Aromatic tetracarboxylic acid dianhydrides

This book reviews some of the results of investigations of chemical conversions of chloral and TNT to new aromatic di(poly)amines and aromatic tetracarboxylic acid dianhydrides useful for the preparation of new polyimides combining good thermal, mechanical and electrical properties with improved processability. 

Along with new aromatic diamines and tetramines based on chloral and its derivatives, new aromatic tetracarboxylic acid dianhydrides were developed. These products were prepared by the interaction of bis-phenols - chloral derivatives - with two-fold molar amounts of nitrophthalimides followed by transformation of bis-phthalimides, containing two ether bonds, into the corresponding aromatic tetracarboxylic acid dianhydrides [30] (Scheme 2.13). 

Polyimides with better viscosity characteristics have been obtained from 3,3 -diamino-4,4 -bis(dimethylamino)-benzophenone and different aromatic tetracarboxylic acid dianhydrides [21] (Scheme 3.4). 

New representatives of such polyimides were prepared from TNT-based perfluoro-substituted m-phenylenediamines and different aromatic tetracarboxylic acid dianhydrides [9-12] in accordance with Scheme 5.2. Reactions were carried out in w-cresol using isoquinoline as catalyst. The reaction temperature was 160 °C and the reaction time 5 hours. 

Interaction of 2-niethyl-3,5-diaminodiphenylsulfide with aromatic tetracarboxylic acid dianhydrides was carried out in accordance with Scheme 5.6. Synthesis of the polyimides was carried out using two general procedures ... 

However, unlike the aromatic tetracarboxylic acid dianhydride that was dominant at the time, a compound having a five-numbered ring structure aliphatic was highly unusual. 

Imides - Polyimides (PI) have been conventionally prepared by the chemical or thermal cyclodehydration of polyamic acids formed from the solution reaction of aromatic tetracarboxylic dianhydrides and aromatic diamines. The early PI were insoluble and relatively intractable. The polyamic acid was the processable intermediate. However, the polyamic acid precursor has two major shortcomings, hydrolytic instability and the evolution of volatiles during the thermal conversion to PI. In addition, residual solvent was left in adhesive tapes and prepregs to obtain tack, drape and flow. During the fabrication of components, the evolution of volatiles caused processing problems and led to porosity in the part. As work progressed on PI, other synthetic routes were investigated (e.g. reaction of esters of aromatic tetracarboxylic acids with diamines... 

Reactions of 3,3 -diamino-4,4 -bis(dimethylamino)-benzophenone with the dianhydrides of aromatic tetracarboxylic acids (pyromellitic, benzophenone-3,3, 4,4 -tetracarboxylic and diphenyloxide-3,3, 4,4 -tetracarboxylic acids) were carried out using a two-stage process including room temperature reaction of starting monomers in NMP, formation of PCA and subsequent cyclodehydration of the... 

Diamino-6-(N-phthalimido)-toluene was reacted with aromatic tetracarboxylic acids, 3,3, 4,4 -tetracarboxydiphenyl ether, 3,3, 4,4 -tetracarboxybenzophenone and dianhydrides, dianhydride 6F and dianhydride A, using high-temperature polycondensation in w-cresol with quinoline as a catalyst (Scheme 5.8). 

Fully imidized soluble polyimides have ben prepared using monomers derived from diphenylindane and aromatic dianhydrides. Technical polymers (XU218, for instance), prepared from 1,1,3-trimethyl-diaminophenylindane and benzophenone-tetracarboxylic acid dianhydride, have been marketed over the last decade. Despite the partially aliphatic nature of polyimides containing the indane group, they show considerable retention of the thermal stability, with Tg values over 300 °C [107-110]. 

The polyimide is prepared from 1,5 naphthlene diamine (1,5 ND) and 3,3, 4,4 diphenylhexafluoroisopropylidene tetracarboxylic acid dianhydride (6F). A polyamide acid is obtained initially and this is cyclized to give the polyimide. Because polyimides are derivatives of polyamides, polyimides are often included in reviews of aromatic polyamides. Another reason polyimides are included in this paper is that they illustrate the role of Structure Level II on gas transport properties in a straightforward manner. 

The softening point determined by thermomechanical methods may be as high as 500°C. A true ladder polymer can also be obtained by condensation of an aromatic tetracarboxylic acid or a dianhydride with an aromatic tetramine. An example is... 

It was shown that soluble PPI can be synthesised directly from DPTA and series of aromatic diamines containing flexible units, namely 2,2-bis[4-(3-aminophenoxy)phenyl]propane and 2,2-bis[4-(3-aminophenoxy)phenyl]hexafluoro-propane were reported (Scheme 1.2) [5]. Previously these diamines were used successfully in the synthesis of soluble polyimides starting from naphthalene-1,4,5,8-tetracarboxylic acid dianhydride [14]. 

