Carboxylic groups polyethylene

Chemically Modified Waxes. Hydrocarbon waxes of the microcrystaHine, polyethylene, and polymethylene classes are chemically modified to meet specific market needs. In the vast majority of cases, the first step is air oxidation of the wax with or without catalysts (11). The product has an acid number usuaHy no higher than 30 and a saponification number usuaHy no lower than 25. An alternative step is the reaction of the wax with a polycarboxyHc acid, eg, maleic, at high temperature (12). Through its carboxyl groups, the oxidised wax can be further modified in such reactions as saponification or esterification. Oxidised wax is easily emulsified in water through the use of surfactants or simple soaps, and is widely used in many coating and poHsh appHcations. 

Polyanhydrides are susceptible to interchange reactions with carboxyl groups in analogy to (I) and (II). Polymeric dimethylsiloxanes readily interchange in the presence of sulfuric acid by a mechanism which may be presumed to involve cations. In some polymers the interunit linkage is too stable to enter readily into interchange reactions. Such an example is polyethylene oxide... 

Imidazole carboxylates of polyethylene glycols prepared with CDI react with amines to give polyethylene glycols (PEG) with carbamate end groups.12071 For example, PEG-... 

As with fullerenes, carbon nanotubes are also hydrophobic and must be made soluble for suspension in aqueous media. Nanotubes are commonly functionalized to make them water soluble although they can also be non-covalently wrapped with polymers, polysaccharides, surfactants, and DNA to aid in solubilization (Casey et al., 2005 Kam et al., 2005 Sinani et al., 2005 Torti et al., 2007). Functionalization usually begins by formation of carboxylic acid groups on the exterior of the nanotubes by oxidative treatments such as sonication in acids, followed by secondary chemical reactions to attach functional molecules to the carboxyl groups. For example, polyethylene glycol has been attached to SWNT to aid in solubility (Zhao et al., 2005). DNA has also been added onto SWNT for efficient delivery into cells (Kam et al., 2005). 

Treatment of polyethylene with 2O3/H2SO4/H2O leads to partial oxidation of its surface and the generation of carboxyl groups [228]. These have been used as attachment points for a functionalized polysaccharide (carboxymethyldextran) to yield a hydrophilic support suitable for the preparation of peptide libraries [228]. 

When equal amounts of solutions of polyethylene oxide) and poly(acrylic acid) are 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 more 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(methacrylic acid) complexes indicate a stoichiometric ratio of three monomeric units of ethylene oxide for each methacrylic acid unit. 

Newkome et al. were the first to synthesise symmetrical, quater-directionaF cascade molecules with a carbon scaffold bearing 36 terminal carboxyl groups -all at an equal distance from the neopentyl core (Fig. 6.20a). The carboxyls were converted into the corresponding ammonium and tetramethylammonium car-boxylates. Synthesis of these dendritic unimolecular micelles with hydrophobic core and hydrophilic shell was accomplished up to the fourth generation by coupling of a dendritic hypercore (constructed from 4,4-bis(4 -hydroxyphenyl)-pentanol monomer) and PEG mesylate (PEG = polyethylene glycol). Dyes such... 

PAS-FTIR spectra have been used to find out the interaction of chlorosulphonated polyethylene (CSM) and carbon black N110 [48]. A number of bands in the 1800 cm1-1680 cm1 region in the spectrum of Nil0 (Figure 2.7) confirm the presence of different carbonyl functionalities, which may include carboxyl group, lactone and quinone. The band at 1651 cm1 is characteristic of aromatic double bonds in the carbon black. The... 

This reaction has been put forward to explain the observed fact that the number of chain scissions corresponds to the number of carboxyl groups formed in the oxidation of polyethylene. Activation energy of both processes is 140 kj/mol. The mechanism of such an elementary fragmentation reaction remains however uncertain. The reactions of a chain scission are likely to precede the isomerization of original secondary alkyl peroxy radicals. 

Modification of sulfydryl groups to produce amine functions alkylating agent reacts with carboxyl groups at acid pH monomer unit for polyethylene amine, a versatile polymer. 

The chloride atom in isophthaloyl chloride is attached to the carboxyl group. In this reaction, the H in the amine group of polyethylene amine reacts with the chloride in the carboxyl group producing HCl, as shown by the product over the arrow, and the PA-100 membrane to the right of the reaction equation. As in the case of the NS-lOO, the reaction forms the closed loop resulting in cross-linked structure of the PA-membrane. Thus, a molecular pore is again produced. 

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