Composition Analysis of an Unknown Redispersible Powder

2017 ◽  
Vol 726 ◽  
pp. 55-59
Author(s):  
Jian Jun Ding ◽  
Wen Yan Zhao ◽  
Hong Yan Guan ◽  
Xuan Li ◽  
Yi Fei Mei
Keyword(s):  
Chemical Composition ◽  
Vinyl Ester ◽  
Inorganic Materials ◽  
Gas Chromatography Mass Spectrometry ◽  
Composition Analysis ◽  
Vinyl Esters ◽  
Pyrolysis Gas ◽  
Pyrolysis Products ◽  
Pyrolysis Mechanism ◽  
The Matrix

As an important type of additive, the redispersible powder is widely applied in cement-based and gyp-based materials, so as to improve the cementing strength, impermeability, workability, hydrophobicity and so on. However, the chemical composition of the redispersible powders determines its applicability, as well as the degree of improvement to the matrix materials. In this paper, the chemical composition of an unknown redispersible powder was analyzed by several instruments. Firstly, Fourier transform infrared spectroscopy (FTIR) analysis indicated that the polymer was polymerized with monomers of vinyl esters. Secondly, pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS) analysis showed the pyrolysis products were mainly acetic acid, methyl acetate and methyl versatates. Considering the pyrolysis mechanism of synthetic polymers and the results from FTIR spectra, the polymer in the redispersible powder was deduced to be the copolymer of vinyl acetate and vinyl ester of versatic acid (VeoVa), which was a monomer with a unique highly branched carbon-rich structure. Thermogravimetry (TG) analysis revealed that the powder contained 74.0% of polymer, 14.5% of calcium carbonate and 11.4% of other inorganic materials.

The flame retardancy and pyrolysis mechanism of polyimide fibers investigated by cone calorimeter and pyrolysis–gas chromatography–mass spectrometry

2017 ◽  
Vol 48 (2) ◽  
pp. 465-481 ◽  
Author(s):  
Xiansheng Zhang ◽  
Xiong Yan ◽  
Meiwu Shi
Keyword(s):  
Electron Microscopy ◽  
Heat Flux ◽  
Flame Retardancy ◽  
Cone Calorimeter ◽  
Gas Chromatography Mass Spectrometry ◽  
Pyrolysis Gas ◽  
Pyrolysis Mechanism ◽  
Pyrolysis Gas Chromatography ◽  
Polyimide Fibers ◽  
Scanning Electron

In the present research, the flame retardancy and pyrolysis mechanism of polyimide fibers were investigated by cone calorimeter, scanning electron microscopy, Fourier transform infrared spectroscopy, thermal gravimetric analysis, and pyrolysis–gas chromatography–mass spectrometry. As it turned out, the polyimide fibers possessed excellent thermal stability and flame retardancy. The onset thermal degradation temperature ( Tonset 10%) of polyimide was 587℃ and 610℃ at nitrogen and air atmospheres, respectively. The polyimide fibers cannot be ignited at the heat flux of 35 and 50 kW/m2, while they can be ignited at the heat flux of 75 kW/m2 with the time to ignition of 33 s and peak heat release rate of 53.4 kW/m2. Moreover, the flame retardancy of woven and knitted fabrics was also discussed, which demonstrated that knitted fabric was easier to become thermally thick than woven fabric. Scanning electron microscopy analysis of the residual chars of fibers showed that the shape of fiber can be maintained irrespective of heat flux, but the chemical structure of the fiber was destroyed at the heat flux of 75 kW/m2. The pyrolysis combustible volatiles at 700℃ include benzonitrile, aniline, and phenol, which can interpret the ignition of polyimide fibers. The results obtained in the present research revealed the flame retardancy and pyrolysis mechanism of polyimide fibers, which can guide its application and further modification.

scholarly journals Investigation of the Resistance and Sensitivity of Infectious Bacteria to Dendrostellera lessertii and Chemical Composition Analysis

2021 ◽  
Vol 6 (1) ◽  
pp. 30-36
Author(s):  
Mostafa Alamholo
Keyword(s):  
Chemical Composition ◽  
Methanolic Extract ◽  
Antibacterial Properties ◽  
Gas Chromatography Mass Spectrometry ◽  
Total Phenolic ◽  
Dilution Method ◽  
Composition Analysis ◽  
Chemical Compositions ◽  
Root Extract ◽  
Chemical Composition Analysis

