How to Identify Plastics

Some plastics may be very similar in appearance, but very different in their properties and capabilities. This downloadable guide provides insight into how to identify plastics based on common properties, such as odour, colour of flame, response to flame, drips, and other characteristics.
MaterialsNo FlameBurns but Extinguishes on
Removal of Flame Source
Continues to Burn After Removal of Flame SourceRemarks 
OdourOdourColour of FlameDripsOdourColour of FlameDripsSpeed of Burning
Thermoplastics
ABSAcridYellow, blue edgesNoAcridYellow, blue edgesYesSlowBlack smoke with soot in air
Acetals----FormaldehydeBlue, no smokeYesSlow
Acrylics----FruityBlue, yellow tipNo (cast) Yes (moulded)SlowFlame may spurt if rubber modified
Cellulosics
Acetate-VinegarYellow with sparksNoVinegarYellowYesSlowFlame may spark
Acetate, Butyrate----Rancid butterBlue, yellow tipYesSlowFlame may spark
Ethyl Cellulose----Burnt sugarYellow, blue edgesYesRapid-
Nitrate----CamphorWhiteNoRapid-
Propionate----Burnt sugarBlue, yellow tipYesRapid-
Chlorinated Polyether--Green, yellow tipNo----Black smoke with soot in air
Fluorocarbons
FEPFaint Odour of burnt hair-------Deforms, no combustion, but drips
PTFEFaint Odour of burnt hair-------Deforms; does not drip
CTFEFaint Odour of acetic acid-------Deforms; no combustion, but drips
PVFAcidic-------Deforms
Nylons
Type 6-Burnt woolBlue, yellow tipYes-----
Type 6/6-Burnt wool or hairBlue, yellow tipYes----More rigid than type 6 nylon
Phenoxies-AcriddYellowcNocAcriddYellowdYesdSlowdBlack smoke/Soot in air
Polycarbonates-Faint, sweet aromatic esterOrangeYes----Black smoke with soot in air
Polyethylene’s----ParaffinBlue, yellow tipYesSlowFloats in water
Polyphenylene
Oxides (PPO)-PhenolYellow-orangeNo----Flame spurts; very difficult to ignite
Modified Grade-PhenolYellow-orangeNo----Flame spurts; difficult to ignite; soot in air
Polyimidesb-------Chars: mat’l very rigid
Polypropylenes-AcridaYellowaNoaSweetBlue, yellow tipYesSlowFloats in water, more difficult to scratch than polyethylene
Polystyrenes----Illuminating gasYellowYesRapidDense black smoke with soot in air
Polysulfones-bOrangeYes----Black smoke
Polyurethanes----bYellowNoSlowBlack smoke
Vinyls
Flexible-Hydro-chloric acidYellow with green spurtsNo----Chars; melts
Rigid-Hydro-chloric acidYellow with green spurtsNo---Chars; melts
Polyblends
ABS/ Polycarbonate----bYellow, blue edgesNo-Black smoke with soot in air
ABS/PVC-AcridYellow, blue edgesNo----Black smoke with soot in air
PVC/Acrylic-FruityBlue, yellow tipNo----
Thermosets
Alkyds---------
Diallyl Phthalates----PhenolicYellowNoSlowBlack smoke, cracks
Diglycol Carbonate----AcridYellowNoSlowBlack smoke with soot
Epoxies----PhenolBlack smokeNoSlowBlack smoke with soot in air
MalaminesFormaldehyde & fish--------
PhenolicsFormaldehyde & PhenolcPhenol & wood or paperdYellowdNo----May crack
Polyesters-Hydrochloric acidaYellowaNoabYellow, blue edgesNoSlowCracks & breaks
Siliconesb-------Deforms
UreasFormaldehyde--------
a Flame retardant gradeb Nondescriptc Inorganic fillerd Organic filler
Ref: Materials Engineering, Penton/IPC, Cleveland, Ohio