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8/10/2019 Lecture - 17 B - Identification_of_Plastics
http://slidepdf.com/reader/full/lecture-17-b-identificationofplastics 1/22
IDENTIFICATION OF PLASTICSIDENTIFICATION OF PLASTICSBY
SIMPLE METHODS
BY
SIMPLE METHODS
8/10/2019 Lecture - 17 B - Identification_of_Plastics
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IDENTIFICATION TECHNIQUESSIMPLE INSTRUMENTAL
1. APPEARANCE 1. THERMAL ANALYZER
2. METHOD OF 2. GPC
FABRICATION
3. PENETRATION TO 3. X RAY DIFRACTIOMETER
HOT ROD AND
CUTTING WITH A 4. I. R. SPECTROSCOPY
KNIFE
5. NMR SPECTROSCOPY
4. FLOTATION TEST
5. SCRATCH RESISTANCE
6. COLOUR
7. ODOUR
8. TEAR
.
10. BURNING
CHARACTERISTICS
11. PYROLYSIS
12. MELTING POINT
13. CONFIRMATION TEST
.
8/10/2019 Lecture - 17 B - Identification_of_Plastics
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HOW TO IDENTIFY A
Look at the sample. Is it transparent, translucent or opaque?
.
like?
Cut the sample with a sharp knife. Does it cut easily: Are the edge smooth or
jagged? Does it crumble or flake?
Subject the sample to a float test. Does it float or sink? (the test is invalid if
plastic foam. Wash with detergent solution initially to stop air bubbles adhering to
surface.)
Try to burn a small piece of sample. What is the size and colour of flame? Is
sample self-extinguishing? Is there any odour when flame has been extinguished?
SAFETY : Use only a small sample held with tongs or pliers. Hold sample over a
me a ray. cau ous y an no w en s gn e .
8/10/2019 Lecture - 17 B - Identification_of_Plastics
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BENDING TEST ( WITH MOULDED BAR)
1. Polyethylene Bends, tends to remain
2. Polypropylene Unbends most of the way
3. Polystyrene Cracks but retains bend
4. ABS Bend tends to remain
.
back quickly
6. Cellulose acetate Bend tends to remain
7. PMMA Cracks and splinters
8. N lon Difficult to bend s rin s back
9. Polycarbonate Tough to bend
8/10/2019 Lecture - 17 B - Identification_of_Plastics
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THERMOPLASTICS
VISUAL OBSERVATION TEST Low gloss easily be scratched by nail - LDPE OR LLDPE
High gloss can be scratched by nail - HDPE
-
DROPPING TEST
When a moulded component is dropped on hard surface
Metallic sound Dull sound
PS, HIPS Cellulosics
,PC, PP S PTFE,PMMA
PPO Polyacetal
Polysulphone PVC ,
Polyolefins
8/10/2019 Lecture - 17 B - Identification_of_Plastics
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TEST TO DIFFERENTIATE
THERMOPLASTICS AND THERMOSETSCUTTING TESTS
a) If a shaving can be pared off with knife, it may be a
ermop as c.
Note:PMMA and Polystyrene are brittle and difficult to pare
b) If the material is rigid and will not pare off instead
flakes of powders, it may probably a thermoset plastic.
Heat an electronic soldering iron to red hot and press against
the unknown sample.
a e p as c ma er a so ens, an e ro pene ra esthe sample is thermoplastic.
b) If the plastic material does not soften and the rod does
not penetrate, the sample is thermoset plastic.
8/10/2019 Lecture - 17 B - Identification_of_Plastics
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FLOTATION TESTWhen the material is dropped in water
loats Sinks
Polyolefins Other thanPolyolefins
o e: e po yo e ns an ce u ar oams are
exceptional for this test.
. .
Talk filled PP PVC , PU
Glass filled PP and PS foams
8/10/2019 Lecture - 17 B - Identification_of_Plastics
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PYROLYSIS TESTHEAT THE SAMPLE IN AN IGNITION TUBE AND TEST THE PYROLYTIC VAPOUR WITH A MOISTENED INDICATOR PAPER.
ACID : TURNS BLUE LITMUS TO RED
: .
ACID VAPOURS
MAY COME FROM CARBOHYDRATE POLYMERS & THEIR DERIVATIVES . [E.G.,
CELLULOSE ACETATE]
OFTEN INDICATES THE PRESENCE OF CHLORINE . [E.G., PVC OR RUBBER NEUTRAL
VAPORS]
EVOLVED FROM HYDRO CARBON POLYMERS, SILICONES AND SOME POLYESTERS
HYDROCHLORIDE.
ALKALINE VAPOURS
INDICATE THE PRESENCE OF N2 . E.G., POLYAMIDE, PUs, PROTEINS & AMINO
FORMALDEHYDE RESINS.
