POLYBENZOXAZINE -SILICON BASED HYBRID NANOSTRUCTURES WITH TUNABLE MORPHOLOGIES AND COMPOSITIONS FOR FLAME RETARDANT APPLICATIONS

FORCHETTI CASARINO, AGUSTIN; NOTELET, DELPHINE; CASIS, NATALIA; M. SPONTON

Cancún

Congreso; IMRC XXIX; 2021

MRS

Most of the thermosetting polymers present fire hazard during their services. For this reason,electrical, electronic, aeronautical, aerospace, transportation and building industries are subjected tostrict criteria for fire retardants. These industries have paid special attention to the use ofpolybenzoxazines due to their outstanding characteristics such as: good thermal stability, high Tgs,good dimensional stability and low flammability. Polybenzoxazines are thermosetting polymers thathave been studied to a lesser extent than conventional epoxy and phenolic resins. They areobtained through thermally-induced oxazine ring opening, generating a phenolic crosslinked network,based on Mannich br idges. Benzoxazine precursors are synthesized a phenolic compound,formaldehyde and primary amines in a 1:2:1 molar ratio. The goal of this work is to developpolybenzoxazine-silicon nanocomposite systems endowed with increased fire retardancy and thermalstability. For this purpose, conventional benzoxazine (BA-a) and a 3-aminopropyl trimethoxy silaneand bisphenol A-based benzoxazine (BA-3aptms) were synthesized [1]. Also, smooth and sphericalSiO2 nanoparticles of 50, 150 y 300 nm size were prepared following the Stöber`s method [2]. Theinfluence of the particle size, composition and type of benzoxazine on the polymer was studied. Asa first stage, the effect of SiO2 size and composition in the BA-a on thermogravimetric propertieswas analyzed. Resulting materials with lower particle size exhibited improved properties. On theother hand, hybrid silane-based benzoxazine underwent a sol-gel process, according Forchetti et al.(2021) [3]. SiO2 nanoparticles were then added in order to obtain hybrid nanostructures siloxanebased precursors. The systems were fully characterized by Differential Scanning Calorimetry (DSC),Thermogravimetric Analysis (TGA), Dynamo Mechanical Thermal Analysis (DMTA), TransmissionElectronic Microscopy (TEM) and UL94 Fire Testing. The role of the Si atoms resulted in an enhancein the thermal and mechanical properties for the systems studied.