Chain copolymerization carbonyl monomer

The free radical initiated copolymerization of CH2CHOAc with CO has been reported 25>. Copolymers with up to 30 mol% CO were obtained. At 60 °C, the monomer reactivitry ratios were rVA = 0.24, rco = 0.33. The magnitude of rc0 indicated the possibility of the presence of vicinal CO groups in the polymer chain. Indeed, the results of a periodate oxidation of the copolymer showed that 30 % of the CO were present in 1,2-diketo structures. The acetate groups in the copolymer could be hydrolyzed in the presence of methanolic NaOH. However, the IR and the UV-vis spectra of the hydrolyzed copolymer showed the presence of significant amounts of a,P-unsaturated carbonyl structures, formed by the base induced dehydration. 

The copolymer can be further fractionated by precipitation from acetone solution to n-hexanc at room temperature. In each case, only the first fraction should be used to obtain narrowly distributed high molar mass copolymer chains for LLS measurement, ll NMR can be used to characterize the copolymer composition. The ratio of the peak areas of the methine proton of the isopropyl group in NIPAM and the two protons neighboring the carbonyl group in VP can be used to determine the VP content. The composition of each NIPAM-co-VP copolymer was found to be close to the feeding monomer ratio prior to the copolymerization. The nomenclature used hereafter for these copolymers is NIPAM-co-VP/x/y, where x andy are the copolymerization temperature (°C) and the VP content (mol%), respectively. The solution with a concentration of as low as 3.0 x 10-6 g/mL can be clarified with a 0.45 cm Millipore Millex-LCR filter to remove dust before the LLS measurement. The resistivity of deionized water used should be close to 18 M 2 cm. The chemical structure of poly(NIPAM-co-VP) is as follows (Scheme 2). 

The above examples of free-radical ring-opening polymerization, which have been explored by Bailey and Endo, produce polymers containing ketonic carbonyl and/or ester groups in the main chain. In addition, these cyclic monomers can be copolymerized with vinyl monomers by free-radical mechanism. Thus, the variety of the polymers produced by radical polymerization has been enlarged. 

These methods suggested in the present form by Caunt83) rely on inhibition (retardation) effects of strong catalyst poisons on polymerization. Typical poisons potentially usable for this purpose are carbon oxides, carbonyl sulfide, carbon disulfide, acetylenes and dienes. All these substances exhibit a strong unsaturation they have either two double bonds or one triple bond. Most of the works devoted to application of the poisons to determination of active centers 10,63 83 102 1O7) confirm a complicated nature of their interaction with the catalytic systems. To determine the active centers correctly, it is necessary to recognize and — as much as practicable — suppress side processes, such as physical adsorption and chemisorption on non-propagative species, interaction with a cocatalyst, oligomerization and homopolymerization of the poison and its copolymerization with the main chain monomer. 

Polyester fibers are composed of linear chains of polyethylene terephthalate (PET), which produces benzene, benzoic acid, biphenyl, and vinyl terephthalate on pyrolysis. Acrylic fibers comprise chains made up of acrylonitrile units, usually copolymerized with less than 15% by weight of other monomers, e.g., methyl acrylate, methyl methacrylate, or vinylpyrrolidone. Thermolysis results in the formation of acrylonitrile monomer, dimers, and trimers with a small amount of the copolymer or its pyrolysis product. In this case, the acrylic is Orion 28, which contains methyl vinyl pyridine as comonomer. Residual dimethyl formamide solvent from the manufacturing process is also found in the pyrolysis products. Cotton, which is almost pure cellulose, comprises chains of glucose units. The pyrolysis products of cellulose, identified by GC/MS, include carbonyl compounds, acids, methyl esters, furans, pyrans, anhydrosugars, and hydrocarbons. The major pyrolysis products are levoglucosan (1,6-anhydro-B-D-glucopyranose) and substituted furans. 

Some polymers are intentionally designed to degrade when exposed to light. There are two basic methods for doing this. One method is to incorporate a chro-mophore into the polymer chains. For example, deliberate incorporation of carbonyl groups leads to light-sensitive polymers, as in the commercial Ecolyte polymers. These polymers are made by copolymerizing vinyl ketones with vinyl monomers... 

In polymers where the carbonyl carbon is on the backbone, both the Norrish Type I and Type II reactions will lead to lowering of the molecular weight (chain scission [874]. Much has been published on the photodegradation of polymers containing small amounts of carbonyl groups in the main chain, obtained by copolymerization of a given monomer with small amounts of carbon monoxide, as polyethylene [809, 866, 917, 933, 934, 1334, 1998], polypropylene [1108], poly(methyl acrylate) [122, 123], poly(methyl methacrylate) [123], poly(acrylonitrile [41], poly(acrylic acid) [1465], poly(vinyl chloride) [320,937,1165], polystyrene [510, 794,936,1015,1164,1166,1429, 1430,1570,1966] aliphatic polyesters [1725] and poly(ethylene terephthalate) [42]. 

The living anionic polymers of protected functional methacrylate monomers herein introduced are very similar in reactivity and stability to those of MMA. Accordingly, these living polymers can initiate the polymerization of MMA, tBMA, and other protected functional methacrylate monomers, resulting in block copolymers with tailored chain structures. Complete aossover block copolymerizations among these methacrylate monomers are possible. Furthermore, living anionic polymers of styrene, a-methylstyrene, isoprene, and 1,3-butadiene initiate the polymerization of protected functional methacrylate monomers to afford well-defined AB diblock copolymers. In order to avoid ester carbonyl attack by the chain-end anions, the living anionic polymers should be end-capped with 1,1-diphenylethylene... 

Monomers of formaldehyde vapor that can be dissolved in an inert hydrocarbon such as heptane along with an initiator. Initiators include Lewis acids such as BFj (Table 17,2, LA) as well as amines, phosphines, arsines, stibenes, organometallic componnds, and transition metal carbonyls. The polymer is often referred to as acetal homopolymer, polyacetal, or poly(oxymethylene). All of these terms distinguish the useful, stable polymer from polyformaldehyde, the thermally unstable, waxy material that forms easily from the pure monomer. Because of the instability of the chain structure and its tendency to unzip, esterification of the end-group hydroxyls or end blocking with acetic acid is one answer (Table 17.2, LA). Another is the copolymerization of formaldehyde with monomers that will interrupt the chain sequence. Ethylene oxide is one such monomer. 

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