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BURNING CHARECTERISTICS OF
THERMOPLASTICS
S. No. Plastic Flame Kind of Melt Odour
Material Characteristics smoke behaviour
1. PE Blue base yellow tip No smoke Drips Waxysmell
2. PP Blue base and No smoke Dri s Lubricatin
yellow tip oil smell
3. PS Orange yellow Black soot No Merry gold
flame (Heavy smoke) dripping smell
4. HIPS -do -do -do- Burning rubber
smell
. - - - - - -
Note: ABS & HIPS can be differentiated by detection of Nitrogen by elemental analysis.
6. SAN -do- -do- -do- Merry gold
smell
Note: SAN & PS can be differentiated by detection of present of extra element Nitrogen.
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S. No. Plastic Flame Kind of Melt Odour
Material Characteristics smoke behaviour
7. PVC Green edged flame emitting white burnt pungent
self extinguishing fume after edges smell
put off the charing of chlorine
flame
Note: A copper wire is heated to redness and the material is taken by the wire and ignited.
Bright green flame confirms presence of chlorine - PVC
8. Polyamides:
Nylon-6 Blue base yellow No smoke Burned face Burned
tip, spurting self bubbles and hair
extinguishing drips smell
Nylon-6,6 -do- -do- -do -do-
Nylon-6,10 -do- -do- -do- -do-
Nylon-11&12 -do- -do- -do- -do-
Note: The individual type of polyamides can be differentiated by melting temperature and
solubility.
Nylon 11 & 12 will not dissolve in formic acid at room temperature. But Nylon 11 will
dissolve in formic acid at elevated temperature.
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S.No. Plastic Flame Kind of Melt Odour
Material Characteristics smoke behaviour9. Cellulose -do- -do- -do- Rancid
Butyrate or charred
milk smell
Cellulose Burns vi orousl Black Sublimation Cam er
Nitrate with bright yellow smoke like camper smell
10. Polyester (thermoplastics)
PBT & PET Orange yellow flame Sooty Drips Fruity
spurting, self flame smell of
extinguishing ester
.
11. PMMA Blue base yellow tip No smoke No driping Fruity
burns continuously but bubbling smell
on the burnt
surface
12. PC Orange yellow flame Black Burnt edge Phenolic
self extinguishing smoke chars smell
(Ink
13. POM Pale blue flame No smoke Driping Pungent burns continuously smell of
formaldehyde
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14. PPS Orange yellow Black No Dripping H2S gas
flame self smoke but charring smell
extinguishing
15. PPO -do- -do- -do- Phenolic
Smell
Note: It can be differentiated with polycarbonate by pyroloising PPO, which emits brown gas
acidic in nature.
16. TPU
MDI based Blue base yellow No smoke Drips like Faint
smell
TDI based Yellow flame self Black Drips very -do-
resin extin uishin smoke fast
17. PTFE Does not burn No smoke No dripping Pungent
smell of HF
ote: en eate strong y ecomes transparent.
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BURNING CHARECTERISTICS OF
S. No. Plastics Flame Kind of Odour
Material Characteristics smoke
1. PF Self extinguishing No Charcoal smell
2. UF -do- No Fishy smell
. - o- o - o-
Note: When the moulded component of all the three materials burn in the flame, the burnt surface
slightly swells and cracks.
4. Polyester Burns with orange Black Ester smell
(unsaturated) yellow flame burns smoke
continuously
. poxy - o- - o- arre our sme
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BURNING CHARACTERISTICS OF
ELASTOMERS
S.No TYPE OF POLYMER COLOUR OF FLAME ODOUR OTHER NOTABLE
& KIND OF SMOKE CHARACTERISTICS
1 POLY BUTYLENE YELLOW, BLUE BASE DISAGREEABLE , CHARS READILY
SMOKY SWEET2 STYRENE - BUTADIENE BURNS CONTINUOUSLY PUNGENT SMELL OF CHARS , DRY
YELLOW SOOTY STYRENE POWDERY
3 EPDM NO SMOKE ,BLUE BASE WAXY SMELL DRY
YELLOW TIP POWDERY
4 N BR YELLOW SOOTY UNPLEASANT TACKY
5 BUTILE RUBBER (IIR) SMOKE FREE , CANDLE HYDROCARBON MELT &
LIKE SMELL TACKY
6 POLYISOPRENE (NR) YELLOW SOOTY PUNGENT LIKE CHARS &
7 POLYCHLOROPRENE (CR) SELF EXTINGUISHING PUNGENT SMELL STRONGLY
YELLOW & SMOKY OF CHLORIN ACIDIC
8 SILICONE RUBBER BURNS CONTINUOUSLY NO ODOUR DRY WHITE
9 EBONITE SMOKE FREE SULPHUR ODOUR CHARS
READILY
8/10/2019 Lecture - 17 B - Identification_of_Plastics
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IDENTIFICATION BY PYROLYSIS TEST
• This scheme is useful for identification of CR , NBR , SBR , NR / IR , IIR
type of rubbers
• Test Procedure : Heat strongly 0.5gm of sample in a test tube until sample
begins to decompose and pass the fume in solution I and II and observe
change in colour initially and after heating.(Refer the following table)
SOLUTION - I : Dissolve one gram of p - dimethyl amino benzaldehyde in
5ml of HCl and add 10ml of ethylene glycol. Adjust the density to 0.851
gm /cc. By addition of methanol.
