Ethylene-carbon monoxide copolymers

Summary

The synthesis, properties and applications of ethylene–carbon monoxide (E/CO) copolymers are described. These photodegradable polymers are now used to control plastic litter caused by polyethylene loop carriers for beverage cans which have been reported to entangle and endanger wildlife.

The rate of photodegradation of E/CO polymers depends on the amount of CO incorporated. At 1% CO, E/CO took about six days to reach zero elongation at break in Texas, USA, and 13% CO film reached the same stage in less than one day. Degradation was substantially longer in more northern climates. At 2.7% CO, E/CO lost nearly all elongation in about a month in New Jersey, USA, and within two months it broke up and blew away. Blends of E/CO polymers with regular polyethylene degraded much more slowly, probably because of the absence of free radical formation in the predominantly Norrish II scission process.

Other packaging applications of E/CO polymers are expected to develop if the Food and Drug Administration sanctions their use in food packaging as petitioned.