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981.
A. R. Mahendran N. Aust G. Wuzella U. Müller A. Kandelbauer 《Journal of Polymers and the Environment》2012,20(4):926-931
A new bio-based non-isocyanate urethane was obtained by the reaction of a cyclic carbonate synthesized from a modified linseed oil and an alkylated phenolic polyamine (Phenalkamine) from cashew nut shell liquid. The incorporation of functional cyclic carbonate groups to the triglyceride units of the oil was done by reacting epoxidized linseed oil with carbon dioxide in the presence of a catalyst. Structural changes and changes in molar mass during the carbonation reaction were characterized using infrared spectrometry (FTIR) and chromatography. The aminolysis reaction of the cyclic carbonate with phenalkamine was monitored using real-time FTIR at 80 and 100?°C, respectively. The decay of the carbonate groups and the appearance of the newly built C=O groups of the urethane linkages were measured in situ through real-time FTIR spectra in dependence on the reaction time. Oscillatory time sweep measurements were used to monitor the viscoelastic properties of the system at 80 and 100?°C. The time of gelation was determined from rheometric measurements. Changes of the apparent activation energy with respect to the conversion of the reaction were calculated from isothermal measurements using Vyazovkin??s free kinetic model. 相似文献
982.
Seasonal changes in river water chemistry and in soil atmospheric CO2 concentrations at two depths and drainage water solute composition at two upland peaty podzol sites in north east Scotland were monitored over 12 months. the CO2 concentrations were controlled by changes in soil temperature and moisture status. Highest CO2 concentrations were observed in late summer 1988 when both soil temperatures and the moisture status of the soils were high. Then maximum CO2 concentrations of 4% (v/v) were recorded for one of the sites. No significant correlations between seasonal changes in soil CO2 concentrations and river water solute composition were observed. Nevertheless the field results and laboratory experiments indicated that in upland areas, where soils with acid surface horizons are common, soil CO2 substantially influences river water chemistry at baseflow, increasing the pH and cation concentration of the soil water draining into the river. the results suggest that transfer of carbon as dissolved CO2 in drainage water is a significant pathway for CO2 transfer to the atmosphere. 相似文献
983.
U. -D. Matzke 《Die Naturwissenschaften》1990,77(5):250-252
Naturwissenschaften aktuell 相似文献
984.
985.
At a MSWI (municipal solid waste incinerator) plant PCDD/PCDF samples (gasphase and particulates) were taken simultaneously be a shock-freezing method in the incinerator combustion chamber at approx. 800°C and in four sampling sections in the boiler at about 490°C, 370°C, 330°C and 270°C. In this way PCDD/PCDF-formation in the flow through the boiler was determined. Two data sets were evaluated. A considerable PCDD/PCDF-formation had occurred already at boiler temperatures of about 490°C; the highest concentration, however, was found at the end of the boiler at about 300°C. The accompanying measuring program of plant parameters made the calculation of the PCDD/PCDF mass flows possible, which allowed the inclusion of the PCDD/PCDF-content in the ESP dust in the mass flow calculations. 相似文献
986.
987.
988.
The importance of reaction-rate theories is outlined and a short review is given over the main theories of unimolecular reactions. A new approach along the lines of the Slater theory is presented. Results of molecular decomposition rates for a chlorinated dioxine and related compounds are presented. 相似文献
989.
990.
Shahamat U. Khan 《Chemosphere》1982,11(8):771-795
A high-temperature distillation technique was developed for determining and chemically identifying the bound (nonextractable) residues of 14C-prometryn in an organic soil and plants. A considerable portion of the bound 14C residues in the incubated organic soil was identified as prometryn. These residues were absorbed by plants grown in the soil. Hono-and di--dealkylated metabolites of prometryn were present in the plant bound 14C residues and a major portion of bound residues as associated with lignin. Soil-bound 14C residues were also released from soil by microbes. The bound 14C residues in soil were associated with humin, humic acid, and fulvic acid fractions. Thermoanalytical methods were used to obtained information on the nature and location of 14C bound residues in soil and humic materials. 相似文献