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.
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.
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 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|