Disclosed is a process for esterifying and/or transesterifying a polymer
having a polyethylenic backbone and pendant acid and/or ester moieties comprising
contacting a melt of the polymer with a transesterifying compound so that the polymer
undergoes esterification and/or transesterification but not alcoholysis. The esterified
or transesterified polymer also has pendant ester moieties which differ in kind
and/or number from the unreacted polymer. In one embodiment, the process also comprises
adding an amount of a transition metal salt that is effective to promote oxygen
scavenging. Also in a further embodiment, the process comprises irradiating the
transesterified polymer with actinic radiation to reduce the induction period before
oxygen scavenging commences. Also disclosed are compositions comprising a component
which comprises an ethylenic or polyethylenic backbone and a pendant or terminal
moiety comprising a benzylic, allylic, or ether-containing radical. The invention
also embodies new polyethylenic oxygen scavenging compositions comprising a transition-metal
salt and the above component. Methods of making the compositions, and methods and
compositions using the ethylenic or polyethylenic compositions, are disclosed.
