SYNTHESIS AND PROPERTIES OF NEW POLYMERIZABLE ANTIOXIDANTS

Five new monomeric antioxidants containing hindered phenol have been s ynthesised by direct addition of 2,6-di-tert-butyl-4-hydroxy methyl ph enol (DBHMP) to m-isopropenyl-alpha,alpha-dimethyl isocyanate (TMI) or allyl isocyanate (AI), and by controlled isocyanation in two steps, i n which methacrylic acid (MAA) or acrylic acid (AA) reacts with toluen e-2,4-diisocyanate (TDI) and hexamethylene diisocyanate (HMDI) in 1 to 1 mole ratio at 60 degrees C, and this product as an intermediate was directly added to DBHMP in 1 to 1 mole ratio in presence of a catalys t dibutyltin dilaurate (DBTDL). These new monomeric antioxidants are 3 ,3-di-tert-butyl-4-hydroxybenzyl, m-isopropenyl-alpha,alpha-dimethyl b enzyl carbamate (A), 3,5-di-tert-4-hydroxy bezyl, allyl carbamate (B), 3,5-di-tert-butyl-4-hydroxy benzyl, (4-methacryloyl amino) tolyl carb amate-2 (C), 3, 5-di-tert-butyl-4-hydroxy benzyl, (6-methacryloyl amin o) hexyl carbamate-1 (D), and 3,5-di-tert-butyl-4-hydroxy benzyl, (6-a cryloyl amino) hexyl carbamate-1 (E). They were characterized by IR, N MR and elemental analyses. Their stabilizing action for protecting pol ypropylene against thermal oxidation and their polymerizability were e xamined. Results show that these new monomeric antioxidants possess st abilising effect against thermal oxidation and they are capable of cop olymerizing with vinyl monomers. (C) 1998 Elsevier Science Limited. Al l rights reserved