Inorganic Polymeric Materials Research Articles

A comprehensive review of synthesis, characterization, and applications of aluminosilicate materials-based geopolymers

The increase in the cement industry's production, especially the production of Ordinary Portland Cement (OPC), increases the amount of CO2 released into the atmosphere, one of the main greenhouse gases responsible for global warming, with harmful effects on the environment and human health. Against this background, geopolymer concrete is a new type of inorganic polymer material that has attracted the attention of researchers in the building area, due to recycling waste by-products to replace OPC and reducing greenhouse gas (CO2) emissions during its manufacture. It also exhibits better mechanical, thermal, chemical, and electrical properties than OPC-based concrete. In the same environmental context, this material has also attracted the attention of researchers in the wastewater treatment area, because of its specific surface area and the capability of adsorption, photodegradation, and encapsulation of organic and inorganic pollutants. The principal focus of this paper is to provide an in-depth overview of the works that have been undertaken to explore geopolymer-type materials. The paper will attempt to develop a comprehensive database, based on the last research works published between 2010 and 2023 with about 247 references, which explains the elaboration, characterization, and application of these materials in several fields. Therefore, it is estimated that geopolymer composites are promising future candidates for recycling industrial solid waste, the partial or total replacement of OPCs in the construction industry, and the development of adsorbents and catalysts for wastewater treatment.

Hybrid Polymer-Inorganic Materials with Hyaluronic Acid as Controlled Antibiotic Release Systems.

In recent years, significant developments have taken place in scientific fields such as tissue and materials engineering, which allow for the development of new, intelligent biomaterials. An example of such biomaterials is drug delivery systems that release the active substance directly at the site where the therapeutic effect is required. In this research, polymeric materials and ceramic-polymer composites were developed as carriers for the antibiotic clindamycin. The preparation and characterization of biomaterials based on hyaluronic acid, collagen, and nano brushite obtained using the photocrosslinking technique under UV (ultraviolet) light are described. Physical and chemical analyses of the materials obtained were carried out using Fourier transform infrared spectroscopy (FT-IR) and optical microscopy. The sorption capacities were determined and subjected to in vitro incubation in simulated biological environments such as Ringer's solution, simulated body fluid (SBF), phosphate-buffered saline (PBS), and distilled water. The antibiotic release rate was also measured. The study confirmed higher swelling capacity for materials with no addition of a ceramic phase, thus it can be concluded that brushite inhibits the penetration of the liquid medium into the interior of the samples, leading to faster absorption of the liquid medium. In addition, incubation tests confirmed preliminary biocompatibility. No drastic changes in pH values were observed, which suggests that the materials are stable under these conditions. The release rate of the antibiotic from the biomaterial into the incubation medium was determined using high-pressure liquid chromatography (HPLC). The concentration of the antibiotic in the incubation fluid increased steadily following a 14-day incubation in PBS, indicating continuous antibiotic release. Based on the results, it can be concluded that the developed polymeric material demonstrates potential for use as a carrier for the active substance.

Improving the performance of geopolymer-based wood adhesives using a green mechanochemical strategy

Geopolymers are a new type of inorganic polymeric cementitious material with excellent properties such as flame retardancy and thermal stability. In this work, an environmentally friendly geopolymer-based adhesive was prepared using a one-step mechanochemical method, and the geopolymer-based adhesive was used to develop a low-cost, aldehyde-free, and highly flame-retardant plywood. Mechanical ball milling generated high temperatures through the collision of the agate balls and the material, which facilitated the polymerization reaction of the geopolymer. This method increased the viscosity of the adhesive and enhanced the “riveting” of the mechanical interlocks between the geopolymer and the wood. When the solid-liquid ratio of the synthetic geopolymer was 2.2, the bonding strength of the plywood developed using the adhesive prepared by the mechanochemical method was 43.0% higher than that of the plywood developed using the electromechanical stirring method, reaching 0.735 MPa, while in compliance with the GB/T 9846-2015 (China) standard for Class II plywood. In addition, the geopolymer-based adhesive had excellent thermal stability, and its mass retention rate was as high as 86.8% after treatment at 800oC. Meanwhile, the geopolymer-based adhesive endowed the flammable plywood with flame-retardant properties, and the heat release rate (HRR), total heat release (THR), and total smoke production (TSP) of the plywood were as low as 275.9 kW/m2, 27.4 MJ/m2 and 0.84 m2, respectively. Therefore, geopolymer-based adhesives show great potential in replacing traditional aldehyde-based adhesives in plywood production, providing a new idea for quick, green, and efficient preparation of inorganic adhesives with excellent bonding properties.

