Polyolefin elastomer grafted unsaturated hindered phenol esters: synthesis and antioxidant behavior

Abstract

Monomeric antioxidants are synthesized from esterification of 3,5-di-tert-butyl-4-hydroxybenzoic acid and 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid with unsaturated fatty alcohols. The antioxidant activity is evaluated both in blending and radical grafting processes. The effect of chain length and phenolic group is investigated on efficiency of antioxidants. It is demonstrated that the esters of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid exhibit significantly longer induction time. The results of radical grafting reaction shows synthesized antioxidants can be successfully grafted onto polymer chains and the phenolic moiety is functional after extraction process, while pure and commercially stabilized samples are degraded instantaneously. Also, different initiator systems are utilized to enhance the extent of grafting. Among MEK, DCP, and DHBP peroxides, DHBP can be more effective in increasing the antioxidant grafted onto polymer. In addition, possibility of rising in graft content is investigated in presence of redox initiator. Using this approach, polymerbound antioxidant with prolonged thermal stability can be achieved.

Increased Elasticity Modulus of Polymeric Materials Is a Source of Surface Alterations in the Human Body

“…The substitution pattern and all correlations indicate the presence of a bis-tert-butyl cresol derivate, which is probably 4,4′-thiobis(6-tert-butyl-m-cresol) (CAS 96-69-5). These compounds belong to the class of sterically hindered phenols, which serve as antioxidizing agents in polyolefins [ 16 ].…”