H3PO4 In Solution Research Articles

Hierarchical Lamellar Aluminophosphate Materials with Porosity as Ecofriendly Inorganic Adhesive for Wood-Based Boards

Aluminophosphate inorganic adhesive (APIA), as a binder for wood-based boards (WBB), is synthesized between Al(OH)3 and H3PO4 in solution with hydrothermal treatment in this study. Aluminophosphate compounds with hierarchical lamellar structure are observed on the fibers’ surface. The rheological behavior analysis reveals that the viscosity of APIA varied with its P/Al molar ratio [n(P)/n(Al)]. P–O–Al bridges are formed during the hydrothermal treatment of the APIA. The amounts of hydrogen bonds are formed between APIA and wood fibers, which could explain the improvement in mechanical properties of the WBB. In this study, the optimal n(P)/n(Al) in APIA is found to be 2.8, where the bonding strength, together with an acceptable viscosity are found at 1.83 MPa and 31.3 m Pa·s, respectively. Thermogravimetric analysis indicates that the residual weight of plywood is 44.97% greater than pure wood fibers, indicating the fire resistance of the WBB in the study is improved.

Porous Biphasic Calcium Phosphate Scaffolds from Cuttlefish Bone

Cuttlefish bone is an inexpensive, readily available, morphologically complex natural material. It has an open structure, consisting of layers separated by pillar-like structures made of calcium carbonate. In this study natural bones from cuttlefish were successfully converted into porous biphasic calcium phosphate (BCP) scaffolds with a range of hydroxyapatite and β-tricalcium phosphate compositions. The process involved reaction with solutions of phosphoric acid (H3PO4) and 2-propanol, followed by heat treatment at high temperatures (up to 1300°C) in air. The crystalline composition of the BCP scaffolds could be controlled by varying the concentration of the H3PO4 in solution, and the duration of reaction time at room temperature. The original microstructure of the cuttlefish bone was preserved in the BCP scaffolds which featured >90% interconnected porosity. The structure consisted of continuous macroporous channels with smallest measured cross-sectional openings of 400 μm × 100 μm size. The BCP scaffolds prepared with 16 wt% H3PO4 solution had a measured compressive strength of 2.38 ± 0.24 MPa, with a characteristic noncatastrophic failure behavior. The ability to tailor the composition of these BCP scaffolds allows development of implants with controlled biodegradation, while their superior mechanical and microstructural properties stand to benefit efficient osteointegration and osteoinduction.

Electrical Properties and DC Conductivity of Phosphoric Acid Doped TGS Single Crystals

Properties of phosphoric acid (H3PO4) doped triglycine sulfate (TGSP) grown from aqueous solutions containing 0.1 to 0.5 moles of H3PO4 have been investigated. Composition analysis indicates a very low incorporation of phosphoric acid in the crystal lattice. Large sized crystals of dimension (70 mm × 40 mm × 25 mm) suitable for IR detector are obtained with 0.2 moles of H3PO4 in solution. The presence of both zwitter and glycinium ions in TGSP is explained through FT-IR analysis. The dielectric dispersion of TGSP crystals in the frequency range from 100 Hz to 100 KHz, and in the temperature range 27 to 65°C has been analyzed. The increased dielectric dispersion in TGSP crystals is found to be related to the increase in dc conductivity, and the increased domain boundary relaxation time. Doped crystals show a broad transition and suppressed value of peak dielectric constant.

Some ferroelectric and dielectric properties of triglycine fluoberyllate

Single crystals of triglycine sulfate (TGS) grown with 25–50 mol% phosphoric acid dopant in solution were investigated for their dielectric, ferroelectric and mechanical hardness properties. A 25 mol% of H3PO4 in solution yielded crystals with a large area in the ac plane without any seed crystal. The room temperature (300 K) dielectric constant (ε′) and tan δ in the frequency range 0.1–100 kHz were found to increase with increasing phosphoric acid concentration. A maximum shift of 2.5 K in the phase transition temperature (Tc) is observed for crystals grown with 50 mol% of H3PO4. Systematic lowering of Curie–Weiss constant (Cf) in ferroelectric phase and an increase in the paraelectric phase (Cp) indicates domain wall clamping effects in the doped samples. The changes in the spontaneous polarization (2.6–3.2 μC cm−2) with phosphoric acid doping are insignificant, but the high coercive fields (Ec=5 kV cm−1), and distorted loops indicate the presence of stresses and inhomogeneities. The activation energy (ΔE) from temperature dependent d.c. conductivity measurements is lower in both the ferroelectric and the paraelectric phase for doped crystals indicating a strong influence of dopants on the conduction process. The microhardness of the doped crystals is lower in comparison to undoped TGS.