Isophthalamides

Example 17. Poly(m-phenylene isophthalamide) in solution.14 To a well-dried 250-mL four-necked straight-wall flange flask with nitrogen inlet/outlet, dropping funnel, and magnetic stirrer (Fig. 3.18a). 2.163 g of 1,3-phenylenediamine, 5.62 g of triethylamine, 5.506 g of triethylamine hydrochloride, and 36 mL of dry chloroform are added. Isophthaloyl chloride (4.06 g) in 14 mL of chloroform is then added through the dropping funnel over a 15-min period at 30° C with slow... 

Poly(phenyleneethynylene)s, 482 optically active, 516-517 synthesis of, 496-500, 502 Poly(m-phenylene isophthalamide), 136 synthesis of, 185-186 Poly(l,4-phenylene terephthalate) liquid crystalline polymers, 51 Poly(para-phenylene)s, 472. See also Poly (p -pheny lene)... 

Synthesis and mechanical and morphological characterization of (AB)n, ABA and BAB type copolymers of m-phenylene-isophthalamide and polydimethylsiloxane have been reported241 242>. The effect of copolymer type, chemical composition and segment molecular weights on phase separation and the solution behavior of these systems have also been discussed. 

MacrocycHc isophthalamides (the tetralactam macrocycles) have been used as a host to build rotaxanes and catenanes by Vogtle and others [15]. Structurally analogous to cyclophanes, their initial usage as a synthetic receptor was for... 

Fig. 2. Rotaxane dendrimers from isophthalamide [2]rotaxane-core and Frechet-type den-dron stoppers...

The photodegradation of synthetic polymers can be prohibited (or at least reduced) upon addition of UV-stabilizers. These compounds transform the absorbed light energy into thermal energy thus preventing all sorts of photochemically initiated reactions. Films of poly-(m-phenylene-isophthalamide) were used which contained appropriate amounts of UV-stabilizers of the 2-(2 -hydroxy-5 -methylphenyl)benzotriazole type or their 21-methoxy derivatives. The following results were obtained ... 

Poly ( 2,4-dif luoro-1. 5-phenylene isophthalamide) and poly(1.3-phenylene isophthalamide... 

The chemical structures of these polymers were characterized using FT-IR. Poly(1,3-phenylene isophthalamide) (PMI) and poly (2,4-difluoro-l,5-phenylene isophthalamide) (2,4-DIF-PMI) shoved N-H stretching bands at 3400-3200 cm l and C==0 stretching bands(amide I) at 1630-1650 cm-. Poly(2,4-difluoro-1,3-phenylene trimellitic amide-imide) (2,4-DIF-PMTAI) showed additional bands at 1740 and 1796 cm l corresponding to imide C==0 stretching band at 1625 cif and C-0-C stretching bands at 1255 and 1050 cm l. 

MP35N multiphase alloy, composition of wear- resistant alloy, 7 221t MPD-1 fibers, 13 372, 373 MPDI fibers. See also Polyfira-phenylene isophthalamide) (MPDI) structure of, 19 727 uses for, 19 733-734 m-phenylenediamine (MPD), 19 714 MQ resins, 22 586-588 applications of, 22 588 manufacture of, 22 587-588 molecular structure of, 22 587 viscoelastic properties of, 22 588 MRI agents, dendrimer-based, 26 795-796 Mrigal, common and scientific names, 3 187t... 

The templated syntheses of amide-based rotaxanes discussed until now have made use of the threading-followed-by-capping method. However there are also examples in which the clipping approach has been employed. Leigh, for example, has used a five-component clipping method to prepare [2]rotaxanes. Isophthalamide and peptide-based threads were shown to template the formation of benzylic amide macrocycles about them in non-polar solvents [69, 70]. When the peptide-based threads (49) contain bulky stoppers at their ends, the [2]rotaxanes (50) can be prepared in high yields (see Scheme 24) [71]. 

NS-300 Membrane. The NS-300 membrane evolved from an effort at North Star to form an interfacial poly(piperazine Isophthala-mide) membrane. Credali and coworkers had demonstrated chlorine-resistant poly(piperazineamide) membranes in the asymmetric form (20). The NS-lOO, NS-200, and PA-300 membranes were all readily attacked by low levels of chlorine in reverse osmosis feedwaters. In the pursuit of a chlorine-resistant, nonbiodegra-dable thin-fiim-composite membrane, our efforts to develop interfaclally formed piperazine isophthalamide and terephthalamide membranes were partially successful in that membranes were made with salt rejections as high as 98 percent in seawater tests. 

This membrane demonstrated a vastly improved flux compared with the poly(piperazine isophthalamide) membrane, but its seawater salt rejection was low — in the range of 60 to 70 percent. A reverse osmosis test with a magnesium sulfate feedwater showed greater than 99 percent salt retention, however, dispelling the possibility that low sodium chloride rejections were due to defects in the polyamide barrier layer. The piperazine polyamide was soon concluded to have the following structure (see Reaction 111). 

The trimesoyl chloride could be mixed with isophthaloyl chloride to produce copolyamide barrier layers. Salt rejections toward synthetic seawater improved as the isophthalamide content of the barrier layer Increased. Surprisingly, membrane flux passed through a peak rather than simply declining as a function... 

As mentioned earlier, amides are less reactive than esters, and diamides are even less reactive. An example of this trend is the low reactivity of the dibenzoyl amides of 1,3- and 1,4-diaminobenzene, which are model compounds for the polymers Nomex [poly(l,3-phenylene isophthalamide)] and Kevlar B [poly (1,4-phenylene terephthalamide)] [243]. 

Poly( j-phenylene isophthalamide) (structure 4.59), sold under the trade name Nomex, exhibits good thermal stability decomposing above 370°C. It is used in flame-resistant clothing. It is also used in the form of thin pads to protect sintered silica-fiber mats from stress and vibrations during the flight of the space shuttle ... 

Figure 5.17 Noncovalent cross-linking strategies of cyanuric acid functionalized poly-CA to form (a) poly-CA-triazine by using a diaminotriazine cross-linking agent or (b) poly-CA-wedge by using an isophthalamide cross-linking agent.

In pursuit of a chlorine-resistant, non-biodegradable thin-film-composite membrane, Cadotte et al. 97 )03,104 fabricated interfacially the poly(piperazineamide) membrane (NS-300). The interfacially formed piperazine isophthalamide and terephthalamide membranes exhibited high salt rejection (98 %) in sea water tests but their flux was low (Table 8). The replacing of the isophthaloyl chloride with its triacyl chloride analog, trimesoyl chloride improved vastly the flux of the membrane but its seawater salt rejection was low — in the range of 60 70 % (55). The trimesoyl... 

The solid state structure of the pyridinium-chloride pseudorotaxane Figure 8) reveals the interpenetrative nature of the components and provides evidence for anion complexation by the macrocycle s isophthalamide motif, n-n donor-acceptor interactions between the electron rich hydroquinone units of the macrocycle and... 

In the latter half of the 1990 s, Crabtree and co-workers1,2 demonstrated that isophthalamides are excellent receptors for fluoride and chloride in organic solution. (Figure 2). 

Figure 2. The isophthalamide motif has been employed in a variety of receptors possessing high affinities for anions.

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