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Foam glass or expanded glass is a porous glass foam material. It is used as a light weight, moisture- and fireproof building material with thermal and acoustic insulating properties.
It is made by heating a mixture of crushed or granulated glass and a blowing agent (chemical foaming agent), often carbon or carbonates such as limestone. Near the melting point of the glass, the blowing agent releases a gas, producing a foaming effect in the glass. After cooling the mixture hardens into a rigid material with gas-filled closed-cell pores comprising a large portion of its volume. Foam glass gravel is produced by letting the glass mass fracture during the cooling process. Often recycled glass, sometimes from disused CRTs, is used as a base material. [1] Igneous rock such as obsidian and industrial waste slag may also be used.
While the term porous glass often indicates glass with pores in the nanometre- or micrometre-range the pore size of foam glass is usually within 0.5 to 5 mm, and the pores make up 80%~90% of the total volume.
Chemical foaming agents facilitate the release of the gaseous phase upon heat treatment. [2] [3] [4] [5] In general, these additives are are either a) redox and neutralization agents, or b) decomposing agents. Redox and neutralization agents include nonoxide materials, e.g. carbides or nitrides. Decomposing agents include sulfates, e.g. CaSO4•nH2O,[ citation needed ] organic compounds, and carbonates, e.g. CaCO3. These materials release gas following decomposition and/or burning.
Expanded glass is widely used in the building industry and for other industrial insulation applications as well as a filler in composite materials. [6]
Foam glass is fireproof, waterproof, non-toxic, corrosion-resistant, non-aging, non-radioactive, and insulating. It is a stable building exterior wall and roof insulation and sound insulation material.
Foam glass does not absorb water. The cells are mostly closed, so there is no capillary rise.
Foam glass has an operating temperature range of -200 to 450 °C and a small expansion coefficient (8 × 10 °C).
Foam glass with open pores absorbs sound and is used as a sound insulation material. Penetration loss can be around 28.3 dB in 60~400 Hz.
Depending on the properties of the foam glass, it can be used as insulation material in various sectors of construction engineering, as well as in shipbuilding, chemical, cryogenic, and high-temperature technologies. As a moisture-proof, fireproof, and chemically resistant material foam glass may be used in harsh environments such as in heat insulation and deep cooling in underground and open-air applications such as pipelines and tank foundations.
Expanded glass is mostly used as a insulation material, e.g. in machine room noise reduction and highway sound absorption barrier. Recently, it has become available in monolithic dimensions of 2.8 x 1.2m.[ citation needed ]
Foam glass insulation aggregate (foam glass gravel) is used in a similar way as porous clay aggregate as a load-bearing hardcore. With a lambda/k value of around 0.08 its thermal conductivity is approximately 20% lower than lightweight expanded clay aggregate. [7]
Depending on the application, foam glass products produced by the corresponding processes can be divided into four categories, namely insulating foam glass, sound-absorbing decorative foam glass, facing foam glass, and granular foam glass.[ citation needed ]
White and stained glass are also used as sound absorbing and decorative materials. Waste in production – foamed glass powder and scrap can also be used as fillers for decorative light concrete and other applications.
In the 1930s, Saint-Gobain of France first developed foam glass with calcium carbonate as a foaming agent. In 1932, it applied for a patent. [8]
An early report of foam glass as a construction material was made by the Soviet scientist, Professor Isaak Ilych Kitaygorodskiy (ru) at the All-Union Conference on Standardization and Manufacture of New Construction Materials in Moscow in 1932. [9] Subsequently, in 1939, the Soviet Union reports experimentally produced foam glass at the intermediate pilot plant of the Mendeleev Institute of Chemical Technology. A glass powder screened through a 0.09 mm mesh was mixed with limestone and later on with anthracite and coal as gasifier. [10]
The product that is known today as Foamglas cellular glass insulation, was developed by Pittsburgh Corning and was later acquired by Owens Corning. It is made of cullet, foaming agent, modified additive and foaming accelerator. After fine pulverization and uniform mixing, it is melted at high temperature, foamed and annealed. An inorganic non-metallic glass material, it consists of a large number of uniform bubble structures with a diameter of 1 to 2 mm. Sound-absorbing Foamglas insulation is more than 50% open cell bubbles, and heat-insulating Foamglas is more than 75% closed-cell air bubbles, which can be adjusted according to the requirements of use through changes in production technical parameters. [11] Similar products by other manufacturers are sold as 'cellular glass' or 'foam glass'.
Thermal insulation is the reduction of heat transfer between objects in thermal contact or in range of radiative influence. Thermal insulation can be achieved with specially engineered methods or processes, as well as with suitable object shapes and materials.
In materials science, a thermosetting polymer, often called a thermoset, is a polymer that is obtained by irreversibly hardening ("curing") a soft solid or viscous liquid prepolymer (resin). Curing is induced by heat or suitable radiation and may be promoted by high pressure or mixing with a catalyst. Heat is not necessarily applied externally, and is often generated by the reaction of the resin with a curing agent. Curing results in chemical reactions that create extensive cross-linking between polymer chains to produce an infusible and insoluble polymer network.
Calcium silicate can refer to several silicates of calcium including:
In materials science, a refractory is a material that is resistant to decomposition by heat or chemical attack and that retains its strength and rigidity at high temperatures. They are inorganic, non-metallic compounds that may be porous or non-porous, and their crystallinity varies widely: they may be crystalline, polycrystalline, amorphous, or composite. They are typically composed of oxides, carbides or nitrides of the following elements: silicon, aluminium, magnesium, calcium, boron, chromium and zirconium. Many refractories are ceramics, but some such as graphite are not, and some ceramics such as clay pottery are not considered refractory. Refractories are distinguished from the refractory metals, which are elemental metals and their alloys that have high melting temperatures.
