Ceramic Residue Research Articles

Thermal Properties of Polysiloxane/Ag Nanocomposites with Different Network Structures and Distributions of Si–H Groups

Polysiloxanes with silver nanoparticles (Ag NPs) have garnered attention for their distinctive physicochemical properties, which make them promising candidates for advanced material applications. This study presents a systematic investigation into the thermal properties and degradation mechanisms of polysiloxane/Ag nanocomposites, emphasising the innovative incorporation of Ag NPs directly into polysiloxane networks via in situ reduction of Ag⁺ ions by Si-H groups. Six polysiloxane matrices were synthesised by hydrosilylation of poly(methylhydrosiloxane) (PMHS) or poly(vinylsiloxane) (polymer V3) with three cross-linking agents of varying molecular structures and functionality. Thermogravimetric analysis combined with mass spectrometry revealed that the introduction of Ag NPs alters the thermal properties of polysiloxane networks, primarily affecting the redistribution of Si bonds that occurs during the pyrolysis of these systems. Monitoring the pyrolysis process using FTIR spectroscopy allowed us to investigate the effect of the presence of Ag NPs on the degradation mechanism of the studied nanocomposites. The presence of the free-carbon phase and metallic silver phase in the Ag-containing silicon oxycarbide materials obtained was confirmed by Raman spectroscopy and XRD analyses, respectively. These findings demonstrate the possibility of fabricating Ag/SiOC materials with ceramic residues in the range of 43 to 84%. This work provides new insights into the thermal behaviour of polysiloxane/Ag nanocomposites and underscores their potential for high-performance applications in thermally demanding environments.

Effect of crystalline phase formed by compound flame retardant on the flame retardancy and ceramization of polyethylene composites

AbstractCeramic polyolefin composites have the capability to transform into hard ceramics when exposed to fire conditions. During the ceramization process, the formation of new crystalline phase plays a crucial role in enhancing flame‐retardant and ceramifiable properties. Consequently, ceramic polyolefin composites show great potential for the applications in fire‐resistant wires and cables. In this article, the incorporation of the compound flame retardant consisting of ammonium polyphosphate/melamine cyanurate/zinc borate (APP/MCA/ZB) was found to enhance the flame retardancy and ceramization of polyethylene/wollastonite fiber/phosphate glass frits (PE/WF/PGF) composites. The results indicated that ceramifiable flame‐retarding PE composites with compound flame retardant exhibited superior flame retardancy compared to pure PE and PE composites with a single flame retardant. Specifically, the limiting oxygen index (LOI) was significantly increased to 26.8%, and the vertical combustion test rating in UL‐94 (test for flammability of plastic materials for parts in devices and appliances) reached V‐0. During the heating process, ZB thermally decomposed to produce 2ZnO ⋅ 3B2O3, which reacted with CaSiO3 to form a silicate glass intermediate phase (CaO ⋅ SiO2 ⋅ 2ZnO ⋅ 3B2O3). APP thermally decomposed to produce (HPO3)n, which reacted with 2ZnO ⋅ 3B2O3 to form a phosphate glass intermediate phase (nP2O5 ⋅ 2ZnO ⋅ 3B2O3). These two glass phases experienced a eutectic reaction with WF, ultimately producing the formation of a new crystalline phase of calcium zinc phosphate (CZP, Ca19Zn2(PO4)14). This newly formed CZP phase made sintered ceramics more compact and had higher flexural strength. The flexural strength of ceramic residues after sintering was 11.68 MPa, meeting the requirements for practical applications.

Fly ash and ceramic residue based geopolymer mortars

A binary geopolymer in the basis of fly ash and ceramic residue was developed under ambient temperature. The alkali medium comprises of commercial Na2SiO3 and NaOH with 10 M dan 12 M. Analyses were carried out to characterize the raw materials and their geopolymer properties. characterization was conducted through X-ray Diffraction (XRD), X-ray Fluorescence (XRF), Scanning Electron Microscope (SEM). The compressive strength, porosity and abrasion rates were measured for determining geopolymer performance. The ceramic residue consists mainly of SiO2 and Al2O3, which is similar to the fly ash. The highest compressive strength produced from the specimens was at 25.2 MPa with the age of 28 days, which complies with class 1 in standard SNI 03-0349-1989. This highest strength was followed by the lowest water absorption and abrasion rate, which are at 1.99% and 0.007 mm/minute, respectively.

