A recent publication in ACS Appl. Mater. Interfaces by Prof. Liang Guozheng and Prof. Gu Aijuan
Multifunctional Cyclotriphosphazene/Hexagonal Boron Nitride Hybrids and Their Flame Retarding Bismaleimide Resins with High Thermal Conductivity and Thermal Stability

Wenqin Jin,   Li Yuan,   Guozheng Liang*(梁国正)  and   Aijuan Gu*(顾嫒娟)  

Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, Department of Materials Science and Engineering College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, Jiangsu 215123, China

ACS Appl. Mater. Interfaces 2014, 6, 14931-14944

A novel hybridized multifunctional filler (CPBN), cyclotriphosphazene/hexagonal boron nitride (hBN) hybrid, was synthesized by chemically coating hBN with hexachlorocyclotriphosphazene and p-phenylenediamine, its structure was systemically characterized. Besides, CPBN was used to develop new flame retarding bismaleimide/o,o′-diallylbisphenol A (BD) resins with simultaneously high thermal conductivity and thermal stability. The nature of CPBN has a strong influence on the flame behavior of the composites. With the addition of only 5 wt % CPBN to BD resin, the thermal conductivity increases 2 times; meanwhile the flame retardancy of BD resin is remarkably increased, reflected by the increased limited oxygen index, much longer time to ignition, significantly reduced heat release rate. The thermogravimetric kinetics, structures of chars and pyrolysis gases, and cone calorimeter tests were investigated to reveal the unique flame retarding mechanism of CPBN/BD composites. CPBN provides multieffects on improving the flame retardancy, especially in forming a protective char layer, which means a more thermally stable and condensed barrier for heat and mass transfer, and thus protecting the resin from further combustion.
Link: http://pubs.acs.org/doi/abs/10.1021/am502364k