Density of Polyolefins by Solution Suspension

Scope:

To measure the relative density of polyolefins, either with or without fillers, by adjusting the density of an aqueous solution using either alcohol or salt. Then measuring the aqueous solution using a hydrometer.

Sample size:  Minimum size is one pellet for polyethylene thermoplastics, or a small part.

Experimental Procedure Summary:                               

A small sample of the plastic is placed into a graduated cylinder containing water. If the polyethylene is absent of inorganic fillers it usually floats because the density is less than water, 1 gram/ml.

A small amount of alcohol/water mixture is added to the graduated cylinder until the polyethylene pellet or specimen is suspended in the solution.

The solution density is measured using a hydrometer. A hydrometer is an instrument used to measure the specific gravity or relative density of liquids. A hydrometer is usually made of glass and consists of a cylindrical stem and a bulb weighted with metal to make it float upright. The aqueous solution to be tested is in the graduated cylinder, and the hydrometer is gently lowered into the aqueous solution until it floats freely. The point at which the surface of the liquid touches the stem of the hydrometer is noted. Hydrometers usually contain a scale inside the stem; so that the specific gravity can be read directly, see Photo 2.

Turnaround Time: 1-2 days from receiving the samples

Payment Terms: Paid in full before test results are released. Contact our office at 518-290-6804 or 518-792-3570 for credit card or PayPal payment. A check can be submitted with samples.

Summary Report: A one page summary report is emailed or a text message sent to your cell phone.