Fiber glass, temperature dependence

A report130 of DSC measurements on polybenzimidazole fibers describes important differences for the glass transition temperature depending on die mechanical treatment of the fiber. An as-spun fiber exhibits a Tg at 387°C instead of 401°C for a drawn fiber free to shrink or 435°C for a drawn fiber widi fixed length. 

Ohsawa, T., Nakayama, A., Miwa, M. and Hasegawa, A. (1978). Temperature dependence of critical fiber length for glass fiber-reinforced thermosetting resins. J. Appl. Polym. Sci. 22, 3203-3212. 

Munro M. and Lai C.P.Z. (1988). The elevated-temperature dependence of fracture energy mechanisms by hybrid carbon-glass fiber reinforced composites. J. Mater. Sci. 23, 3129-3136. 

Morimoto and Suzuki (12) studied the flexural properties of continuous-glass-fiber-strand mat-reinforced rigid polyurethane foam, and found that both the flexural modulus and the flexural strength increased and the temperature dependence decreased when longer fibers were used as reinforcement. The density of the matrix foam also enhanced these tendencies. 

Silicate melts suitable for fiber production have to fulfill many requirements first a sufficient fiber drawing potential, which is dependent upon the ratio of surface tension to viscosity. Fixing of the molten filament in the form of a fiber is a consequence of the increase in vi.scosity with decreasing temperature. Got)d fiber formation requires a viscosity-temperature dependence which is relatively flat. The glass must also not exhibit a tendency to crystallization. 

Temperature dependence of friction and wear of some heat resistant polymers was studied. Except the one filled with glass fibers of kO wt. PPS, the specimen polymers were unfilled. 

Figure 3.2 Temperature-dependent conversion degree of glass transition and volume fraction of glassy state (derived from glass transition of an E-glass fiber polyester composite during a dynamic mechanical analysis (DMA) test at a heating rate of5°Cmin and a dynamic oscillation frequency of 1 Hz) [3]. (With permission from SAGE.)...

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