A revisited history of cacao domestication in pre-Columbian times revealed by archaeogenomic approaches

Humans have a long history of transporting and trading plants, contributing to the evolution of domesticated plants. Theobroma cacao originated in the Neotropics from South America. However, little is known about its domestication and use in these regions. In this study, ceramic residues from a large sample of pre-Columbian cultures from South and Central America were analyzed using archaeogenomic and biochemical approaches. Here we show, for the first time, the widespread use of cacao in South America out of its native Amazonian area of origin, extending back 5000 years, likely supported by cultural interactions between the Amazon and the Pacific coast. We observed that strong genetic mixing between geographically distant cacao populations occurred as early as the middle Holocene, in South America, driven by humans, favoring the adaptation of T. cacao to new environments. This complex history of cacao domestication is the basis of today's cacao tree populations and its knowledge can help us better manage their genetic resources.

Sustainable experimental study of ceramic residues and waste fabrics

Objective: To explore feasible solutions to realize the recycling of waste materials for sustainable application in response to the existing problem of idle accumulation of large quantities of waste textile fabrics and ceramic residues. Methods: Through the experimental method, waste porcelain powder was substituted for some of the ridged raw materials in the traditional ceramic formula to make a slurry, and then mixed with waste fabrics to be fired into a new ceramic material. Then its characteristics were recorded, summarized, explored, and analyzed to explore the unique value of the material. Results: The experiments found that the mixing of the waste materials produced a good chemical reaction. The waste ceramic powder can enhance the flexural strength of the new material, reduce the deformation rate, and make the new material’s performance more stable. Waste fabrics can make the new materials enjoy the advantages of easy production, good light transmittance, and lightweight. Conclusion: This research lays a technical foundation for future entry into the design market. This contributes to the recycling of waste fabrics and ceramic residues in a sustainable way.

Interdisciplinary evidence for early domestic horse exploitation in southern Patagonia

The introduction of domestic horses transformed Indigenous societies across the grasslands of Argentina, leading to the emergence of specialized horse cultures across the Southern Cone. However, the dynamics of this introduction are poorly chronicled by historic records. Here, we apply archaeozoological and biomolecular techniques to horse remains from the site of Chorrillo Grande 1 in southern Argentina. Osteological and taphonomic analyses suggest that horses were pastorally managed and used for food by Aónikenk/Tehuelche hunter-gatherers before the onset of permanent European settlement, as early as the mid-17th century. DNA-based sex identifications suggest consumption of both male and female horses, while ceramic residue also shows use of guanaco products. Sequential isotope analyses on horse dentition reveal an origin in southern Patagonia and movement of these animals between the Río Coig and Río Gallegos basins. These results reinforce emerging evidence for rapid Indigenous-mediated dispersal of horses in the Americas and demonstrate that horses catalyzed rapid economic and social transformations.

Improving thermal insulation and fire resistance of ceramifiable EVA/ceramic hybrid composites via low temperature sintering and foaming strategy

Energy efficient buildings, propulsion components and thermal protection systems require materials with high thermal protective properties. Traditional polymer composites or ceramic materials have limited comprehensive applications because of their poor thermal protective properties or poor processability. Herein, a novel fire resistant and thermally insulating polymer/ceramic hybrid ceramifiable composite was developed based on low temperature sintering principle and foaming on fire strategy. Specifically, the influences of raw materials of low temperature ceramics, such as glass frit, phosphate, etc, on the properties of ceramifiable ethylene-vinyl acetate (EVA) composites were investigated. Its fire resistance and thermal insulation properties were evaluated by simulating different sintering environments. The results show that the ceramifiable composite exhibits the highest improvement in fire resistance because a crystalline phase was formed at high temperatures. Gas evolution from the thermal decomposition of ammonium polyphosphate (APP) and EVA contributes to the formation of the porous structure in ceramic residues. The optimal system can resist above 1000 °C flame for 30 min without disintegration, and the temperature of the unfired side was maintained around 200 °C. The reliability of the strategy was verified by the effective medium theory model.

