Thermal Properties and Flame Behaviour
topic
PET limiting oxygen index (LOI): 20–22 (flammable, below 21% atmospheric O₂). Burns with melting and dripping (thermoplastic behaviour), reducing flame spread. Flame retardant polyester: phosphorus compounds (DOPO, phosphinate) react in condensed phase inhibiting char formation; bromine compounds (gas-phase radical quenching). Reactive FR: phosphonate comonomers incorporated in polymer backbone. FR standards: EN 13501 (building), ISO 15025 (protective clothing), California TB 117 (furniture).
Role
Flame retardancy of polyester is a critical safety engineering topic with important regulatory, chemical, and environmental dimensions. Understanding PET combustion mechanisms and FR mechanisms is essential for protective textile design and regulatory compliance.