Carboxylation of poly

Koshechko, V.G., Titov, V.E. and Sednev, D.V. (1994) New route for producing acrylic add copolymers, based on electrochemical carboxylation of poly(vinyl halide)s and polybutadiene. Polymer 35, 1787-1788. 

Multiple carboxylation of poly(allyl)stannanes also can be effected with Pd(0) catalysis. Thus, diallyldibutyltin reacted completely with CO2 under the standard conditions to afford dicarboxylates (overall yield >90%). In the Pd-catalyzed reaction of tetraaUyltin with CO2 a complex mixture of... 

Table VIII. Carboxylation of Poly (vinyl chloride) at 180° Ca...

Carboxylated PAES can be synthesized by sequential lithiation and carboxylation of poly(arylene ether sulfone) in tetrahydrofuran. The carboxyl groups are then converted into acid chloride groups by thionyl chloride and treatment with V-oxypyridine-2-thione gives the thiohydroxamic ester [60], A grafting reaction is obtained by adding to the polymer styrene and irradiation. Homopolymerization of the styrene does not take place under these conditions. Other vinyl monomers, including methyl methacrylate and acryl-... 

The (o,a), (o"-trilithiumpolystyrene (96) was also functionalized with carbon dioxide to form the corresponding (o,a), a)"-tricarboxypolystyrene (98) as shown in Scheme 32. Although significant amounts of dimer (11-12%) were observed when carbonation was effected in the presence of THF [241] or after end-capping the styryllithium chain ends with 1,1-diphenylethylene [141], procedures that were previously shown to be effective for quantitative carboxylation of poly(styryl)lithium, less than 2% dimer formation and formation of a tricarboxylated, three-arm, star-branched polystyrene with a functionality of 2.9s were obtained upon carboxylation of a freeze-dried [141] sample of 96. Previous studies indicate that dimer and trimer formation during carboxylation are enhanced by chain-end association [141, 241]. 

Almost all synthetic binders are prepared by an emulsion polymerization process and are suppHed as latexes which consist of 48—52 wt % polymer dispersed in water (101). The largest-volume binder is styrene—butadiene copolymer [9003-55-8] (SBR) latex. Most SBRlatexes are carboxylated, ie, they contain copolymerized acidic monomers. Other latex binders are based on poly(vinyl acetate) [9003-20-7] and on polymers of acrylate esters. Poly(vinyl alcohol) is a water-soluble, synthetic biader which is prepared by the hydrolysis of poly(viayl acetate) (see Latex technology Vinyl polymers). 

When equal amounts of solutions of poly(ethylene oxide) and poly(acryhc acid) ate mixed, a precipitate, which appears to be an association product of the two polymers, forms immediately. This association reaction is influenced by hydrogen-ion concentration. Below ca pH 4, the complex precipitates from solution. Above ca pH 12, precipitation also occurs, but probably only poly(ethylene oxide) precipitates. If solution viscosity is used as an indication of the degree of association, it appears that association becomes mote pronounced as the pH is reduced toward a lower limit of about four. The highest yield of insoluble complex usually occurs at an equimolar ratio of ether and carboxyl groups. Studies of the poly(ethylene oxide)—poly(methacryhc acid) complexes indicate a stoichiometric ratio of three monomeric units of ethylene oxide for each methacrylic acid unit. 

These association reactions can be controlled. Acetone or acetonylacetone added to the solution of the polymeric electron acceptor prevents insolubilization, which takes place immediately upon the removal of the ketone. A second method of insolubiUzation control consists of blocking the carboxyl groups with inorganic cations, ie, the formation of the sodium or ammonium salt of poly(acryhc acid). Mixtures of poly(ethylene oxide) solutions with solutions of such salts can be precipitated by acidification. 

The two-step poly(amic acid) process is the most commonly practiced procedure. In this process, a dianhydride and a diamine react at ambient temperature in a dipolar aprotic solvent such as /V,/V-dimethy1 acetamide [127-19-5] (DMAc) or /V-methy1pyrro1idinone [872-50-4] (NMP) to form apoly(amic acid), which is then cycHzed into the polyimide product. The reaction of pyromeUitic dianhydride [26265-89-4] (PMDA) and 4,4 -oxydiani1ine [101-80-4] (ODA) proceeds rapidly at room temperature to form a viscous solution of poly(amic acid) (5), which is an ortho-carboxylated aromatic polyamide. 

Alpert has shown [47] that poly(succinimide)-silica can be further hydrolyzed to poly (aspartic acid)-silica or condensed with [3-alanine in aqueous solution to form a covalently bonded copolymer of 2-carboxyethyl aspartamide and aspartic acid. The content of carboxyl groups generated by this way has not been quantified directly, but the cation-exchange hemoglobin capacity has been measured for a series of the packings. Thus, the optimal concentration of poly(succinimide) used in the synthesis was found to be 2 5%. 

Shimidzu etal.111 studied the catalytic activity of poly (4(5)-vinylimidazole-co-acrylic add) 60 (PVIm AA) in hydrolyses of 3-acetoxy-N-trimethylanilinium iodide 61 (ANTI) and p-nitrophenylacetate 44 (PNPA). The hydrolyses of ANTI followed the Michaelis-Menten-type kinetics, and that of PNPA followed the second-order kinetics. Substrate-binding with the copolymer was strongest at an imidazole content of 30 mol%. The authors concluded that the carboxylic acid moiety not... 

Further improvements were made by carboxylating the polystyrene anion, leading to quantitative yields39S 396. Multiblock copolymers of molecular weight 500,000 consisting of sixty segments of poly-THF and polystyrene were prepared397. The effect of the molar feed ratio of the two components is shown in Fig. 7. 

