-
Molecules (Basel, Switzerland) Dec 2019A design of atomic and oligomer level structure in organic-inorganic hybrid materials is highly important for various applications. Nonaqueous acid-base reaction allows...
A design of atomic and oligomer level structure in organic-inorganic hybrid materials is highly important for various applications. Nonaqueous acid-base reaction allows us to prepare silicophosphates with controlled inorganic networks (-(O-P-O-Si)) at atomic level because phosphorous and silicon-based precursors can react directly, resulting in an alternating copolymer network. Organic functionalization in those materials has been realized so far by using organic-modified phosphorous acid and/or organo-chlorosilane as precursors. In the present study, silicophosphate oligomers exhibiting inorganic-organic hybrid chains of (-(O-P-O-Si-R-Si)) (R: bridging organic functional groups), are prepared from phosphoric acid and organo-bridged bis(chlorosilane). The 1, 2-bis(chlorodimethylsilyl)ethane ((CH)(MeSiCl)) and 1, 4-bis(chlorodimethylsilyl)benzene ((CH)(MeSiCl)) were used as organo-bridged bis(chlorosilane). Different types of silicophosphate oligomers with different network structures and terminal groups (P-OH and/or Si-Cl) were prepared by changing the reaction temperature and molar ratio of precursors. The formation of low molecular weight oligomers of ring and cage morphologies (ring tetramer, cage pentamer, and ring hexamer) is suggested in the product prepared from phosphoric acid and (CH)(MeSiCl) molecule at 150 °C. Those silicophosphate hybrid oligomers are expected to be used as building blocks of hybrid materials with well-defined network structures for desired functionalities.
Topics: Phosphoric Acids; Polymers; Silicon
PubMed: 31905676
DOI: 10.3390/molecules25010127 -
Cellular Physiology and Biochemistry :... 2017This experimental study aimed to evaluate the effect of low-concentration phosphoric acid on the surface structure of cortical allografts.
BACKGROUND/AIMS
This experimental study aimed to evaluate the effect of low-concentration phosphoric acid on the surface structure of cortical allografts.
METHODS
Allogenic cortical bones were obtained from femurs and tibias of New Zealand white rabbits. The bones were modified by treatment with various concentrations of phosphoric acid (10%, 20% or 30%) for 10, 30 or 60 minutes, then evaluated by the following methods: 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) and LIVE/DEAD assay, alkaline phosphatase (ALP) assay, biomechanical properties testing, contact angle detection, quantitative real-time polymerase chain reaction (Q-PCR), western blotting and scanning electron microscopy (SEM).
RESULTS
Compared with the other groups, the group modified with 10% H3PO4 for 10 minutes had lower cytotoxicity according to MTT and LIVE/DEAD assays, higher hydrophilicity in the contact angle detection test and greater stability in the biomechanical properties test. Moreover, an up-regulation of osteopontin (OPN) in bones modified with 10% H3PO4 was observed by Q-PCR and western blotting. In addition, ALP assay and SEM showed that surface porosity and osteoinductivity were increased in the group modified with 10% H3PO4.
CONCLUSIONS
Low-concentration phosphoric acid may be a potential method for surface modification of cortical allografts. Further animal experiments and animal infection model studies are required to validate the efficacy of surface-modified cortical allografts to repair large segmental bone defects.
Topics: Allografts; Animals; Bone Transplantation; Cell Line; Femur; Mice; Phosphoric Acids; Rabbits; Tibia
PubMed: 28365682
DOI: 10.1159/000470823 -
Journal of Applied Biomaterials &... Jan 2017This study evaluated the surface morphology, chemical composition and adhesiveness of lithium disilicate glass ceramic after acid etching with hydrofluoric acid or...
BACKGROUND
This study evaluated the surface morphology, chemical composition and adhesiveness of lithium disilicate glass ceramic after acid etching with hydrofluoric acid or phosphoric acid.
METHODS
Lithium disilicate glass ceramic specimens polished by 600-grit silicon carbide paper were subjected to one or a combination of these surface treatments: airborne particle abrasion with 50-μm alumina (AA), etching with 5% hydrofluoric acid (HF) or 36% phosphoric acid (Phos), and application of silane coupling agent (Si). Stainless steel rods of 3.6-mm diameter and 2.0-mm height were cemented onto treated ceramic surfaces with a self-adhesive resin cement (Clearfil SA Cement). Shear bond strengths between ceramic and cement were measured after 24-hour storage in 37°C distilled water.
