Ethylene-carbon monoxide copolymers ECO

Random ethylene-carbon monoxide copolymers have been known for many years and have properties somewhat similar to low density polyethylene. Alternating ECO copolymers were first produced long ago by Reppe of BASF in 

The regular structure of the alternating copolymer with its absence of side chains enables the polymer to crystallise with close molecular packing and with interchain attraction augmented by the carbonyl groups. As a result these polymers exhibit the following characteristics  

Some typical properties are given in Table 11.13 in comparison with typical properties for nylon 66 (see Chapter 18) and a polyacetal (see Chapter 19) for which it has been suggested that these materials will be competitive. 

A significant modification has been the introduction of a second olefin sueh as propylene or a butene which substitutes randomly for the ethylene and this has 

Property Units Aliphatic polyketone Acetal Nylon 66 conditioned 

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Ethylene-Carbon Monoxide Copolymers (ECOs). These polymers are random copolymers of ethylene and carbon monoxide, with properties similar to low-density polyethylene. They are sold by Shell under the trade name Carilon. These polymers exhibit low water absorption and good barrier properties, but they are susceptible to UV degradation. They find application in packaging, fuel tanks, fuel hnes, and in blends. 

Figure 6.1 Average elongation at break versus total global solar radiation (45° South) for all locations [42], ECO = ethylene-carbon monoxide copolymer ( 1% CO), of Illinois Tool Works Co LDPE/MX = LDPE film produced by Plastigone, containing metal compound pro-oxidant additives LDPE/Starch/MX = LDPE film produced by ADM. containing 6% by weight of starch and metal compound pro-oxidant additives.

Photodegradation may involve use of inherently photo-unstable polymers or the use of photodegradant additives. An example of the former are ethylene-carbon monoxide polymers in which absorption of light by the ketone group leads to chain scission. The polymer becomes brittle and forms a powder. Such materials are marketed by Dow and by Du Pont. Other examples are the copolymers of divinyl ketone with ethylene, propylene or styrene marketed by Eco Atlantic. 

A recent study compared the performance of two types of enhanced pho-todegradable polyethylene film samples under marine exposme conditions [99]. One of them was a copolymer of ethylene and carbon monoxide ( 1%) (ECO) typically used in six-pack rings, and the other was a polyethylene film containing low levels of a metal compound catalyst (MX). The degradable samples as well as control samples of polyethylene film were exposed at two locations, Biscayne Bay, Florida, and Puget Sound, Washington, both in air and floating in... 

The value of B (days" ) listed in Table 10.4 for films of LDPE, ethylene-carbon monoxide (1%) copolymer (ECO), and photodegradable LDPE (containing a metal catalyst pro-oxidant) quantify their rates of degradation. The ECO copolymer is the same as that used in photodegradable six-pack rings (and supplied by the manufacturer... 

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