Synthesis And Properties Of Novel Dendritic Phenolic Antioxidant

Hindered phenolic antioxidant is one of primary antioxidants. It is used extensively in crude rubber,synthetic rubber, polyolefin plastic and fiber polymer, and in petroleum product and fatty food processing. Thedevelopment and research of hindered phenolic antioxidant are always concerned.Dendrimers are a new category of dendritic macromolecules appearing during the mid of 1980s, whichare three-dimensional, highly ordered and can be controlled and designed molecule size, shape, structure andfunctional groups from the molecule scale. According to its own specialties, studying systematacially themolecular structure and performance, developing the function macromolecule with new-type terminal group isan important research direction. The surface terminal group can carry on function transform. There are amido,hydroxyl, carboxyl, ester base, alkyl, acylamino group, metal chelate compound etc that have already beenreported at present. The active sites among the center and inside of dendrimers make this kind ofmacromolecule have well enough application prospects in drug deliver, catalyst carrier, gene therapy, metalmillimicron composite and membrane material etc.The thesis has introduced briefly the structure and performance of dendrimers, and has reviewed thenewest progress in synthesizing and function of dendrmers systematically. A new method of terminal grouptransform of dendrimers was put forward for the first time. The method is that oxidationresisting functionalgroups were grafted into dendrimers by molecule design. A new-type dendritic phenolic antioxidant has beensynthesized successfully. The oxidationresisting functional intermediate compound β-(3,5-diterbutyl-4-hydroxyphenyl) propionyl chloride (3,5-propionyl chloride) was synthesized with β-(3,5-diterbutyl-4-hydroxyphenyl) methyl propionate as raw material via hydrolytic reaction and replacementreaction.The effects of the reaction conditions on hydrolytic reaction and replacement reaction were examined;The novel dendritic phenolic antioxidant (Ⅰ) was synthesized via grafting 3,5-propionyl chloride into 1.0 GPAMAM. The yield is 65%, and the melting point is 202.2~205.2℃. The intermediate compound2,6-di-tert-butyl-4-aminophenol was synthesized with 2,6-di-tert-butylphenol as raw material via nitration andreduction. The reaction conditions were researched and optimized. The novel dendritic phenolic antioxidant(Ⅱ) was synthesized with 2,6-di-tert-butyl-4-aminophenol and 0.5 G PAMAM as raw material and thereaction conditions were researched. The yield of crude procuct is 66%, and the melting point is107.2~143.3℃.The molecular structures of the intermediate compound and the novel dendritic phenolic antioxidant havebeen characterized by means of element analysis, infrared spectrum (IR). The validity of the molecularstructure of dendrimer was proved to match with the designing target molecular. The novel dendritic phenolicantioxidant(Ⅰ) was evaluated in HDPE using differential scanning calorimetry (DSC) to determine theoxidation induction time (OIT). It was compared to the commercial antioxidant 1076. The OIT-value of thenovel dendritic phenolic antioxidant(Ⅰ) is 58.8 min, which is the same as 1.8 times of the OIT-value of theantioxidant 1076. The conclusion is drawn that the novel dendritic phenolic antioxidant is of oxidationresistingfunction.