RESULTS
SEM images of AA revealed the formation of conventional microretentive grooves, but acid etching with HF or Phos produced a porous surface. Bond strengths of AA+HF+Si (28.1 ± 6.0 MPa), AA+Phos+Si (17.5 ± 4.1 MPa) and HF+Si (21.0 ± 3.0 MPa) were significantly greater than those of non-pretreated controls with Si (9.7 ± 3.7 MPa) and without Si (4.1 ± 2.4 MPa) (p<0.05). In addition, HF etching alone (26.2 ± 7.5 MPa) had significantly higher bond strength than AA alone (11.5 ± 4.0 MPa) (p<0.05). AA+HF, AA+Phos and HF showed cohesive failures.
CONCLUSIONS
Etching with HF or Phos yielded higher bond strength between lithium disilicate glass ceramic and self-adhesive resin cement without microcrack formation.
Topics: Dental Porcelain; Glass; Hydrochloric Acid; Phosphoric Acids; Surface Properties
PubMed: 27647389
DOI: 10.5301/jabfm.5000303 -
The Angle Orthodontist Nov 2006To compare the effects of erbium-doped yttrium aluminum garnet (Er:YAG) laser ablation and of phosphoric acid etching on the in vitro acid resistance of bovine enamel.
OBJECTIVE
To compare the effects of erbium-doped yttrium aluminum garnet (Er:YAG) laser ablation and of phosphoric acid etching on the in vitro acid resistance of bovine enamel.
MATERIALS AND METHODS
Teeth were polished to make the surface flat. The polished enamel was either etched with 37% phosphoric acid for 30 seconds or ablated with a single 33 J/cm2 pulse from an Er:YAG laser. The control specimens were free from acid etching and laser ablation. Changes in crystal structure, dissolved mineral (calcium [Ca] and phosphorus [P]) contents, and calcium distribution in the enamel subsurface after a pH-cycling process were evaluated.
RESULTS
After laser treatment, poor crystal structures improved without forming any new phases, such as tricalcium phosphates. Among the tested enamels, dissolved mineral contents were significantly different (P < .05). Er:YAG laser-treated enamels had the lowest mineral dissolution (Ca, 13.78 ppm; P, 6.33 ppm), whereas phosphoric acid-etched enamels had the highest (Ca, 15.90 ppm; P, 7.33 ppm). The reduction rate and reduced depth of calcium content along the subsurface were lowest in Er:YAG laser-treated enamels.
CONCLUSION
The Er:YAG laser-treated enamels are more acid resistant to acid attack than phosphoric acid-etched enamels.
Topics: Animals; Calcium; Cattle; Crystallography, X-Ray; Dental Enamel; Dental Etching; Diphosphonates; Electron Probe Microanalysis; Erbium; Hydrogen-Ion Concentration; Lactic Acid; Lasers; Phosphoric Acids; Phosphorus
PubMed: 17090176
DOI: 10.2319/11405-398 -
Brazilian Dental Journal 2016The objective of this study was to evaluate the effect of passive or active phosphoric acid (PA) application after hydrofluoric acid (HA) treatment on the microshear...
The objective of this study was to evaluate the effect of passive or active phosphoric acid (PA) application after hydrofluoric acid (HA) treatment on the microshear bond strength of lithium disilicate. Thirty ceramic discs were made with IPS Emax 2 (10 mm thick and 10 mm diameter). The specimens were divided into 3 groups, A: 9.6% HA application; AF: 9.6% HA application + cleaning with 37% PA in passive mode and AFF: 9.6% HA application + cleaning with 37% PA in active mode. For the microshear test, four tygons (0.9 mm diameter and 0.2 mm high) were filled with resin cement (RelyX Ultimate) and placed on the ceramic disks. After testing, the fracture modes were examined under scanning electron microscopy. Data were analyzed by one-way ANOVA and Tukey's post test (α=0.05). The bond strength values were significantly higher in Group AFF (11.0±2.5 MPa) compared with group A (8.1±2.6 MPa) (p<0.002). AF group was not statistically different (9.4±2.5 MPa) from Group A. It was concluded that the active application of 37% PA after 9.6% HA increases the microshear bond strength values between the resin cement and lithium disilicate ceramic.
Topics: Acid Etching, Dental; Dental Bonding; Dental Porcelain; Phosphoric Acids
PubMed: 27007353
DOI: 10.1590/0103-6440201600428 -
PloS One 2017A key requirement for three-dimensional printing (3-DP) at room temperature of medical implants depends on the availability of printable and biocompatible binder-powder...