A novel conjugated polymers, PI based on N, N , N , N substituted paraphenyl-enediamine and dianhydrides of aromatic tetracarboxylic acids, was successfully prepared via Suzuki coupling reaction. The polymer exhibits excellent solubility in common organic solvent, and has high thermal stability such as T j at 453°C in nitrogen atmosphere and T at about 140°C. 

In 1965, workers from DuPont first prepared a linear thermoplastic polyimide. When aromatic diamines are reacted with aromatic dianhydrides, aromatic tetracarboxylic acids, or dialkyl esters of aromatic tetracarboxylic acids, in a solvent such as DMF (Table 13.7), they were converted to a polyamic acid, which when heated, cured by cyclization (imide ring closure, or imidization). This ring closure is a condensation process, releasing either water, or an alkyl alcohol, or both [36]. 

In a different smdy, they synthesized another five series of poly(ether imide)s based on five different cardo moiety containing diamines, designated as BPI, BAPA, FBP, BIDA, and SBPDA, as presented in Scheme 3.21. Five different aromatic dianhydride, 4,4 -(4,4 -isopropylidenediphenoxy) w(phthalic anhydride) (BPADA), 4,4 -(hexafluoro-isopropyli-dene) diphthalic anhydride (6-FDA), 3,3 4,4"-benzo-phenone tetracarboxylic acid dianhydride (BTDA), 4,4 -oxydiphthalic anhydride (ODPA), and benzene-1,2,4,5-tetracarboxylic dianhydride (PMDA), were used to prepare each series of poly(ether imide)s. The O2-N2 and CO2-CH4 separation properties for... 

Polycondensation is a typical method for polyimide syntheses, which need aromatic tetracarboxylic acids and aromatic diamines as monomers. Figure 10.1 shows that the polymerization process goes through two reactions The ring-opening polyaddition of aromatic diamines to aromatic tetracarboxylic dianhydrides in solution at room temperature gives soluble precursor polyamic acids, followed by solid-state thermal cyclodehydration to polyimides. 

Synthetic studies on the preparation of polyimides via the imidization route together with characterization studies have been made on systems derived from bis(4-amino-3-methoxyphenyl)methane and pyrazine tetracarboxylic acid, m- and p-carboranylenediamines and tetracarboxylic acids, and aromatic diamines and a new class of dianhydride monomers. Copolymers have also been prepared from the reaction of 3,3, 4,4 -benzophenone tetracarboxylic acid dianhydride with 3,3 -sulphonyl bis(phenylisocyanate) and 4,4 -sulphonyl bis(phenylisocyanate). ... 

By using monomers other than dianhydrides and diamines, a number of methods has been outlined to synthesize polyimides, for instance from tetracarboxylic acids and their half diesters. This method can be successfully applied to the preparation of aliphatic-aromatic polyimides by melt polycondensation of the salt from the diamine and an aromatic tetracarboxylic acid or half-diester (Scheme 8). The reaction achieved some importance when polyimides appeared in the 1950s as an alternative for uses such as... 

Polyamic acid methacrylate esters are the first self-patternable, pure organic polyimide precursors to be described. They are the polymer basis of the first technically applied resist to produce polyimide patterns in a direct process. They are synthesized simply by the addition of hydroxyethylmethacrylate to aromatic acid dianhydride, and subsequent polycondensation of the intermediate tetracarboxylic acid diester with aromatic diamines. These polyimide precursors give rise to a number of special photoresist properties which lead to important applications, such as photolithographically produced protection layer against a-radiation on memory... 

By extending this reaction to the use of aromatic diamines one can obtain tetracarboxylic acids which may be subsequently converted to the dianhydride by the following series of reactions ... 

The most general method for the preparation of high temperature polyimides is based on the reaction between an aromatic diamine and an aromatic dianhydride or tetracarboxylic acid. This proceeds via the formation of the intermediate polyamic acid which in further heating undergoes a ring closure condensation reaction leading to imide formation. The reaction is as follows... 

Polyimides (Figure 2.58) are typically prepared by reacting a tetracarboxylic acid anhydride such as pyromellitic dianhydride with aromatic diamines such as 4,4 -diaminodiphenylether. Heat... 

The use of tetracarboxylic acid anhydride instead of the dicarboxylic acids used in the manufacture of polyamides yields polyimides. The general method of preparation of the original polyimides by the polymerization of pyromellitic dianhydride and aromatic diamine is shown in Figure 1.18a. A number of diamines have been investigated, and it has been found that certain aromatic amines, which include m-phenylendediamine, benzidine, and di-(4-aminophenyl)ether, give polymers with a high degree of oxidative and thermal stability. 

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