Poly m-phenylene

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)... 

Figure 19. Left) l,3-Dichloro-5-(l-adamantyl)benzene monomer and (Right) adamantyl-substituted poly(m-phenylene), which is shown to have a high degree of polymerization and stability, decomposing at high temperatures of around 350 °C. Taken from Ref [89] with permission.

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 ... 

Very recently, Liang et al. [198] reported the first poly(m-phenylene vinylene) homopolymer 168. Due to all-meta-linking of the phenylene units, the PL maxima (417 nm with a shoulder at 434 nm) of 168 is further shifted in the blue region and the emission band is very narrow, which promises to deliver a pure blue-emitting PLED (although a device fabrication was not yet reported). 

Y. Pang, J. Li, B. Hu, and F.E. Karasz, A highly luminescent poly[(m-phenylene vinylene)-a/t-(p-phenylene vinylene)] with defined conjugation length and improved solubility, Macromolecules, 32 3946-3950, 1999. 

Preparation of poly(m-phenylene)iso/terephthalate (80/20). The polymers were prepared by solution condensation of the acid chlorides with resorcinol in methylene chloride solution using triethyl amine as the acid acceptor as described by Korshak (10). 

Preparation of poly(m-phenylene)phenyl phosphonate. These polymers were prepared by the method of Toy using resorcinol and phenylphosphoric dichloride (11). 

Preparation of Polymer Blends. A series of polymer blends was prepared by co-solutioning predetermined amounts of the poly(m-phenylene)isophthalate/terephthalate (80/20) with poly (m-phenylene)phenyl phosphonate, in methylene chloride. The polymer blends were recovered by evaporating the solution to dryness and ground to 40 mesh with a Wiley Mill. The composition of these blends and their analyses are summarized in Table I. 

Woo FIS, Czerw R, Webster S, Carroll DL, Ballato J, Strevens AE, O Brien D, Blau WJ (2000). Flole blocking in carbon nanotube-polymer composite organic light-emitting diodes based on poly (m-phenylene vinylene-co-2, 5-dioctoxy-p-phenylene vinylene). Appl. Phys. Lett. 77 1393-1395. 

These facts can be explained by a simple comparison of the stretched conformations of poly(p-phenylene terephthalamide) and poly(m-phenylene iso-phthalamide). Whereas the all-para linked polyamide can build up many hydrogen bonds to the neighboring molecules, this is less possible for the all-wcta linked polymer ... 

The first commercial aramid fiber was based on poly(m-phenylene isophtha-lamide) and has the trade name Nomex (Du Pont) [26-29] ... 

Filters can be grouped on the basis of different characteristics. For example, they can be grouped on the basis of the design capacity of the filters according to the particle concentration or loading [Svarovsky, 1981] or they can be grouped on the basis of the materials of the filters, e.g., fabric or nonfabric [Cooper and Freeman, 1982], Most filters in use are bag filters, which are fabric. The common fabric materials include cotton, polyester, wool, asbestos, glass, acrylic, polytetrafluoroethylene (Teflon), poly (m-phenylene isophthalate) (Nomex), polycaprolactam (Nylon), and polypropylene. 

Mw of 73 000 (Scheme 55) [229]. Colquhoun and coworkers also reported a ring-chain interconversion system in poly(m-phenylene isophthalamide) (Nomex) [230]. Cyclodepolymerization was best achieved by treating a solution of the polymer in DMSO containing CaCl2 or IiCl as a solubilizing... 

Fig. 9 Hiickel MO diagrams of diphenylcarbene [15 m = 1], tn-phenylenebis(phenylcarbene) [15 m = 2] and poly(m-phenylene-carbenes) [15].

In spite of the considerable difference in experimental and theoretical results obtained by different authors for the dimensions of macromolecules of aromatic polyamides, these results indicate a sharp asymmetry of the macromolecules. It should be pointed out, for the sake of comparison, that for flexible chain polymers the Kuhn segment amounts to only 20-50 A. For example, for an aromatic polyamide which does not exhibit coaxial rotation of the bonds, poly(m-phenylene isophtalamide), the Kuhn segment is equal to 50 A, i.e. it is 10-15 times as small as that for its para-analog. 

Points in Fig. 34 denote experimental values in the Inl/lnl vs. M plot for a number of polymers with aromatic chains. For the polymer with the lowest rigidity, poly(m-phenylene iso-phthalamide), the ratio [nj/(r l is virtually constant over the whole range of M investigated and equal to the limiting value ([n)/(r)l)< permitting the determination of = a j - ck2. The param-meters 0 and Aa for this polymer are calculated taking into account the known value of A computed from hydrodynamic data (Table 3). 

Applying this method to aromatic polymers listed in Table 9, assuming that (31 = 02 and using as a standard for comparison poly(m-phenylene isophthalamide) for which A = 47 A (from hydrodynamic data in Table 3) the values of A given in the last column of Table 9 can be obtained. These values are in reasonable agreement with the values of A in the same Table. 

If one of these structural conditions is not fulfilled, the molecule loses its unique properties. This is exemplified byTV-methyl substituted poly(p-phenylene terephthalamide) Its equilibrium rigidity (Table 10) is 20 times lower than that of the unsubstituted analog (Table 9) and approaches that of poly(m-phenylene isophthalamide). Probably, in this ase, the coplanar rrans-structure of the amide group is distorted by steric interactions of the pendant methyl group as in poly(alkyl iso-cyanate)s. 

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