Dispersion Analysis

Assessment of dispersion quality of carbon nanomaterials in any medium is a crucial prerequisite for processing optimization, unveiling the factors that will lead to peak performance from nanomaterial additives.

 

 

  • ASI uses this understanding to provide its clients with evaluations that help maximize the performance of our carbon nanofiber which allows for lower loading levels and reduced material costs.

 

  • In addition to lowering material costs, attaining optimum dispersion  can reduce development time of new formulations to reduce the time to market, while also optimizing available development funding.

 

 

 

 

Background

Dispersion of carbon nanotubes and nanofibers remains one of the daunting technical challenges for commercial use of these remarkable materials.    Capturing the multi-functionality of these materials is only possible if the tubes and fibers are uniformly dispersed and distributed throughout the host resin. Inadequate dispersion is generally seen as a major impediment to successful, widespread commercialization of most CNF/CNT applications.

ASI’s Dr. Carla Lake has pioneered the development of a dispersion analysis methodology to quantify the level of dispersion and is now offering this service to ASI’s clients.  The concept for the dispersion analysis is based on Muti-Scale Image Analysis (MSIA).

Multi-Scale Image Analysis

Dispersion Analysis

  • Optical micrographs => greyscale
  • Grey-scale histograms
Histogram Analysis

  • The shape of the grey-scale histogram is directly related to the quality of the dispersion.
  • Low Variance = Good Dispersion

 

High Density Polyethylene with 5 weight % Carbon Nanobiber Masterbatches

The images above represent the same polymer/CNF mixtures but were produced using different processing conditions.  It is clear from these images how important identification of appropriate processing conditions is for achieving the necessary dispersion for specific applications.  The use of the MSIA method can help to optimize the processing conditions to yield the best performing composite system.

 

Optimizing Processing Conditions is Key

 

Different processing methods and conditions generate distinct flow conditions that influence the composites morphology, leading to different dispersion levels. In extrusion, the processing conditions, screw profile and viscoelastic properties of the continuous phase determine the fillers aggregate size, its distribution/dispersion and the final aspect ratio of the filaments.  To be able to predict certain properties it is critical to optimize the processing history of the material and quantify the micro structure developed from the processing history.

High Density Polyethylene with 5 weight % Carbon Nanofiber Masterbatches Nanofiber Masterbatches. The optical micrographs are converted to grey-scale histograms, which are then plotted to determine the variance.  The variance of each condition can then be compared to determine the best processing conditions for a given application.

Conclusion

Quantitative description is key to understanding processing-morphology-properties relationships.  There is a clear relationship between processing history, the resulting quantitative description of the carbon nanofiber dispersion in the composites and the final composite properties.

 

 

Contact Carla Lake to discuss the performance targets for your masterbatch.

As a Polymer Engineer, Dr. Carla Lake has invested several years of study on the effects of processing on carbon nanofiber morphology and the resultant composite properties.  Dr..Lake brings significant expertisein polymer processing to Applied Sciences, Inc. and is focusing her time on the development of high quality CNF based composites as well as providing processing advice to customers.