Introduction: Herbal plants are important sources for finding new and rare products of medicinal value for drug development. The present research aimed to investigate the antibacterial properties of Dendrostellera lessertii against infectious bacteria and analyze its chemical composition. Methods: The different organs comprising root, stem, and leaf of D. lessertii from Lorestan province, Iran, were tested. Antibacterial activity was assessed using the agar well-diffusion assay. The total phenolic content (TPC) and total flavonoid content (TFC) were assessed by the Folin Ciocalteu and aluminum chloride methods, respectively. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were tested by the serial dilution method, and chemical compositions were analyzed by gas chromatography-mass spectrometry (GC/MS). Results: The chemical composition analysis showed the dominance of bergamotol (10.62%) and bis (2-ethylhexyl) phthalate (7.49%) in the stem extract. However, phytol (12.64%) and E-11-hexadecenal (12.53%) were major constituents in the root extract. Furthermore, major constituents in the leaf extract were phytol (19.658%) and hexadecanoic acid (7.151%). The methanolic extract of root exhibited the highest TPC as 109.1±2.2 mgGA/g and TFC as 2.1±0.33 mgQ/g. The root methanolic extract demonstrated a MIC of 3.125 mg/mL against Enterococcus faecalis. Accordingly, the highest sensitivity and resistance were observed on E. faecalis and Pseudomonas aeruginosa, respectively. Conclusion: Dendrostellera lessertii extract is suggested as a source for antimicrobial drugs, especially to treat bacterial infections.

scholarly journals Effect of peat quality on microbial greenhouse gas formation in an acidic fen

2009 ◽  
Vol 6 (5) ◽  
pp. 8775-8803
Author(s):  
M. Reiche ◽  
G. Gleixner ◽  
K. Küsel
Keyword(s):  
Organic Matter ◽  
Greenhouse Gas ◽  
Quality Index ◽  
Gas Chromatography Mass Spectrometry ◽  
Sampling Location ◽  
Pyrolysis Gas ◽  
Pyrolysis Products ◽  
Climate Change Research ◽  
Gas Formation ◽  
Peatland Restoration

Abstract. Peatlands play an important role in the global carbon cycle and represent both an important stock of soil carbon and a substantial natural source of relevant greenhouse gases like CO2 and CH4. While it is known that the microbial availability of organic matter affects degradation and mineralization processes in peatlands, the manner in which peat organic matter affects the formation of CO2 and CH4 remains unclear. In this study we developed a fast and simple peat quality index in order to estimate its greenhouse gas potential by linking the thermo-degradability of peat with anaerobic CO2 and CH4 formation rates. Peat samples were obtained at several depths (0–40 cm) at four sampling locations from an acidic fen (pH∼4.7). CO2 and CH4 formation rates were highly spatially variable and depended on depth, sampling location, and the composition of pyrolysable organic matter. Peat samples active in CO2 and CH4 formation had a quality index above 1.35, and the fraction of thermally labile pyrolyzable organic matter (comparable to easily available carbon substrates for microbial activity) obtained by thermogravimetry was above 35%. Curie-point pyrolysis-gas chromatography/mass spectrometry mainly identified carbohydrates and lignin as pyrolysis products in these samples, indicating that undecomposed organic matter was found in this fraction. In contrast, lipids and unspecific pyrolysis products, which indicate recalcitrant and highly decomposed organic matter, correlated significantly with lower CO2 formation and reduced methanogenesis. Our results suggest that undecomposed organic matter is a prerequisite for CH4 and CO2 development in acidic fens. Furthermore, the new peat quality index should aide the estimation of greenhouse gas formation potential resulting from peatland restoration and permafrost thawing and help yield more robust models of trace gas fluxes from peatlands for climate change research.

Pyrolysis gas chromatography - mass spectrometry of humic substances extracted from Canadian lake sediments

2000 ◽  
Vol 78 (1) ◽  
pp. 51-63 ◽  
Author(s):  
Helen A Joly ◽  
Hongbo Li ◽  
Nelson Belzile
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Humic Acid ◽  
Lake Sediments ◽  
Humic Substances ◽  
Gas Chromatography Mass Spectrometry ◽  
Pyrolysis Gas ◽  
Pyrolysis Products ◽  
Pyrolysis Gas Chromatography ◽  
Chromatography Mass Spectrometry

Humic substances (HS) were extracted with the aid of 0.1 M Na4P2O7 and 0.5 M NaOH solutions from the sediments of four lakes located in the Sudbury area in Ontario, Canada, namely, Tilton, Clearwater, Silver and Ramsey Lake. The humic acid (HA) and fulvic acid (FA) extracts, purified and characterized using classical methods i.e., elemental analysis, FTIR spectroscopy, and CPMAS 13C NMR (see N. Belzile, H.A. Joly, and H. Li. (1997)), were submitted to pyrolysis - gas chromatography - mass spectrometry (Py-GC-MS). The pyrolysates of the HA and FA extracts were found to be complex mixtures of at least 200 compounds. Results based on statistical analysis of the abundances of pyrolysis products (of known origin) revealed trends similar to those obtained from the classical bulk characterization techniques. The Py-GC-MS technique supported the observation, obtained from classical methods, that the chemical composition of HA extracts varied less significantly among the four lake sediments than for the FA extracts. The abundances of lignin and carbohydrate pyrolysates showed the highest variation among the FA extracts. Pyrolysis products originating from lignin, carbohydrates, proteins, and fatty acids were identified. Key words: humic substances, humic acid, fulvic acid, pyrolysis, pyrolysis – gas chromatography – mass spectrometry, lake sediments.

