Functional reactive polyesters

Figure 11.3. By choosing a suitable monomer, the degree of branching, and molecular weight of the polyester, one can customize the properties of the resulted polyester acrylate oligomers, such as flexibility (Tg), viscosity, functionality, reactivity, and other end properties of the final coatings. The performance properties of polyester acrylates lie between those of epoxy acrylates and urethane acrylates (Table 11.2).

The presence of reactive sites such as double bonds, hydroxyl and carboxyl groups and phenyl rings in aromatic anhydride and ester linkages all provide tremendous potential for the modification of oil-modified polyester. Epoxy resins are considered to be polyols, which react with the carboxylic functions of polyester resin. The modification of oil-modified polyesters with epoxy resins results in products with excellent adhesion properties and improved water and chemical resistance. Epoxy modified polyesters are less expensive than epoxy resins. 

Functional polyesters were synthesized through the specific catalysis of lipase, and their properties and functions were evaluated. Enantio- and regioselec-tive polycondensations produced chiral and sugar-containing polyesters, respectively [20,23]. Using lipase catalyst reactive polyesters were conveniently obtained, some of which were crosslinked to biodegradable coatings. Recently, polyester-based biomaterials have been developed by lipase-catalyzed polymerizations. 

Versatile functional aliphatic polyesters have been prepared by copolymerization with the above mentioned functional monomers. The introduction of reactive groups along the chains is highly desirable for fine tuning the polymer properties, such as chemical reactivity, biocompatibility, biodegradability and... 

The amino resins can react with several functionalities on the main binder resins such as hydroxyl, amide, carboxyl, and urethane (or carbamate). Most commonly, the binder resins are hydroxyl functional acrylics, polyesters, or modifications of these. Recently, there has been an increase in product offerings and literature references to urethane or carbamate functional resins being paired with amino resins (16-18). The curing reactions require acid catalysis and heat. There is a significant variety of reactivities (and therefore curing temperatures) possible with amino resins, but the lower temperature cure materials... 

Mani R, Bhattacharya M, Tang J (1999), Functionalization of polyesters with maleic anhydride by reactive extmsion , J. Polym. Sci, A Polym. Chem., 37 (11), 1693-1702. 

Polymers. The molecular weights of polymers used in high energy electron radiation-curable coating systems are ca 1,000—25,000 and the polymers usually contain acryUc, methacrylic, or fumaric vinyl unsaturation along or attached to the polymer backbone (4,48). Aromatic or aUphatic diisocyanates react with glycols or alcohol-terrninated polyether or polyester to form either isocyanate or hydroxyl functional polyurethane intermediates. The isocyanate functional polyurethane intermediates react with hydroxyl functional polyurethane and with acryUc or methacrylic acids to form reactive p olyurethanes. 

On the organic side of the interface, chemical bonds are formed between the organofunctional R group of the silane and the reactive species in the polymer matrix. For example, a methacrylate- or styryl-functional silane reacts with polyesters copolymerized with styrene or similar monomers, while amino- or chloroalkyl-functional silanes are unsuitable in this particular case. Polybutadiene... 

Liquid organic rubbers with reactive functionality can be prepared by several methods. End-functional oligomers are preferred. Chains attached to the network at only one end do not contribute as much strength to the network as those attached at both ends [34], Urethane chemistry is a handy route to such molecules. A hydroxy-terminated oligomer (commonly a polyester or a polyether) can be reacted with excess diisocyanate, and then with a hydroxy methacrylate to form a reactive toughener [35]. The methacrylate ends undergo copolymerization with the rest of the acrylic monomers. The resulting adhesive is especially effective on poIy(vinyl chloride) shown in Scheme 2. 

To design amphiphilic and/or reactive copolymers containing aliphatic polyesters, one of the most promising approaches is copolymerization with functional monomers having protected reactive side-chain groups. Some kinds of monomers having reactive (hydrophilic) side-chain groups have been reported (Fig. 3). Recently, the synthesis of various types of functional polyesters has been reviewed [15-19],... 

Acid dye affinity, 19 759 Acid dyes, 9 184-186, 189-190, 215-216, 226, 243 26 395-396 anthraquinone, 9 301, 327-329 azo, 9 389-394 Acid dyestuffs, 9 223 Acid extractants, 10 750 Acid fixing reactive dyes, 9 478-481 Acid foods, heat preservation of, 12 80 Acid functional polyesters, 10 402 Acid gas constituents, 12 376-378 Acid gases, 10 612-613... 

Telechelic polymers rank among the oldest designed precursors. The position of reactive groups at the ends of a sequence of repeating units makes it possible to incorporate various chemical structures into the network (polyether, polyester, polyamide, aliphatic, cycloaliphatic or aromatic hydrocarbon, etc.). The cross-linking density can be controlled by the length of precursor chain and functionality of the crosslinker, by molar ratio of functional groups, or by addition of a monofunctional component. Formation of elastically inactive loops is usually weak. Typical polyurethane systems composed of a macromolecular triol and a diisocyanate are statistically simple and when different theories listed above are... 

The future direction of polyester R D efforts is likely to involve further progress in polyester synthesis given the wide range of potential monomer combinations, new blending technology and the use of advanced functional additives such as nanoclay reinforcements, reactive impact modifiers, anti-hydrolysis agents and chain extenders. 

---