Isolation and Characterisation of the Phenolic Fractions of Wood Pyrolytic Oil

A fraction of pyrolytic oils (PyO) – obtained by fast pyrolysis of alder (Alnus incana), ash-tree (Fraxinus excelsior) and aspen (Populus tremula) in a laboratory scale reactor – was precipitated in water. This hydrophobic moiety of PyO is called pyrolytic lignin (PyL). The composition of the volatile monomeric compounds of PyO and the PyL fraction was determined by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). It has been found that PyL has a high content of phenolic products (between 75% and 83%), which varies depending on the wood species. The antioxidant properties of the PyL fraction were studied and it was demonstrated that the antioxidant activity determined in different tests exceeded the corresponding activity of alkali lignin. The antioxidant properties of PyL are on the same level as those of the widely used antioxidants, such as rutin, trolox, curcumine, and tert-butylhydroquinone (TBHQ). A new method was developed for the extraction of a monomeric phenol fraction (Py-monPh) from PyO by means of the organic solvent methyl tert-butyl ether (MTBE). The Py-monPh can be considered as a promising source of antioxidants

Isolation and Characterization of the Phenolic Fractions of Wood Pyrolytic Oil

A fraction of pyrolytic oils (PyO) – obtained by fast pyrolysis of alder (Alnus incana), ash-tree (Fraxinus excelsior) and aspen (Populus tremula) in a laboratory scale reactor – was precipitated in water. This hydrophobic moiety of PyO is called pyrolytic lignin (PyL). The composition of the volatile monomeric compounds of PyO and the PyL fraction was determined by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). It has been found that PyL has a high content of phenolic products (between 75% and 83%), which varies depending on the wood species. The antioxidant properties of the PyL fraction were studied and it was demonstrated that the antioxidant activity determined in different tests exceeded the corresponding activity of alkali lignin. The antioxidant properties of PyL are on the same level as those of the widely used antioxidants, such as rutin, trolox, curcumine, and tert-butylhydroquinone (TBHQ). A new method was developed for the extraction of a monomeric phenol fraction (Py-monPh) from PyO by means of the organic solvent methyl tert-butyl ether (MTBE). The Py-monPh can be considered as a promising source of antioxidant

Orientational Relaxation of Three Different Dendrimers in Polycarbonate Matrix Investigated by Optical Poling

We report on all-optical poling relaxation of E-O active dendrimers photo-patterned in the polycarbonate matrix. Three kinds of polyester type dendrimers G0, G1 and G2 containing azobenzene in the core were used as second-order nonlinear optical active chromophores to create noncentrosymmetry inside the material. We used a guest–host type system of these structures spin-coated on a glass substrate. These samples were poled by using an all-optical poling method, where the polar electric field of electromagnetic waves enables us to orient dendrimer molecules creating a quasi-phase-matched grating of nonlinear second-order susceptibility χ(2). Molecular orientation and subsequent dark relaxation kinetics in the samples with different poling beam applied energies were measured. Theoretical modeling of the poling relaxation kinetic revealed a set of characteristic time constants, which were interpreted by different relaxation mechanisms