Esters unsaturated poly

The cationic ring opening polymerization of oxolane (THF) or of N-substituted aziridines can be initiated by oxocarbenium salts [42]. The methacrylic ester unsaturation is insensitive to cationic sites, and polyoxolanes (poly-THF) macromonomers are obtained in good yields. 

Polyesters [2] find use in fibers [poly(ethylene terephthalate), poly(ethylene oxybenzoate), poly(ester ethers), poly(ester amides), etc.] [1], coatings (especially unsaturated polyesters) [4], plasticizers, adhesives, polyurethane base resins, films, etc. Cross-linked polyesters prepared from glycerol and phthalic anhydride (alkyd resins) have been reviewed [20], High-melting poly aryl esters have been investigated for high-temperature applications. 

Pyrazolines have also been incorporated as modifying groups by 1,3-addition of azomethine ylides to the carbon-carbon double bond of unsaturated poly(esters) (186 Scheme 89) (68MI11100). Poly(isoxazolines) were prepared in similar fashion by reaction of an unsaturated polymer with a nitrile oxide (75MI11106). 

Keywords. Saturated poly(ester-imide)s, Unsaturated poly(ester-imide)s, Imide modified alkyds, Imide modified coatings, Thermoplastic poly(ester-imide)s, Wire enamels, Impregnating materials, Engineering plastics, Other applications... 

Poly(ester-imide)s are a class of thermally stable polymers having a wide use mainly in the electrical industry. In 1997 the demand of the electrical industry for saturated poly(ester-imide)s based wire enamels was approximately 40,000 tons and for unsaturated poly(ester-imide)s for coil impregnation it was also several thousand tons world-wide. 

Nowadays ethanolamine (9) is of no importance in the production of poly(es-ter-imide)s for wire enamels, but it is still a key monomer for the manufacturing of unsaturated poly(ester-imide)s. 

Unsaturated poly(ester-imide) resins are known having imide structures at the end of the molecule or in the backbone. Chain termination by imide is frequently done with the tetrahydrophthalic anhydride (23) aminoethanol (9) reaction product [10,201-204]. In the synthesis of these resins, maleic anhydride is used. It is cheap and a world-wide available raw material, having the advantage of generating per mol only one mol of distillate. Patents are known where fumar-ic acid is claimed, e.g., in [205], but it is probably not frequently used in industrial processes. Anyway, under the conditions of the esterification reaction, a part of the maleate is isomerised into the fumarate [206]. To get materials with good heat resistance the use of THEIC is claimed for branching the unsaturated poly(ester-imide) resins [202]. Flexibility and heat resistance are improved when fatty acids, e.g., castor oil fatty acid [205,207], are build into the macromolecule. 

Fig. 8. Reaction scheme for unsaturated poly(ester-imide) preparation...

The imide structure generated from trimellitic anhydride (7) and 4,4 -diami-nodiphenylmethane (8) are used for the preparation of unsaturated poly(ester-imide)s having the imide in the polymer backbone. Thermal properties are su-... 

The bicyclo(2,2,2)-oct-2-ene-2,3,5,6-tetracarboxylic dianhydride (15) was also used for making unsaturated poly(ester-imide)s [216]. 

Interpol . [Freeman] Unsaturs poly-ester/urethane hybrid system for liq. iqj. molding or casting applies. 

In unsaturated poly (ester) resins, the addition of LCP improves the adhesion to glass fibers. In addition, the mechanical properties are enhanced. In elastomer matrix polymers, the addition of LCP causes an enhancement of thermal stability ... 

Unsaturated poly(ester amide) resins were also prepared by reaction between diglycidyl ether of bisphenol-A-based epoxy and unsaturated aliphatic bisamic acids, using a base catalyst (Fig. 5.4). These resins were then blended with styrene to produce homogeneous resin syrups which were cured by using BPO as the free radical initiator. 

Guo K, Chu C C, Chkhaidze E and Katsarava R (2005), Synthesis and characterization of novel biodegradable unsaturated poly(ester-amide)s , / Polym Sci Polym Chem, 43,1463-1477. 

Guo K and Chu C C (2007b), Biodegradation of unsaturated poly(ester-aiiiide)s and their hydrogels . Biomaterials, 28(22), 3284-3294. 

