Physical testing scanning electron microscopy

Physical testing appHcations and methods for fibrous materials are reviewed in the Hterature (101—103) and are generally appHcable to polyester fibers. Microscopic analyses by optical or scanning electron microscopy are useful for evaluating fiber parameters including size, shape, uniformity, and surface characteristics. Computerized image analysis is often used to quantify and evaluate these parameters for quaUty control. 

Durability testing takes a long time in an operation environment, which is difficult as normally several thousand hours are necessary to obtain a meaningful conclusion. In the development of durability testing, some in situ and ex situ methods and techniques for material evaluation have been used, such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), inductively coupled plasma mass spectrometry (ICP-MS), CV, EIS and so on. However, new electrochemical and/or physical techniques are desirable to gain a better understanding of durability failure modes and then improve fuel cell durability and reliability. 

Physical properties were determined by differential scanning calorimetry (dsc) with a Perkin-Elmer DSC-4 instrument and by dynamic mechanical thermal analysis (dmta) using a Polymer Laboratories dmta instrument. Stress-strain tests were performed on an Instron Table Model TM-M at a cross-head speed of 1mm min. The Young s modulus was obtained from the tangent of the initial slope of the force vs. elongation curve. Scanning electron microscopy (s.e.m.) employed an AMR 900 instrument. Specific experimental details are given elsewhere (9,10,11). 

The characterization techniques of MD membranes are physical methods, which can be divided in two main groups (i) the techniques related to membrane permeation such as liquid and gas flow tests and (ii) the techniques permitting to obtain directly the morphological properties of the membranes, including scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM), and atomic force microscopy (AFM). 

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