The Chemistry of New Heat‐Resistant Films and Fibers

Abstract

the transition metal ion, and also on passing from the first to the second and third transition series. Similar behavior is also observed in the d* complexes referred to above, where the compounds of palladiuni(I1) and platinum(I1) are almost always square-planar. regular conliguration distorted configuration 4. Conclusion -. m crossover point distortion Fig. 9. The effect of distortion on the energy levels of trigonal bipyramidal complexes of d6 metal ions.This survey is principally concerned with papers published since 1959 on hydrocarbon polymers, aliphatic poIy(terephtha1amide) fibers, poly(hydroxybenzoic acid) films, poly-(oxadiazole) fibers, poly(benzimidazo1e) films, poly(phenyltriazo1e) films, poly(pyr0mellitimide) films, and fibers from cyclized poly(acrylonitri1e). All these materials have extremely high melting points and satisfactory in-use characteristics at high temperatures.

Molecular Rods. 1. Simple Axial Rods

“…p-Oligophenylenes ([n]7) are among the most thermally stable rods in the molecular kit, and the high molecular weight polymers were reported to be stable up to 800 or 900 °C. 213 Unsubstituted oligomers [n]7 with more than five units melt above 300 °C.…”

“…1,3-Disubstituted squaric acid derivatives 212a (squaraines) have been known for over 30 years. 394 They are usually prepared by a condensation of squaric acid (213) with two equivalents of electronrich aromatic compounds and azeotropic water removal (Scheme 101). Common substrates are N,Ndisubstituted anilines, [395][396][397][398] stilbenes, 399 azulenes, 400 pyrroles, 394,401 thiophenes, 402 2-methylbenzothiazolium salts, 403 2-methylindolinium salts, 404 and 2methylquinolinium salts.…”

“…Properties and Uses. p -Oligophenylenes ( [ n ]7 ) are among the most thermally stable rods in the molecular kit, and the high molecular weight polymers were reported to be stable up to 800 or 900 °C …”

Alkylbenzene‐Maleic anhydride photoadducts as dianhydrides for epoxies and polyimides

“…It is probable that the intermediate alkyl groups (R = CzHs to CeH, 3) give the compound just the right amount of nonpolar character to off set the polar anhydride groups. The methyl group then does not possess enough and the higher alkyl groups have too much nonpolar character.…”