Guo K and Chu C C (2007c), Controlled release of Paclitaxel from biodegradable unsaturated poly(ester amide)s/poly(ethylene glycol) diacrylate hydrogels , / Biomater Sci Polym Ed, 18(5), 489-504. 

Selective Electrochemical Fluorination, Scheme 16 Solvent-free electrochemical fluorination of cyclic unsaturated esters in poly HF salt... 

Guo, K. Chu, C.C. Chkhaidze, E Katsarava, R. Synthesis and Characterization of Novel Biodegradable Unsaturated Poly(ester amide)s.j/ Pohm. Sci. Part A Pohm. Chem. 2005. 43, 1463-1477. 

By certain physical factors like thermal, ultraviolet irradiation, high pressure and other chemical parameters like organic solvents the helical pol5mers are easily denaturalized. A variety of helical polymers are synthesized, which include polyisocyanates, polyisocyanides, polychloral, polymethacrylates, polysilanes, polythiophenes, poly (p-phenylene)s, poly(l-methylpropargyl-ester)s, poly(phenylacetylene)s and poly (-unsaturated ketone) [18-24] (Fig. 1). Other polymers are whose optical activity is main chain or side chain chirality dependent e.g. amino-acid-based polymers are nontoxic, biocompatible and biodegradable. 

Unsaturated poly(ester) resins are polycondensation products made from saturated and unsaturated dicarboxylic acids or their anhydrides with diols. They are cured by free radical polymerization using initiators, e.g., peroxides and accelerators. The double bonds of the poly(ester) chain react with the double bond of the copolymer-izable solvent monomer. The most important dicarboxylic acids are maleic anhydride, fumaric acid and terephthalic acid. The most frequently used diol is 1,2-propanediol, but ethylene glycol, diethylene glycol and neopentyl glycol, inter alia, are also often used (20). 

The most suitable crosslinking monomer is styrene. Styrene can be mixed freely with the poly(ester) resins and is easily copolymerized. The styrene content in unsaturated poly(ester) resins is normally from 25-40%. In free-flowing unsaturated poly(ester) resins, the monomer used is usually diallyl phthalate. 

Unsaturated poly(ester) resins may be made flame retardant by using bromine-containing or chlorineacid components or alcohol components, for example hexachloroendomethyl-enetetrahydrophthalic acid (HET acid), tetrabromophthahc acid or dibromoneopentyl glycol. Antimony trioxide is frequently used as synergist. 

Unsaturated poly(ester) resins, in the form of molding compositions, may be provided with fillers such as aluminum hydroxide, which have a quenching action. At filling rates of from 150-200 parts of aluminum hydroxide per 100 parts of unsaturated poly-(ester) resin, it is possible to achieve self-extinguishing and a low smoke density. 

However, such formulations cannot be used for injection processes, since homogeneous distribution of the aluminum hydroxide cannot be achieved with the reinforcing materials used. For injection processes, chlorinated or brominated unsaturated poly(ester) resins are used. 

The use of phosphorus compounds in vmsaturated poly(ester) resins in order to establish adequate flame retardancy has already been proposed in a number of ways. The use of phosphoric esters in halogen containing unsaturated poly(ester) resins has been described (21). Melamine diphosphate has also been tested as a flame retardant for vmsaturated poly(ester) resins (22). In addition, 2-methyl-2,5-dioxo-l-oxa-2-phospholane has been proposed as flame retardant (20). 

In crosslinked unsaturated poly(ester)s, the crosslinking density can serve in evaluating the extent of degradation. However, in the range of high conversions, spectrometric measurements of the ester concentration are recommended (4). 

Special types of hydrogen donors include phenols and aromatic amines. Notably, aromatic amines are also known as accelerators in peroxide curing of unsaturated poly(ester)s resins. The mechanism of the decomposition of peroxide radicals by aromatic amines is shown in Figure 19.3. 

The second reaction in Eq. 20.7 regenerates the original metal ion M". In the combined reaction, the hydroxyl anion and the hydrogen cation recombine to water. This reaction is used purposely in hydroperoxide curing of unsaturated poly(ester) resins. 

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