Synthesis and properties of fluorine-containing aromatic polybenzoxazoles from bis(o-aminophenols) and aromatic diacid chlorides by the silylation method

Structural Foams of Improved Strength and Thermal Stability From Random-Coil and Rigid-Rod Polymers

“…Particular attention was also paid to several high-temperature polymers of special [14][15][16][17][18][19][20] interest to the AFOSR, such as polybenzobisoxazoles (PBO) , polybenzobisthiazoles [19][20][21][22] (PBZT) , and sulfonated poly(p-phenylenebenzobismidazole)(SPBI) to make them more tractable and bondable to various matrix materials 23 …”

Synthesis and Characterization of Hyperbranched Polybenzoxazoles.

“…The solubility or processability of these polymers could be improved by the structure modification of monomers, for example, introduction of the flexible units such as bulky fluorinated substituents, phenyl pendant groups or ether linkages in the main chain. [7][8][9][10][11] Recently, hyperbranched macromolecules have received much attention due to some interesting properties derived from their unique highly branched structure. [12][13][14][15] As compared to their linear analogues, hyperbranched polymers have good solubility in organic solvents and lower viscosity.…”

Thermal Rearrangement of Poly(o-hydroxyimide)s Synthesized from 4,6-Diaminoresorcinol Dihydrochloride

“…[1][2][3][4] PBOs have been prepared by several methods, i.e., a one-step solution polycondensation of bis(oaminophenol)s with aromatic dicarboxylic acids in polyphosphoric acid, a melt polycondensation of bis(oaminophenol)s with diacid diphenyl esters. 8 Alternatively, they have been synthesized by two-step methods starting from bis(o-aminophenol)s or their trimethylsilylated derivatives [5][6][7]9 with aromatic dicarboxylic acid chlorides or tetracarboxylic anhydrides giving precursor poly(o-hydroxyamide)s (PAOHs) or poly(ohydroxyimide)s (PIOHs) followed by thermal rearrangement of the hydroxy-containing precursors to the final PBOs. Using the precursor polymers has advantage in processability of precursors even though almost PBOs do not dissolve in organic solvents, and do not melt at elevated temperatures.…”

“…There have been many reports for PBOs preparation via the PAOHs precursor method, 5,[16][17][18][19][20][21][22][23] whereas not so many papers describe about the thermal conversion of PIOHs to PBOs. After the first synthesis of poly(3,3 -dihydroxy 4,4 -diphenylene) pyromellitimide and thermal conversion to the corresponding PBO was reported by Kardash et al in 1967, 24 several studies have been reported.…”