Porous Hybrid PVDF/BiFeO3 Smart Composite with Magnetic, Piezophotocatalytic, and Light-Emission Properties

The creation of multi-stimuli-sensitive composite polymer–inorganic materials is a practical scientific task. The combination of photoactive magneto-piezoelectric nanomaterials and ferroelectric polymers offers new properties that can help solve environmental and energy problems. Using the doctor blade casting method with the thermally induced phase separation (TIPS) technique, we synthesized a hybrid polymer–inorganic nanocomposite porous membrane based on polyvinylidene fluoride (PVDF) and bismuth ferrite (BiFeO3/BFO). We studied the samples using transmission and scanning electron microscopy (TEM/SEM), infrared Fourier spectroscopy (FTIR), total transmission and diffuse reflection, fluorescence microscopy, photoluminescence (PL), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), vibrating-sample magnetometer (VSM), and piezopotential measurements. Our results demonstrate that the addition of BFO increases the proportion of the polar phase from 76.2% to 93.8% due to surface ion–dipole interaction. We also found that the sample exhibits laser-induced fluorescence, with maxima at 475 and 665 nm depending on the presence of nanoparticles in the polymer matrix. Furthermore, our piezo-photocatalytic experiments showed that under the combined actions of ultrasonic treatment and UV–visible light irradiation, the reaction rate increased by factors of 68, 13, 4.2, and 1.6 compared to sonolysis, photolysis, piezocatalysis, and photocatalysis, respectively. This behavior is explained by the piezoelectric potential and the narrowing of the band gap of the composite due to the mechanical stress caused by ultrasound.

Impact of geopolymers on hard sludge formation on the secondary side of PWR steam generators under transient conditions

In modern steam generators (SG), some tube degradation phenomena are promoted by the formation of hard sludge (HS) on top of tubesheet. These phenomena reduce the efficiency of nuclear power plants (NPP). In some cases, SG deposits are primarily constituted by HS. This HS usually presents high concentrations of aluminum and silicon (up to 6.0 ± 0.1 wt% of Al and 2.7 ± 0.1 wt% of Si), together with high microhardness values (above 800 HV) at specific locations. In fact, there is evidence that the presence of aluminum and silicon is at the origin of the problematic of HS in SG during normal operation.Geopolymers are inorganic polymer materials constituted by a 3D-network of interlinked silica and alumina tetrahedra. Geopolymers present cementitious properties similar to HS. Geopolymers are formed under highly alkaline conditions and low temperature, by the polymerization of aluminosilicate and/or silicate oligomers. During NPP transient periods, geopolymer formation could be favor by the physicochemical conditions in the gaps arisen due to the different thermal contraction of SG tubes, deposits and tubesheet. Thus, it could be though that part of the HS formed in the crevice between tube and tubesheet of SG could correspond to geopolymers. In order to demonstrate this hypothesis, the mayor constituents of HS (magnetite, aluminum and/or silicon sources) have been autoclaved in representative secondary circuit transient conditions (cooldown). The effect the Si to Al ratio, the aluminosilicate source, the presence of magnetite and the chemical conditions in the crevice is also studied. The chemical, structural and morphological characterization of the resulting solids shows the presence of aluminosilicate compounds in some of the tested experimental conditions. However, these aluminosilicate compounds do not act as cementing agents agglomerating magnetite particles and therefore, they do not contribute to HS formation.

