Latexes specimen preparation methods

Preparation and Test Methods In the preparation of cement mortar or concrete, content of ash was varied with or without polymer latex. In order to compare the properties of the cement mortar or concrete at a same flow property, flow values were maintained 120 5 mm. Mix formulations studied are given in Table 5, Table 6, and Table 7. Test methods of the specimens prepared are given in Table 8. 

Walter and Bryant [414] described a method for freeze drying latex specimens in a home made vacuum system rather than a commercially available device (as was typical of the state of the art at that time). Later, a freeze drying/image analysis method using commercially available equipment was described [413]. Important details of that method included specimen preparation, placement onto a TEM (or SEM) grid, the hardware for the experiment and the metal coating. 

The major structural unit of interest in emulsions, microemulsions, colloids and latexes is the particle. It is well known that the particle shape, size and distribution of a latex controls the properties and end use applications. Many latexes are manufactured with a controlled and sometimes monodisperse distribution of particle sizes. Polymer liquids, in the form of emulsions and adhesives, are wet and sticky, and therefore specimen preparation for electron microscopy is very difficxilt. As a result of the importance of the determination of particle size distribution, microscopy techniques have focused on specimen preparations which do not alter this distribution or which alter it as little as possible. Methods have included special cryotechniques (Section 4.9), staining-fixation methods (Section 4.4), microtomy (Section 4.3) and some simple methods (Section 4.1) such as dropping a solution onto a specimen holder. This section is meant to provide a brief survey of the types of microscopy applications which have been foimd useful in the evaluation of emulsions and latexes. 

Kuhlmann developed a test method that accurately measures the bond strength of latex-modifled mortar or concrete to conventional concrete under direct tension, using the specimens prepared by casting the latex-modified mortar or concrete on the concrete substrates in 76-mm (diameter) steel pipe nipples as molds. The bond test by this method demonstrated a coefficient of variation of less than 10%. 

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