Heller, J., Ng, S. Y., and Penhale, D. W. H., Preparation of poly(carboxy-ortho esters) by the reaction of diketene acetals and carboxylic acids. In Preparation. 

Perhaps the most interesting finding of our synthetic studies was that the interfacial preparation of poly(iminocarbonates) is possible in spite of the pronounced hydrolytic instability of the cyanate moiety (see Illustrative Procedure 3). Hydrolysis of the chemically reactive monomer is usually a highly undesirable side reaction during interfacial polymerizations. During the preparation of nylons, for example, the hydrolysis of the acid chloride component to an inert carboxylic acid represents a wasteful loss. 

Poly(malic acid) is a biodegradable and bioadsorbable water-soluble polyester having a carboxylic acid in the side chain. The chemoenzymatic synthesis of poly(malic acid) was achieved by the lipase-catalyzed polymerization of benzyl (3-malolactonate, followed by the debenzylation. The molecular weight of poly(benzyl (3-malolactonate) increased on copolymerizafion with a small amount of (3-PL using lipase CR catalyst. ... 

A methacryl-type polyester macromonomer was synthesized by lipase PF-catalyzed polymerizahon of DDL using vinyl methacrylate as terminator ( terminator method ), in which the vinyl ester terminator was present from the beginning of the reachon (Scheme 17). In using divinyl sebacate as terminator, the telechelic polyester having a carboxylic acid group at both ends was obtained. Various non-protected thiol compounds were used as inihator or terminator for the thiol end-funchonalizahon of poly(8-CL). ... 

Polymeric aliphatic carboxylates, the poly(alkenoic add)s, were very much more strongly adsorbed than the difunctional carboxylates (Ellis et al., 1990). Results showed that adsorption depended on the conformation of the polyanion. When extended, as in dilute solutions, a polyanion is adsorbed onto a relatively large number of sites and further adsorption is hindered. Thus, increases in acidity (and concentration) were found to result in greater adsorption because the polyanion adopted a more compact... 

Ellis, J., Jackson, A. M., Scott, R. P. Wilson, A. D. (1990). Adhesion of carboxylate cements to hydroxyapatite. III. Adsorption of poly(alkenoic acid)s. Biomaterials, 11, 379-84. 

Hunt et al. [354] used cSFC for the separation of extracts of poly(alkylene glycol) lubricants and sorbitan ester formulations. Doehl et al. [337] have compared the performance of cSFC-FID and pSFC-FID with both scC02 and scN20 in the analysis of the antiblocking agents oleamide and erucamide, the antistatic Armostat 400 and antioxidant Hostanox SE-10, none of which can be detected by UV absorption. By using open-tubular capillary columns, PAs as well as (un)substituted heavy carboxylic acids (> C ) can be eluted. 

Although the potassium superoxide route can be universally applied to various alkyl methacrylates, it is experimentally more difficult than simple acid hydrolysis. In addition, limited yields do not permit well-defined hydrophobic-hydrophilic blocks. On the other hand, acid catalyzed hydrolysis is limited to only a few esters such as TBMA, but yields of carboxylate are quantitative. Hydrolysis attempts of poly(methyl methacrylate) (PMMA) and poly(isopropyl methacrylate) (PIPMA) do not yield an observable amount of conversion to the carboxylic acid under the established conditions for poly(t-butyl methacrylate) (PTBMA). This allows for selective hydrolysis of all-acrylic block copolymers. 

Alternatively, esterification of carboxylic acid can be carried out in aqueous media by reacting carboxylic acid salts with alkyl halides through nucleophilic substitutions (Eq. 9.10).20 The reaction rate of alkyl halides with alkali metal salts of carboxylic acids to give esters increases with the increasing concentration of catalyst, halide, and solvent polarity and is reduced by water. Various thymyl ethers and esters can be synthesized by the reactions of thymol with alkyl halides and acid chlorides, respectively, in aqueous medium under microwave irradiation (Eq. 9.11).21 Such an esterification reaction of poly(methacrylic acid) can be performed readily with alkyl halides using DBU in aqueous solutions, although the rate of the reaction decreases with increasing water content.22... 

In an attempt to identify new, biocompatible diphenols for the synthesis of polyiminocarbonates and polycarbonates, we considered derivatives of tyrosine dipeptide as potential monomers. Our experimental rationale was based on the assumption that a diphenol derived from natural amino acids may be less toxic than many of the industrial diphenols. After protection of the amino and carboxylic acid groups, we expected the dipeptide to be chemically equivalent to conventional diphenols. In preliminary studies (14) this hypothesis was confirmed by the successful preparation of poly(Z-Tyr-Tyr-Et iminocarbonate) from the protected tyrosine dipeptide Z-Tyr-Tyr-Et (Figure 3). Unfortunately, poly (Z-Tyr-Tyr-Et iminocarbonate) was an insoluble, nonprocessible material for which no practical applications could be identified. This result illustrated the difficulty of balancing the requirement for biocompatibility with the need to obtain a material with suitable "engineering" properties. 

Photophysical Processes and Photodegradation of Poly(ethylene terephthalate-co-2,6-naphtha1enedi carboxyl ate) Copolymers. We have recently reported the photophysical processes and the photo-degradative behavior of Doly(ethylene terephthalate-co-2,6-naphthalenedicarboxyl ate), PET-2,6-ND, copolymer yarns containing 0.5 - 4.0 mole percent 2,6-naphthalenedicarboxyl ate, 2,6-ND (1) and the parent naphthalenedicarboxyl ate monomer, Figure 3 and 4. 

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