Problem solving applications

Characterization of fiber microstructure normally requires several microscopy techniques, as was shown in the simple example in the last section. An optical cross section of a fiber may have a dogbone shape (Fig. 5.2D), and yet this image does not reveal much about the internal fiber structure. On the other hand, a fracture surface of a fiber may reveal the presence of internal detail when viewed in the SEM (Fig. 5.11), and yet still not provide a complete picture of the structure. Clearly, complementary microscopy techniques and nonmicroscopy techniques must be applied to solving structural problems. Specific problem solving examples are described here which are representative of the wide range of studies conducted and documented in the many journals that publish polymer research. 

Direct observation of a fiber in the optical microscope or study of a fiber cross section provides information relating to the size and distribution of added particles. A longitudinal view of a PET fiber, in an OM micrograph (Fig. 5.1) reveals dense particles. The distribution of the particles can be seen, but their size and their relationship within the fiber are not clear at this magnification. Fiber cross sections (Fig. 5.2) show the particle distribution more clearly. Only a small, thin section about 5 /un thick is observed optically and a great number of such sections must be examined to define a statistical distribution. 

50 nm wide and are oriented parallel to the fiber axis. Such structures are usually observed by TEM techniques [52]. These structures have only recently been resolved and identified by high resolution SEI techniques [53]. 

Cross sections of particulate loaded fibers are required for accurate particle size determination and for studying the effect of the particles on the microstructure. Optical cross sections of PET fibers (Fig. 5.13A inset) have more particles 

Further structural study can be conducted by simple peeling methods for SEM and by staining 

Transmission electron microscopy techniques are Characterization of fiber microstructure normally very important for the elucidation of details of requires several microscopy techniques, as was 

Further structural study can be conducted by simple peeling methods for SEM and by staining methods for TEM. The peeling of a segment of a fiber to reveal the internal structure, as first 

Another approach to the characterization of fiber microstructure is the isoprene inclusion method (Section 4.4.2.5). This was applied to the study of PET fibers [57] and to aramid fibers [58] for the purpose of showing their radial microporous and fibrillar texture. Any holes or voids are filled by inclusion of isoprene in the fiber. They are then stained by the reaction of osmium tetroxide with the included isoprene. Longitudinal sections of high speed spim PET are shown in the TEM micrographs in Fig. 5.15A and B of fibers before and after the reaction, respectively. Similar views at lower magnification were shown (Fig. 4.12) in 

Characterization of the microstructure of high speed spun polyester fibers has been demonstrated using combined SEM of bulk peeled fibers and fiber surfaces, OM of thin sections and TEM of sections both stained and unstained. 

Direct observation of a fiber in the optical microscope or study of a fiber cross section provides information relating to the size and distribution of added particles. A longitudinal view of a PET fiber in an OM micrograph (see Fig. 

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Gas Theory, Problem Solving, Applications, Absolute Zero, and the Ideal Gas Law... 

For more specific examples of the 40 inventive principles, see Simplified TRIZ New Problem-Solving Applications for Engineers and Manufacturing Professionals, second edition, by K. Rantanen and E. Domb, Boca Raton, FL Auerbach, 2007, or go to www.triz-journal.com/archives/contradiction matrix. 

Computers can also be used for marking individual assignments. The students can verify the results on the computer before entering them on a mark-sense card for grading. Such a problem-solving application of the computer has been developed by N. D. Yaney of the Purdue University at Hammond, Indiana (USA) 7). 

The discussion of the interpretation of relative intensities in electron spectra has so far concentrated on specimens where the concentration is uniform over the analyzed depth and the analyzed area. For many materials encountered in the laboratory for problem-solving applications, these approximations do not hold. The derivation of information concerning variations in concentration with depth is dealt with in the following section here, laterally inhomogeneous surfaces are considered. 

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