Poly-p-phenylene-1,3,4-oxadiazole

Pyrolysis and Graphitization of Polyoxadiazole. Table 1 shows electrical conductiyity at room temperature for yarious condensation polymers heat-treated at 1000 and 2500 C. For a HTT near 1000 C, poly(p-phenylene-1,3,4-oxadiazole) (POD) has the highest conductivity of 340 S/cm, twice as high as that of polyimide (KAP)... 

Values of x/gj plotted according to data in Ref. 43) and molecular weights according to data in Ref.43) (a) 4 poly(amide benzimidazole) in sulfuric acid 44) ( ) 5 poly(p-phenylene-1,3,4-oxadiazole) in sulfuric acid43) (v). The curve corresponds to theory as in Ref. 1). A and B are theoretical values for kinetically rigid Gaussian coils with strong (A) and weak (B) hydro-dynamic interactions 4 3)... 

Experimental attempts to synthesize any of the polymers described above have not been successful except a preliminary preparation of poly-perylene (Murakami and Yoshimura, 1984). Alternative efforts are currently being made to obtain polyacenic material through pyrolysis of various organic polymers such as phenol-formaldehyde resin (Yamabe et al., 1983 Tanaka et al., 1984b), polyacrylonitrile (Teoh et al., 1982, 1983), and poly(p-phenylene-1,3,4-oxadiazole) (Murakami et al., 1983). The group of these pyrolytic polymers behaves rather like amorphous semiconductors and is considered to be composed of fragments of polyacene to graphite, that is, a sort of coke, coal, and so on. 

E. Leibnitz. ZurOptimierungderSynthesevonPoly(p-phenylen-l,3,4-oxa-diazol) in Oleum (Optimization of preparation of poly(p-phenylene-1,3,4-oxadiazole) in oleum). Angew. Makromol. Chem., 204 101-110, 1993. 

High aromatic PODA types, such as poly(p-phenylene-1,3,4-oxadiazole), can be graphitized to... 

High aromatic PODA t5 es, such as poly(p-phenylene-l,3,4-oxadiazole), can be graphitized to yield a high quality graphite." The graphitization takes place at 2,800-3,000°C. From a heat-treated PODA film at 3000°C, an electrical conductivity of 1.4—1.8 10" Scm has been obtained. Graphite fibers with excellent mechanical properties have been obtained. 

Fig. 10.2. Dependence of the viscosity of 19% solutions of PPTA with [t]] = 5.54 dl/g at 80°C on the concentration of incorporated polymen 1) poly-m>phenylene iso thalamide 2) poly-p-phenylenebenzimidazole terephthalamide 3) poly>p-phenylene>l 3 4-oxadiazole 4) polynaphthoylene-benzimidazole.

Chang EM, Huang SL, Lee CT, Lin HC, Chen CY, Huang YY, et al. Synthesis and characterization of soluble conjugated poly(p-phenylen-evinylene) derivatives constituted of alternating pyrazole and 1,3,4-oxadiazole moieties. Aust J Chem 2009 62(10) 1355-62. 

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