Polybenzoxazoles properties

Polybenzaylene benzimidazoles (pyrrones) Polybenzoxazoles Thermally stable to 600°C (1112°F) insoluble in common solvents good mechanical properties. Stable in air to 500°C (932°F) insoluble in common solvents except sulfuric acid nonflammable chemical resistant film. 

TABLE 1. Physical Properties of Selected Polybenzoxazole Films after Curing for 60 minutes at 350°C... 

Evers published numerous investigations on the outstanding thermal properties of these polybenzoxazoles. 

Y. Maruyama, Y. Oishi, M.A. Kakimoto, Y. Imai, Synthesis and properties of fiuorine-containing aromahc polybenzoxazoles from bis(o-ami-nophenols) and aromahc diacid chlorides by the silylahon method. Macromolecules 21 (8) (1988)2305-2309. 

Y. Oishi, A. Konno, J. Oravec, K. Mori, Synthesis and properties of fiuorine containing polybenzoxazole by in-situ silylation method, Photopolym. Sci. Technol. 19 (5) (2(X)6) 669-672. 

C.H. Park, E. Tocci, S. Kim, A. Kumar, Y.M. Lee, E. Drioli, A simulation study on OH-containing polyimide (HPI) and thermally rearranged polybenzoxazoles (TR-PBO) relationship between gas transport properties and free volume morphology, J. Phys. Chem. B 118 (10) (2014) 2746-2757. 

Both negative and positive tone aqueous developable materials have been introduced. Negative tone materials have been derived from tbe covalent-type polyamic ester precursors through the use of additives that enhance solubility of the unexposed film in aqueous developers (53). Positive tone materials are based on either polyamic ester precursors containing carboxylic acid (54) or phenolic oxygen substituents (55,56) or on aromatic poly(ortho-hydroxyamides) as precursors to polybenzoxazoles (57,58), a class of high temperature stable, heterocyclic polymers with thermal and mechanical film properties similar to polyimides (Fig. 18). In both approaches, the acid-base reaction of the phenolic or carboxylic... 

Sakaguchi Y, Kitamura K, Nakao J, Hamamoto S, Tachimori H, Takase S (2001) Preparation and properties of sulfonated or phosphonated polybenzimidazoles and polybenzoxazoles. 

Table 3 contains reaction conditions and polymer properties for polybenzoxazoles prepared by one-step thermal polymerizations and by cyclization of the intermediate polyamides. The latter dehydration process was readily followed by IR. The polyamides have strong bands near 1655 cm which gradually disappear during the cyclization. Concomitant appearance of the characteristic benzoxazole band at 1600-1620 cm confirms the process and the product structure. In addition, microanalysis data have been obtained for the polybenzoxazoles from monomers and Calculated and found values for C, H, and N were within 0.3% of each other for the former. The values for the latter were consistent with either equivalent of bound H2O per repeat unit and/or incomplete cyclization. 

Table 3. Polymerization conditions and polymer properties for polybenzoxazoles from or monomer methyl ester la-6a.

Hsu SL-C, Chang K-C (2002) Synthesis and properties of polybenzoxazole-clay nanocomposites. Polymer 43 4097 101... 

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