forensics lab tests (plastics, fibers)

PETE

shrivels with heat, Yellow/orange flame

Plastic drips, Burns slowly, light black smoke

no char, bubbles.

Copper wire test: produces orange flame, chemically resistant

HDPE

Blue, yellow tipped flame,

Burns slowly, Plastic drips,

Smells like candle wax (paraffin)

higher melting point than LDPE

PVC

Yellow flame+green spurts,

does not drip, Self extinguishing, chars

Smells like HCL

In Beilstein Copper wire flame test, chlorine reacts w/copper in wire to form CuCl2 (which burns green)

LDPE

Blue, yellow tipped flame

Burns slowly, drips

Smells like candle wax (paraffin)

Floats in water.

PP

Blue, yellow tipped flame, Burns slowly, Plastic drips

sweet odor

dissolves in nonpolar solvents

PS

reacts with acetone, yellow flame

burns quickly, plastic drips

illuminating gas odor (naphtha)

dense black smoke w/ soot (floating particles)

flame rises then drops softly

PC

clear, orange flame, Self extinguishing, Plastic drips,

black smoke w/ soot (floating particles),

Faint, sweet aromatic odor, reacts w/acetone

PMMA

reacts w/acetone

highly flammable & burns with a bright, smoky, crackling flame

light blue, w/white top after moved away

sweet & fruity smell (b/c of ester group)

NO DRIP

Plastics that polymerize by condensation

PETE (esterification)

PC (step-growth)

Ziegler-Natta catalyst

PP

free radical vinyl

PMMA, make polymers from vinyl monomers

Wool

shrivels

smells like burning hair/feathers

very self-extinguishing, burns slow, little smoke & moderate fume,

hard, brittle brown-black residue

Dissolves in NaClO(Sodium hypochlorite) b/c animal fibers are acidic

Silk

Shrivels, curls away, sputters.

Smells like burning hair/charred meat

self-extinguishing, no smoke, no fume hazard

soft, crushable black residue that reflects light and is shimmery in appearance

Dissolves in NaClO(Sodium hypochlorite), NaOH, bleach, more concentrated HCl

Cotton

quick yellow flame

able to blow flame from thread like a match, continues to glow after

gray/white smoke

smells like burning paper/campfire,

charred whitish ash that smears black

no melted bead left behind

Dissolves in sulfuric acid

Linen

burns at constant rate (slower than cotton)

continues to glow, takes longer to ignite, yellow flame

very little white wispy smoke

smells like burning grass/straw/wood,

Burnt edges/tips slightly hard, hold shape but crushable

charred white-gray ash that smears gray in hands.

Polyester

melts, only ignites when in the flame

Looks like a sparkler,

burns quickly & shrinks away from flame, self-extinguishing

no ash, black smoke

sweet odor

Drips and bonds quickly to any surface it drips on

hard, black ash as well as black uncrushable bead. Leaves black smoke stains

dissolves in dichloromethane

Nylon

curls, melts, produces black residue

ignites only when brought into flame – more melts than burns

burn quickly and shrink, hard (yellow) gray uncrushable bead

smells like burning plastic/celery

self extinguishing

drip dangerous, no ash but hazardous fume.

dissolves in HCl, formic acid, phenol

Spandex

melts quickly, doesn’t shrink away, sharp, bitter chemical odor

soft black ash