Investigation of eucalypt and pine wood acid-soluble lignin by Py-GC-MS

Holzforschung ◽  
2020 ◽  
Vol 74 (2) ◽  
pp. 149-155
Author(s):  
Gabriel Castro Brumano ◽  
Jorge Luiz Colodette ◽  
Sérgio A. Fernandes ◽  
Bianca Moreira Barbosa ◽  
Fernando José Borges Gomes
Keyword(s):  
Paper Industry ◽  
Pulp And Paper Industry ◽  
Gas Chromatography Mass Spectrometry ◽  
Pyrolysis Gas ◽  
Pyrolysis Products ◽  
Pine Wood ◽  
Quantification Method ◽  
Acid Soluble Lignin ◽  
Dry Wood ◽  
Soluble Lignin

AbstractThe Klason method is adequate for quantifying lignin in softwood (SWD) but is less so for hardwood (HWD). The latter contains a fraction of acid-soluble lignin (ASL) that is not measurable under the conditions prevailing in the Klason method and that must be quantified by other means. This study aimed at investigating the composition of ASL obtained from eucalypt and pine woods by using pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS). About 2.7% and 0.9% ASL by dry wood weight were measured in the acid filtrate of eucalypt and pine, respectively, by the Technical Association of the Pulp and Paper Industry (TAPPI) UM 250 method. The acid filtrate was lyophilized and processed by Py-GC-MS, allowing identification of 26 primary pyrolysis products, with 2% and 52% relative molar abundance coming from lignin and carbohydrates, respectively, for eucalypt and 24 primary pyrolysis products, with 1% and 54% relative molar abundance from lignin and carbohydrates, respectively, for pine. The main products derived from lignin were phenol, 4-methylphenol, guaiacol, 4-methylcatechol, syringol, acetosyringone and vanillin. It was concluded that measurements of ASL remain a requirement for accurate eucalypt and pine wood lignin quantification because lignin derivatives remain in the acid filtrate from the Klason lignin quantification method. Corrections for carbohydrate-derived compounds are not necessary, despite their predominance in the filtrate, because these derivatives do not interfere with ultraviolet (UV) absorption.

scholarly journals Ramped thermal analysis for isolating biologically meaningful soil organic matter fractions with distinct residence times

SOIL ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 131-144 ◽  
Author(s):  
Jonathan Sanderman ◽  
A. Stuart Grandy
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Gas Chromatography Mass Spectrometry ◽  
Residence Times ◽  
Mineral Surfaces ◽  
Pyrolysis Gas ◽  
Pyrolysis Products ◽  
Organic Matter Fractions ◽  
Increasing Temperature

Abstract. In this work, we assess whether or not ramped thermal oxidation coupled with determination of the radiocarbon content of the evolved CO2 can be used to isolate distinct thermal fractions of soil organic matter (SOM) along with direct information on the turnover rate of each thermal fraction. Using a 30-year time series of soil samples from a well-characterized agronomic trial, we found that the incorporation of the bomb spike in atmospheric 14CO2 into thermal fractions of increasing resistance to thermal decomposition could be successfully modeled. With increasing temperature, which is proportional to activation energy, the mean residence time of the thermal fractions increased from 10 to 400 years. Importantly, the first four of five thermal fractions appeared to be a mixture of fast- and increasingly slower-cycling SOM. To further understand the composition of different thermal fractions, stepped pyrolysis–gas chromatography–mass spectrometry (Py-GC/MS) experiments were performed at five temperatures ranging from 330 to 735 ∘C. The Py-GC/MS data showed a reproducible shift in the chemistry of pyrolysis products across the temperature gradient trending from polysaccharides and lipids at low temperature to lignin- and microbe-derived compounds at middle temperatures to aromatic and unknown compounds at the highest temperatures. Integrating the 14C and Py-GC/MS data suggests the organic compounds, with the exception of aromatic moieties likely derived from wildfire, with centennial residence times are not more complex but may be protected from pyrolysis, and likely also from biological mineralization, by interactions with mineral surfaces.

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