Pyrolysis Of Starch Research Articles

Distributed activation energy model of pyrolysis kinetics of starch and lignin with blast furnace slag as heat carriers

Molten blast furnace slag (BFS) can be used as heat carrier for biomass pyrolysis, which has high industrial value. Lignin (LG) and starch (ST) were chosen as model compounds of lignocellulosic biomass, which were mixed with different proportions of BFS, respectively. Thermogravimetry-process mass spectrometry studied the characteristics of LG-BFS and ST-BFS pyrolysis. The activation energies were obtained by Kissinger-Akahira-Sunose (KAS) method and four kinds of Distributed Activation Energy Model (DAEM) methods. The results showed BFS has little effect on the temperature of LG and ST pyrolysis. The average activation energy of LG-BFS-30% and ST-BFS-50% calculated by KAS method was 167.74 and 155.57 kJ∙mol−1 respectively, which meant the addition of 30% and 50% BFS promoted the pyrolysis of LG and ST, respectively. The activation energy distribution (AED) obtained by the four kinds of DAEM methods could reflect the actual pyrolysis process more completely. The results showed that the Double Gaussian distribution (GAUSS-2)and the distribution-free method (DAEM-NM) were more closer to the pyrolysis process of LG-BFS and ST-BFS. Compared with the pure LG, the CO2 content in pyrolysis gas decreased by 9.61%, and the CO content increased by 22.14% in the LG-BFS-30% pyrolysis. Compared with ST-BFS and LG-BFS, LG-BFS-30% was more conducive to the generation of CO.

UV protective bio-based epoxy/carbon quantum dots nanocomposite coatings: Synthesis and investigation of properties

This research focuses on synthesis and study of the properties of castor oil-based epoxy/carbon quantum dots (COEp/CQDs) nanocomposite coatings possessing resistance against UV. First, CQDs were synthesized by pyrolysis of starch using microwave-assisted method and characterized via various spectroscopic and microscopic methods. Next, certain quantity of castor oil as a renewable resource, CQDs with different weight percentages and a curing agent were added to epoxy resin and consequently COEp/CQDs were prepared. Through findings of FTIR, photoluminescence and UV-visible spectroscopy analyses, existent functional groups and fluorescent feature of the nanocomposite coatings were confirmed. UV-vis spectroscopy approved UV resistance of the COEp/CQDs coatings. As concentration of CQDs increased in resin matrix, UV absorption was maximized. The morphology and uniform dispersion of CQDs in the coatings matrix were verified by FESEM analysis. Results of TGA, pull-off adhesion strength and tensile tests, and DMTA analysis proved adding CQDs to the resin matrix led to progress of thermal endurance, adhesion strength, mechanical and viscoelastic properties of the synthesized coatings including an increase in storage modulus and Tg.

The effect of the grafting percent on some of the physico-chemical and thermal properties and the decomposition course of novel starch-g-poly(cinnamyl acrylate) copolymers

This paper focuses on the chemical modification of potato starch by the cinnamyl acrylate monomer during the graft copolymerization. The maximum of the grafting percent (G) was found to be 49.2% ± 0.3 at the temperature of 65 °C for 120 min in the presence of 1.0 wt% of potassium persulfate at the starch and monomer ratio 1:2.5. The copolymers exhibited excellent resistance to polar solvents and moisture which was independent of their G values. It was due to the presence of poly(cinnamyl acrylate) chains in their structure and their very compact, non-porous structure. The chemical stability of the copolymers was dependent on the G values. The copolymers showed the highest chemical resistance to neutral and acidic environments rather than to the alkaline one. Their thermal stability was ca. 210 °C under the inert and oxidative conditions. The decomposition mechanism of the copolymers was complex and included a lot of multiple simultaneous processes combined with the emission of various volatiles. The interesting fact was that the pyrolysis of starch from the copolymers occurred before that of the grafted polymer. However, the oxidative decomposition of the grafted polymer began at lower temperatures than that of starch from the copolymers.

