The aim of electron microscopy is to produce good micrographs which enable the defect structure of the specimen to be accurately studied and convincingly illustrated in reports and publications. It cannot be over emphasised that good specimen preparation is the key to producing good electron micrographs. Consequently, it is essential to perfect a suitable specimen preparation technique before embarking upon a detailed microstructural investigation.

Electron Microscope Specimen Preparation Techniques in materials Science

The morphology and crystallization kinetics of oligoamidophosphates of molecular weight between 300 and 1800 prepared with various reaction times (1–12 hr) and different mole ratios of poly-caproamide and orthophosphoric acid (PA/AC = 0.5–1.6) has been studied. Very large, thin (several microns thick) or three-dimensional (diameter up to 8–10 cm) spherulites from aqueous solutions of oligoamidophosphates have been observed. Fully transparent lamellae with perfect angles, about 0. 2 cm thick, 1–12 cm wide, and 6–8 cm long can be formed too. The investigation of the kinetics of isothermal crystallization of oligoamidophosphates with various molecular weights in the temperature range of −5 to +90°C showed the well known bell-shaped curves. The dependence of the spherulite growth rate on the molecular weight generally observed was confirmed. It has been found that the morphologic and kinetic changes, established in the crystallization of the products prepared under various conditions (duration of tre...

Morphology and kinetics of crystallization of oligoamidophosphates

The effect of solvents and mixed solvents on the formation of crystalline entities in polycarbonate, polysulphone, polyphenylene oxide and a phenoxy resin has been investigated. It is shown that by the correct choice of solvent or mixed solvent many crystalline entities previously observed in other polymers can be formed. It appears that despite increased difficulty in assuming folded structures these polymers attempt to crystallize in a manner similar to simpler ones.

H. Boudevska

Papers

Structure building in tetracyanoethylene complexes of polymers