The diffusionless pseudobinary phase diagram, monodomain properties, and free energy of (1 − x)Ba(Zr 0.2 Ti 0.8 )O 3 -x(Ba 0.7 Ca 0.3 )TiO 3 are computed for comparison with experimental results. Specifically, the variation of the spontaneous polarization, anisotropy energy, and free energy with respect to temperature, composition, and polarization direction are discussed relative to the results of resonant piezoelectric measurements performed over a wide compositional range as a function of temperature. The phase angle, relative permittivity, piezoelectric and coupling coefficients, and elastic compliances were used to investigate relations between the computed and measured pseudobinary phase diagrams and the measured piezoelectric and elastic properties. It was found that d 33 values along the orthorhombic to tetragonal phase boundary are ∼30% higher than those both along the rhombohedral to orthorhombic phase boundary and in the region where phases converge. It is shown that the reduction in anisotropy energy in these regions of the phase diagram is by itself insufficient to explain the measured properties. The highest small signal piezoelectric activity is found along the orthorhombic to tetragonal phase boundary due to a combination of reduced anisotropy energy, high remanent/spontaneous polarization, and increased elastic softening. The combined computed and experimental results are used to demonstrate that the interdependent behavior of these properties should be considered in the design of engineered piezoelectric ceramics.

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The relative permittivity of polycrystalline BaTiO3 was measured from –150 °C to 250 °C at compressive bias stresses up to −500 MPa. Mechanical loading shifted the rhombohedral-orthorhombic, orthorhombic-tetragonal, and tetragonal-cubic phase transition temperatures and produced a pronounced broadening of the dielectric softening in the vicinity of all three transitions. The inter-ferroelectric rhombohedral-orthorhombic and orthorhombic-tetragonal phase transitions were found to be less stress sensitive than the ferroelectric-paraelectric transition occurring between tetragonal and cubic phases at the Curie point. The application of compressive stress resulted in a strong suppression of the relative permittivity, such that at the highest applied stress of −500 MPa, the permittivity in the single phase regions away from the phase transitions was found to display only a weak dependence on temperature between −100 °C and 125 °C. The experimental observations closely followed the predictions of a 2-4-6 Landau polynomial wherein the dielectric stiffness and higher-order dielectric stiffness coefficients are linear functions of uniaxial stress.

We report microwave assisted synthesis of a series of highly hydrophobic porous organic polymers of poly divinylbenzene (PDVB), for the first time, which were modified by amine-rich co-monomers of vinyl imidazole (VI) and vinyl triazole (VT) resulting in PDVB-VI and PDVB-VT adsorbents. There is an optimum amount of incorporated co-monomer and initiator which led to high adsorptive activity of the material towards CO2. Atmospheric CO2 adsorption was enhanced by the addition of amine moieties while maintaining an optimum surface area and pore volume. A certain amount of initiator led to better incorporation of VT monomer while surface area and pores remain accessible. A maximum CO2 adsorption of 2.65 mmolg-1 at 273 K/1 bar was achieved for triazole based adsorbent (PDVB-VT) with 0.7 g of VT and 0.07 g of initiator. In comparison with a non-functionalized material (PDVB) with 1.2 mmolg-1 CO2 uptake, the adsorption efficiency was enhanced more than twice. The adsorbent maintained its efficiency up to seven cycles. Theoretical modeling confirms the active site is nitrogen on the imidazole/ triazole ring and that incorporation of VT to the polymeric networks enhanced the adsorptive properties better than vinyl imidazole (VI) due to more active sites.While absorption by amine-solution has drawbacks of corrosion, considerable energy loss, and inefficient regeneration, this has been the most widely adopted strategy [9]. Adsorption by solids provides some Porous polymers provide several advantages of (i) clear design of the high surface area and well-defined porosity, (ii) easy processing, (iii)and light elemental composition which provide weight advantages [53]. Recently, several porous polymers (mesoporous or microporous) have been developed for CO 2 capture [54,55]. Amine modified porous polymers have also been drawn up to adsorb CO 2 more