Benzotriazole-based conjugated microporous polymers as efficient flame retardants with better thermal insulation property
Abstract
The development of high performance flame retardant materials with better thermal insulating properties is of great importance for energy saving for modern building construction. Herein, we report for the first time the synthesis of novel conjugated microporous polymers (CMPs) using monomers containing benzotriazole moiety as building blocks via Sonogashira–Hagihara cross-coupling polymerization. The synthesized ZCMPs show high thermal stability with a decomposition temperature above 330 oC and high specific surface area up to 691 m2 g-1. The resulting CMPs samples possess excellent flame retardancy with a peak heat released rate (PHRR) of as low as 9.9 W g-1, which is nearly one magnitude lower than many traditional polymeric flame retardants reported previously. Also, they also show better thermal insulation property with a thermal conductivity of ca.0.03 W m-1 k-1 in air. More importantly, the introduction of benzotriazole moiety into CMPs could generate the nitrogen (a “green” gas compared with many flame retardants) to produce a flame-retardant effect. In addition, the rigid porous structure of CMPs could nearly remain to form a carbon layer as a barrier to block oxygen, mass, and heat transfer to the substrate when it undergos high temperature treatment. Taking the advantages mentioned above, the CMPs may hold great potentials for future thermal insulation and flame retardant applications.
