Fiber loading

In general, Mooney viscosity increases with increasing fiber loading as shown in Figure 12.15 [64]. 

Fig. 4. Composite thermal conductivity as a function of density and fiber loading.

Figure 5 contains experimental profiles of the reaction temperature at the bottom of the sample as a function of time for nearly adiabatic photopolymerizations of Derakane resins containing between 0 and 60 wt.% of the glass fibers. The figure illustrates that for all fiber loadings, upon illumination the temperature exhibits an initial increase from room temperature to a final plateau value around 130°C. Moreover, the figure illustrates that as the fiber loading is increased, both the rate of the initial temperature increase, and the final plateau value, are reduced. These trends are easily explained by the reduction in the reactive fraction of the sample... 

Figure 5. Reaction temperature as a function of time for nearly adiabatic photopolymerizations of vinyl esters with various fiber loadings.

Figure 6. Flexural modulus as a function of cure time for fiber loadings between 0 and 60 wt.% with an incident light intensity of 480 mW/cm2.

Figure 10. Flexural modulus as a function of illumination time for photocured composites with fiber loadings of 0, 25, and 50 wt.%.

Studies were performed to demonstrate the effects of process variables such as light intensity, cure time, initiator concentration, and fiber loading on the evolution of the mechanical properties of the polymers and composites. Even with moderate incident light intensities (less than 500 mW/cm2) and high fiber loadings (60 wt.% random fibers) the photopolymerizations proceed to completion in minutes and exhibit mechanical properties equivalent to samples prepared by traditional... 

The effects of toxins are, generally, proportional to dosage. Well-controlled dosage, as in these cell systems, provides the best opportunity for relating carcinogenicity to levels of exposure. In live animal experiments, the amount administered is usually defined as the exposure. However, not all fibrous particles will ultimately reach a specific target tissue. Measurement of the fiber load at the tissue site and the pathologic response are tedious but necessary procedures to evaluate this aspect of the problem. 

The force needed to close the mold can be substantial. This is a particularly important problem for large area molds with a high-fiber loading because the pressure to compact the fibers can be high. In addition, the clamping system must resist the full injection pressure without leakage at the mold seals. 

The performance of composites is influenced by many factors, including the amount of reinforcement present relative to the matrix, referred to as fiber loading and the degree of contact between the fibers and the matrix. Both strength and stiffness tend to be improved by an increase in fiber loading and by increased contact between the phases. 

Figure 13. Fiber loading vs. longitudinal tensile strength for various fibers...

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