What is an antioxidant?

　　Some organic compounds that can inhibit or delay the thermal oxidation of polymers and other organic compounds in the air. For example, foods are prone to oxidative deterioration, and a small amount of antioxidants can be added to extend their storage time. Polymer materials such as plastics, synthetic fibers and rubber are prone to thermal and oxygen degradation reactions. Adding antioxidants can maintain the excellent performance of polymer materials and prolong their service life. The study of the specific surface area of antioxidants is very important. The detection data of the specific surface area of antioxidants is only real and reliable when the results are detected by the BET method. At present, there are many instruments in China that can only be tested by the direct comparison method. Was eliminated. At present, the multi-point BET method is used uniformly for the specific surface area testing at home and abroad. The specific surface area measurement standards developed at home and abroad are based on the BET test method. Please refer to China's national standard (GB/T19587-2004)-Gas adsorption BET principle measurement The method of specific surface area of solid materials. The measurement of specific surface area is actually a time-consuming task. Due to the different adsorption capacity of samples, the testing of some samples may take a whole day. If the test process is not fully automated, then the tester can’t leave at all times. A high degree of concentration, observing the instrument panel, manipulating the knob, and a little inattention will lead to the failure of the test process, which will waste a lot of precious time of the tester. The F-Sorb2400 specific surface area tester is an instrument that can truly realize the detection function of the BET method (both with direct comparison method). The more important F-Sorb2400 specific surface area tester is the only fully automated intelligent specific surface area detection device in China so far. The test results are highly consistent with international standards, and the stability is also very good. At the same time, it reduces human errors and improves the accuracy of test results.

　　The thermal oxidation process of organic compounds is a series of free radical chain reactions. Under the action of heat, light or oxygen, the chemical bonds of organic molecules break, generating active free radicals and hydroperoxides. Hydrogen peroxide decomposes, and also generates hydrocarbon oxygen radicals and hydroxyl radicals. These free radicals can initiate a series of free radical chain reactions, leading to fundamental changes in the structure and properties of organic compounds. The role of antioxidants is to eliminate the free radicals just produced, or to promote the decomposition of hydroperoxides, to prevent the chain reaction. Antioxidants that can eliminate free radicals include aromatic amines and hindered phenols and their derivatives, known as primary antioxidants; antioxidants that can decompose hydroperoxides include organic compounds containing phosphorus and sulfur, known as Supplementary antioxidants.

　　Important aromatic amine antioxidants are: diphenylamine, p-phenylenediamine, dihydroquinoline and other compounds and their derivatives or polymers, can be used in natural rubber, styrene-butadiene rubber, neoprene and isoprene rubber products in. Such antioxidants are inexpensive and have a significant antioxidant effect. Because they can discolor products, their application in light-colored or white products is limited. The hindered phenolic antioxidants are: 2,6-tertiary butyl-4-methylphenol, bis(3,5-tertiary butyl-4-hydroxyphenyl) sulfide, tetra[β-(3, 5-tertiary butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester, etc. This type of antioxidant has a significant anti-oxidation effect and will not contaminate products. It is mainly used in plastics, synthetic fibers, latex, petroleum products, food, medicines and cosmetics. Thiodipropionate is a type of auxiliary antioxidant Agents, often used in combination with hindered phenolic antioxidants, the effect is remarkable, the main products are: dodecyl alcohol ester, ditetradecyl alcohol ester and dioctadecyl alcohol ester. Phosphite is also an auxiliary antioxidant, the main products are: trioctyl ester, tridecyl ester, tri (dodecyl alcohol) ester and tri (hexadecyl alcohol) ester.

　　Antioxidant

　　A substance that can prevent the deterioration of polymer materials due to oxidation.

　　Not recommended: oxidation inhibitor.

　　Among them, the antioxidant BHT invented by Bayer of Germany is widely used in industrial applications.

　　1. Antioxidant BHT can inhibit or delay the oxidative degradation of plastics or rubber and extend the service life.

　　2. Antioxidant BHT can prevent the increase of acid value or viscosity of lubricating oil and fuel oil.

　　3. Antioxidant BHT is also a stabilizer for synthetic rubber (styrene-butadiene, nitrile, polyurethane, cis-butadiene, etc.), polyethylene, and polyvinyl chloride. Antioxidant BHT is a phenolic antioxidant commonly used in rubber. The agent BHT has a protective effect on the thermal oxygen aging of natural rubber, cis-butadiene, styrene-butadiene, butyl, isopentyl, butyl green, ethylene-propylene and other synthetic rubbers, acrylates and latex products. The antioxidant BHT can more effectively inhibit copper damage. Combined with ozone resistance and wax, it can prevent damage to vulcanized rubber by various factors such as weather resistance. This product is easy to disperse in rubber. The antioxidant BHT can be directly mixed into the rubber or added to the latex as a dispersion. It can be used to manufacture the sidewalls of tires. White, brilliant and transparent rubber and dairy products, as well as daily use, medical and health, rubber cloth, rubber shoes and food products rubber products, antioxidant BHT can also be used as a stabilizer for post-processing and storage of synthetic rubber.

　　4. The solubility of antioxidant BHT is: ethanol 25% (20), soybean oil 30% (25), cottonseed oil 20% (25), lard 40% (40).

　　5. Antioxidant BHT can delay food rancidity as a food additive. Antioxidant BHT is used in animal and vegetable fats and oils and foods containing animal and vegetable fats. In addition, the antioxidant BHT can also be used in inks, adhesives, leather, casting, printing and dyeing, coatings, and the electronics industry.

　　6. Antioxidant BHT is also a stabilizer for cosmetics and medicine. Addition amount of antioxidant BHT: 0.01%-2%.

　　7. Antioxidant BHT is an excellent antioxidant additive for various petroleum products. When the operating temperature of antioxidant BHT is 100 degrees, the antioxidant effect is the best. Antioxidant BHT is widely used as an antioxidant and anti-adhesive agent for turbine oil, transformer oil, hydraulic oil, thermal oil, brake oil, spindle oil, precision mechanical oil and paraffin. Antioxidant BHT can be added to the product directly or as a mother liquor. In order to improve the product's antioxidant performance and extend its service life. Antioxidant BHT is used in combination with long-chain alkaline ZDDP, TCP metal deactivation and rust inhibitor, and can be used to prepare anti-wear hydraulic oil and other products. The dosage is generally 0.1-1%.