Synthesis of Inorganic Polymeric Materials from Industrial Solid Waste

Synthesis of Inorganic Polymeric Materials from Industrial Solid Waste

Exploring the In Situ Formation Mechanism of Polymeric Aluminum Chloride-Silica Gel Composites under Mechanical Grinding Conditions: As a High-Performance Nanocatalyst for the Synthesis of Xanthene and Pyrimidinone Compounds.

The use of mechanical ball milling to facilitate the synthesis of organic compounds has attracted intense interest from organic chemists. Herein, we report a new process for the preparation of xanthene and pyrimidinone compounds by a one-pot method using polymeric aluminum chloride (PAC), silica gel, and reaction raw materials under mechanical grinding conditions. During the grinding process, polymeric aluminum chloride and silica gel were reconstituted in situ to obtain a new composite catalyst (PAC–silica gel). This catalyst has good stability (six cycles) and wide applicability (22 substrates). The Al–O–Si active center formed by in situ grinding recombination was revealed to be the key to the effective catalytic performance of the PAC–silica gel composites by the comprehensive analysis of the catalytic materials before and after use. In addition, the mechanism of action of the catalyst was verified using density functional theory, and the synthetic pathway of the xanthene compound was reasonably speculated with the experimental data. Mechanical ball milling serves two purposes in this process: not only to induce the self-assembly of silica and PAC into new composites but also to act as a driving force for the catalytic reaction to take place. From a practical point of view, this “one-pot” catalytic method eliminates the need for a complex preparation process for catalytic materials. This is a successful example of the application of mechanochemistry in materials and organic synthesis, offering unlimited possibilities for the application of inorganic polymer materials in green synthesis and catalysis promoted by mechanochemistry.

Properties of synthesized inorganic polymeric phosphate materials and possibilities for production of new environmentally friendly and economically viable supplies from local industrial waste

Properties of synthesized inorganic polymeric phosphate materials and possibilities for production of new environmentally friendly and economically viable supplies from local industrial waste. / M. Avaliani, V. Chagelishvili, E. Shapakidze, M. Gvelesiani, N. Barnovi, M. Vibliani, K. Chikovani. / Nano Studies. – 2020. – # 20. – pp. 65-70. – eng. In the paper, the data on obtaining and general properties of polymeric phosphates first time synthesized by the authors are considered. There are analyzed the possibilities of production of new geopolymeric binder materials by inclusion of small amounts of these condensed materials into industrial waste and using phosphoric acid. Ref. 34.

Surface modification of SiO2 nanoparticles for bacterial decontaminations of blood products

Bacterial infections can be caused by contamination of labile blood products with specific bacteria, such as Staphylococcus aureus and Staphylococcus epidermidis. Hospital equipment, bio-protective equipment, delivery systems, and medical devices can be easily contaminated by microorganisms. Multidrug-resistant bacteria can survive on various organic or inorganic polymeric materials for more than 90 days. Inhibiting the growth and eradicating these microorganisms is vital in blood transfusion processes. Blood bags and other related medical devices can be improved by the incorporation of organic or inorganic nanomaterials, particularly silicon dioxide (SiO2) nanoparticles. The addition of solid organic or inorganic nanoparticles to synthetic polymers or biopolymers can provide new properties in addition to antimicrobial activity. Among these NPs, formulations composed of SiO2 nanoparticles and polymers have been shown to improve the mechanical and antimicrobial properties of catheters, prosthetic inserts, blood bags, and other medical devices SiO2 nanoparticles possess several advantages, including large-scale synthetic availability, simple one-pot synthesis methods, porous structure for loading antibacterial agents, good biocompatibility, and thermal stability. Plasticized polyvinyl chloride is the main polymer, which has been functionalized by these nanoparticles. In this review, we discuss the recent advances and challenges regarding the functionalization of polyvinyl chloride by SiO2 nanoparticles to hinder bacterial contaminations in blood products.

