Imide aromatic imides

Almost insoluble in cold water. Higher alcohols (including benzyl alcohol), higher phenols (e.g., naphthols), metaformaldehyde, paraldehyde, aromatic aldehydes, higher ketones (including acetophenone), aromatic acids, most esters, ethers, oxamide and domatic amides, sulphonamides, aromatic imides, aromatic nitriles, aromatic acid anhydrides, aromatic acid chlorides, sulphonyl chlorides, starch, aromatic amines, anilides, tyrosine, cystine, nitrocompounds, uric acid, halogeno-hydrocarbons, hydrocarbons. 

Polyamide Imides. Polyamide imides (PAIs) are formed from the condensation of trimellitic anhydride and aromatic diamines (33). The polymer is called amide—imide because the polymer chain comprises amide linkages alternating with imide linkages, with the general chemical stmcture ... 

In the narrow sense, bis-maleimide resin means the thermosetting resin eom-posed of the bis-maleimide of methylene dianiline (BMI, bis(4-maleimidophenyl)-methane) and methylene dianiline (MDA, bis(4-aminophenyl)methane) (Fig. 1). Beeause of the addition meehanism, the resin is eured without elimination, whieh is a eharacteristic of this resin. Bis-maleimide resin is used as a thermally stable matrix up to 204°C (400 F) whieh typical epoxy resins may not normally be used. However, in spite of having an imide structure, bis-maleimides are classified as being moderately thermally stable resins. The aliphatic structure of the resin is not stable for long periods above 232°C (450°F.) If a highly aromatic thermally stable thermosetting resin is necessary, acetylene end-capped aromatic imide-based oligomers should be used. 

The competition at 200°C between an aliphatic and an aromatic amine toward the formation of an imide is a very selective reaction (Fig. 5.1) for the formation of an aliphatic imide.141 This reaction suggests that the reactive processing in extruder, for example, could be used to transform a melt-processable polyimide with an oligomer end capped with an aliphatic amine. In order to get a perfecdy alternate block polyimide-block siloxane, Rogers et al. used low-temperature transimidization.142 An oligomeric aromatic imide was end capped... 

The saiq>les studied were a BCB terminated aromatic imide oligomer and a BCB terminated imide monomer blended with a compatible bismaleimide (BMI) resin. Neat properties studied on both resin systems included the thersial and rheological properties of the uncured specimens subsequently used to determine appropriate cure conditions. Thermal and mechanical properties of the cured materials are also discussed. 

The structure formed through a linear addition of the molecules is Shown at the top of the illustration. The benzocyclobutene groups on either end of the BCB terminated resin molecules react with two other BCB groups as shown to form a poly(o-xylyene) strands. With BCB reactive groups present at both ends of the resin molecules, a double strand of poly(o-xylyene) is formed which is bridged by the aromatic imide chains. 

Monomers bearing these functional groups must also be thermally stable. The main types of chemical compounds used are imides, aromatic ether sulfones, aromatic sulfides, aromatic esters, aromatic ketones or... 

The double bond of maleimides in very reactive towards electron-rich dienes, to give a normal Diels-Alder cycloaddition. Thus BMIs were used to obtain linear polyimides by reaction with several kind of dienes [46-51]. However the dienes are often difficult to prepare [51] and functionalized dienes have been used. Furan terminated oligomers react with BMIs at 70 °C leading to an oxygen-containing cycloadduct [52-57] which can react with acetic anhydride to give an aromatic imide (Fig. 13) [58-59]. 

Polyimides have excellent dielectric strength and a low dielectric constant, but in certain electrolyte solutions they can electrochemically transport electronic and ionic charge. Haushalter and Krause (5) first reported that Kapton polyimide films derived from 1,2,4,5-pyromellitic dianhydride (PMDA) and 4,4 -oxydianiline (ODA) undergo reversible reduction/oxidation (redox) reactions in electrolyte solutions. Mazur et al., (6) presented a detailed study of the electrochemical properties of chemically imidized aromatic PMDA- derived polyimides and model compounds in nonaqueous solutions. Thin films of thermally... 

Photosensitive resins consisting of pre-imidized aromatic polyamic acids, (III), having a light transmittance of 365 nm and a low residual stress after cure were prepared by Dueber [3] and used for coating silicon wafers. 

Aromatic imides are another type of product which can be synthesized by catalytic ammoxidation. o-Xylene is converted over vanadium-titanium oxide catalysts to tolunitrile and then, depending on catalyst composition and reaction conditions, phthalimide or phthalonitrile can be selectively synthesized (Scheme 20.3) [94]. 

Aliphatic and aromatic imides have relatively low reduction potentials (e.g. N-methylphthalimide —1.4 V relative to the SCE [147]) and absorb in the near ultraviolet region (260-320 nm). These properties have been widely used in synthetic transformations of imides and in catalytic processes in which imides serve as redox... 

Several new developments in silanes have been reported re cently. One deficiency of existing silanes was that they were not applicable to high-temperature polymers such as polyimides, either because they were not thermally stable or because they did not facilitate adhesion. A new aromatic imide silane was synthesized with two silane groups attached to the terminal phenyls in the molecule. A... 

Greenfield S. R., Svec W. A., Gosztola D. and Wasielewski M. R. (1996), Mnltistep photochemical charge separation in rod-like molecules based on aromatic imides and diimides , J. Am. Chem. Soc. 118, 6161-6111. 

The role of Structure Level II on membrane properties is not limited to RO membranes. In fact, the secondary structure is probably even more important in membranes that are intended for gas separations. Patents exist for gas separation membranes where Structure Level 1 is aromatic amide, aromatic ester and aromatic imide combined with Structure Level 11 of a precisely defined type (12, 13). For example, the repeating segmental unit (a) contains at least one rigid divalent subunit the two main chain single bonds which extend from it are not colinear, (b) is sterlcally unable to rotate 360° around one or more of the main chain single bonds, and... 

The facile reaction of an aromatic imide with an amine seemed surprising, perhaps because... 

Polyetherimide has a chemical structure based on repeating aromatic imide and ether units. High performance strength characterisitics at elevated temperatures are provided by rigid imide units, while the ether linkages confer the chain flexibility necessary for good melt processing and flow. 

N( per la 0gellate(j carbon atoms)+ 4 (BB aromatic imide groups)... 

The correction for aromatic imide groups (+41) is much larger than the correction (+17) for other types of aromatic heterocyclic fused rings, such as benzimidazole, benzoxazole, benzothiazole and quinoxaline rings. 

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