Carbon monoxide-containing copolymers

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... 

The photodegradation of copolymers of ethylene and carbon monoxide containing l-9mol% CO results in a decrease in molecular weight, accompanied by the evolution of carbon monoxide. The photodegradation reaction occurs by the Norrish Type I (radical) (3.71) and the Norrish Type II (non-radical) (3.73) mechanisms (cf section 3.2.1) [871, 917, 1334] ... 

Chromium Oxide-Based Catalysts. Chromium oxide-based catalysts were originally developed by Phillips Petroleum Company for the manufacture of HDPE resins subsequendy, they have been modified for ethylene—a-olefin copolymerisation reactions (10). These catalysts use a mixed sihca—titania support containing from 2 to 20 wt % of Ti. After the deposition of chromium species onto the support, the catalyst is first oxidised by an oxygen—air mixture and then reduced at increased temperatures with carbon monoxide. The catalyst systems used for ethylene copolymerisation consist of sohd catalysts and co-catalysts, ie, triaLkylboron or trialkyl aluminum compounds. Ethylene—a-olefin copolymers produced with these catalysts have very broad molecular weight distributions, characterised by M.Jin the 12—35 and MER in the 80—200 range. 

Free-radical copolymers of vinyl chloride with carbon monoxide have been suggested to contain pendent C0C1 groups (as in. )... 

Alternating copolymers of ethylene with olefins containing double bonds in the cis configuration, like ds-2-butene, cyclopentene, cycloheptene,115 and norbomene,116 have been described. Recently also copolymers of carbon monoxide with styrene and styrene derivatives, having syndiotactic117 and isotactic118 configurations, have been synthesized and characterized. 

When ethylene-vinyl acetate copolymers are manufactured, the decomposition products also contain carbon monoxide and carbon dioxide. When decomposition takes place in a tubular reactor or in a multi-chamber or cascade of autoclaves, up to 50% of the decomposition gases can consist of undecomposed ethylene. 

However, when (5,5)-3,3 -(2,3-butanediol)-2,2 -bipyridine or (/ )-3,3 -(l, 2-propanediol) -2,2 -bipyridine was used as the ligand [125], copolymers were obtained that had a higher content of isotactic triads. An effective control towards the isospecificity of copolymerisation (<98 % isotacticity in the copolymer) is fulfilled for the copolymerisation of ring-substituted styrene such as p-t-butylstyrene and carbon monoxide with catalysts containing cationic methylpalladium species [117] ... 

Ihe extent of ring opening is hi ier because the acyl radical XXIV is more stable than the primary radical that one would e qpect to obtain from the 2-meti lene-l,3-oxetane (XXI). In the seal tube the acyl radical XXIV does not lose very much carbon monoxide to give a copolymer XXV which contains a large amount of the... 

Aromatic polyimides, containing trifluoromethyl groups, have been used to separate hydrogen over carbon monoxide, with a-values of 26-66 and hydrogen over methane with a-valves of 73-380.160 An a-valve of 22 was obtained with a membrane of a copolymer of methyl methacrylate and tris (trimethylsiloxy) y (met ha cry loxy)propyl] silane, in a process estimated to cost only 40% of the cost of the present cryogenic distillation.161... 

The aliphatic aldehydes and ketones have a weak absorption with a maximum between 270 and 290 nm and a tail which spreads into the region beyond 300 nm. This absorption is attributed to a forbidden (nit ) transition, in which an electron in a nonbonding orbital localized on the oxygen atom is promoted to a delocalized antibonding it orbital distributed over all the carbonyl groups (13). Similar absorption was found for polyolefins containing carbonyl groups in their chain such as ethylene-carbon monoxide copolymer (1 % of CO) (14). 

The most recent addition to the engineering polymer field is the ethylene/carbon monoxide (COPO) alternating copolymers initially introduced by Shell. The commercial polymer is highly crystalline and believed to contain small amounts of propylene to reduce the crystalline melting point to allow a broad window of process-ability. COPO should offer serious competition to polyacetal, PA, and PBT. With the favorable raw materials cost, COPO should be a successful and competitive entry. As is now expected with new polymers, intense blend patent activity accompanies the introduction. This has also occurred with COPO as is noted in various U.S. patents involving COPO blends (See Table 17.4). COPO polymers are available from Shell (Carilon ) and BP (Ketonex ). 

Ethylene/carbon monoxide copolymers containing 2 or 3 wt. o carbon monoxide are photo degradable polymers with the same general processing properties as high pressure, low density polyethylene. Exposure to UV radiation causes decomposition. The polymer is essentially a low density polyethylene with an environmental feature. Commercialization of these materials took place in the late 1960s. 

Ethylene-vinyl acetate (EVA) polymers (containing 65%-70% by weight of vinyl acetate) are of industrial interest as high-molecular weight plasticizers for PVC, mainly because of their low cost. A polymeric plasticizer PB-3041 available from Du Pont allows the preparation of a highly permanent plasticized PVC formulation. It is believed to be a terpolymer of ethylene, vinyl, acetate, and carbon monoxide. Also, butylene terephthalate-tetrahydrofuran block copolymers, with the trade name of Hytrel (Du Pont), are used as excellent permanent plasticizers of PVC. 

Primary decomposition products of oxygen-containing polymers (such as polyformaldehyde and methacrylates) consist mainly of monomers or side-chain fragments (as in the case of vinyl acetate polymers and copolymers) while the secondary decomposition products are very rich in carbon monoxide and carbon dioxide which are essentially responsible for the toxicity. 

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