Micro-CT has been found to be an effective tool for studying and contributing to improvements of consumer hygiene products such as tampons. Tampons are typically made up of fibrous materials, including rayon and other natural and/or polymeric fibers, and are a key product in the world of women’s health and hygiene. The ability of a tampon to absorb and effectively manage menses fluids during a woman’s monthly menstrual cycle is vital to her overall sense of health and well-being. Thus, a better understanding of both the external and internal characteristics of tampons that lead to effective absorbency performance is extremely important. Our customers at the Kimberly-Clark Corporation utilized their SkyScan 1272 high resolution micro-CT as a key tool for increasing their understanding of the product’s structural characteristics, which has led to improvements and new innovations for better performance.
Micro-CT Imaging of Tampon Samples
Kimberly-Clark Corporation’s utilization of micro-CT allows research and development on the manufacturing and performance of many of their products, including tampons. As can be seen in Figure 1 above, the individual fibers of the tampon structure are relatively well defined from one another, in part due to the high spatial resolution provided by the SkyScan 1272 desktop micro-CT.
Figure 2: Planar views through three samples highlighting manufacturing differences
As can be seen in Figure 2, manufacturing designs can be altered using the same base components to produce samples with vastly different properties from one another. In this case, three different designs were compared to observe the final product orientation that impacts the absorbency characteristics of the samples. When moving from right to left through the images, the grooves become either wider or deeper between the samples. The grooves are added to the product to increase the total surface area available for absorption while maintaining the same nominal diameter.
Figure 3: Axial views through two tampon samples highlighting key groove measurements
In addition to a qualitative view of the grooves, Kimberly-Clark is also able to quantify differences between the samples by measuring key dimensions, as shown in Figure 3. For these tampon samples, the depth and the outer width of the grooves along with the total perimeters were characterized for the samples to allow for direct comparison among manufacturing methods.
Figure 4: Radial analysis of tampon data for average grayscale intensity
In addition to the key planar measurements obtained, Kimberly-Clark also was able to examine average grayscale intensity within four radial sections of the sample by utilizing CTAnalyzer along with commercially available image analysis software to provide an approximation of material density from the edge to the center of each sample, as shown in Figure 4. The insights based on material density from core to edge could then be related back to observed differences in measured absorbency.
Figure 5: Axial slice highlighting fissures within a tampon sample
While the qualitative and quantitative insights related to manufacturing effect on absorbency are key, the tampon samples were also examined for any defects which might arise during the manufacturing process, such as fissures within the internal structure (Figure 5). For this manufacturing method, deep grooves were produced with wide openings, but fissures were also introduced within the core of the product, which are undesired.
Figure 6: Volumetric maximum intensity projection rendering highlighting the string path within a tampon sample
After characterizing the structure of the product, further investigation into the path of the string woven into the tampon leads to insights on how the position of the string differs from the top to the bottom of the sample (Figure 6). To produce enhanced contrast of the string from the rest of the cellulosic material, the strings were exposed to a copper sulfate solution prior to product assembly, leading to additional X-ray attenuation within the string compared to the rest of the sample.
Conclusion
The high-resolution micro-CT imaging that is possible using the SkyScan 1272 allows the Kimberly-Clark Corporation’s Analytical and business research teams to make decisions during the product development pipeline relating the performance of their products to manufacturing changes in order to unlock additional benefits and help guide the journey to new products. From both a qualitative and quantitative perspective, the development of advances in tampon technology were assisted by micro-CT imaging and analysis.
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Scan Specifications
|
Sample |
Tampon |
|
Voltage (kV) |
35 |
|
Current (µA) |
231 |
|
Pixel Size (µm) |
8 |
|
Rotation Step |
0.2 |
This scan was completed by Dave Biggs on a high-resolution desktop SkyScan 1272 system present at the Kimberly-Clark Global Research and Engineering headquarters in Neenah, WI. Reconstructions were completed using NRecon and visualization of 2D and 3D results were completed using Dataviewer and CTVox with analysis utilizing CTAn.
This work is featured with the permission of the Kimberly-Clark Corporation. We thank them for their collaboration in sharing the great user example for how micro-CT imaging plays a key role in product development.
Would you like your work to be featured in our monthly newsletter? If so, please contact us by calling Seth Hogg at 610-366-7103 or e-mailing seth.hogg@microphotonics.com.