Aromaticity bisphenols

A key step in the synthesis of the simple aromatic bisphenol tetrangulol (3) by Brown and Thomson [18] was a Michael-type cyclization of a phenol to the chloronaphthoquinone moiety (Scheme 3). The starting material 8, connecting the naphthoquinone and the protected phenol, was prepared by an interesting radical alkylation of the chloronaphthoquinone 6 with a carboxylic acid 7 in the presence of silver ions and persulfate with concomitant decarboxylation (Torsell reaction [19]) to yield the dihydrobenzo[a]anthraquinone 9. The synthesis of tetrangulol (3) was concluded by dehydrogenation in boiling nitrobenzene. 

A similiar comparison can be made between permeability data of polyesters and polycarbonates containing "polyester-like" monomers. For example, polycarbonates 26 and 27, which contain predominantly bisphenols which are structurally similiar to the repeat unit (circled) of an alkyl terephthalate polymer (PBT), possess essentially the same low permeability as that polyester (Table V). Furthermore, there has been a recent announcement (3 ) that aliphatic polycarbonates, such as polypropylene and polyethylenecarbonate, are being developed as potential gas barrier materials. In summary these results suggest that the relative low permeabilities of commercial polyesters and high permeabilities of commerical polycarbonates are not a direct consequence of the ester or carbonate links, but are due instead to the structure of the monomers they are prepared from, i.e., the aliphatic diol and aromatic bisphenol, respectively. 

The simple aromatic polyestericetones, which are of interest as constmc-tional plastics and film materials, capable of operating within the long time at 200 °C, have been synthesized [376-381] by means of polynitrosubstitution reaction of l,l-dichlor-2,2-di(4-nitrophenyl)-ethylene and 4,4 -dinitrobenzo-phenone with aromatic bisphenols. 

Epoxy resins n. Plastic or resinous materials used for strong, fast-setting adhesives, as heat resistant coatings and binders, etc. Cross-linking resins based on the reactivity of the epoxides group. One common type is the resin made from epichlorohydrin and bisphenol A. Aliphatic polyols such as glycerol may be used instead of the aromatic bisphenol A or bisphenol F. 

Poly(arylene ethers) are obtained from -propyl isocyanate blocked highly aromatic bisphenols and difluoroarenes. In this manner polsrmers containing hole (electron) transport moieties are obtained (97). 

This chapter reviews the research and the most relevant progresses in polycarbonates (PC)s science and provides a comprehensive source of information on history, synthesis, processing and applications. The application of different polymerization procedure of the commercial aromatic bisphenol-A polycarbonate (referred herein as PC) and the innovative enzymatic catalysed polymerization of aliphatic polycarbonate are summarized. Due to the high engineering performance of PC polymer, an extensive section on mechanical, electrical, chemical and thermal properties is included. The thermo and photo oxidative behaviours, the hydrolytic stability and the consequent modification on PC chemical structure are also discussed. The development of PC polymeric materials such as composites and blends are also addressed, emphasizing in particular the properties and the applications of impact modified PC blends and even of the PC/Polyester systems. 

Poly-p-Hydroxybenzoic Acid n A homopolyester of repeating p-oxyenzoyl units with a high degree of crystallinity. It does not melt below its decomposition temperature, 550°C, but can be fabricated at 300-360°C by compression sintering and plasma-spray processes. Copolymers with aromatic dicarboxylic acids and aromatic bisphenols are processable by normal means. Applications include electrical connectors, valve seats, high-performance-aircraft parts, and automotive parts. 

A new double adamantyl-substituted aromatic bisphenol monomer, 4,8-bis (l-adamantly)-l,5-dihydroxynaphthalene (AdNp) was successfully S5mthesized via the Friedel-Crafts reaction as depicted Scheme 10.11, and two new PAEKs containing adamantly groups (Ad-PAENKs) were synthesized based on the new monomer of AdNp, (3-trifluoromethyl)phenyl hydroquinone (3FHQ) and 4,4 -difluorobenzophenone (D ) via the nucleophilic aromatic substitution polymerization as depicted Scheme 10.12. 

The performance of ACE and four other commercial mono-functional acrylates as reactive diluents was compared with four different oligomers (i) an aromatic bisphenol A difunctional epoxy acrylate (2) a flexible difunctional polyester urethane acrylate ... 

A variety of aromatic bisphenols can be condensed with isophthaloyl... 

Poly(aryl ether ketone) of ],8-bis(4-fluorobenzoyl) naphthalene and aromatic bisphenols Poly(ether ether ketone)... 

Miscellaneous Applications. Ben2otrifluoride derivatives have been incorporated into polymers for different appHcations. 2,4-Dichloroben2otrifluoride or 2,3,5,6-tetrafluoroben2otrifluoride [651-80-9] have been condensed with bisphenol A [80-05-7] to give ben2otrifluoride aryl ether semipermeable gas membranes (336,337). 3,5-Diaminoben2otrifluoride [368-53-6] and aromatic dianhydrides form polyimide resins for high temperature composites (qv) and adhesives (qv), as well as in the electronics industry (338,339). 

