Make your own free website on Tripod.com

Testing Plastics

 

Procedure

 

1.       Examine several samples of each recycle-coded plastic listed in Data Table 1. Be careful not to get your samples mixed up.

 

2.       Record the rigidity and the appearance (can be translucent or not) of  each plastic type.

 

3.       Burn a small piece of each plastic type with a match over a piece of aluminum foil.  Record if the plastic burns when lit.   Record if the plastic drips when melted and the color of any smoke (black/white) given off.

 

4.       Perform the Bilstein Test as directed in the Flame Test instructions.  Record your results.

 

5.       Determine and record the relative density of each type of plastic as instructed in the Density instructions.

 

 

Flame Test

 

1.       Heat a copper wire red hot in the flame of a burner.

 

2.       Quickly touch the plastic sample, removing some of the plastic with the wire.

 

3.       Place the wire-coated plastic in the flame and look for a green flame as evidence of chlorine.  If the flame turns green when the plastic is burned, record a positive for the Bilstein Test.  If the flame does not turn green, record a negative for the Bilstein Test.


 

Density Instructions

 

A material that is more dense than a given liquid will sink in that liquid, while a material that is less dense than the given liquid will float in that liquid.  For example, corks and oil float in water because they are less dense than water; pennies and syrup will sink in water because they are more dense than water.  

 

It is possible to estimate the density of a material by observing its sinking or floating behavior in solutions of known densities.  In this activity, the approximate densities of plastic samples will be determined by making such observations.  For example, if it is observed that a plastic sinks in Solution B (density = 0.93 g/mL) but floats in Solution C (density = 1.00 g/mL) then the density of the plastic must be greater than Solution B, but less than Solution C.  Therefore, The density of the plastic sample must lie between 0.93 g/mL and 1.00 g/mL.

 

Procedure

 

1.       Arrange the test solutions in the order given below:

 

Density (g/mL)

 

1. Glycerol……………………………….1.2613

2. Ethylene glycol……………………….1.1090

3. Water………………………………….1.0000

Stock isoporpanol/water (mL/mL/)

4.       20/80………………………………….0.9624

5.       30/70………………………………….0.9436

6.       40/60………………………………….0.9248

7.       50/50………………………………….0.9061

8.       60/40………………………………….0.8873

9.       65/35………………………………….0.8779

10.   Stock isopropanol (91%)……………0.8121

 

2.       Cut a plastic sample small enough to fit into the bottles of the test solutions.

3.       Determine the density range of each type of plastic by finding to consecutive solutions, one in which the plastic sinks and one in which the plastic floats.  CAUTION: Each plastic sample should be rinsed and dried before being put into a new solution.

4.       Record the density range of each plastic type in Data Table 1.


Data Table 1.

 

Coded Plastic Type

 

Rigidity

Appearance

-

transluent

Density Range

 

Flammability

Drips

when melted

Smoke color

Bilstein Test

 

 

1

 

 

 

 

 

 

 

 

 

      2

 

 

 

 

 

 

 

 

 

 

 

3

 

 

 

 

 

 

 

 

 

 

4

 

 

 

 

 

 

 

 

 

 

5

 

 

 

 

 

 

 

 

 

6