scholarly journals CONDENSED TANNINS OF THE SPECIES PINUS TAEDA: EXTRACTION, CHARACTERIZATION AND POTENTIAL FORMULATION OF WOOD BIOADHESIVE

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Helder Ricardo Marchini ◽  
Sirlei Dias Teixeira ◽  
Raquel Dalla Costa da Rocha
Keyword(s):  
Pinus Taeda ◽  
Condensed Tannins ◽  
Sodium Sulfite ◽  
Extraction Yield ◽  
Phenolic Resins ◽  
X Ray ◽  
Potential Formulation ◽  
Extraction Processes ◽  
Commercial Source ◽  
Scanning Electron

The species Pinus taeda was evaluated as a source of condensed tannins for the potential formulation of phenolic adhesives from the extraction of the wood cortex. Extraction yield, percentage of tannins and non-tannins, and reactivity to the formaldehyde by the Stiasny number were analyzed in the responses of the extraction processes with extractive agents sodium sulfite (Na2SO3), sodium hydroxide (NaOH), and urea [(NH2)2CO] in the percentages of 2, 4, 6, 8, and 10 in relation to the weight of the bark of this species. The extracts were analyzed using the techniques of IR - Infrared Spectroscopy, SEM - Scanning Electron Microscopy, DRX- X-ray Diffractometry, and EDS - Energy-Dispersive X-ray Spectrometry. In another step, the formation time of the commercial tannin gel and of the P. taeda were compared in relation to formaldehyde. The results show that the specie have condensed tannins, and sustain that they are catechins. These catechins form polymers identified by SEM in less time in relation to the formaldehyde in the formation of the gel, suggesting that the tannins can be extracted from the species as a potentially new commercial source that lumber companies can use to manufacture phenolic resins.

scholarly journals Growth of Carbon Nanofibers in Phenolic Resin for Carbon-Contained Refractory Using Different Catalysts

2017 ◽  
Vol 2017 ◽  
pp. 1-4 ◽  
Author(s):  
Jun Yu ◽  
Huizhong Zhao ◽  
Han Zhang ◽  
Jingjie Li ◽  
Xiongfeng Ding
Keyword(s):  
Carbon Nanofibers ◽  
Phenolic Resin ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
X Ray Diffraction ◽  
Phenolic Resins ◽  
X Ray ◽  
Cracking Process ◽  
Carbon Losses ◽  
Scanning Electron

Various phenolic resins modified with carbon nanofibers were prepared using Fe(NO3)3, Co(NO3)2, and Ni(NO3)3 as catalyst, respectively. The influences of different catalysts on the phase, microstructure evolution, and oxidation resistance of the modified phenolic resin were investigated by X-ray diffraction analysis, field-emission scanning electron microscopy, and thermal gravimetric analysis. The results showed that, compared with a single catalyst, the mixed catalysts (Co(NO3)2 : Fe(NO3)3 = 1 : 1) promoted the growth of the carbon nanofibers, which have the higher crystallinity, homogeneous dispersion, and nonagglomeration. These carbon nanofibers can effectively reduce carbon losses, increase char yield, and fill the holes in the thermal cracking process of phenolic resins.

scholarly journals Preparasi Katalis MgO/C dari Pirolisis Polimer Berbasis Magnesium Salisilat dan Aplikasinya untuk Reaksi Transesterifikasi

2021 ◽  
Vol 15 (1) ◽  
pp. 84
Author(s):  
Imam Prasetyo ◽  
Dwiana Ayu Kiranti Nur’aeni ◽  
Pandu Timur Bhaskara
Keyword(s):  
Electron Microscopy ◽  
Magnesium Oxide ◽  
Phenolic Resin ◽  
Solid Base ◽  
Base Catalyst ◽  
X Ray Diffraction ◽  
Solid Base Catalyst ◽  
Phenolic Resins ◽  
X Ray ◽  
Scanning Electron

