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Flame Retardancy of Synthetic Fibers
Published in Asim Kumar Roy Choudhury, Flame Retardants for Textile Materials, 2020
A number of flame retardant systems containing halogen, metal hydroxide, phosphorous, and nitrogen are used to provide flame retardancy to PA6. The halogen compounds are famous for being highly efficient flame retardants at low dosage, but the usages are limited because of the toxicity of their combustion products and potential corrosion to spinning equipment (Isitman et al., 2009). Among the metal hydroxides that can be used as flame retardants in polymer materials, magnesium hydroxide, Mg(OH)2 and aluminum hydroxide, Al(OH)3 are the most important and are widely used. Although they have low toxicity, good anticorrosion properties, low cost, and low smoke emission during processing and burning, metal hydroxides have some serious disadvantages, such as relatively low flame retardancy, low thermal stability, and deterioration of the physical and mechanical properties of the matrix. (Balakrishnan et al., 2012). NFRs and PFRs are environmentally friendly and of low dosage, and have acceptable flame retardancy, and both of them have been studied extensively in providing flame retardancy to polymer materials. By comparison, NFRs add no new elements to polyamides such as PA6, and show good compatibility with them.
List of Chemical Substances
Published in T.S.S. Dikshith, and Safety, 2016
Aluminum hydroxide is a white amorphous powder, incompatible with strong bases. It is the most stable form of aluminium in normal conditions and is insoluble in water and etha-nol. Aluminium hydroxide is amphoteric. It is soluble in strong acids and forms Al(H2O)63+, alkalis, and Al(OH)4. Aluminum hydroxide forms a gel on prolonged contact with water; it absorbs acids and carbon dioxide. It is used in waterproof textiles, printing ink, glassware, filler for paper, mordant, and in the manufacture of aluminum and lubricants. Aluminum hydroxide is a flame retardant. Heat-dried aluminium hydroxide powder is known as activated alumina and is used in gas purification, as a catalyst support, and an abrasive. Pharmacologically, aluminum hydroxide is used as an antacid (as Alu-Cap, Aludrox, or Pepsamar). The hydroxide reacts with excess acid in the stomach, reducing its acidity.
Alkali-silica reaction in calcium aluminate cement mortars induced by deicing salts solutions
Published in Road Materials and Pavement Design, 2022
Since the conditions of the ASTM C1260 test are severe, first it was determined if CAC matrix is durable towards hot solutions of investigated deicing salts as well as sodium hydroxide solutions. To do it, mortar bars were immersed in abovementioned solutions, and their strength was tested after 1 and 14 days. In Figure 3 results of strength test are presented. Strength of mortar after 24 h of curing in moulds and 24 h of curing in water at 80°C was equal to 33.8 MPa. Then samples were immersed in solutions and stored for 14 days. For all the investigated salt solutions, strength after both 1 day, as well as 14 days of soaking in deicers solutions, was higher compared to the starting value. It means that investigated solutions of potassium acetate, sodium acetate and sodium chloride do not cause deterioration of CAC hardened cement matrix, at least during the duration of the test. One can suspect that there should also be no significant increase in permeability of mortars, since the strength was not lowered, and actually it even raised. For samples immersed in sodium hydroxide, a significant decrease of strength was noticed during the test, especially in the case of 6.5 M solution. It is a well-known fact that CAC hardened paste is not durable towards alkaline environment (Bensted, 2002; Ideker et al., 2019). This is because aluminium is an amphoteric element, and thus aluminium hydroxide is not resistant to a highly alkaline environment, forming aluminate ions in high pH solutions.
Aluminum hydroxide crystallization from aluminate solution using carbon dioxide gas: effect of pH and seeding
Published in Mineral Processing and Extractive Metallurgy, 2021
Valeh Aghazadeh, Somayeh Shayanfar, Peyman Hassanpour
Nepheline syenite (Na3K(Al3SiO4)4) is used to produce alumina (Al2O3) as most important aluminum non-bauxite source, moreover, sodium and potassium carbonate and cement can be produced (Arlyuk and Pivnev 2016). Carbonation is one method used for alumina production from aluminate solution obtained from alkaline leaching of sintered nepheline syenite (Czajkowski et al. 1981). Carbonation of aluminate solution is performed by injection of carbon dioxide gas into the solution. Aluminum hydroxide (Al(OH)3) is precipitated and the residual solution containing carbonate, potassium, and sodium ions is used for production of potassium and sodium carbonate salts (Jorjani and Amirhosseini 2007).
Effect of aluminum hydroxide (ATH) on flame retardancy and smoke suppression properties of SBS-modified asphalt
Published in Road Materials and Pavement Design, 2023
Xiaolong Yang, Guangchen Wang, Mingmei Liang, Taiping Yuan, Hongliu Rong
Aluminum hydroxide (ATH) is an inorganic flame retardant with highly cost-effective due to its good flame retardancy and smoke suppression, its excellent economy of use, a wide range of sources, and environmental friendliness (Huang et al., 2016; Jiang et al., 2019). Therefore, as one of the important flame retardants, ATH is often used as part of the composite flame retardants to enhance the flame retardancy and smoke suppression effect.