SOLUTION - II : Dissolve 2gm sodium citrate , 200mg of citric acid , 300mg
of bromocresol green and 300mg of metanil yellow in 500ml of water.
8/10/2019 Lecture - 17 B - Identification_of_Plastics
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COLOUR REACTION WITH SOLUTION - I & II
RUBBER SOLUTION - I SOLUTION II
INITIAL AFTER HEATING
BLANK SOLUTION PALE YELLOW PALE YELLOW GREEN
GREEN
NBR ORANGE RED RED GREEN
SBR YELLOW GREEN GREEN GREEN
NR / IR BROWN VIOLET BLUE GREEN
I I R YELLOW PALE BLUE GREEN GREEN
DROPLET FLOATS
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DETERMINATION OF SPECIFIC GRAVITY
PROCEDURE:
Weight of empty specific gravity bottle : a gm
+
Weight of the material + S. G. bottle + liquid: c gm
Weight of the S. G. Bottle + Liquid : d gm
Weight of the material (b-a) : e gm
Specific Gravity of the material : e x D
(e + d) - c
Where D - specific gravity of the liquid taken for testing
specific gravity of the material x 0.999 (gm/cc)
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DENSITY & MELTING POINT OF PLASTICSS. NO. POLYMER ABBREVATION DENSITY MELTING
gm/cc POINT Deg. C
.
1. Low density Polyethylene LDPE 0.91 - 0.92 110
2. High density Polyethylene HDPE 0.94 - 0.96 130
3. Linear low density polyethylene LLDPE 0.91 - 0.93 125
4. High Molecule HDPE HMHDPE 0.94 - 0.97 135
5. Ultra High Molecular HDPE UHMHDPE 0.97 130
6. Polypropylene PP 0.89 - 0.91 160
.
1. Poly vinyl chloride PVC 1.38 - 1.41 160 - 220
2. Poly vinyledene chloride PVDC 1.65 - 1.75 190 - 200
3. Chlorinated PVC PVCC 1.44 - 1.47 200 - 210
4. Co-polymer of vinyl chloride & PVC Co VA 1.16 - 1.36 130
5. Poly vinyl Alcohol PVAI 1.21 - 1.32 218
6. Poly vinyl Acetate PVAc 1.17 - 1.26 175
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III. FLUORINATED POLYMERS
1. Polyvinyl fluoride PVF 1.44 200
2. Poly vinyledene Fluoride PVDF 1.76 - 1.771 172
3. Poly chloro tri fluoro ethylene PCTFE 2.10 - 2.20 210
4. Poly Tetra Fluoro ethylene PTFE 2.10 - 2.30 320
IV. POLY STYRENE & CO-POLYMERS
1. Acrylonitrile-Butadiene styrene ABS 1.07 - 1.10 200 - 210
2. Styrene Acrylo nitrile SAN 1.06 200
3. Po ystyrene PS 1.04 - 1.07 190
V. POLYAMIDES
1. Nylon 6 PA 6 1.10 - 1.16 215
2. Nylon 66 PA66 1.09 - 1.14 265
. y on . - .
4. Nylon 12 PA12 1.01 - 1.02 180
5. N lon 6,10 PA6,10 1.07 - 1.09 210
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VI. ACRYLIC POLYMERS
1. Polymethamethacrylate PMMA 1.17 - 1.20 190
2. Polyacrylonitrile PAN 1.16 - 1.19 -
.
1. Polyoxym,ethylene(homo) POM 1.43 175
2. Polyoxymethylene (Co) POM 1.41 163
VIII. ESTERS
. .
2. Poly ethylene terepthalate PET 1.37 255
3. Poly butylene terepthalate PBT 1.32 225
IX. POLYURETHANES
. . - . -
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X. CELLULOSIC POLYMERS
1. Cellulose acetate CA 1.25 - 1.35 230
2. Cellulose acetate butyrate CAB 1.15 - 1.25 180
3. Cellulose noitrate CN 1.58 - 1.66 -
4. Cellulose propinate CP 1.20 - 1.24 -
XI. HEAT RESISTANCE POLYMERS
1. Poly phenylene oxide PPO 1.06 262
2. Poly phenylene sulphide PPS 1.35 290
3. Poly sulphone PSU 1.24 260
4. Poly imide PI 1.42 -
5. Poly ether ether ketone PEEK 1.27 335