Inorganic Polymeric Materials for Injured Tissue Repair: Biocatalytic Formation and Exploitation.

Two biocatalytically produced inorganic biomaterials show great potential for use in regenerative medicine but also other medical applications: bio-silica and bio-polyphosphate (bio-polyP or polyP). Biosilica is synthesized by a group of enzymes called silicateins, which mediate the formation of amorphous hydrated silica from monomeric precursors. The polymeric silicic acid formed by these enzymes, which have been cloned from various siliceous sponge species, then undergoes a maturation process to form a solid biosilica material. The second biomaterial, polyP, has the extraordinary property that it not only has morphogenetic activity similar to biosilica, i.e., can induce cell differentiation through specific gene expression, but also provides metabolic energy through enzymatic cleavage of its high-energy phosphoanhydride bonds. This reaction is catalyzed by alkaline phosphatase, a ubiquitous enzyme that, in combination with adenylate kinase, forms adenosine triphosphate (ATP) from polyP. This article attempts to highlight the biomedical importance of the inorganic polymeric materials biosilica and polyP as well as the enzymes silicatein and alkaline phosphatase, which are involved in their metabolism or mediate their biological activity.

Glass Waste Based Geopolymers and Their Characteristics

Inorganic polymer materials (Geopolymers) are synthesized using alumino-silicate sources as solid components with an alkaline solution. This material is used as an alternative for building materials and provides thermal protection as foaming materials. This paper presents the preparation of these materials by the reaction between glass waste (from brown color bottles BP) with sodium hydroxide NaOH and sodium aluminum (AN5) solutions as alkali activators. For the preparation of mortars (BP-N5 and BP-AN5), sand was used as aggregate. The compressive strengths were assessed (24 and 6 MPa) respectively before heat treatment, the hydrolytic stability (PH and conductivity) tests were performed. Furthermore, hardened mortars have been heated at very high temperatures in the range of 200℃ to 800℃ within two hours. Based on the nature of the foaming behavior of such materials, various variables have changed; (80-140) % volume increase and porosity rise through the process of heat treatment, particularly at 600℃ and 800℃. On the other hand, (3.5-7) % mass reduction occurred. It can be said that the more significant porosity with different geometrical configurations (sizes and shapes) of such materials can be considered as acoustic insulation and thermal materials.

Inorganic Polymeric Materials Based on Natural Silicate and Aluminosilicate Raw Materials

The prospects of implementing the mechanochemical activation method of volcanic silicate and aluminosilicate rocks - perlites, tuffs, pumice, etc. are being considered for the production of a wide range of building materials using energy-conserving technologies. The thermodynamic and kinetic parameters of interaction in the systems of aluminosilicate – NaOH have been presented, indicating low-temperature sintering of volcanic rocks with sodium hydroxide. According to the degree of activity, the rocks have the following order: perlites, tuffs, obsidian, microcline. Kinetic parameters are presented: concentration, temperature, conversion degree, reaction rate constant, time of complete reaction and product layer thickness.

Recent Advances in Fly-Ash-Based Geopolymers: Potential on the Utilization for Sustainable Environmental Remediation.

