Polyamide-imides monomers

Several classes of P- and N-containing polymers have been reported in literature. These include polybenzimidazoles, polyester-imides, polyamide-imide, polyanhydride-imides, polyurethanes, polyamides, and polymaleimide-amines. Heretofore, phosphorus-containing bisimide resins have received little attention. Bisimide monomers, which cure by addition-type polymerization without the elimination of volatile products, are suitable as matrix resins for fabrication of graphite-fabric reinforced composite materials. 

Fig. 10. (a) The structure of a solvent-soluble polyimide based on DAPI monomer, (b) The structure of a solvent-soluble polyamide-imide. 

Schleuter and Siggia [69-71] and Frankoski and Siggia [72] used the technique of alkali fusion reaction gas chromatography for the analysis of imide monomers and aromatic poiyimides, polyamides, and poly(amide-imides). Samples are hydrolysed with a molten potassium hydroxide reagent at elevated temperatures in a flowing inert atmosphere ... 

Figure 7.25 Chemical structures of monomers used to make polyamide-imides.

In order to improve the mechanical properties and the heat resistance of TPE-A, other links have been investigated. For instance, a poly(ether-6-amide) with an imide link was prepared by reacting polyamide-forming monomers and a diamino polyether together with trimellitic anhydride [61]. Naphthalene-1,2,5-tricarboxylic acid can also be used for this purpose. 

Coordination carbonylation polycondensation has been extended from the synthesis of polyamides [scheme (15)] and polyarylates [scheme (16)] to reactions using other nucleophilic monomers that, with dihaloarenes and carbon monoxide, yield poly(imide-amide)s, poly(acylhydrazide)s, and poly(benzoxa-zole)s [165,170,171],... 

In addition, isosorbide and other l,4 3,6-dianhydrohexitols (isomannide derived from D-mannose, isoidide derived from L-fructose) are also attractive to serve as monomers for polymer production due to their rigidity, chirality, and non-toxicity (Fig. 6). Such features may introduce special properties into the polymers formed, such as enhanced Jg and/or special optical properties. Their innocuous nature also opens the possibility of applications in packaging or medical devices. As a bifunctional monomer, isosorbide can be polymerized with other bifunctional monomers via condensation polymerization. A recent review described various isosorbide-based polymers synthesized, including polyesters, polyamides, poly(ester amide)s, poly(ester imide)s, polycarbonates, polyurethanes, and so on [308], and the present... 

The chemistry of imidization has been reviewed elsewhere [1-5]. It is briefly outlined below in Eq. (8.1). The key elements are reaction of a diamine and a dianhydride to form an amide-acid polymer via ring opening of the anhydride by nucleophilic attack of the diamine. The polyamide acid is then formed into a polyimide by removal of water. These polymerizations are usually conducted in high-boiling polar solvents to dissolve the monomers and keep the polyamide acid in solution. Heating is frequently used to drive off water and form the polyimide. In some cases, other means of dehydration may be used. 

The general methods to synthesize poly(amide imide)s are rather simple and include those monomers and reactions conducting to polyimides or polyamides, consequently, the number and variety of chemical structures reported are countless [174]. The most important ones will be mentioned here. 

Monomers derived from trimellitic anhydride, mainly V-carboxyphenyltrimel-litimides and V-(co-carboxyalkylene)trimellitimides have been also used many times as starting materials for the synthesis of poly (amide imide)s. These poly (amide imide)s have been traditionally prepared by low temperature solution polycondensation, from diamines and imide-diacid chlorides [182], but they have been also successfully synthesized by the phosphorylation method of direct polyamidation [184], from diamines and imide-diacids [185-188] as depicted in Scheme (36). Trimellitic acid imide (4-carboxyphthal-imide) has also been used for the preparation of poly(amide imide)s, by reaction with aliphatic and aromatic diamines in solution at moderate temperatures [189]. 

A number of polymers containing unsaturated imide side groups susceptible to cure by a thermal treatment (maleimide, nadimide, tetrahydrophthalimide), have been described [247,248]. The reactive side groups are generally introduced in this case by means of modified condensation monomers bearing reactive imide groups (Scheme 48). This approach has been applied for the preparation of cross-linkable aromatic polyamides and polyesters [248,249]. 

Polyimides Polyimides are actually a subset of polyamides, but forms when both carboxylic acid groups in diacid monomer react with an amine. As shown, a benzene ring with two acid groups on adjacent carbons (in the ortho position) condenses with an amine to form a single bond. The result is an imide linkage. 

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