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Composite Density Calculator


There are many cases where a formulator needs to hit a certain density target. For example, a company asked me to make them a golf grip formulation using fillers to increase the density to a value they specified. Most people mistakenly believe that it is possible to calculate the density of a composite by taking the weighted mean of the densities of the polymer and filler. That is not the case. A graph of composite density versus weight % filler is a curve (see diagram below), not a straight line, so an equation is needed in order to calculate the correct density. For convenience, this page contains a composite density calculator to help you in your formulation design work.

As an example take 50 weight % filler with a density of 3 and 50 weight % of polymer with a density of 1 g/ml. You would expect the density of the composite to be (3+1)/2 which comes out to 2 g/ml. The actual density of that composite is 1.5 g/ml. What went wrong? The density and other properties of composites all depend on the volume %, not the weight %.


In the past, I used an Excel spreadsheet I had made using my feeble abilities in that program. It worked but was clumsy. Now I have been very lucky to have the support of AnnaLytix, experts in data analysis, to put together an online calculator. The online composite density calculation tool includes preset values for most plastics and filler so you don’t even have to look them up. I hope you find it useful and I thank AnnaLytix for making this dream of mine come true (see for information on their business intelligence and data analytics services).

High Density Plastics or Polymers

The Calculator

Here is the tool allowing you to instantly see the density of any polymer and filler combination. Just select your plastic and filler from the drop-down menus. Find out more about the different functional fillers on this page. If you have requests for materials to add then please contact us.

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