Electrochemical stability of optimized Si/C composites anode for lithium-ion batteries

We present a simple versatile strategy to synthesized the Si/C composites as anode material for lithium batteries through the pyrolysis of starch as the precursor. Different ratios of Si to starch are used to optimize the compound and the electrochemical properties of the composites. The structure and morphology of the Si/C composites are investigated systematically by thermogravimetric and differential thermal analysis, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The electrochemical properties of Si/C composites electrode are investigated by constant current charge–discharge, cyclic voltammetry, and electrochemical impedance spectra techniques. As an anode material for lithium-ion batteries, the Si/(48 wt%)C composites exhibit the best electrochemical properties with the capacity retention of 91.3 % after 50 cycles with a current density of 100 mA g−1. The improvement could be attributed to the introduction of carbon in the Si/(48 wt%)C composites, which can provide a rapid lithium transport pathway, reduce the cell impedance, and stabilize the electrode structure during the lithium alloying–dealloying process.

New ceramic materials derived from pyrolyzed poly(1,2-dimethylsilazane) and starch as a potential anode for Li-ion batteries

Abstract New materials were obtained by pyrolysis of starch (S) and poly(1,2-dimethylsilazane) (PSN) (weight ratio: PSN/S 30/70) at temperature a) 500 °C, b) 700 °C and c) 900 °C. Ceramic materials were characterized by infrared spectroscopy, TGA, Raman spectroscopy and SEM. New Si O and shifted Si C stretching vibration modes emerged confirming direct interaction between silicon originating from silazane and oxygen coming from starch. The specific capacity of PSN/S 30/70 pyrolyzed at 900 °C was 301 mAh/g with capacity fading about 6% after 100th cycles. These values are higher (~ 50%) in comparison with the capacity of pure starch pyrolyzed at the same conditions. Electrochemical impedance spectroscopy allowed to establish temperature dependence of the particular components of an electrical equivalent circuit. The Arrhenius type behavior was confirmed for ionic transport within SEI. The charge transfer resistance, being a part of modified Randles circuit, was found to increase with temperature. Ionic transport within the electrode bulk material is represented by semi-infinitive Warburg impedance. The reciprocal of Warburg coefficient (1/σW) diminishes with temperature.

Preparation and formation mechanism of levoglucosan from starch using a tubular furnace pyrolysis reactor

Tubular furnace pyrolysis reactor for the production of organic liquids from biomass has been demonstrated at a pilot-scale of 500g/batch of dry feed at a temperature of 360–420°C. Treatment of starch gives high yields of 1,6-anhydro-β-d-glucopyranose (levoglucosan, LG). The yield depends on the heater temperature and the vacuum pressure in the reactor. The maximum yield of levoglucosan from corn starch is about 56% (analytical value) at ultimate pressure of 6×10−2Pa, pumping speed of 15L/s and temperature of 390°C. Under the same conditions, the products of levoglucosan pyrolysis are exactly the same as starch pyrolysis. Based on these experimental results and further thermal analysis, a new pyrolysis mechanism is provided and discussed.

澱粉の熱変性と酵素作用 難消化性デキストリンの特性

We have studied digestibility of pyrodextrin and its function as dietary fiber. We have established a procedure to obtain a high amount of indigestible moiety content through the pyrolysis of starch and which made possible industrial-scale production. Then, we studied digestibility and absorption of these products in vivo. The time course of blood sugar and insulin level in normal adults after intake of these products suggests that the indigestible moiety of these products is hardly digestible and absorptive in the upper tract . The recovery in feces is 5 to 20% relative to intake and the rest, we assumed, are fermented by intestinal flora and are transformed into volatile fatty acids, etc. The results of these studies showed that dextrin is recognized as dietary fiber physiologically as well as in vitro.

Production of Levoglucosan by Pyrolysis of Carbohydrates. Pyrolysis in Hot Inert Gas Stream

Starch pyrolysis was carried out in a hot gas stream to establish optimum conditions for the production of levoglucosan. Helium, nitrogen, and steam were used. Steam was most effective and convenient because of its high heat capacity and because it is easily condensed. Yields of levoglucosan increased as pressures decreased. The effect of temperature, feed weight, gas flow rate, reduced air pressure, and catalyst on the yield of levoglucosan is reported. Optimum operating conditions for the acid-catalyzed process were established. A maximum yield of 44.5% levoglucosan was obtained from cornstarch.