The wheat straw lignin as renewable polyol for polyurethanes elastomers

The novel wheat straw) produced on CIMV pilot plant (France) was sequential extracted with organic solvents of different polarity (dichloromethane, methanol and dichloromethane/methanol mixture. Parent lignin was characterized by a weak activity in reaction with MDI in comparison with fractionated lignins. In this study the effects of lignin on the properties of PU elastomers obtained from three components systems included polyethelene glykol (Mn=400 g/mol) as a soft segment, fractionated lignins and commercial polymeric diphenylmethane diisocyanate Voratec SD 100 were investigate

Combination of Analytical Pyrolysis and fractionation of technical lignin as a tool for improvement of its antioxidant properties

Antioxidant properties of parent lignin and its fractions was assessed in the tests with free radicals ABTS•+ and DPPH. Increasing ratio between content of syringyl and guaiacyl substructures and the extent of conjugation of lignin macromolecule (Py-GC/MS data) enhanced lignin radical scavenging capacity. The compositional heterogeneity (the presence of lipophillic extractives) had negative impact on the lignin radical scavenging capaci

Study of the reactivity of Kraft and organosolv lignins with 4, 4’–diphenylmethane diisocyanate and characterization of the obtained products

The interaction of two types of lignins: Kraft lignin (KL), isolated according to the LignoBoost process (Sweden), and Alcell organosolv (OL) lignin (Canada), with 4,4’-diphenylmethane diisocyanate (MDI) in the dry dioxane media at 25 degrees of Celsius, was investigated. In the presence of dibutiltin dilaurate (DBTD) the second order rate reaction and 43-56 % conversion were observed. After that the negative deviation from the second order kinetic was observed. The complete NCO conversion in the case of KL takes more time than that of OL

Effect of lignins on structure, tensile and thermal properties of polyurethanes films

The organosolv lignins of wheat straw acts as a cross linking macromonomer in PU compositions. The fractionation of lignin and variation of fractions contents in PU composition allow to control the properties of PU films and to obtain the elastomers in high elastic state at room temperature or rigid and glassy crosslinked PU

Polyoxometallate catalyzed oxidative modification of lignin as a favorable pre-treatment for copolymerization with propylene oxide for polyurethanes production

The oxypropylation of the parent and oxidized lignins with propylene oxide (PO) was studied in high pressure Parr reactor using KOH as a catalyst. It was shown that oxypropylation of lignin pre-oxidized in the system POM/H2O2 proceeded in the similar manner as the parent lignin but the rate of the process was some lower due to the presence of higher amount of -COOH groups with lower nucleophilicity

Fractionation of CIMV wheat straw lignin as an approach for promoting it interaction with isocyanates and characteristic of products obtained

The reactivity of CIMV lignin fractions with MDI has been investigated in extra dry dioxane (DOX) in argon atmosphere at 25 degrees of Celsius, using FTIR spectroscopy (absorbance band at 2273 cm^-1) for monitoring the NCO group disappearance during reaction. Five CIMV lignin fractions were obtained and investigated: 2 fractions obtained by separate extractions with DOX and methanol and 3 fractions obtained in the process of sequential extraction of CIMV lignin with dichloromethane, methanol and methanol/dichloromethane mixture. The highest second rate constants was detected for both methanol soluble lignin fractions

Work with the mediatext as an indispen sable component of information culture of a teacher o f music

При финансовой поддержке Российского гуманитарного научного фонда, проект № 07-06-14162

Potential of Pyrolysis for valuable products obtaining from wheat straw lignin produced by CIMV technology

Two configurations of fast pyrolysis realized in flowing (inert gas flow) and ablative-type reactors were used for phenolic fraction obtaining. The maximum yield of phenolic compounds was achieved at 450 degrees of Celsius in the case of ablative reactor usage (7,6%). Application of catalysts (Na+ and K+) allowed to increase the yield of phenolic compounds up to 8,5%

Determination and Separation of Diarylheptanoids From Alder Growing in Latvia

The composition of diarylhepatnoids fraction isolated from bark of two alder species (grey alder and black alder) was studied. The efficiency of three extraction methods used for isolation of diarylhepatnoids from alder bark was compared. Two diarylhepatnoids: 1,7-bis-(3,4-dihydroxyphenyl)-heptan- 3-one-5-O-β-D-xylopyronoside (oregonin) and 1,7-bis-(3,4-dihydroxyphenyl)-3-hydroxyheptane-5-O-β-D- xylopyranoside were isolated from the bark of grey alder. The phenolic components of the extracts were analyzed by high-performance liquid chromatography (HPLC). Quantitative determination of oregonin was performed using an internal standard method. The results obtained show that alder barks are rich source of diarylhepatnoids

The Peculiarities of a Teacher of Arts' with a Work with an Artistic Text

При финансовой поддержке Российского гуманитарного научного фонда, проект № 08-06-14134