The objective of the study is to produce carbon-based magnesium oxide (MgO) solid base catalyst by pyrolysis of phenolic resin and to examine the material effectiveness as a catalyst for transesterification reaction. The phenolic resins were prepared by polymerization process of phenol, derivative salicylic acid (magnesium salicylate), and formaldehyde aqueous solution under acidic condition using H2SO4 as catalyst. The molar ratio of magnesium salicylate:phenol:formaldehyde was 0.33:0.67:2.80. Carbon-based magnesium oxide solid base catalyst (MgO/C) was produced from phenolic resins via physical activation process using steam at 850°C.  Material was characterized using N2-sorption analysis, X-ray diffraction (XRD) and scanning electron microscopy (SEM). Pyrolysis process for carbon formation resulted in 75% burn-off. The specific surface area of catalyst was 494 m2/g and the presence of MgO was confirmed by XRD diffraction pattern (2θ position of 36-43°, 61-63°, dan 74-78° according to JCPDS No.89-7746) and SEM image. Characteristic comparison of MgO/C with carbon produced from phenol formaldehyde resin (without magnesium salicylate) corroborate the finding that MgO/C was achieved. The catalyst was tested for transesterification reaction between palm oil and methanol. Conversion of 28.3% was achieved at temperature of 65 °C, reactant ratio of methanol: palm oil = 6:1 and reaction time of 2.5 hours. The activation energy of 6,444 cal/mol was obtained when evaluated in the range of 55-65 °C reaction temperature.Keywords: biodiesel; catalyst; magnesium oxide; phenolic resin; porous carbonA B S T R A KTujuan penelitian ini adalah membuat katalis magnesium oksida (MgO) yang teremban dalam karbon hasil dari proses pirolisis resin fenolik dan menguji efektivitasnya sebagai katalis reaksi transesterifikasi. Resin fenolik diperoleh melalui proses polimerisasi fenol, turunan asam salisilat (magnesium salisilat), dan formaldehid dalam kondisi asam menggunakan H2SO4 sebagai katalis. Rasio mol dari magnesium salisilat:fenol:formaldehid adalah 0,33:0,67:2,80. Katalis magnesium oksida teremban pada karbon (MgO/C) diperoleh dari pirolisis resin fenolik menggunakan steam pada suhu 850°C. Material dikarakterisasi dengan N2 adsorpsi-desorpsi isotherm, X-ray diffraction (XRD) dan scanning electron microscopy (SEM). Pirolisis untuk menghasilkan karbon memiliki burn-off sekitar 75%. Hasil penelitian menunjukkan bahwa katalis MgO/C memiliki luas permukaan sekitar 494 m2/g dan keberadaan MgO dikonfirmasi dari hasil pola difraksi XRD (posisi 2θ antara 36-43°, 61-63°, dan 74-78° sesuai dengan standar JCPDS No.89-7746) dan gambar SEM. Pembandingan karakteristik MgO/C dengan karbon hasil polimer fenol formaldehid (tanpa magnesium salisilat) memperkuat kesimpulan bahwa MgO/C dapat diperoleh. Katalis yang diperoleh digunakan sebagai katalis transesterifikasi antara minyak kelapa sawit dengan metanol. Konversi reaksi sebesar 28,3% didapatkan pada suhu 65 °C dan rasio reaktan metanol:minyak kelapa sawit = 6:1 dan waktu reaksi 2,5 jam. Energi aktivasi sebesar 6.444 kal/mol diperoleh pada rentang suhu reaksi 55-65 °C.Kata kunci: biodiesel; karbon berpori; katalis; magnesium oksida; resin fenolik

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Sem Studies of Co-Cr-Mo Surgical Implant Alloy Corrosion Behavior

1982 ◽  
Vol 40 ◽  
pp. 520-521
Author(s):  
Ann Chidester Van Orden ◽  
John L. Chidester ◽  
Anna C. Fraker ◽  
Pei Sung
Keyword(s):  
Electron Microscopy ◽  
Corrosion Behavior ◽  
Anodic Polarization ◽  
Saline Solution ◽  
Saturated Calomel Electrode ◽  
Physiological Saline ◽  
X Ray ◽  
Physiological Saline Solution ◽  
Scanning Electron

The influence of small variations in the composition on the corrosion behavior of Co-Cr-Mo alloys has been studied using scanning electron microscopy (SEM), energy dispersive x-ray analysis (EDX), and electrochemical measurements. SEM and EDX data were correlated with data from in vitro corrosion measurements involving repassivation and also potentiostatic anodic polarization measurements. Specimens studied included the four alloys shown in Table 1. Corrosion tests were conducted in Hanks' physiological saline solution which has a pH of 7.4 and was held at a temperature of 37°C. Specimens were mechanically polished to a surface finish with 0.05 µm A1203, then exposed to the solution and anodically polarized at a rate of 0.006 v/min. All voltages were measured vs. the saturated calomel electrode (s.c.e.).. Specimens had breakdown potentials near 0.47V vs. s.c.e.

Quantification of Silica Uptake by Alveolar Macrophages - An Emperical Scanning Electron Microprobe Method

1982 ◽  
Vol 40 ◽  
pp. 332-333
Author(s):  
V. V. Damiano ◽  
R. P. Daniele ◽  
H. T. Tucker ◽  
J. H. Dauber
Keyword(s):  
Quantitative Analysis ◽  
Alveolar Macrophages ◽  
Bulk Sample ◽  
Silica Particles ◽  
Empirical Method ◽  
Phagocytic Cells ◽  
Calibration Standards ◽  
X Ray ◽  
Accurate Quantitative Analysis ◽  
Scanning Electron

An important example of intracellular particles is encountered in silicosis where alveolar macrophages ingest inspired silica particles. The quantitation of the silica uptake by these cells may be a potentially useful method for monitoring silica exposure. Accurate quantitative analysis of ingested silica by phagocytic cells is difficult because the particles are frequently small, irregularly shaped and cannot be visualized within the cells. Semiquantitative methods which make use of particles of known size, shape and composition as calibration standards may be the most direct and simplest approach to undertake. The present paper describes an empirical method in which glass microspheres were used as a model to show how the ratio of the silicon Kα peak X-ray intensity from the microspheres to that of a bulk sample of the same composition correlated to the mass of the microsphere contained within the cell. Irregular shaped silica particles were also analyzed and a calibration curve was generated from these data.

