How Do I Test Density of a PVC Product That Has Been Mixed with Calcium?

What form was the calcium added as? Is it ground limestone, a fine calcium powder, a calcium doped pellet???

Usually in the form of calcium powder, Mess 400-800. Please help me......

Density is mass / volume. Do you know the volume of the object precisely? If so, you should be able to weigh the object and discover your density. The percentage of calcium can be calculated from the density difference.

Take a beaker and place the compound inside to any volume amount you want. (100ml, 250ml, whatever). Weigh the beaker with its contents inside. Obviously, you must weigh the beaker without the compound first. Divide the known volume by the weight of the compound and you have density. Weigh a compund known to not contain any filler in it and do the same thing. Observe the difference in density. Then use the following equation:

% of filler = (Density of compound with filler - Density of compound without filler)/Density of compound without filler * 100

It could work. Give it a try.

If it is already processed, use Archimedes principle of volume displacement. Place water inside a beaker to a known volume (100ml, 200ml, whatever), and drop the sample inside. Watch how the water will rise and take the measurement. Subtract the final volume of water from the original and the difference is the volume of your sample. Weigh the example and calculate the volume. Procede as I wrote on the other reply.

I tried to. The density of original PVC seems to be 1.38-1.41 gr/ml. When i checked for the density of the sample, it was 1.13g/ml. (Lower than the density of the original PVC). The sample seems to not only contain calcium but also some lubricant/oil in the process. If i use your calculation, the result will be minus and inaccurate. I think the lubricant/oil is the factor that make the density lighter.

If so, how do i get rid of the lubricant?

The way that people do it in the real world is to get a series of solvents with densities that span a range of densities that you expect to find in your sample. In your case, all over 1.0 to maybe 1.3 Sp G. Pour a 100 ml or so of each solvent, one at a time, into a graduate or a similar cylinder, and drop in a piece of the sample. If it sinks in that solvent, go to the next denser solvent, and so on until the sample just floats in the solvent. Now you have bracketed the density. You can refine your density by choosing new solvents close to the "good" solvent's density. Look in a "Solvent" handbook, Handbook of Chemistry & Physics, Lange's Handbook, or go on line to find the solvents you need by their density.

Dear Cardio07,

I tried to measure the density of the sample by using a weighscale and a 100 ml flask, the weight is 17 grams and the volume is 15ml.It turns out that the result is 1.13 gr/ml. If it's mixed with calcium, it should be more than 1.38gr/ml, right? I think there is some lubricant/oil inside. How do i get rid of this oil and measure the content of the calcium?

Thank you.

In the industry this is not a physical test. Many PVC products have foam core or sections and other additives and extenders including calcium. The density could be a poor indicator.

A solvent extraction would give a crude split between PVC with other additives, (plasticizers, process aids, stabilizers and the like) from the calcium compounds and other fillers.

IF you need to know the PVC content the test would be a solvent extraction and an examination of the extracted components. The undissolved portion could also be evaluated for content.

Dear Paddler,

I get your point, but there seems to be a long process involved. Actually I need to disaggregate the content inside the compound, but prefereably without any chemical test. This process is actually for my incoming new material . When i get the material from the waste supplier, I want to know the composition of the compund so i am not cheated regarding the price. Higher percentage of calcium means lower price, like wise. The composition later on will be used to equate a formula to generate a standardized product, PVC sheet. I was hoping to make a standardized product with a standardized formula.

Thank you

The density of calcium is higher than that of PVC, 1.55. Therefore, your supplier must be adding something else (air?) to your PVC.

You are right in that if you are not set up for solvent extraction it would be difficult.

A different test I have seen used is to take a sample of material and run an FTIR. ( Fourier Transform Infrared Spectroscopy)

This optical test may tell you what the % PVC is against other stuff. The challenge where to find a lab that has your material in the library and will test for free or at a reasonable cost.

If you do not have one, there may be labs that could help. I would suggest contacting PVC locations and asking for help. They may have a library that has exactly what you need.

Please advise:

Where are you?

Do you use one or several suppliers?

Are your suppliers PVC producers (making PVC from VCM) or "fabricators" that take PVC and make products?

Someone probably knows what they are selling you as part of their accountability balance. Your challenge is to ask the right questions to find who it is.

Dear Paddler,

My supplier is actually "garbage men". They collect PVC scraps and not new resin. That is why i'm haveing problems with the standardization of the raw material. Scraps are difficult to standardize. We don't really know what we are getting UNLESS we have some tests to run the content.

I;m located in Indonesia and it's a bit hard for that kind of lab and if exists, they will be definitely expensive.

I use many suppliers by the way