Utilizing porcelain tile polishing residue in eco-efficient high-strength geopolymers with steel microfibers

Geopolymers are an alternative that produces low environmental impact binders with satisfactory mechanical properties. This research evaluated the influence of adding steel microfibers to a binary geopolymer matrix composed of metakaolin and ceramic tile polishing residue. Three mortar compositions (1:2, 1:3 and 1:4 cement:sand mass ratios) were produced with three microfiber concentrations (vf = 0.45, vf = 0.90 and vf = 1.35 % of total volume). The mechanical properties were evaluated by testing compressive strength, dynamic modulus of elasticity, flexural strength, and toughness. For 1:3 mortar, autogenous shrinkage measurements were performed for the 3 microfiber concentrations. Equivalent carbon dioxide emissions and binder intensity were also quantified. The mechanical properties classify the geopolymer concrete as high strength, achieving up to 95 MPa (composition 1:3) of compressive strength at 28 days and low binder consumption (9.82 kg.m−3. MPa−1). An improvement in flexural tensile strength was observed as the concentration of steel microfibers increased, reaching 20 MPa with vf= 1.35 %. For the concentration vf= 0.90 %, there was a reduction of ∼38 % of the autogenous shrinkage measurements about the reference (vf=0.0 %) at 28 days. In addition, regarding the CO2 intensity index, the lowest values were obtained for the 1:3 compositions, being minimum for vf= 0.90 % (9.01 [kg. ECO2-eq /m³ of mortar]/MPa), producing geopolymeric composites with low CO2 emissions, allowing the production of construction materials with low environmental impact.

Vinylhydridosilsesquioxne: Synthesis and characterization of a potential filler material for vinyl‐containing polysiloxanes

AbstractThis paper reports the synthesis and characterization of an organic silsesquioxane (SQ) containing Sivinyl and SiH groups named as vinylhydridosilsesquioxane (SQVH‐12). Detailed investigation of the structure of this organosilsesquioxane revealed that SQVH‐12 has a highly cross‐linked (polycyclic) SiO network of silsesquioxane with Sivinyl and SiH functional groups. Thermogravimetric analysis of the pyrolysis behavior of SQVH‐12 yielded a high percentage of ceramic residue (~92%) at 1200°C under an argon atmosphere. The presence of functional groups in SQVH‐12 and the high rate of ceramic residue highlights the potential usefulness of SQVH‐12 as a filler for vinyl‐containing polysiloxanes. Thus, further research of SQVH‐12 can find applications in a wide variety of areas such as additive manufacturing, protective coatings, and advanced composites.

Fractionation and speciation of metals in lakes formed by abandoned clay pits from industrial effluents (Santa Gertrudes, São Paulo, Brazil) using the diffusive gradient in thin films (DGT) technique

Environmental impacts caused by mining activities (mainly tailings and effluents) are presenting serious challenges for humanity worldwide. In Brazil, clay extraction activities in the Ceramic District of Santa Gertrudes (CDSG) have led to the formation of abandoned drainage wells causing environmental and human health concerns. In the 90's, it was discovered that in one of the production areas, known as the region of the lakes of Santa Gertrudes, several ceramic industries had contaminated lakes created by abandoned clay pits with industrial effluents containing toxic metals. In the present study, analysis of total and dissolved concentrations of Al, Cd, Co, Cu, Mn, Ni, Pb and Zn in the waters of these lakes were combined with the diffusive gradients in thin films (DGT) technique to assess the lability and bioavailability of the target elements, representing one of the first studies to investigate the real environmental impact of contamination caused by ceramic production wastes to an aquatic system. Furthermore, based on the total concentrations and main physicochemical characteristics of each lake, a speciation analysis was performed using the MINTEQ software which data was compared with other surface water systems. The results indicated the presence of metals associated with ceramic residues in total, dissolved and labile fractions. It was verified that Zn, Ni and Cu were the only target metals found in labile form and according to speciation were present in the form of “free” ions, and thus may present risk in terms of bioavailability, although the majority of the total concentrations are within the limits established by the national environmental agency.

