Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) imaging is an effective means of determining morphological characteristics of materials. The presence of structural features, sizes, and distributions can often be correlated to end properties and performance of materials.

TEM Examples

• Blending incompatible polymeric materials, such as those found in a waste recycle stream, involves the use of interfacialy active additives. In a recent project, TEM was used to determine domain size and distribution of each of the phases in the blend. The location and effectiveness of the interfacial additive and processing conditions were also revealed. Correlating TEM images and results with physical property data allowed the blends, additives, and processing conditions to be optimized for useful end properties and economical processing.

• A research project that focussed on synthesizing a new latex polymer needed latex particle size and distribution information. Fixing and staining the latex permitted the particles to be imaged with TEM. The particle size and shape characteristics were then measured and the data were used to guide the synthesis process. The information from the TEM was useful for tailoring the product to the desired specifications.

SEM Examples

• An epoxy formulator requested SEM imaging for comparison of an elastomer modified epoxy system with that of a competitor. The SEM images revealed significantly different morphology between the two systems. The difference in relative proportions of the additives was also apparent and of interest. The formulator was able to use the information to correlate and understand performance differences between the two products.

• A manufacturer of injection molded parts experienced failures of the part when installed in the field. SEM imaging was used to examine the failure region and determine the weld line did not knit well, resulting in a weak point in the molded article. As a result of this work, the manufacturer adjusted the molding conditions to prevent future part failure.