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Polyurethane synthesis, wherein the urethane groups −NH−(C=O)−O− link the molecular units A kitchen sponge made of polyurethane foam . Polyurethane (/ ˌ p ɒ l i ˈ jʊər ə ˌ θ eɪ n,-j ʊəˈr ɛ θ eɪ n /; [1] often abbreviated PUR and PU) refers to a class of polymers composed of organic units joined by carbamate (urethane) links.
Polyurethane dispersion, or PUD, is understood to be a polyurethane polymer resin dispersed in water, rather than a solvent, although some cosolvent may be used.Its manufacture involves the synthesis of polyurethanes having carboxylic acid functionality or nonionic hydrophiles like PEG (polyethylene glycol) incorporated into, or pendant from, the polymer backbone. [1]
Rigid foam manufacturers sell foam that replace wood in carved sign and 3D-topography industries. PU foam is also used as a thermal insulator in many houses. Polyurethane resin is used as an aesthetic flooring material. Being seamless and water resistant, it is gaining interest for use in (modern) interiors, especially in Western Europe.
Phosphorgypsum-based concrete with sawdust aggregate. Gypsum concrete is a building material used as a floor underlayment used in wood-frame and concrete construction for fire ratings, sound reduction, radiant heating, and floor leveling. [1] It is a mixture of gypsum plaster, Portland cement, and sand. [1]
Construction block made from hempcrete Illustration of hemp concrete carbon emissions and sequestration, with a net emissions balance indicating carbon negativity. Hempcrete or hemplime is biocomposite material, a mixture of hemp hurds and lime, [1] sand, or pozzolans, which is used as a material for construction and insulation. [2]
Air entrainment in concrete is the intentional creation of tiny air bubbles in a batch by adding an air entraining agent during mixing. A form of surfactant (a surface-active substance that in the instance reduces the surface tension between water and solids) it allows bubbles of a desired size to form.
Michigan Concrete Association recommends a regular salt like Morton table salt instead of an ice melter because it’s 100 percent sodium chloride (NaCl). This, however, is recommended for ...
Unlike regular concrete, ECC has a tensile strain capacity in the range of 3–7%, [1] compared to 0.01% for ordinary portland cement (OPC) paste, mortar or concrete. ECC therefore acts more like a ductile metal material rather than a brittle glass material (as does OPC concrete), leading to a wide variety of applications.