Comparison of two high temperature treatment methods on preparing electrically conductive polysulfide/Ag composites for aerospace sealant applications

Abstract

AbstractHigh electrical conductivity of aircraft fuel tank sealant is vital to prevent charge accumulation during operation. In this work, we prepare highly conductive polysulfide (PS)/Ag composite (106 S m−1) via two thermal treatment methods‐namely post cure annealing and high temperature (HT) curing, where the room temperature (RT) cured sample was previously found insulative. The HT cure samples resulted in a milder hardness increase compared to the RT cure‐annealed ones. Through various chemical and thermal analyses, a strong coordination of the sulfide components on Ag surfaces is found blocking the electron tunneling pathways at RT, which turns out to be weakened at HT. Post cure annealing causes the decomposition of the coordinated segments and provides intimate contact of Ag particles to support conductivity. HT cure on the other hand prevents the Ag/S coordination in the first place, therefore producing highly conductive PS/Ag composite with softness well maintained which makes it the preferred method for conductive sealant applications.