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Evaluation of the influence of selected liquefaction factors on the spectral parameters of liquefied wood

Bielejewska N., Janiszewska D.

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology

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2018

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No. 104

492--495

EN

This work focuses on spectroscopic characterization of lignin extracted from wood liquefaction residues. The aim of the research was to evaluatethe influence of the amount of the solventand the raw material typeused for liquefaction on the spectral parameters of the lignin isolated from liquefaction residues.Different types of biomass assortments were liquefied according to the previously described procedures.The amount of the propylene glycol used as the liquefying agent has been modified. The lignin isolated from the residues after wood liquefaction process has been subjected to spectroscopic studies. Absorption spectra were obtained using a double-beam spectrophotometer. As a reference the lignin extracted from standard untreated samples was used. Based on the research it has been concluded thatthe amount of the solvent and the raw material type do not have significant influence on the spectral properties of liquefied wood products.

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Application of selected agents for wood liquefaction and some properties of particleboards produced with the use of liquefied wood

Janiszewska D., Frąckowiak I., Bielejewska N.

Drewno : prace naukowe, doniesienia, komunikaty

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2016

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vol. 59, nr 197

223--230

EN

This work presents the characteristics of wood liquefied using different types of solvents in terms of its application for binding particleboards. Standard pine particles from barked wood were used for the liquefaction experiments. The liquefaction reaction was carried out in high temperature conditions using a mixture of solvents from the polyhydroxy alcohol group, including glycerine, ethylene glycol, propylene glycol, diethylene glycol, and dipropylene glycol. The microstructure of both the liquefied wood and the liquefaction residues was determined by means of optical microscopy analysis. The basic parameters of the adhesive mixture modified with the liquefied wood, such as viscosity, pH and gel time were determined. Particleboards containing liquefied wood were produced. The following physicochemical and mechanical properties of the particleboards were measured: tensile strength, bending strength, modulus of elasticity, and formaldehyde content. The influence of the liquefying agent on the board properties was investigated. In all the tests, a control particleboard, bonded with a urea-formaldehyde adhesive resin with no inclusion of liquefied wood, was used for the purposes of comparison.

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Spectral properties of naphthalimide dyes mixed with 4-heptyl-4'-cyanobiphenyl (7CB) in Langmuir-Blodgett films

Bielejewska N., Chrzumnicka E., Stolarski R., Bauman D.

Opto-Electronics Review

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2010

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Vol. 18, No. 2

197-207

EN

Langmuir-Blodgett (LB) films formed of some fluorescent dyes, namely derivatives of 4-aminonaphthalimide, and their binary mixtures with the liquid crystal 4-heptyl-4'-cyanobiphenyl (7CB) have been studied. The electronic absorption and fluorescence spectra were recorded. On the basis of these spectra, the spectral properties of the dyes and the intermolecular interactions in ultrathin ordered films were determined. The conclusions about the tendency to the creation of aggregates by dye molecules in LB films have been drawn. The measurements of absorption by using linearly polarised light have allowed us to determine the arrangement of the dye and liquid crystal molecules on the air-solid substrate interface.

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Spectral and orientational properties of new group of naphthalene derivatives of bicarboxylic acid in liquid crystal 7CB

Bielejewska N., Wolarz E., Stolarski R., Bauman D.

Opto-Electronics Review

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2008

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Vol. 16, No. 4

367-374

EN

The spectral and orientational properties of some dichroic fluorescent dyes (naphthalene derivatives of bicarboxylic acid) in some isotropic solvents and in an anisotropic matrix have been studied. The order parameter of the dyes in the nematogenic liquid crystal 7CB has been determined from measurements of polarized electronic absorption and fluorescence. The influence of the dye addition on the nematic-isotropic phase transition temperature of 7CB has been investigated. It was found that some of the dyes studied could be successfully utilized in guest-host liquid crystal display devices.