A key requirement for three-dimensional printing (3-DP) at room temperature of medical implants depends on the availability of printable and biocompatible binder-powder systems. Different concentration polyvinyl alcohol (PVA) and phosphoric acid solutions were chosen as the binders to make the artificial stent biocompatible with sufficient compressive strength. In order to achieve an optimum balance between the bioceramic powder and binder solution, the biocompatibility and mechanical properties of these artificial stent samples were tested using two kinds of binder solutions. This study demonstrated the printable binder formulation at room temperature for the 3D artificial bone scaffolds. 0.6 wt% PVA solution was ejected easily via inkjet printing, with a supplementation of 0.25 wt% Tween 80 to reduce the surface tension of the polyvinyl alcohol solution. Compared with the polyvinyl alcohol scaffolds, the phosphoric acid scaffolds had better mechanical properties. Though both scaffolds supported the cell proliferation, the absorbance of the polyvinyl alcohol scaffolds was higher than that of the phosphoric acid scaffolds. The artificial stents with a hydroxyapatite/beta-tricalcium phosphate (HA/β-TCP) weight ratios of 60:40 depicted good biocompatibility for both scaffolds. Considering the scaffolds' mechanical and biocompatible properties, the phosphoric acid scaffolds with a HA/β-TCP weight ratio of 60:40 may be the best combination for bone tissue engineering applications.
Topics: Animals; Bone Marrow Cells; Bone Substitutes; Calcium Phosphates; Durapatite; Materials Testing; Phosphoric Acids; Polyvinyl Alcohol; Printing, Three-Dimensional; Rabbits; Stem Cells; Tissue Engineering; Tissue Scaffolds
PubMed: 28406922
DOI: 10.1371/journal.pone.0174870 -
Journal of Applied Biomaterials &... Dec 2014The aim of this study was to evaluate enamel acid-induced structural changes after 2 different treatments, by means of Raman and infrared (IR) spectroscopy analyses, and... (Comparative Study)
Comparative Study
PURPOSE
The aim of this study was to evaluate enamel acid-induced structural changes after 2 different treatments, by means of Raman and infrared (IR) spectroscopy analyses, and to correlate these findings with permeability measured as fluid discharge from outer enamel.
METHODS
Two different treatments were investigated: 10 enamel slices were etched with 15% hydrochloric acid (HCl) for 120 seconds and 10 slices with 37% phosphoric acid gel (H3PO4) for 30 seconds, rinsed for 30 seconds and then air-dried for 20 seconds. Powders of enamel treated as previously described were produced. Replicas of enamel subjected to the same treatments were obtained to evaluate the presence of fluid droplets on enamel surface.
RESULTS AND CONCLUSIONS
Raman and IR spectroscopy showed that the treatment with both hydrochloric and phosphoric acids induced a decrease in the carbonate content of the enamel apatite. At the same time, both acids induced the formation of HPO42- ions. After H3PO4 treatment, the bands due to the organic component of enamel decreased in intensity, while they increased after HCl treatment. Replicas of H3PO4 treated enamel showed a strongly reduced permeability. Replicas of HCl 15% treated samples showed a maintained permeability. A decrease of the enamel organic component, as resulted after H3PO4 treatment, involves a decrease in enamel permeability, while the increase of the organic matter (achieved by HCl treatment) still maintains enamel permeability.The results suggested a correlation between organic matter and enamel permeability. Permeability was affected by etching technique and could be involved in marginal seal, gap and discoloration at the enamel interface, still causes of restoration failure.
Topics: Acid Etching, Dental; Adult; Dental Enamel; Female; Humans; Hydrochloric Acid; In Vitro Techniques; Male; Phosphoric Acids; Surface Properties; Young Adult
PubMed: 24700262
DOI: 10.5301/jabfm.5000179 -
Journal of Oleo Science 2022Phosphoric acid is used in the refining of palm oil for the removal of phosphatides. The high concentration of phosphorus in solvent extracted palm-pressed mesocarp...
