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Plastic packages material identification Lab 1

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IDENTIFICATION OF DIFFERENT
PLASTIC PACKAGING MATERIALS
Resin Identification Code
Plastics Codes
POLYETHYLENE TEREPHTHALATE (PETE)
Items made from this plastic are commonly
recycled.
Feel: Ranges from a tough, semirigid sheet
(such as a soda bottle) or soft fibres (such as a
pile jacket). PETE (sometimes just called PET is
a type of polyester)
Flotation: Sinks in water
Burn test: Burns with a smoky flame. Has a
rather sugary smell. PETE bottles have a lot of
stress built in and the pieces shrink quite
dramatically when heated.
Solubility in common solvents: Insoluble
Resin Identification Code
• HIGH DENSITY POLYETHYENE (HDPE)
• HDPE products are commonly recycled.
• Uses:
Used for many types of plastic
containers (e.g. milk bottles) and water pipes.
• Feel: A tough, slightly waxy feel.
• Is either translucent or coloured
• Flotation: Floats in water
• Burn test: Burns easily with a yellow flame
with blue tips. Smells like a candle melts and
drips burning drops. (TAKE CARE!)
• Solubility in common solvents: Insoluble
Resin Identification Code
• POLYVINYL CHLORIDE (PVC)
• PVC is not often recycled and it can be
harmful if ingested.
Feel: Depends on the grade and use
Flotation: Sinks in water
Burn test: Often hard to light.
• Burns with an intensely smoky flame and
usually goes out quickly after the flame is
removed.
• The smell is sharp and has some "bite".
Resin Identification Code
• POLYVINYL CHLORIDE (PVC)
• A quick test is made with piece of
copper wire.
• First heat the copper wire red hot in a
flame them while still hot rub it onto
the plastic.
• Put the wire back in the flame and if
you see green (or green/blue) colours
the plastic is probably PVC
Resin Identification Code
• POLYVINYL CHLORIDE (PVC)
Solubility
in
common
solvents:
Dissolves in solvents like (2-butanone) or
THF (tetrahydrofuran).
Resin Identification Code
• LOW DENSITY POLYETHYENE (LDPE)
• LDPE is not commonly recycled but it is
recyclable in certain areas.
• Uses: Used for plastic shopping bags, plastic food
containers.
• Feel: Soft waxy feel.
• When a thin sample is pulled it can be stretched
out.
• Flotation: Floats in water
• Burn test: Burns easily with a clean yellow
flame with large blue tips. Smells like a candle.
Melts and drips a lot while burning. The melted
pieces will often fall off the sample as a burning
liquid blob.
• Solubility in common solvents: Insoluble.
Resin Identification Code
• POLYPROPYLENE (PP)
• It is commonly recycled
• Uses: Used for similar uses as HDPE but is
tougher. Most common familiar uses are as the
tape in sticky tape or as packages for chips,
candy etc.
• Feel: Varies. It is easy to mistake for HDPE.
The grades used for film give the crisp crinkly
feel of a typical packet of junk food.
• Flotation: Floats in water
• Burn test: Burns like HDPE but more slowly,
drips less and has a rather fuel-like smell (it
doesn't really smell like a candle).
Resin Identification Code
POLYSTYRENE (PS)
• It is commonly recycled
• Uses: Pure PS is the clear brittle plastic in
clear disposable drinking glasses.
• The addition of a little butadiene rubber
makes it a bit cloudy but a lot tougher.
• It is used for many molded items.
• Familiar examples are yoghurt containers,
disposable spoons, forks etc. plastic
models, many other kinds of toys and the
tags on bread bags.
• PS is also made as a foaming grade.
Resin Identification Code
• Small balls of PS are produced with a
trace of a volatile solvent inside.
• When this is heated, the balls inflate and
stick together to make the familiar
expanded polystyrene (foam cups,
packaging materials etc.)
Resin Identification Code
Feel: Depends on the form
Flotation: Sinks in water. (foams
of course float well because they
are full of air)
Burn test:
Burns with a very
sooty flame. The burning PS has a
characteristic styrene smell.
Solubility in common solvents:
Dissolves in many common
solvents, especially chlorinated
solvents and acetone.
Resin Identification Code
• The six main kinds of plastics may be identified through
an analysis scheme that separates each one based on
chemical and physical properties of density, reaction in
a flame, reaction with acetone and reaction when
heated.
• Density test
• Cut several or a long narrow strip of each plastic.
Weigh it dry. Measure the volume of a graduated
cylinder half to ¾ filled with water. Place the plastic
sample(s) in the cylinder completely submerged in
water and measure the total volume. Subtract to get the
volume of the plastic.
• Divide the mass by the volume to get the density.
Resin Identification Code
Compare to the following chart for identification:
Resin Identification Code
Flame Test
1. Heat up a copper wire and melt a portion of the plastic on
the end of it.
2. Using the copper wire, place the plastic in a flame and
observe and record the color. Use the flow chart to help
identify the plastic.
Acetone Test
1. Place a piece of the plastic in a small test tube of acetone.
2. Observe and record if it dissolves or not and use the flow
chart to help identify the plastic.
Resin Identification Code
Heat Test
1. Using tongs hold a piece of the plastic high over a
flame or a hot plate and observe how readily it melts.
2. Do not put the plastic directly in the flame or heat the
sample too high. Do not allow melted plastic to drop onto
a hot plate or burner.
3. Compare samples to see which one is more readily
melted.
Resin Identification Code
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