A vacuum insulated panel (VIP) is a form of thermal insulation consisting of a gas-tight enclosure surrounding a rigid core, from which the air has been evacuated. It is used in building construction, refrigeration units, and insulated shipping containers to provide better insulation performance than conventional insulation materials.
Bioactive glasses are a group of surface reactive glass-ceramic biomaterials and include the original bioactive glass, Bioglass. The biocompatibility and bioactivity of these glasses has led them to be used as implant devices in the human body to repair and replace diseased or damaged bones. Most bioactive glasses are silicate-based glasses that are degradable in body fluids and can act as a vehicle for delivering ions beneficial for healing. Bioactive glass is differentiated from other synthetic bone grafting biomaterials, in that it is the only one with anti-infective and angiogenic properties.
In materials science, a metal foam is a material or structure consisting of a solid metal with gas-filled pores comprising a large portion of the volume. The pores can be sealed or interconnected. The defining characteristic of metal foams is a high porosity: typically only 5–25% of the volume is the base metal. The strength of the material is due to the square–cube law.
Ceramic engineering is the science and technology of creating objects from inorganic, non-metallic materials. This is done either by the action of heat, or at lower temperatures using precipitation reactions from high-purity chemical solutions. The term includes the purification of raw materials, the study and production of the chemical compounds concerned, their formation into components and the study of their structure, composition and properties.
Nanofoams are a class of nanostructured, porous materials (foams) containing a significant population of pores with diameters less than 100 nm. Aerogels are one example of nanofoam.
Ceramic foam is a tough foam made from ceramics. Manufacturing techniques include impregnating open-cell polymer foams internally with ceramic slurry and then firing in a kiln, leaving only ceramic material. The foams may consist of several ceramic materials such as aluminium oxide, a common high-temperature ceramic, and gets insulating properties from the many tiny air-filled voids within the material.
A blowing agent is a substance which is capable of producing a cellular structure via a foaming process in a variety of materials that undergo hardening or phase transition, such as polymers, plastics, and metals. They are typically applied when the blown material is in a liquid stage. The cellular structure in a matrix reduces density, increasing thermal and acoustic insulation, while increasing relative stiffness of the original polymer.
Building insulation materials are the building materials that form the thermal envelope of a building or otherwise reduce heat transfer.
Spray foam is a chemical product created by a chemical reaction of two component parts, commonly referred to as side A and side B. Side A contains very reactive chemicals known as isocyanate. Side B contains a polyol, which reacts with isocyanates to make polyurethane, and a mixture of other chemicals, including catalysts, flame retardant, blowing agents and surfactants. These react when mixed with each other and expand up to 30-60 times its liquid volume after it is sprayed in place. This expansion makes it useful as a specialty packing material which forms to the shape of the product being packaged and produces a high thermal insulating value with virtually no air infiltration.
Porous glass is glass that includes pores, usually in the nanometre- or micrometre-range, commonly prepared by one of the following processes: through metastable phase separation in borosilicate glasses (such as in their system SiO2-B2O3-Na2O), followed by liquid extraction of one of the formed phases; through the sol-gel process; or simply by sintering glass powder.
Polyurethane foam is a solid polymeric foam based on polyurethane chemistry. As a specialist synthetic material with highly diverse applications, polyurethane foams are primarily used for thermal insulation and as a cushioning material in mattresses, upholstered furniture or as seating in vehicles. Its low density and thermal conductivity combined with its mechanical properties make them excellent thermal and sound insulators, as well as structural and comfort materials.
Foam concrete, also known as Lightweight Cellular Concrete (LCC) and Low Density Cellular Concrete (LDCC), and by other names, is defined as a cement-based slurry, with a minimum of 20% foam entrained into the plastic mortar. As mostly no coarse aggregate is used for production of foam concrete the correct term would be called mortar instead of concrete; it may be called "foamed cement" as well. The density of foam concrete usually varies from 400 kg/m3 to 1600 kg/m3. The density is normally controlled by substituting all or part of the fine aggregate with the foam.
Aerogels are a class of synthetic porous ultralight material derived from a gel, in which the liquid component for the gel has been replaced with a gas, without significant collapse of the gel structure. The result is a solid with extremely low density and extremely low thermal conductivity. Aerogels can be made from a variety of chemical compounds. Silica aerogels feel like fragile styrofoam to the touch, while some polymer-based aerogels feel like rigid foams.
Foam glass gravel is a building material made from recycled glass.
Praseodymium(III,IV) oxide is the inorganic compound with the formula Pr6O11 that is insoluble in water. It has a cubic fluorite structure. It is the most stable form of praseodymium oxide at ambient temperature and pressure.
Titanium foams exhibit high specific strength, high energy absorption, excellent corrosion resistance and biocompatibility. These materials are ideally suited for applications within the aerospace industry. An inherent resistance to corrosion allows the foam to be a desirable candidate for various filtering applications. Further, titanium's physiological inertness makes its porous form a promising candidate for biomedical implantation devices. The largest advantage in fabricating titanium foams is that the mechanical and functional properties can be adjusted through manufacturing manipulations that vary porosity and cell morphology. The high appeal of titanium foams is directly correlated to a multi-industry demand for advancement in this technology.
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