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Barium titanate‐based nanodielectrics of two chemically recyclable thermosets
Author(s) -
Bello Roger H,
Priebe Jacks P,
Coelho Luiz AF
Publication year - 2019
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/pi.5755
Subject(s) - materials science , nanocomposite , barium titanate , dielectric , polymer , thermosetting polymer , composite material , glass transition , dynamic mechanical analysis , chemical engineering , nanoparticle , polymer chemistry , ceramic , nanotechnology , optoelectronics , engineering
In this work was investigated the effect of the addition of barium titanate (BaTiO 3 ) on electrical properties of two chemically recyclable thermosets, polyhemiaminal (PHA) and polyhexahydro‐ s ‐triazine (PHT), both fabricated from 4,4′‐oxydianiline (ODA), an ether derivative of aniline and paraformaldehyde. Thermal and mechanical properties as well as chemical recyclability of the two polymers and their nanocomposites/nanodielectrics were also investigated. In addition, a quantitative analysis was conducted of the nanoparticle dispersion in the PHA‐/PHT‐based BaTiO 3 ‐containing nanocomposites using transmission electron microscopy imaging and the nearest‐neighbor distance index and this index was used to analyze the investigated properties in connection with the proper mechanisms. Regarding the electrical properties for both neat polymers, conductivity values of the order of 10 −8 S m −1 at 100 Hz were observed and dielectric constant values close to 2.80 for both polymers at 1 kHz. The addition of 0.5 wt% of BaTiO 3 ferroelectric nanoparticles increased by about 44% the dielectric constant (1 kHz) and conductivity (10 2 Hz) of the PHA‐based nanocomposite. PHA and PHT exhibited glass transition temperature ( T g ) values in the range 125–180 °C. An increase of 7 °C in T g was observed after the incorporation of 0.5 wt% of BaTiO 3 into PHA. Concerning the mechanical properties, values in the range 4.00–4.45 GPa for reduced modulus and 0.30–0.43 GPa for nanohardness for PHA and PHT polymers were observed. Independently of filler content or polymer matrix, both mechanical properties were enhanced after the addition of BaTiO 3 . The chemical recycling of PHA/PHT and all nanocomposites in the initial ODA reagent after sulfuric acid treatment was successfully characterized using the NMR and Fourier transform infrared spectroscopic techniques. © 2018 Society of Chemical Industry