Polybenzimidazole foam

Polybenzimidazole foams with phenolic or glass microspheres also have good thermal properties. Since they are not combustible they retain good mechanical properties up to 350 °C, starting to lose mass at 600 °C 109). 

MISCELLANEOUS AND SPECIALTY FOAMS (Epoxy Foams, Polyester Foams, Silicone Foams, Urea-Formaldehyde Foams, Polybenzimidazole, Foams, Polyimide Foams, Polyphosphazene Foams, and Syntactic Foams)... 

The newer open-cell foams, based on polyimides (qv), polybenzimidazoles, polypyrones, polyureas, polyphenylquinoxalines, and phenolic resins (qv), produce less smoke, are more fire resistant and can be used at higher temperatures. These materials are more expensive and used only for special applications including aircraft and marine vessels. Rigid poly (vinyl chloride) (PVC) foams are available in small quantities mainly for use in composite panels and piping applications (see Flame retardants Hrat-rrststantpot.ymf.rs). 

Microcellular foaming, bimodal cell size distributions, and high open-celled contents of molecular composites of HT-polymers were reported by Sun et al. [33], investigating blends of a rod-like polymer polybenzimidazole with an aminated PSU and poly(phenyl sulfone) by using carbon dioxide as a blowing agent. The complex foaming behavior was related to phase separation within the otherwise... 

Fourteen insulations were examined in this study. The insulations included three types of polyurethane, three varieties of polymethacrylimide, one polybenzimidazole, two polyisocyanurates, two polymetric isocyanate foams (one with chopped fiberglass reinforcement, one without), a modified isocyanate foam, and two insulation systems (one of polymeric isocyanate foam, one of toluenedi isocyanate foam, both with two vapor barriers and fiberglass reinforcement) ... 

The general process used to synthesise aromatic polybenzimidazoles (PBIs) is presented in Section 4.3.3. More detailed information can be found in previously published books [87,88]. During 1960-1970 a number of publications, comparable to those on polyimides, reported the synthesis and properties of all aromatic and aryl-aliphatic polybenzimidazoles. Most of these polymers were prepared by the two-step process illustrated in Fig. 14 with the reaction of 1,3-benzenedicar-boxylic acid diphenyl ester 27 and [l,l -biphenyl]-3,3, 4,4 -tetramine 11 yielding ultimately PBI 29. All the applications - laminates and filament winding resins, adhesives, fibres and foams - used polymer 29, which was produced in semicommercial quantities by the Whittaker Corporation (Narmco Division) under the generic trade mark Imidite . Currently, forty years later, this polymer is manufactured by Hoechst-Celanese and its only commercial success is in the area of heat resistant fibres and fabrics. It is, however, worth noting the adhesive properties of this polymer and the reasons explaining the major obstacles to the development of PBIs as heat-resistant adhesives. 

Aromatic polybenzimidazoles were synthesized by H. Vogel and C. S. Marvel in 1951 with anticipation, later justified, that the polymers would have exceptional thermal and oxidative stability. Subsequently, NASA and the Air Force Materials Laboratory (AFML) sponsored considerable work with polybenzimidazoles for aerospace and defense applications as a non-flammable and thermally stable textile fiber and as high temperature matrix resins, adhesives and foams. The route to fiber used solutions of high molecular weight polymer. Structural applications used low temperature melting pre-polymers that were cured (polymerized) in place. Applications of polybenzimidazoles were not implemented in the 60 s and 70 s since the polymers tetraamine precursors were not commercially available. 

Technical Bulletins, Acurex, Aerotherm Div., 485 Clyde Ave., Mt. View, CA Polybenzimidazole Prepolymers PBI 1850 Laminating Material PBI 850 Adhesive PBI SA Syntactic Foam Material PBI PC Syntactic Foam Material. 

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