A number of HFIP-derived polyethers are known which exhibit good mechanical, thermal, and electrical properties (112,113). Aromatic polyethers have been synthesi2ed from bisphenol A (R = H) or AF (R = F) and fluorkiated aromatics (Ar = perfluorophenyl, perfluorobiphenyl, or... 

A polyester backbone with two HFIP groups (12F aromatic polyester of 12F-APE) was derived by the polycondensation of the diacid chloride of 6FDCA with bisphenol AF or bisphenol A under phase-transfer conditions (120). These polymers show complete solubkity in THF, chloroform, ben2ene, DMAC, DMF, and NMP, and form clear, colorless, tough films the inherent viscosity in chloroform at 25°C is 0.8 dL/g. A thermal stabkity of 501°C (10% weight loss in N2) was observed. 

The first HFIP-based polycarbonate was synthesi2ed from bisphenol AF with a nonfluorkiated aromatic diol (bisphenol A) and phosgene (121,122). Incorporation of about 2—6% of bisphenol AF and bisphenol A polycarbonate improved the dimensional stabkity and heat-distortion properties over bisphenol A homopolycarbonate. Later developments in this area concern the flame-retardant properties of these polymers (123,124). 

Also in 1972 (6), Carbomdum researchers described a family of aromatic copolyesters which were recognized later to form Hquid crystalline melts. The polymers are based on a bisphenol monomer. In 1976, in a patent assigned to Carbomndum, a hydroxybenzoic acid—terephthaHc acid—bisphenol system, modified and softened with isophthaHc acid, was reported to be melt spinnable to produce fiber. 

The birefringence for phenyl-substituted PC (4) (T = 176 C) is reduced to about 50%, for benzyl substituted PC (5) (T = 138 C) to about 25%, and for four-ring bisphenol PC (6) to 8% of the value for BPA-PC (183,190,195,197,198) on condition of an optimum conformation of the phenyls in the side groups perpendicular to the aromatic rings in the backbone. In reaUty, however, these low birefringence values are not achieved, because the optimum conformation of the phenyl rings cannot be achieved in injection-stamped disks. 

Polycarbonates are prepared commercially by two processes Schotten-Baumaim reaction of phosgene (qv) and an aromatic diol in an amine-cataly2ed interfacial condensation reaction or via base-cataly2ed transesterification of a bisphenol with a monomeric carbonate. Important products are also based on polycarbonate in blends with other materials, copolymers, branched resins, flame-retardant compositions, foams (qv), and other materials (see Flame retardants). Polycarbonate is produced globally by several companies. Total manufacture is over 1 million tons aimuaHy. Polycarbonate is also the object of academic research studies, owing to its widespread utiUty and unusual properties. Interest in polycarbonates has steadily increased since 1984. Over 4500 pubflcations and over 9000 patents have appeared on polycarbonate. Japan has issued 5654 polycarbonate patents since 1984 Europe, 1348 United States, 777 Germany, 623 France, 30 and other countries, 231. 

Table 3. Aromatic Polycarbonates Derived from Bisphenols...

The first aromatic sulfone polymer produced commercially was introduced as Bakelite polysulfone but now is sold by Union Carbide under the trade name Udel. It is made by reaction of the disodium salt of bisphenol A (BPA) with 4,4 -dichIorodiphenyl sulfone in a mixed solvent of chlorobenzene and dimethyl sulfoxide (eq. 12). 

Polyetherification is similar to a polycondensation process formation of high molecular weight polymer requires precise adjustment of composition to approximately 1 1 ratio of bisphenol to dihalosulfone. Trace amounts of water gready reduce the molecular weight attainable owing to side reactions that unbalance the stoichiometry (76). The reactivity of the halosulfone is in the order expected for two-step nucleophilic aromatic displacement reactions ... 

Solvent for Displacement Reactions. As the most polar of the common aprotic solvents, DMSO is a favored solvent for displacement reactions because of its high dielectric constant and because anions are less solvated in it (87). Rates for these reactions are sometimes a thousand times faster in DMSO than in alcohols. Suitable nucleophiles include acetyUde ion, alkoxide ion, hydroxide ion, azide ion, carbanions, carboxylate ions, cyanide ion, hahde ions, mercaptide ions, phenoxide ions, nitrite ions, and thiocyanate ions (31). Rates of displacement by amides or amines are also greater in DMSO than in alcohol or aqueous solutions. Dimethyl sulfoxide is used as the reaction solvent in the manufacture of high performance, polyaryl ether polymers by reaction of bis(4,4 -chlorophenyl) sulfone with the disodium salts of dihydroxyphenols, eg, bisphenol A or 4,4 -sulfonylbisphenol (88). These and related reactions are made more economical by efficient recycling of DMSO (89). Nucleophilic displacement of activated aromatic nitro groups with aryloxy anion in DMSO is a versatile and useful reaction for the synthesis of aromatic ethers and polyethers (90). 

Aromatic polysulfites can be produced if bisphenols, eg, bisphenol A, are heated with diphenyl sulfite in the presence of lithium hydride (112). Halosulfates and Halosulfites. A general method for the preparation of alkyl halosulfates and halosulfites is the treatment of the alcohol with sulfuryl or thionyl chloride at low temperatures while passing an inert gas through the mixture to remove hydrogen chloride (113). 

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