Synthesis And Application Of A New Type Of Composite Hindered Phenolic Antioxidant

Polymer materials are offen affected by light,heat,metal ions and other external effects in the use or storage process,there will be discoloration,sticky,hard brittle,crack and other aging phenomena,resulting in mechanical properties of materials decreased,finally,lost the use of their value.In order to overcome these problems,to extend the service life of materials and improve the use value,people add some substances in the polymer material to delay aging,this is the antioxidants.The most widely used in the field of polymer materials is hindered phenolic antioxidant.The traditional hindered phenolic antioxidants are generally used as the main antioxidant in polymer products,at the same time,it needs to add some auxiliary antioxidants,such as thioether.The two together can achieve the purpose of inhibiting the aging of the polymer through synergistic action.However,there are many disadvantages in the,use of this kind of multi component antioxidant system,such as poor compatibility,poor coordination and so on.The purpose of this paper is to solve this problem.A novel hindered phenol antioxidant 2,4-di-tert-butyl-6-octylthiomethylphenol was designed at the molecular level in this paper.And investigate the synthetic scheme,We finally use 2,4-di-tert-butylphenol,paraformaldehyde and octanethiol to synthesize the target product successfully.On this basis,we have screened feasible reaction catalyst and optimized the reaction conditions,in order to improve yield and provide a reference for the industry production.The results showed the optimal conditions:（1）Dipropylamine as catalyst,the dosage is 10%of the total mass of the reactants,n（2,4-di-tert-butylphenol）:n（octanethiol）:n（paraformaldehyde）=:1:1:2,KHCO₃,DMF as solvent,nitrogen protection,110℃ reflux reaction for 4 hours.On this basis of optimal conditions,the result of repetitive test was well,the yield of the product was about 86%.（2）Piperidine as catalyst,the dosage is 15%of the total mass of the reactants,n（2,4-di-tert-butylphenol）:n（Octanethiol）:n（paraformaldehyde）=1:1:2.5,DMF as solvent,nitrogen protection,120℃ reflux reaction for 5 hours.On this basis of optimal conditions,the result of repetitive test was well,the yield of the product was about 87.7%.The application of synthetic antioxidants in the yellowing experiments of SBR proves its antioxidant property is better than traditional hindered phenolic antioxidant BHT,and we also put forward some suggestions on the problems that may exist in the course of using.