performing and cheaper alternative to existing solutions implemented in industry.

Analyzing the compressive strength of green fly ash based geopolymer concrete using experiment and machine learning approaches

In this research, two different machine learning approaches are proposed for predicting the compressive strength of fly ash based geopolymer concrete. Experimental work with a total of 335 mix proportions were conducted to produce the data for training and validating processes. In the proposed models, the amount of fly ash, water glass solution, sodium hydroxide solution, coarse aggregate, fine aggregate, water, concentration of sodium hydroxide solution, curing time, and curing temperature were considered as nine input variables, while compressive strength was the output feature. The performance of the machine learning approaches was evaluated using a set of three metrics, including correlation coefficient (R), mean absolute error (MAE) and root mean square error (RMSE). Good correlation between machine learning models and experimental results was obtained. The proposed models can be employed to build a standard mix, and for designing the mix proportions of fly ash based geopolymer concrete.