How can antioxidants effectively inhibit the rate of thermal oxidation?
Antioxidant is added to plastic resin to effectively inhibit or reduce the thermal oxidation reaction speed of plastic macromolecules, delay the thermal and oxygen degradation process of plastic resins, different types of primary and secondary antioxidants, or different molecular structures of the same type. Antioxidants, different functions and application effects, each with its own strengths and shortcomings. The composite antioxidant is compounded by two or more different types or different types of antioxidants, plastic Resin in the synthesis and post-treatment process, plastic products in the process of processing and use.
Due to the action of heat, oxygen and other factors, plastic polymers will have different degrees of degradation. The use of antioxidants is one of the methods to effectively delay the degradation of resins and products or thermal aging. Commonly used plastic antioxidants are generally classified into five types of hindered phenols, phosphites, thio compounds, complexes, and hindered amines according to their molecular structure and mechanism of action. Plastic resins are polymerized due to different molecular structures or molecular structures. Different processes, different processing techniques, different use environments and conditions, their thermal oxidation reaction rate and resistance to thermal oxidation reaction are very different, and there are applications of antioxidants.
Hindered phenolic antioxidants are the main antioxidants of plastic materials. Their main function is to react with oxidative free radicals generated by oxidation in plastic materials, interrupting the growth of active chains. Hindered phenolic antioxidants are classified into monophenols according to their molecular structure. Bisphenol, polyphenols, nitrogen heterocyclic polyphenols, etc., the application varieties and addition amounts of antioxidants are mainly determined by the molecular structure, polymerization process, processing conditions and product use of plastic resins, and the physical properties of resins and products directly degraded. Performance, mechanical properties, appearance color, use function and other aspects have a negative effect.