Resins carboxyl-functionalized

Key Words Epoxy resin, Carboxyl functionalized glucose copolymer, Curing characteristics. Water absorption behavior... 

Nylon resins are made by numerous methods (53) ranging from ester amidation (54) to the Schotten-Baumann synthesis (55). The most commonly used method for making nylon-6,6 and related resins is the heat-induced condensation of monomeric salt complexes (56). In this process, stoichiometric amounts of diacid and diamine react in water to form salts. Water is removed and further heating converts the carboxylate functions to amide linkages. Chain lengths are controlled by small amounts of monofunctional reagents. The molten finished nylon resin can be dkectly extmded to pellets. 

The most important single reactions produced in the carboxyl functionality of the resin acids are salt formation, Diels-Alder additions, and esterification. Other reactions, such as disproportionation and polymerization, are less important. For some specific applications, rosins are subjected to a combination of these reactions. 

The first example of microwave-promoted solid-phase methodology in heterocyclic chemistry was the arylation of thiophene and indole via Suzuki couplings on TentaGel S RAM resin, as demonstrated by Hallberg and coworkers in 1996, before temperature- and pressure-controlled microwave instruments were even available [189]. Three years later Schotten and coworkers presented analogous but aqueous Suzuki couplings of 5-bromo-thiophene anchored to PEG soluble support via a carboxylic function at its C-2 position [116]. Unfortunately, this work was performed in a do-... 

Coreactants, in microencapsulation, 16 444 Coreactive curing agents, 10 388-389, 392-411, 418. See also Curing agents amine functional, 10 392 401 carboxylic functional polyester and anhydride, 10 401—406 cyanate ester, 10 411 cyclic amidine, 10 410 isocyanate, 10 410 melamine-, urea-, and phenol-formaldehyde resins,... 

Chlorosulfonated styrene resins and carboxyaminoacid polymers were also found to possess thromboresistant properties by Josefonwicz and coworkers [483]. Studies included investigation of the effect of spacer length between amine and carboxylic groups as well as modification of styrene/isoprene/styrene blocks with chlorosulfonyl isocyanate giving sulfamate and carboxylic functionality [484],... 

Scheme 2 depicts an application of the carboxyl-functionalized IRC-50S resin 48 to quench parallel-array organometallic reactions.20 Nonisolable alkoxide salts formed from the reaction of aldehydes with organolithiums... 

We have prepared a wide series of Mo(VI)-grafted poly(amido amine) resins based on aminoacids with varying distances between the aminic and carboxylic groups. We have found that the catalytic activity of these resins is strongly dependent on that distance, maximum activity within this series being obtained when the resin supposedly co-ordinates to a Mo(VI)02 core in a quadridentate manner throught the use of two suitably located adjacent carboxylic functions. 

Functionalized, liquid polybutadiene derivatives have also been developed as hybrid flexiblizers for epoxy resins. Carboxyl-terminated butadiene/acrylonitrile polymers, butadiene homopolymers, and maleic anhydride-amino acid grafted butadiene homopolymers have been used as flexibilizers to impart good low-temperature strength and water resistance to DGEBA-based epoxy adhesives. An epoxy system toughened by polybutadiene with maleic anhydride is claimed to provide a hydrophobic backbone, low viscosity, softness, and high tensile strength and adhesion (Table 7.10). 

Structures 3.3-3.10 possess two potential handles for their support on SP. The obvious choice is the carboxylic function, which could be linked either to a chlo-romethyl or to a hydroxymethyl PS resin through an ester bond. The insertion of a commercially available acid-labile linker, possibly already supported onto the resin, would allow the release of the target into solution under mild conditions. Different functionalities could be released by cleaving the acid-labile linker with, for example, TFA (free acid) and amines (amides). Another possible handle is the secondary amine, which could be anchored to resin-bound carboxylates or halides and finally released as an A-acyl or A-aUcyl moiety. For both handles the protection of the other functional... 

Fluorourethanes can also be applied using powder coating technology. Resins suitable for this should have Tg values between 35°C and 120°C (95°F and 248°F) to optimize flow out and cure at the annealing temperature. Blocked isocyanates, which form free isocyanates after being heated above certain temperatures, are frequently used [50]. Certain FEVE copolymers with hydroxyl and carboxyl functionalities combined with blocked isophorone diisocyanate are suitable for powder coating technology [51]. 

The addition level is predicated on the degree of crosslinking required and is dependent upon the concentration of the carboxyl functionality of the resin (polymer) used. The optimum ZINPLEX 15 level must be determined experimentally to assure maximum performance properties and stability of the end coating. With certain polymer systems, prestabilization may be necessary prior to the addition of ZINPLEX 15. Surfactants such as the high ethylene oxide nonionics (i.e. TRITON X405) offer good stabilizing properties. 

Tramontane and Blank (1995) reported the preparation of a low molecular weight, hydroxyl/carboxyl functional water-borne polyurethane dispersion via monoisocyanate chemistry which is readily cross-linkable with melamine-formaldehyde resin. Such cross-linking can improve the water resistance because of the reaction of some of the hydrophilic groups (Tramontano and Blank, 1995). 

Crowley and Rapoport have made a detailed investigation, including labeling studies, of the reaction, both with one carboxylic function attached to a resin, and in solution with the carboxylic functions esteri-fied by different alcohols. Cyclization of the resin-attached methyl (51 R = Me) or r-butyl ester (51 R = Bu ) with BuOK gave the methyl (52 R = Me) or r-butyl 2-oxocarboxylates (52 R s Bu ) as the exclusive autocleaved product. Similar results were obtained with the half-benzyl esters in solution but the products were less readily isolated (equation 22). 

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