PARTICLE SHAPE APPLICATION EXAMPLE: Cellulose fiber properties

The challenge

Here we study the properties of certain cellulose fibers from natural sources. They are sold as thickening agents in a variety of household consumer products such as cosmetics, shampoos, etc. Length, width (thickness) and curl strongly affect the viscosity of the final product.

Typical image

Notes

Fibers of this type are suspended in propanol to prevent rapid dissolution, and then mixed well. Because long fibers tend to align themselves with the direction of flow, lengths longer than the width of the flow cell can be handled.

The image above shows Fiber Length values. The fiber shape model straightens out long thin fibers and reports length, width, and aspect ratio of the straightened rectangle.

Results

Fiber Width is symmetrical about the mean (16 microns). Fiber Length shows a sharp rise and then a straight dropoff down to 500 microns. The dropoff is almost linear (on the log scale). Fiber length distributions typically do not conform to the usual particle size distribution shapes.

Curl is actually a measure of straightness, numerically — 1.0 is perfectly straight; lower values mean more curl to the shape. Aspect ratio, the ratio of length to width, shows a mean value of 7.7. The largest aspect ratio seen was about 50.