Morphology study procedure

The polymers, whose characteristics are summarized in Table 1, were melt mixed in a Brabender-like apparatus at 200 C and at two residence times 6 min, at 2 r.p.m. and further 10 min. at 32 r.p.m. The blend compositions are listed in Table 2. After premixing, cylindrical specimens were obtained directly by extrusion using a melting-elastic miniextruder (CSI max mixing extruder mod. CS-194), Thermal and tensile mechanical tests were performed on these specimens by an Instron Machine (mod. 1122) at room temperature and at cross-head speed of 10 mm/min. Also made were morphological studies by optical microscopy of sections microtomed from tensile samples and scanning electron microscopy of fractured surfaces of samples broken at liquid nitrogen temperature. Further details on the experimental procedures and on the techniques used are reported elsewhere . 

The results of the morphological study were used to outline an improved fabrication schedule for Zircaloy-2 [132]. This schedule has been used successfully by commercial fabricators while more complete fabrication studies are being made. The material obtained from this procedure has a microstructure such as that shown in Fig. 5-21. It is essentially free of stringers, contains little or no intcrmetallic precipitate, and has small equiaxed grains with essentially a random orientation as seen under polarized light. 

A procedure for proplnts is presented by J.W. French (Ref 27), who used both OM and EM (electron microscope) to study plastisol NC curing. He found that the cure time of plastisol NC is a logarithmic function of temp, and direct functions of chemical compn and total available surface area, as well as of particle size distribution. It should be noted that extensive use of statistics is required as a time-saving means of interpreting particle size distribution data. The current state-of-the-art utilizes computer techniques to perform this function, and in addition, to obtain crystal morphology data (Ref 62)... 

Catalyst films for electrochemical promotion studies should be thin and porous enough so that the catalytic reaction under study is not subject to internal mass-transfer limitations within the desired operating temperature. Thickness below 10 pm and porosity larger than 30% are usually sufficient to ensure the absence of internal mass-transfer limitations. Several SEM images of such catalyst films have been presented in this book. SEM characterization is very important in assessing the morphological suitability of catalyst films for electrochemical promotion studies and in optimizing the calcination procedure. 

In most of the studies discussed above, except for the meta-linked diamines, when the aromatic content (dianhydride and diamine chain extender), of the copolymers were increased above a certain level, the materials became insoluble and infusible 153, i79, lsi) solution to this problem with minimum sacrifice in the thermal properties of the products has been the synthesis of siloxane-amide-imides183). In this approach pyromellitic acid chloride has been utilized instead of PMDA or BTDA and the copolymers were synthesized in two steps. The first step, which involved the formation of (siloxane-amide-amic acid) intermediate was conducted at low temperatures (0-25 °C) in THF/DMAC solution. After purification of this intermediate thin films were cast on stainless steel or glass plates and imidization was obtained in high temperature ovens between 100 and 300 °C following a similar procedure that was discussed for siloxane-imide copolymers. Copolymers obtained showed good solubility in various polar solvents. DSC studies indicated the formation of two-phase morphologies. Thermogravimetric analysis showed that the thermal stability of these siloxane-amide-imide systems were comparable to those of siloxane-imide copolymers 183>. 

Virtually all subsequent surface science-related studies on Fe oxide films have been performed using the Pt(l 1 1) surface as a metallic substrate. The established preparation procedure for well-ordered Fe oxide films on Pt(l 11) involves PVDof Fe in 1-2 M L quantities onto clean Pt(l 11), followed by annealing in oxygen at elevated temperature this process can be repeated until oxide layers of the desired thickness have been formed. The preparation of Fe oxides on Pt(l 1 1) and the morphology of the resulting films as a function of the preparation parameters as well as the properties of Fe oxides in relation to catalysis have been comprehensively reviewed by Weiss and Ranke [106]. 

Recent developments have allowed for more detailed studies of polymer surface morphology by ESCA. Angle-resolved ESCA (ARXPS) allows for providing chemical compositions from shallower depths. By varying the angle of incidence different depths can be probed, and procedures have been developed to arrive at three-dimensional reconstruction of the surface. An example is shown in Figure 2, where a PVC/PMMA polymer blend has been analysed using such an approach [9]. 

Volumetric and morphological brain measurements are made with MRI. Modern MRI can produce detailed, high-contrast images of the entire brain in relatively short scan times with no invasive procedures or radioactivity. Thus, it is the modality of choice for detailed neuroanatomic studies in various neuropsychiatric disorders. Many groups have addressed the challenge of how to quantify subtle structural characteristics in the brain that appear to differ consistently between comparison groups. Methods such... 

For example, studies of the morphology of a number of flame-generated aggregates (different carbonaceous soots, A1203 aerosols, etc.) [203] by both TEM and ALS procedures resulted in D2 = 1.7 0.15, while analysis of silhouettes of computer models of seven proteins [211] gave a value of D2 = 1.120 0.025, etc. 

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