Imidization polymerization

Monomeric thionyl imide polymerizes very rapidly. Even at above — 60° a yellow solid separates from the liquid which, with further warming becomes glass-clear yellow-brown, red, and finally brown. The brown polymer, which does not dissolve in organic solvents, is found from the infrared spectrum to contain NH groups 18), so that Formula (XLIX) proposed by Schenk appears to be established. 

As mentioned previously, the key to making BPADA was the development of nitro displacement chemistry, which forms ether hnkages as shown in Eq. (8.4). This chemistry allows bisphenol salts, commonly used to make polycarbonates and epoxies, to become monomers for polyimide synthesis. The bis AT-methyl imide intermediate is converted to the dianhydride that is used in imide polymerizations. Nitro displacement has been shown to work with many bisphenol salts to make a family of dianhydrides. The BPA dianhydride is commercially the most important. 

Treatment of the dianhydrides with various diamines finally gives polyetherimides in very high yields. Again, we could list a very large number of polyetherimides prepared via imidization polymerization. Suffice it to say the most important one at the moment is that derived from bis-phenol-A, 4-nitro phthalimide, and meta-phenylenediamine. It s glass transition temperature is 218°C. 

The presence of small amounts of moisture is inconsequential in imidization polymerization since it is simply removed along with that formed as a by-product. 

As you should expect, there are commercial refinements and improvements for a number of the steps in the imidization polymerization route. These are the kinds of changes which make large scale synthesis feasibile and commercially viable. 

N-Acoxydicarboxylic acid imides, polymeric -, peptide synthesis via -18, 435 suppl. 27 l-Acoxy-l,3-dienes -, diene synthesis with -prepared in situ 27, 805... 

N-acoxydicarboxylic acid imides, polymeric carbodiimides, --, dual-function -, synthesis of peptides, cyclic, on - 20, 629 suppl. 26... 

The majority of polyetherimides are tractable and their polymerization can be performed in solution or in the melt. High molecular weight polyetherimides have been synthesized via one-step imide—amine exchange reaction between bis(etherimide)s and diamine (67) according to the following ... 

Polymerization by G—G Goupling. An aromatic carbon—carbon coupling reaction has been employed for the synthesis of rigid rod-like polyimides from imide-containing dibromo compounds and aromatic diboronic acids ia the presence of palladium catalyst, Pd[P(CgH )2]4 (79,80). 

Thionyl imide, HNSO, is a thermally unstable gas, which polymerizes readily. It can be prepared by the reaction of thionyl chloride with ammonia in the gas phase. Organic derivatives RNSO have higher thermal stability, especially when R = Ar. The typical synthesis involves the reaction of a primary amine or, preferably, a silylated amine with thionyl chloride. A recent example is the preparation of FcNSO (Fc = ferrocenyl) shown in Eq. 9.8. In common with other thionylimines, FcNSO readily undergoes SO2 elimination in the presence of a base, e.g., KO Bu, to give the corresponding sulfur diimide FcNSNFc. 

The first use of ionic liquids in free radical addition polymerization was as an extension to the doping of polymers with simple electrolytes for the preparation of ion-conducting polymers. Several groups have prepared polymers suitable for doping with ambient-temperature ionic liquids, with the aim of producing polymer electrolytes of high ionic conductance. Many of the prepared polymers are related to the ionic liquids employed for example, poly(l-butyl-4-vinylpyridinium bromide) and poly(l-ethyl-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide [38 1]. 

Peptide synthesis requires the use of selective protecting groups. An N-protected amino acid with a free carboxyl group is coupled to an O-protected amino acid with a free amino group in the presence of dicydohexvlcarbodi-imide (DCC). Amide formation occurs, the protecting groups are removed, and the sequence is repeated. Amines are usually protected as their teit-butoxy-carbonyl (Boc) derivatives, and acids are protected as esters. This synthetic sequence is often carried out by the Merrifield solid-phase method, in which the peptide is esterified to an insoluble polymeric support. 

Polyamide-6 (PA-6), synthesis of, 174-176. See also PA-6 entries Polyamide endgroups, 161 Poly amide-imide, synthesis of, 291 Polyamides (PAs), 135-193. See also Nylons PA entries acid chloride polymerization of, 155-157... 

Amine-terminated siloxane oligomers have also been utilized in the synthesis of various siloxane-amide and siloxane-imide copolymers, High molecular weight siloxane-amide copolymers have been synthesized by the solution or interfacial co-polymerization of siloxane oligomers with sebacoyl chloride or terephthaloyl chloride respectively 1S5,165). In some reactions diamine chain extenders have also been utilized. Thermal and dynamic mechanical characterization of these copolymers have shown the formation of multiphase systems160). Compression molded films displayed very good elastomeric properties. 

Since that time much work has been done in the area of siloxane-imide systems, especially in industrial laboratories. Therefore most of the available information is enclosed in the patent literature 168 175) and, unfortunately, description of the actual polymerization chemistry is very vague. A great majority of these applications utilized disiloxanes in high concentrations in order to obtain soluble polymers with improved toughness. 

AIN, GaN, and InN are attractive materials for applications such as blue lasers and field emitters single-source precursors for these of formula [R2MNR 2]2 (R = alkyl, R = alkyl or H) have been reported.236 The reaction of alkylamines with group 13 trialkyl metal compounds affords oligomeric or polymeric ring and cage structures of metal amides and imides (see section on nitrides). 

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