Identification of calcium oxalate crystals in dried or fixed tobacco leaf

1984 ◽  
Vol 42 ◽  
pp. 288-289
Author(s):  
Vicki L. Baliga ◽  
Mary Ellen Counts
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Oxalate ◽  
Growth And Development ◽  
Polarized Light ◽  
Calcium Oxalate Crystals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Calcium is an important element in the growth and development of plants and one form of calcium is calcium oxalate. Calcium oxalate has been found in leaf seed, stem material plant tissue culture, fungi and lichen using one or more of the following methods—polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction.Two methods are presented here for qualitatively estimating calcium oxalate in dried or fixed tobacco (Nicotiana) leaf from different stalk positions using PLM. SEM, coupled with energy dispersive x-ray spectrometry (EDS), and powder x-ray diffraction were used to verify that the crystals observed in the dried leaf with PLM were calcium oxalate.

Use of SEM, X-ray analysis and TEM to localize Fe3+ reduction in roots

1988 ◽  
Vol 46 ◽  
pp. 392-393 ◽  
Author(s):  
William P. Wergin ◽  
P. F. Bell ◽  
Rufus L. Chaney
Keyword(s):  
Electron Microscopy ◽  
Root Hairs ◽  
Rapid Reduction ◽  
X Ray ◽  
Physical Evidence ◽  
Transmission Electron ◽  
Young Root ◽  
Insoluble Precipitate ◽  
Uptake And Transport ◽  
Scanning Electron

In dicotyledons, Fe3+ must be reduced to Fe2+ before uptake and transport of this essential macronutrient can occur. Ambler et al demonstrated that reduction along the root could be observed by the formation of a stain, Prussian blue (PB), Fe4 [Fe(CN)6]3 n H2O (where n = 14-16). This stain, which is an insoluble precipitate, forms at the reduction site when the nutrient solution contains Fe3+ and ferricyanide. In 1972, Chaney et al proposed a model which suggested that the Fe3+ reduction site occurred outside the cell membrane; however, no physical evidence to support the model was presented at that time. A more recent study using the PB stain indicates that rapid reduction of Fe3+ occurs in a region of the root containing young root hairs. Furthermore the most pronounced activity occurs in plants that are deficient in Fe. To more precisely localize the site of Fe3+ reduction, scanning electron microscopy (SEM), x-ray analysis, and transmission electron microscopy (TEM) were utilized to examine the distribution of the PB precipitate that was induced to form in roots.

Sem and X-Ray Analysis of Renal and Biliary Calculi

1976 ◽  
Vol 34 ◽  
pp. 306-307
Author(s):  
R. J. Narconis ◽  
G. L. Johnson
Keyword(s):  
Chemical Constituents ◽  
Natural State ◽  
X Ray Diffraction ◽  
Chemical Methods ◽  
X Ray ◽  
Additional Dimension ◽  
Biliary Calculi ◽  
Calculus Formation ◽  
Scanning Electron

Analysis of the constituents of renal and biliary calculi may be of help in the management of patients with calculous disease. Several methods of analysis are available for identifying these constituents. Most common are chemical methods, optical crystallography, x-ray diffraction, and infrared spectroscopy. The application of a SEM with x-ray analysis capabilities should be considered as an additional alternative.A scanning electron microscope equipped with an x-ray “mapping” attachment offers an additional dimension in its ability to locate elemental constituents geographically, and thus, provide a clue in determination of possible metabolic etiology in calculus formation. The ability of this method to give an undisturbed view of adjacent layers of elements in their natural state is of advantage in determining the sequence of formation of subsequent layers of chemical constituents.

Scanning Electron Microscopy and X-Ray Analyses of Dental Tissues from a Hibernator

1976 ◽  
Vol 34 ◽  
pp. 178-179
Author(s):  
M. L. Zimny ◽  
A. C. Haller
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Body Temperature ◽  
Ground Squirrel ◽  
Alveolar Bone ◽  
X Ray ◽  
Dental Tissues ◽  
Bone Minerals ◽  
Apical Tooth ◽  
Scanning Electron

During hibernation the ground squirrel is immobile, body temperature reduced and metabolism depressed. Hibernation has been shown to affect dental tissues varying degrees, although not much work has been done in this area. In limited studies, it has been shown that hibernation results in (1) mobilization of bone minerals; (2) deficient dentinogenesis and degeneration of alveolar bone; (3) presence of calculus and tears in the cementum; and (4) aggrevation of caries and pulpal and apical tooth abscesses. The purpose of this investigation was to study the effects of hibernation on dental tissues employing scanning electron microscopy (SEM) and related x-ray analyses.

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