Processing of Ceramics from Polysil(sesquioxane)‐Type Precursors: Coatings, Tapes, Tailored Surfaces, and Porosity Control

Poly(silsesquioxane)‐based polymer‐derived ceramics (PDCs), may be manufactured by a great variety of processes and process combinations leading to ceramic parts seven with high functionality. Advantage of the use of poly(silsesquioxane)s as starting materials with a defined amount of oxygen is that low‐temperature‐processing steps such as shaping and cross‐linking may be carried out in air, and a disadvantage often discussed is a maximum service temperature below 1200 °C. In this article, the focus is set to PDC tapes, coatings, tailored surfaces, and tailored porosity. And, a rough distinction is made between materials pyrolyzed below 1200 °C and far above 1200 °C. The later provides porosity formed by high‐temperature reactions between particulate fillers and the ceramic residue from pyrolysis.

Flame retardancy, combustion, and ceramization behavior of ceramifiable flame‐retardant room temperature vulcanized silicone rubber foam

AbstractTwo types of ceramifiable flame‐retardant room temperature vulcanized (RTV) silicone rubber foam containing mica power (MP) were prepared by using glass powder (GP) as fluxing agents and aluminum hydroxide (ATH) as flame‐retardant agent, respectively. The flame retardant, combustion behavior, and thermal stability of ceramifiable flame‐retardant RTV silicone rubber foams were investigated. The results show that GP is not conducive to the flame retardancy and thermal stability improvement of the foams. On the contrary, MP and ATH can significantly improve the flame retardancy and thermal stability at high temperatures of the foams. The foams with addition of MP and ATH can reach to a high limiting oxygen index value of 35.8 with V‐0 rating in the vertical combustion test, and the total heat release and total smoke production of the foams are 21.0% and 61.7% lower than of the pure RTV silicone rubber foam, respectively. Furthermore, the structural and morphological changes of the foams under different pyrolysis conditions were studied, so as to reveal its ceramifiable mechanism under different fire scenarios. The results show that GP does not promote the formation of more char residue during pyrolysis, but it can greatly lower the ceramifiable temperature, resulting in a superior ceramic phase char residue. The foams including MP and ATH have a high char residue content; nevertheless, a comparatively higher temperature is necessary to create ceramic phase char residue.

Effect of glass frits on ceramifiable properties of polyethylene composites

AbstractCeramification of polymer composites is an excellent method for enhancing the flame retardancy of the materials. The low temperature softening glass frit added in the composites plays a key role in the ceramification process of the composites. Ceramizable polyethylene (PE)/wollastonite fiber (WF) composites are processed by mixing with three types of glass frit. The ceramic residues formed were characterized by the linear shrinkage, weight loss, flexural strength, apparent porosity, and self‐supporting property measurements. The density and strength of the ceramic increased with the increasing sintering temperature, but were affected by the wettability and fluidity of the glass frit. The addition of glass frit can increase the thermal decomposition temperature of PE. X‐ray diffraction (XRD) analysis found the form of a new phase of hydroxyapatite (Ca10(PO4)6(OH)2) in the ceramifiable PE/WF composites by adding phosphate glass frit, which improved the self‐supporting properties of the ceramic residues.

Starch grain analysis of ceramic residue from forest islands associated with raised fields in west central Mojos, Bolivia

This study analyzed starch grain residues from 65 ceramic artifacts recovered from excavations of inhabited forest islands situated near raised fields in the Llanos de Mojos region of the southwestern Amazon Basin. The assemblage of starch grains from the forest island contexts represents a diverse array of plant resources including maize and manioc, but also other plants such as achira, arrowroot, and the first archaeological evidence for arracacha in the southwest Amazon. The artifacts sampled and plants identified in this study represent resource use by people living on forest islands who constructed and maintained adjacent raised fields for cultivation. The study highlights the importance of research into the diversity of local and regional foodways in the Llanos de Mojos.