This Mini-Review provides the fundamentals and the state-of-the-art overview on geopolymers, novel inorganic polymeric materials (also known as alkali-bounded ceramics), synthesized from aluminosilicate sources and explores their current and potential sustainable environmental applications. It summarizes and examines concisely the recent scientific advances on geopolymers widely synthesized from abundantly available fly-ash-based aluminosilicate materials via alkaline activation at relatively low temperatures. Although geopolymerization is not a new concept and has offered valuable solutions to some environmental challenges as a low-cost and environmentally benign alternative to conventional energy-intensive Portland cement-based construction materials and has also been used as a barrier in immobilizing toxic and radioactive metals, the application of this technology to produce effective adsorptive materials for mitigation of liquid- and gas-phase contaminants is relatively recent. The valorization of the fly-ash waste in the sustainable and cost-effective development of geopolymeric adsorbents and catalysts for the treatment and control of environmental contaminants and energy production and storage could lead to many economic benefits due to the low cost and resource recycling of this globally abundant raw material. Perspectives on the synthesis and utilization of new geopolymer-based adsorbents for environmental and energy applications with insights into future research directions, prospects, and challenges for economic large-scale production are addressed.

Raman spectroscopy potentiality in the study of geopolymers reaction degree

AbstractAlkali‐activated materials (AAMs) and “geopolymers” are inorganic polymeric materials obtained by mixing of solid aluminosilicate precursors with an alkaline solution (generally, KOH or NaOH and Na2SiO3 mixed in various ratios). This class of aluminosilicate materials has emerged as a greener alternative to traditional concrete, for large‐scale as well as for niche applications such as conservation and restoration of built heritage. In this work we apply Raman spectroscopy both to aluminosilicate precursors (metakaolin, pumice, volcanic ash, volcanic soils, clayey sediments, ceramic waste) and to the respective AAMs. In the field of vibrational spectroscopy, Raman is much less employed in the literature with respect to Fourier transform infrared (FTIR) to have insights into the alkali activation process from a molecular point of view. The aim of this paper is to investigate the potentiality of a Raman approach to the comparison of the employed raw materials with the respective AAMs. Raman analyses during the first hours of geopolymerization were also carried out on the clayey sediments and ceramic waste‐based products. The results, differentiated according to the employed precursors, exhibit spectra relative to crystalline and amorphous phases that can give an indication about the newly formed aluminosilicate gel.

Mechanical Properties of Glass-Based Geopolymers Affected by Activator and Curing Conditions under Optimal Aging Conditions

Inorganic polymeric materials react slowly at room temperature and therefore, usually require high-temperature curing. This study determined the correlation between temperature and duration in high-temperature curing. The results revealed optimal values for each alkali equivalent of an activator (weight ratio of Na2O/glass powder), curing temperature, and curing duration. Increasing the curing duration and curing temperature had positive effects when the alkali equivalent was lower than the optimal percentage. However, over-curing resulted in the visible cracking of the specimens. Furthermore, despite being initially high, the compressive strength of specimens gradually diminished after standing in air. To ensure the durability of glass-based geopolymers, the curing temperature and duration should not exceed 70 °C, and 1 day, respectively.

Catalyst: Uranium Extraction from Seawater, a Paradigm Shift in Resource Recovery

Shilpi Kushwaha received her PhD (2012) from the Maharaja Sayajirao University (MSU), Vadodara, and then worked as a Fulbright-Nehru Postdoctoral Research Fellow (PDF) at Arizona State University and as a Young Scientist (DST-YS) at the National Chemical Laboratory (CSIR-NCL), Pune. She is an assistant professor at the Academy of Scientific and Innovative Research (AcSIR) and a scientist at the Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI). Her current research is focused on materials (i.e., small molecules, polymers, self-assemblies, and nanomaterials) for molecular recognition, pollutant scavenging, and recovery. Ketan Patel received his PhD (2013) from MSU and later worked as a PDF at the Texas Tech University Health Sciences Center and as a DST-YS at CSIR-NCL, Pune. He is currently an assistant professor at AcSIR and a senior scientist at CSIR-CSMCRI. His ongoing research focuses on organic and inorganic polymeric and hybrid materials for catalysis and separation.

