Wyniki wyszukiwania - BazTech

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Raman system for on-line monitoring and optimisation of hybrid polymer gelation

Gnyba M., Keränen M., Maaninen A., Suhonen J., Jędzrzejewska-Szczerska M., Kosmowski B. B., Wierzba P.

Opto-Electronics Review

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2005

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Vol. 13, No. 1

9--17

EN

Authors designed and built a Raman spectroscopic system for non-invasive, remote, on-line monitoring of gelation, which is the first step of a sol-gel process used for synthesis of hybrid polymers for photonics. The system was connected with typical glass reaction vessel. Suitable design of an optical system reduced excitation of interfering Raman signal in the wall of the reactor. Application of two excitation wavelengths reduced influence of fluorescence on measurements and provided high efficiency of the Raman system in wide range extending from 200 to 3500 cm⁻¹. Synthesised materials were based on silane precursors having epoxy and amino functionality. Raman spectroscopy enabled strict control over molecular structure of the materials during the polymerization process. Time and efficiency of monomers hydrolysis were measured. Products of this reaction were evaluated. The obtained data enabled us optimisation of the process parameters which ensured high efficiency of hydrolysis and subsequent control of solution viscosity. Moreover, behaviour of amine groups and epoxy rings was investigated and influence of water and solvents was found.

2

Raman system for monitoring dye dopingto hybrid polymer network

Gnyba M., Keränen M.

Materials Science Poland

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2005

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Vol. 23, No. 1

41--48

EN

Being a relatively low-temperature technique, the sol-gel technology enables the synthesis of hybrid polymers doped by organic dyes. In order to ensure the required properties of the final product, however, the mixing of sol and dye must be strictly controlled to avoid unwanted chemical reactions between them. Raman spectroscopic in-situ monitoring of the process was used to address this problem. Problems encountered in spectroscopic studies of non-transparent dye-doped sols, arising from intensive scattering, attenuation of the Raman signal inside the investigated material, and fluorescence induced by the laser beam, are discussed. The Raman measuring system constructed for the research presented in this paper uses a diode laser and a compact spectrometer connected to a reaction glass vessel by a fibre optic probe. Proper selection of the excitation beam wavelength and suitable design of the opto-mechanical setup results in an increase of the Raman signal and improved rejection of interfering signals. The system presented does not require access inside the vessel. In-situ monitoring was carried out for the process conducted at room temperature and up to 87 ?C. As the intensity of the Raman bands assigned to the dye did not change during the process, it can be concluded that dye does not decompose.

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Diagnostyka ramanowska w procesie wytwarzania polimerów hybrydowych dla optoelektroniki

Gnyba M., Keränen M., Bogdanowicz R., Kozanecki M.

Elektronizacja : podzespoły i zastosowania elektroniki

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2002

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nr 4

5-9