Study on char reinforcing of different inorganic fillers for polyethylene composites

Ceramifiable polymer composite is an excellent method for enhancing the flame retardancy of the materials. In case of fire, ceramifiable polymer composites are converted into a ceramic barrier that can impede heat transfer, segregate combustible material from oxygen and prevent the polymer matrix from pyrolysis. The ceramic fillers added to the composites play a key role in the ceramic forming process of the composites. Here, the effects of three types of Si-based mineral fillers on the ceramifiable and mechanical properties of polyethylene composites were investigated. Wollastonite (CaSiO3), silica powder (SiO2), or pyrophyllite (Al2Si4O10(OH)2) was incorporated into low-density polyethylene with glass powder to prepare the composite materials. The composites were subjected to sintering at various temperatures (600, 800, and 1000 °C). The ceramic residues formed were characterized by flexural strength, apparent porosity, linear shrinkage, and thermogravimetric measurements. All these three fillers greatly enhanced the ceramifiable properties of the polyethylene composites and the mechanical properties of the ceramic residues. X-ray diffraction analysis and scanning electron microscopy reveal that the filler molecules were firmly connected by the molten glass while the pores in the ceramic residues were released at elevated temperatures, leading to a dense ceramic structure with excellent mechanical properties.

High-temperature behavior of silicone rubber composite with boron oxide/calcium silicate

Abstract The ceramifiable silicone rubber (SR) composite is prepared using boron oxide, calcium silicate, and kaolin as ceramifiable fillers. The effects of the content of CaSiO3/B2O3 on the high-temperature properties of composites are investigated. In the process of decomposition and oxidation of the ceramifiable SR composite in air, B2O3, and low-melting-point glass frit that participate in the formation of the residue network structure in different temperature regions, it continuously produces a liquid phase during the process of the ceramifying transformation. Microscopic images reveal that different structures are formed at different temperatures. The network structure of the ceramic residue becomes increasingly compact with the increase in temperature from 600°C to 800°C, which has a better protective effect on heat transfer and mass loss. At 900°C, with the lattice reconstruction of calcium silicate and the change of crystal structure, volume expansion occurs after cooling, alleviating the volume shrinkage caused by ceramic phase formation in the process of ablation. When the ratio of CaSiO3/B2O3 reaches 1:1 (both are 15 phr), the bending strength and linear shrinkage of the composites reach a satisfactory balance, the bending strength and the shrinkage reach 18.5 MPa and 12.1%, respectively.

Diet, economy, and culinary practices at the height of precolonial Swahili urbanism

• Combined ethnographic, historic, and biomolecular approaches to Swahili cuisine. • Pottery lipid residue analysis revealed mixing of C 3 plants, milk, and meats. • Isotope results underscore C 4 plant and cattle/chicken consumption. • Informative contrasts among residue, stable isotopic, and zooarchaeological results. • Multiproxy approach provides a nuanced picture of precolonial urban cuisine. Swahili cuisine is known across Africa and globally as a highly distinctive product of a cosmopolitan, coastal, urban society. Here we present a comprehensive study of precolonial Swahili diet and culinary practices at the coastal town of Songo Mnara, positioning archaeological and ethnographic understandings of cuisine in a long-term coastal tradition. We explore contemporary food cultures and then present the first direct evidence for precolonial cuisine by combining ceramic lipid residue analysis with archaeobotanical, zooarchaeological, and faunal and human stable isotopic data. Integrating these datasets produces a detailed picture of diet at the site of Songo Mnara during the peak of precolonial Swahili urbanism. Lipid residue analysis demonstrates how plant and animal products were consumed and valued in ways not discernible from plant and animal remains alone. We also note special treatment for particular foodstuffs, including an association of fish consumption with high-status spaces and vessels, and preferential management of cattle for milk. A more complex picture of urban life emerges, recognizing influences of taste, class, and culture. Our findings demonstrate the potential of multi-layered anthropological studies for exploring cuisine and urban life in coastal contexts across the globe.

