Synthesis of degradable network polymers containing peroxy units in the main chain or the cross-linking point

We have synthesized degradable network polymers containing readily labile peroxy bonds as the repeating units in the main chain or as the cross-linking point in the side chain. Poly(2-hydroxyethyl sorbate-alt-O2) was obtained by the radical copolymerization of 2-hydroxyethyl sorbate with oxygen, and then cross-linked using tolylene 2,4-diisocyanate as the cross-linking agent to obtain a new type of degradable gel. We also investigated the cross-linking of conventional polymers by the reaction of the diene moieties introduced into the polymer side chain with oxygen. The hydroxy group in the side chain of poly(vinyl alcohol) (PVA) was reacted with 1-isocyanate-1,3-pentadiene in order to introduce a diene moiety into the side chain of the PVA. The dienylated PVA was reacted with oxygen in the presence of a radical initiator, leading to the formation of a gel containing a labile peroxy linkage at the cross-linking point. These gels containing peroxy units in the main chain or at the cross-linking points degraded upon heating.