Cross‐linked Salen‐based polyphosphazenes (<scp>Salen‐PZNs</scp>) enhancing the fire resistance of epoxy resin composites
Yabin Zhang, Jinfeng Cui, Lurong Wang, Hailong Yu, Fuchong Li, Baoping Yang, Junhong Guo, Bo Mu, Li Tian
Abstract
Abstract In this work, two cross‐linked Salen‐based polyphosphazenes (Salen‐PZNs: Salen‐PZN‐1 microspheres and layered Salen‐PZN‐2), which contains Salen‐Schiff base and phosphazene components, were synthesized. The results showed that the peak heat release rate and total smoke production of 3% Salen‐PZN‐1/epoxy resin (EP) (3 wt% addition) were reduced by 23.8% and 87.3%, respectively. Meanwhile, after introducing the layered Salen‐PZN‐2 into EP, efficient flame resistance was obtained. The results of thermogravimetric analysis/infrared spectrometry proved that the harmful gasses of 5% Salen‐PZN‐1/EP composites were reduced during the combustion. The possible flame retardancy mechanism was considered to be the synergy of phosphate group catalysis, release of nitrogen‐containing noncombustible gasses and gas phase quenching. Therefore, this work provides a method for preparing polymers with highly efficient flame‐retardant properties.