Fiber length measurement

It is difficult to determine the cross-sectional area of a fiber. Direct observation and measurement of a cross section under a microscope is the most accurate method (15). This is a destmctive test that does not allow subsequent study of fiber mechanical properties, and is slow and tedious. Also, it does not take into account any variations in the cross-sectional area along the fiber length. Measurement of fiber diameters from microscopic observations of longitudinal views is somewhat easier, but the eUipticity of the cross section in certain fibers can lead to serious errors. 

POLYMERSCONTAININGSULFUR - POLYPHENYLENE SULFIDE)] (Vol 19) Fiber length measurement... 

Figure 11.9 The area of breakage of biopolymer molding containing 22% glycerol and 5% flax fibers (length measurement).

Because fiber frictional properties are so important in the conversion of staple yams to spun yams, ASTM D2612 has been designed to measure the cohesive force encountered in the drafting or fiber alignment of sHver and top under static conditions. This frictional force is affected by surface lubrication, linear density, surface configuration, fiber length, and fiber crimp. 

In addition to fiber length, strength, and fineness, two other properties that have significant bearing on fiber and yam properties are color and trash measurements, which have been accompHshed by instmmentation such as the Colorimeter and the Shirley Non-Tint Analyzer. 

Velapoldl et al. (64) used a similar approach but prepared fibers of uniform diameter (5-45 pm) from Inorganic Ion-doped glasses. The fluorescence parameters of these materials can be changed by substituting various Ions, such as Tb , Sm , Eu , Mn, UOj, Cu, and Sn. They show excellent stability under Irradiation using Incident excitation (measurement Imprecision of 1% under continuous Irradiation In the microscope for 24 h) and have a fluorescence flux density proportional to the fiber length. 

Glass fiber diameter can also affect the physical properties. In general, fiber diameters from 6-17. im have been used in PBT, with the narrower fibers giving slightly better properties. However, fiber length distribution and fiber content may play a more important role than diameter [32], Fiber content in a PBT composite is often measured by specific gravity and by ash content. Both of these measurements need to be corrected in cases where the blend is pigmented or combined with other materials. 

However, recent in-situ synchrotron radiation WAXD studies of PTT fiber deformation by Wu et al. [76] showed that the PTT crystal 002 -spacing could be stretched to a length corresponding to a fully trans chain. The increase in the c-axis dimension was accompanied by a decrease in the >-axis length, measured from the 010 reflection (Figure 11.14). When the strain was increased above a... 

Since fiber pull-out length, p , is difficult to measure with any accuracy from the fracture surface of composite specimens containing high V(, Rpo is often expressed in terms of the inherent properties of the composite constituents. There are three cases considered here depending on the fiber length relative to the critical transfer length. 

Fiber Length Distribution, for industrial applications, the fiber length and length distribution are of primary importance because they are closely related to the performance of the fibers in matrix reinforcement. Representative distributions of fiber lengths and diameters can be obtained through measurement and statistical analysis of microphotographs fiber length distributions have also been obtained recently from automated optical analyzers. 

Measurements of the fiber length using a Kajaani instrument indicate that y irradiation does not affect the length of the fibers. The average fiber length is... 

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