Nitro groups, combined polymers

Bartlett and co-workers concluded that addition to the nitro group also occurs. Price and Read found that several m-dinitrobenzene molecules were combined with the polymer for each fragment from the p-bromobenzoyl peroxide used as initiator in the retarded polymerization of styrene. They inferred that the radical corresponding to IV transfers its hydrogen atom to a molecule of styrene as follows ... 

To demonstrate the potential of this method, a model library of isoxazolidines on Rink amide resin was synthesized by the split-and-combine method [25] (Scheme 16.1). The polymer-bound library obtained consists of a total of 18 compounds. If one considers the different building blocks of the synthesis, a nitro group or the carboxamidomethyl residue is found in 50 % each of the compounds, a cyano, N,N-dimethylamino, or trifluoromethyl group in 33 % each and a succinimide, N-methylsuccinimide, or sulfone group in 33 % each. 

A combined catalyst such as imidazole-containing polymer and imidazole acylated by a long chain acyl group gives a similar result in the hydrolysis of 3-nitro-4-acyloxy benzoic acid (8) (72). 

For polyimides to be useful polymers, they must be processable, which means that they have to be meltable. Melt processability of polyimides can be improved by combining the basic imide structure with more flexible aromatic groups. This can be achieved by the use of diamines that can introduce flexible linkages like aromatic ethers and amides into the backbone. Polyamide-imides (5) are obtained by condensing trimellitio anhydrides and aromatic diamines, while polyetherimides (6) are produced by nitro displacement reaction involving bisphenol A, 4,4 -methylenedianiline, and 3-nitrophthalic anhydride. 

It is pertinent from these structiues that nitro arrd azide groups make plasticizers to have energetic properties. In addition to these plasticizers, also neutral plasticizers such as DOP and other plasticizers are used in these applications. The plasticizers or their combinations are selected to achieve the reqirired effect. Inert plasticizers usrrally lower the energy content of polymers used in explosives (e.g., nitrocellulose). 

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