The combustion and residue properties of various rubber materials are summarized below for quick identification:
1. NR (Natural Rubber)
Appearance: Pale yellow and translucent
Flammability: Highly flammable
Flame features: Dark yellow flame with black smoke; the rubber softens while burning
Residue & odor: Distinct rubber odor; non-sticky residue
2. IR (Isoprene Rubber)
Appearance: Pale yellow and translucent
Flammability: Highly flammable
Flame features: Dark yellow flame with black smoke; the rubber softens while burning
Residue & odor: Distinct rubber odor; non-sticky residue
3. BR (Butadiene Rubber)
Appearance: Pale yellow and translucent
Flammability: Highly flammable
Flame features: Dark yellow flame with black smoke; the rubber softens while burning
Residue & odor: Non-sticky residue with no special distinctive odor
4. SBR (Styrene Butadiene Rubber)
Appearance: Pale yellow or light reddish-brown translucent
Flammability: Highly flammable
Flame features: Dark yellow flame with black smoke; the rubber softens while burning
Residue & odor: Strong styrene odor; residue slightly expanded and non-sticky
5. NBR (Nitrile Butadiene Rubber)
Appearance: Pale yellow to light brown translucent
Flammability: Highly flammable
Flame features: Dark yellow flame with black smoke; the rubber softens while burning
Residue & odor: Odor similar to burning protein; non-sticky residue
6. IIR (Butyl Rubber)
Appearance: Colorless, transparent to translucent
Flammability: Highly flammable
Flame features: Smoke-free, dispersed wispy flame
Residue & odor: Melts when burned, releases a sweet pungent odor
7. EPDM (Ethylene Propylene Diene Monomer Rubber)
Appearance: Opaque white
Flammability: Smoke-free with dispersed wispy blue flame
Residue & odor: Emits paraffin wax-like odor
8. CR (Chloroprene Rubber / Neoprene)
Appearance: Pale yellow to light brown, opaque
Flammability: Hard to ignite
Flame features: Green flame
Residue & odor: Residue expands after combustion; releases hydrogen chloride odor
9. SR (Silicone Rubber)
Appearance: White, translucent to opaque
Flammability: Moderately flammable
Flame features: Bright white flame with white smoke
Residue & odor: Forms white ash after burning with faint odor
10. FKM (Fluorocarbon Rubber)
Appearance: Opaque white
Flammability: Extremely hard to ignite
Flame features: Self-extinguishing green flame
Residue & odor: Softens upon heating; releases toxic fumes
