Acid-functionalized polymers

Some of the most remarkable achievements include microencapsulation in polystyrenes such as entrapped 0s04 for olefin hydroxylation (exploiting the interaction between n-electrons of benzene rings of the polystyrenes used as polymer backbones and the vacant orbitals of the catalysts) 5 polyurea-entrapped palladium (PdEnCat)6 for a multiplicity of C C forming reactions and the use of carboxylic acid-functionalized polymer (FibreCat).7 In general, however, metal leaching cannot be avoided. The PdEnCat catalyst, for instance, leaches some 4% of palladium per catalytic reaction run. 

Petersen et al., Petersen and Voth,i Spohr, Spohr et al., and Walbran and Kornyshev developed EVB-based models to study the effect of con-finemenf in nanometer-sized pores and fhe role of acid-functionalized polymer walls on solvation and transport of protons in PEMs. The calculations by the Voth group revealed an inhibiting effect of sulfonate ions on proton motions. The EVB model by Kornyshev, Spohr, and Walbran was specifically designed to sfudy effecfs on proton mobilify due to charge delocalization within SOg groups, side chain packing density, and fluctuations... 

Further characterization of the product required that it be soluble in solvents like THF and chloroform. Therefore, the acid-functionalized polymer was converted to an ester-functionalized polymer using ethanol/sulfuric acid. The general procedure is given below. 

To determine whether this association is due to carboxylic acids or whether it also involves the aluminum salt of carboxylic acid, the acid-functionalized polymer was evaluated using X-ray photoelectron spectroscopy (XPS). Figure 2 shows that there is no metal aluminum. Thus the association is most likely due to dimerization of carboxylic acids, as is commonly seen in smaller organic molecules. The XPS spectrum also shows the incorporation of oxygen functionality into the copolymer by the acylation reaction. The reaction scheme is as follows ... 

Cyclic carbonate functional polymers have been explored on a limited basis over a number of years. The cyclic carbonate group is an attractive functional group due to its reactivity with primary amines at ambient or slightly elevated temperatures to form crosslinked networks [7]. Cyclic carbonate functional polymers will also react with carboxylic acid functional polymers [2] at higher temperatures to form crosslinked coatings. 

As part of their formulation, polyacid-modified composite resins also contain a small fraction of basic glass filler of the type used in glass-ionomer cements [1]. Such glasses are typically calcium (or strontium) alumino-fluorosiUcates, and react with acids in the presence of water to release ions. The ions released, particularly calcium (or strontium) and aluminium react with the acid to form salts, which in the case of glass-ionomers, are insoluble because they form ionic crosslinks with the polymeric acid. The ions effectively insolubilize the acid-functional polymer chains by this reaction, as well as stiffening the material due to coil expansion and ion-binding. This type of chemistry is available to polyacid-modified composite resins once moisture is present, and these materials are designed for this reaction to occur in the early part of their existence. 

Boronic acid-functionalized polymers have been widely studied in view of the construction of biomaterials based on the capability of boronic acid to precisely recognize saeeharides. The boronic acid moieties can be easily introduced into the polymer ehain mainly through free-radical polymerization techniques. One versatile vinyl monomer for this purpose is m-acrylamidophenylboronic acid. Numerous polymers have been synthesized from this monomer in combination with various vinyl... 

This section focuses on molecular recognition of small diol molecules by a series of boronic acid-functionalized polymers in most cases, the target molecule is glucose because of the need for a glucose-sensing system or an insulin delivery system. 

Related to boronie acid-functionalized polymers, end-functionalized polymers are intriguing because of the boron-diol reactivity of their ends. Boronic acid moieties can be selectively incorporated into the end of the... 

Barkac, K. A., et al. (2000). Thermosetting compositions containing carboxylic acid functional polymers and epoxy functional polymers prepared by atom transfer radical polymerization. In PCT Int. Appl. WO 0012583, Ppg Industries Ohio, Inc., USA, 72 pp. 

PEMs of particular interest contain acid-functional polymers, such as add-functional fluoropolymers, and electrolytes, such as water. Suitable examples of acid-fimctional fluoropol5mers include... 

A special PEM has been developed (151). This membrane contains an acid-functional polymer, and an additive incorporated in at least a portion of the membrane. The additive is a fluorinated cycloaliphatic additive, or a hydrophobic cycloaliphatic additive. The additive should have a boiling point greater than about 120°C (151). Suitable additives of this type are collected in Table 2.12. 

J.M. Harris, A. Kozlowski, L. Guo, Method of preparing carboxylic acid functionalized polymers. U. S. Patent 8067505, assigned to Nektar Therapeutics, November 29,2011. 

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