SYNTHESIS AND CHARACTERIZATION OF NEW THERMOSETTING POLYBENZOXAZINES WITH OTHER FUNCTIONAL GROUPS IN THE NETWORK

GILBERT E.A.; MORALES G.; TAVERNA M.E; ESTENOZ D.A.; SPONTÓN M.E.

Córdoba

Simposio; XII SIMPOSIO ARGENTINO DE POLÍMEROS; 2017

Polybenzoxazines are a relatively new type of thermosetting materials that have become of great interest due to their improved properties compared to traditional phenolic systems, such as low toxicity of raw materials, mechanical behavior, relatively low precursors viscosity and a wide processability window.[1] In addition, these polymers offer a large number of attractive properties, including high glass transition temperatures, enhanced electrical properties, low volume contraction upon curing, thermal, chemical and dimensional stability, flame resistance and relatively low cost [2]. They are widely applied in various fields such as protection coatings of electronic devices, airplanes bodies, aerospace engineering, curing agents, and varnishes with a good water resistance, alkali and solvents [3].In this work, novel thermosetting systems based on multi- functional benzoxazineswith improved mechanical and thermal properties respect to the conventional polybenzoxazine were developed. First, BzOH and BzPOH monomers were synthesized by reaction between phenol or bisphenol A, paraformaldehyde, and ethanolamine. Then, BzOH and BzPOH were functionalized with maleic anhydride using a stoichiometric ratio of oxazine:maleic anhydride to produce oligomers with acid functionality, named BzFA and BzPFA. The products were characterized by Nuclear Magnetic Resonance (NMR), Size-Exclusion Chromatography (SEC), and Fourier Transform Infrared Spectroscopy (FTIR). BzFA and BzPFA oligomers showed average molecular weights of 5000 g/mol and 50000 g/mol respectively. Mixtures between the new precursors synthesized and the conventional benzoxazine (BzBA) were prepared. The curing process was studied by FTIR and Differential Scanning Calorimetry (DSC), and mechanical, thermal, and morphological properties of the materials were also evaluated. Materialsobtainedexhibitedbetter properties thanconventional polybenzoxazine. SEM measurements indicated homogeneous material surfaces.