Ceramifiable Silicone Rubber Composites with Enhanced Self-Supporting and Ceramifiable Properties.

Ceramifiable silicone rubber (SR) composites with excellent self-supporting properties and ceramifiable properties were prepared by incorporating silicate glass frits (SGFs) and sodium tripolyphosphate (STPP) into the SR. Ceramic residues were obtained by firing ceramifiable SR composites at 700, 850, and 1000 °C for 30 min. The bending angles of the composites were tested for evaluating the self-supporting property. To evaluate the ceramifiable properties of the ceramifiable SR composite, flexural strength, water absorption, and bulk density of its residues were tested. It was found that the addition of STPP improved the shape stability and the self-supporting property of the composites at high temperatures. The flexural strength of the ceramic residue of the composite with STPP firing above 850 °C is more than 5 MPa. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analysis showed that the relative content of the crystalline phase was enhanced by about 25% due to the addition of STPP. Furthermore, a possible mechanism for the formation of the crystalline phase was proposed. Scanning elector microscope (SEM) and energy dispersive spectrometry (EDS) analysis demonstrated that with the temperature increase, the inter-infiltration between these melts became easier, which implies that the bulk density of the ceramic residue was improved.

Low temperature mullite forming pre-ceramic resins of high ceramic yield for oxide matrix composites

Monophasic mullite precursors, namely aluminosiloxanes were synthesized by a novel synthetic route, in which co-hydrolysis and condensation of aluminium tri secbutoxide and tetraethoxy silane was achieved in presence of con. HCl in a non-polar medium. Aluminosiloxanes were characterized by FT-IR, NMR, and elemental analyses. Spectral analysis confirms the presence of Si-O-Al bonds in all the samples and also validates the incorporation of more aluminium via Si-O-Al bonds with increasing Al/Si mole ratio in the precursor. These FT-IR and NMR data also attest the precursor level homogeneity in all the samples. The aluminosiloxanes are obtained as low viscous resins and are capable of giving high ceramic residue qualifying them as ceramic matrix precursors for CMCs. The effect of Al/Si ratio on the ceramic conversion was studied. All the precursors showed the formation of mullite at 1000 °C. This low temperature mullite formation is a key factor in developing oxide CMCs without fiber damage. The results obtained from the study show that the composition of the ceramic can be controlled between a silica rich mullite phase and near-stoichiometric mullite phase by suitably selecting the Al/Si monomer feed ratio of the precursors. This aspect provides a greater scope for designing application-specific ceramic matrices for space applications.

Red ceramic and concrete waste as replacement of portland cement: Microstructure aspect of eco-mortar in external sulfate attack

The use of red ceramic and concrete waste as a replacement for cement has great importance from an environmental point of view, and it is necessary to understand its influence on the cement matrix's performance. In this paper, mortar mixtures with partial replacement of the Portland cement by the addition of 3, 5, 12, and 20% of limestone filler (as reference), concrete waste, and red ceramic were subjected to sulfate attack. The accelerated test was monitored until the age of 98 days and microstructure analysis techniques were applied. Mortars with ceramic and concrete waste addition had greater expansion than the reference mortar. The addition of 12% of limestone filler mitigated the expansive reactions. The mortars with any type of addition had greater porosities. In this case, the aluminum oxide content in the ceramic and the calcium carbonate and calcium oxide contents in the concrete waste acted as a source for reaction with the sulfate ions. Due to the attack, the pore size distribution changed, showing that the pores in the band between 0.01 and 1 µm were filled with ettringite. The microcracks from the attack increased the pores with diameters over 1 µm. This performance reduction against sulfate attack must be considered for the use of ceramic and concrete residues in eco-efficient mortars, especially when it is inserted in environments subjected to this type of degradation.