Progress on the Industrial Applications of Red Mud with a Focus on China

Red mud (RM), also called bauxite residue, is a strong alkaline industrial waste generated during the alumina production process. The annual production of RM in China is large, but its average utilization rate is low (only 4%). High generation and low consumption make the disposal of RM mainly by stockpiling, which has caused serious heavy metal pollution and radioactive contamination. In this paper, the various industrial utilization methods of RM in China during the past 60 years have been introduced. Moreover, some recent industrial progresses were referred. The results show that RM can be widely used in building materials, valuable metals extraction, and some novel utilization methods, such as silica-calcium fertilizer, inorganic polymer material and desulfurizer. Most of the industrial utilization methods of RM have been used until now and some successfully applied to other aluminum plants, providing some feasible routes for a large amount utilization of RM. Some industrial utilization methods (such as oil well cement and calcium silicon fertilizer) have not been used due to some problems that cannot be ignored, but it provided a lot of valuable experience and was helpful for the subsequent RM utilization. Moreover, some novel and feasible RM utilization methods were proposed and successfully industrialized, which showed that RM has a broader application prospect. Many actual practices showed that the best way to safely dispose of RM was to develop technology that could consume large amounts of RM or transform it into secondary resources, which may need more time and effort.

Structure-Property Relationship of Geopolymers for Aqueous Pb Removal.

The geopolymer—an inorganic polymeric material synthesized from the reaction of aluminosilicate precursors and alkaline activating solutions—has gained wide research attention in recent decades as a promising adsorbent for the removal of aqueous heavy metals. However, the high variability of the material and several unanswered questions have limited its development and general adoption in the industry. This study evaluates the impacts of composition and microstructure on the performance of geopolymers for aqueous lead (Pb) removal to elucidate the composition–structure–property relationship. The Pb sorption kinetics and efficiency of four geopolymers, prepared using different fly ash precursors and activating solutions, were investigated. Although all the four geopolymer compositions studied displayed a high Pb removal efficiency of over 99.5%, with a slight decrease in efficiency with increasing Ca/(Si + Al) and Al/Si contents, the results show that the sorption kinetics decreases exponentially with increasing Ca/(Si + Al) and Al/Si molar ratios. The performance of the geopolymers also shows strong correlation to the microstructure, wherein the sorption kinetics increases exponentially, while the efficiency increases slightly, with increasing mass fraction of the amorphous phase in the geopolymer’s phase assemblage. The results of this research indicate that using appropriate precursor formulation and curing conditions to evoke the best microstructures, geopolymer materials can be optimized for high performance in removing heavy metals, thereby improving the chances of the material’s general acceptability in the adsorbent industry.

Enhanced chemical stability and boosted photoactivity by transition metal doped-crosslinked polymer-inorganic materials

Transition metal doped-crosslinked polymers have attracted noteworthy attention in this respect due to their economical, simplicity and durability properties. So far, it remains demanding to fabricate transition metal doped-crosslinked polymer-inorganic films with controlled photoelectrochemical performance that were stable in the aggressive solutions. Here, we report a new strategy to preparing transition metal doped-crosslinked polymer-inorganic layers with improved photoelectrochemical activity by manipulating the types of metal ions (Fe(III) and Co(II)) in the presence of polyvinyl alcohol (PVA) and ethylenediaminetetraacetic acid (EDTA), as crosslinking agents, in the hydrogen film “PEM” (P: PVA; E:EDTA; M: Fe(III)/Co(III)). PEM is prepared by interfacial crosslinking and then complexing process via static chemical conversion (SCC) on the inorganic layer (IL) surface fabricated via plasma electrolysis (PE). The photoelectrochemical performance is improved significantly in the order of IL-PEFe, IL-PECo, and IL-PEFe*Co, which may be due to transition metal ions and crosslinked polymers.

Utilisation of Glass for the Production of Inorganic Polymeric Materials for Construction Industry

This paper deals with the utilisation of glass coming from municipal waste mainly for the production of inorganic polymeric materials, with advanced mechanical properties, intended for the construction industry. The development of glass-based geopolymers, achieving high compressive strength and low water absorption, is described, and the produced materials are compared with some common construction and building materials.