Synthesis And Application Of Modified Silica Gel Grafted Antioxidants

Hindered phenolic antioxidants are some phenolic compounds with steric hindrance.Because of their remarkable thermal oxidation effect and not contaminating products, theyhave shown great progress. These antioxidants are primarily utilized in plastics, syntheticfibers, rubber, petroleum products, food, medicine and cosmetics.In this paper, silica was amino-functionalize by using a kind of silane coupling agent onits surface at first, then the modified silica was reacted with methyl acrylate and ethylenediamine alternatively and repeatedly till the poly amidoamine-modified silica (PAMAM-SG)was2.0generation. The antioxidant intermediate β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl chloride was designed to graft onto the integral generation PAMAM-SG skeletonand another antioxidant intermediate2,6-tert-butyl-4-amino-phenol was designed to graft ontothe half generation PAMAM-SG skeleton in order to obtain two new types (Class A and B)hindered phenolic antioxidant with the silica gel as the core. The synthetic antioxidant wasmelt blended with polypropylene (PP), then obtained composites were pressed into sheets forphoto-thermal aging test. Synthetic intermediates and antioxidants were characterized byinfrared, scanning electron microscopy (SEM) and simultaneous thermal analysis. Syntheticantioxidants had also gone through anti-oxidation performance evaluation. In PP,SG-PAMAM-AO had exhibited better dispersion state than SG-PAMAM. The addition ofSG-PAMAM and SG-PAMAM-AO in PP enhanced the thermal stability of PP.SG-PAMAM-AO had better oxidation resistance compared to AO (2,6-di-tert-butylphenol).