Ozonization of atactic and tactic polymers having vinyl, methylvinyl and dimethylvinyl pendant groups

Atactic and syndiotactic 1,2-polybutadiene, atactic 3,4-polyisoprene and poly(4-methyl-1,3-pentadiene)1,2 syndiotactic, having respectively vinyl, methylvinyl and dimethylvinyl pendant groups have been ozonized. The reaction products and the reaction speed toward ozone attack in solution have been studied by FT-IR spectroscopy. The tacticity seems to have no influence on either the reaction products or the reaction speed with ozone. The main product formed by ozonization of syndiotactic 1,2-polybutadiene and of poly(4-methyl-1,3-pentadiene)1,2 syndiotactic is a poly(acrolein) or poly(propenal). Thus each vinyl or dimethylvinyl monomer unit can be mainly converted into an aldehyde pendant group. In the case of atactic 3,4-polyisoprene, ozonization allows changing the methylvinyl group into a methylketone pendant group. Ozonization of atactic 3,4-polyisoprene and also poly(4-methyl-1,3-pentadiene)1,2 syndiotactic, introduces some epoxy groups into the vinyl double bonds as a secondary reaction. The reaction speed with ozone was found to be faster with the most alkyl-substituted double bond in agreement with a general rule. Thus the reaction speed is from the fastest to the slowest as follows, [poly(4-methyl-1,3-pentadiene)1,2 syndiotactic] > [3,4-polyisoprene] > [1,2-polybutadiene]. Ozonization of vinyl polymers could be a way for introducing oxygenated functional groups which can then be used as sites for crosslinking these polymers to prepare new polymer networks. (C) 2000 Elsevier Science Ltd. All rights reserved.