Phosphoric acid is used in the refining of palm oil for the removal of phosphatides. The high concentration of phosphorus in solvent extracted palm-pressed mesocarp fiber oil hinders palm oil mills to recover this phytonutrients-rich residual oil in pressed fiber which typically contains 0.1 to 0.2% of total oil yield. This study aimed to refine the palm-pressed mesocarp fiber oil and determine the optimum dosage of phosphoric acid for acid-degumming of palm-pressed mesocarp fiber oil while retaining its phytonutrients. The refining process was carried out with combination of wet degumming, acid degumming, neutralisation, bleaching and deodorization. The optimum dose of phosphoric acid was identified as 0.05 wt.% by incorporating the wet degumming process. The refined palm-pressed mesocarp fiber oil showed a reduction in phosphorus content by 97% (from 901 ppm to 20 ppm) and 97% free fatty acid content removal (from 6.36% to 0.17%), while the Deterioration of Bleachability Index increased from 1.76 to 2.48, which showed an increment of 41%. The refined oil retained the key phytonutrients such as carotenoids (1,150 ppm) and vitamin E (1,540 ppm) that can be further developed into high-value products. The oil meets the quality specification of refined, bleached, and deodorized palm oil while preserving the heat-sensitive phytonutrients, which in turn provides a new resource of nutritious oil.
Topics: Carotenoids; Food Handling; Food Quality; Liquid-Liquid Extraction; Palm Oil; Phospholipids; Phosphoric Acids; Phosphorus; Phytochemicals; Solvents; Vitamin E
PubMed: 35110462
DOI: 10.5650/jos.ess21256 -
Australian Dental Journal Jun 2012Enamel etching for brackets is usually done with phosphoric acid. Er:YAG lasers have been recently used for this purpose with conflicting results. The effects of lasers... (Comparative Study)
Comparative Study
BACKGROUND
Enamel etching for brackets is usually done with phosphoric acid. Er:YAG lasers have been recently used for this purpose with conflicting results. The effects of lasers on tooth demineralization and the effects of different combinations of laser treatments and bonding agents were evaluated in this study.
METHODS
The enamel contents of fluorine, calcium oxide and phosphorus pentoxide (P(2) O(5)) were analysed using acid etching, laser treatment or both. The tensile bond strength of metallic and ceramic brackets using Transbond XT and Fuji Ortho LC were also tested, using acid etching, laser treatment or a combination of both.
RESULTS
All treatments reduced the contents of fluorine, P(2)O(5) and calcium oxide, and acid reduced P(2) O(5) levels more than laser. The bond strength with laser was weaker than with acid, and stronger when combining both. When using laser, the best adhesive was the Fuji Ortho LC. The combination of laser and acid produced the best results when using Transbond XT.
CONCLUSIONS
The demineralization promoted by laser was lower than the one produced with acid. Laser treatment produced lower tensile stress strength than acid, but still enough to produce clinically efficient retention. The combination of laser and acid produced the best retention results.
Topics: Acrylic Resins; Aluminum Silicates; Analysis of Variance; Calcium Compounds; Dental Bonding; Dental Enamel; Dental Etching; Dental Stress Analysis; Fluorine; Humans; Lasers, Solid-State; Microscopy, Electron, Scanning; Orthodontic Brackets; Oxides; Phosphoric Acids; Phosphorus Compounds; Resin Cements; Spectrometry, X-Ray Emission; Statistics, Nonparametric; Tensile Strength
PubMed: 22624760
DOI: 10.1111/j.1834-7819.2012.01679.x -
International Journal of Molecular... Dec 2022Heterogeneous Brønsted acidic catalysts such as phosphoric acids are the conventional activators for organic transformations. However, the photocatalytic performance of...
Heterogeneous Brønsted acidic catalysts such as phosphoric acids are the conventional activators for organic transformations. However, the photocatalytic performance of these catalysts is still rarely explored. Herein, a novel Zr-based metal-organic framework with phosphoric acids as a heterogeneous photocatalyst has been fabricated, which shows high selectivity and reactivity towards the photo-oxidation of sulfides under white light illumination. A mechanism study indicates that the selective oxygenation of sulfides occurs with triplet oxygen rather than common reactive oxygen species (ROS). When is irradiated, the hydroxyl group of phosphoric acid is converted into oxygen radical, which takes an electron from the sulfides, and then the activated substrates react with the triplet oxygen to form sulfoxides, avoiding the destruction of the catalysts and endowing the reaction with high substrate compatibility and fine recyclability.
Topics: Metal-Organic Frameworks; Sulfides; Oxidation-Reduction; Reactive Oxygen Species; Oxygen; Phosphoric Acids
PubMed: 36555762
DOI: 10.3390/ijms232416121