What structural changes occur in PTFE high-temperature fabric during the aging process?
This article examines structural changes in PTFE high-temperature fabric during aging. Four aspects: PTFE coating microstructure — molecular chain scission and oxidation (carbonyl/carboxyl group formation), crystallinity changes (early rise then collapse), micro-crack and pinhole formation, surface powdering; Glass fiber substrate and interface — sizing/coupling agent decomposition causing loss of bonding, interfacial debonding and delamination (blistering, white areas), glass fiber network erosion and embrittlement, alkali metal oxide precipitation causing stress corrosion; Macroscopic structure and appearance — color change (white→beige→brown→black), shrinkage deformation and curling, surface roughening and gloss loss, powdering upon touch, complete loss of flexibility. Essence of aging: progressive process of "coating degradation → interface failure → substrate degradation."
