Ultraviolet absorption spectrometer is widely used in adhesive testing with infrared Spectrophotometer . And it is mostly carried out by solvent extraction or thermal cracking method or connected with cracking chromatography.
(1) Determination of the styrene content in the copolymer The styrene content in the water-soluble copolymer has ultraviolet absorption properties and can be determined by ultraviolet absorption spectroscopy. However, the standard polystyrene is not water-soluble, and only the optical resonance similar to styrene is taken. Ethylbenzene was used as a standard sample to make a standard curve. The styrene content in the copolymer was measured at 263 nm. During the test, sodium lauryl sulfate micellar solution was used as the common medium of ethylbenzene and water-soluble styrene copolymer.
(2) Monitor and determine the extracts or dissolved substances of additives related to adhesives in adhesives. The ultraviolet spectrum at 200-300nm should be recorded and compared with the spectrum of possible known additives for identification. It is also possible to collect gas lysates in the gas tank. And record the ultraviolet absorption spectrum in the range of 180~260nm, such as the characteristic absorption peak of butadiene copolymer gas cracking product at 195~225nm; acrylic adhesive pyrolysis gas has a single absorption band between 195~200nm .
(3) Determine the structure of phenylsilane - in p-phenylsiloxane, the maximum wavelength and pattern of ultraviolet absorption of monophenyl and diphenyl are different, as shown in the figure. According to this, it can be determined whether a phenyl group or a diphenyl group is connected to the silicon atom through the spectrum, and the ratio between them can be further calculated.
(4) Monitor and determine the type of synthetic rubber adhesive, dissolve the pyrolysis gas and pyrolysis solution of the adhesive in a certain solvent, record the ultraviolet spectrum at 200-~300nu, and compare it with the mental map. Table 107 lists the ultraviolet spectra of pyrolysis gases of several rubbers, and Fig. 2 and Fig. 3 list the ultraviolet spectra of pyrolysis gases of corresponding rubbers.
name | characteristic absorption band | secondary absorption band | Remark |
natural rubber SBR polysulfide rubber Nitrile rubber Butadiene Copolymer Butyl rubber Chlorosulfonated polyethylene Acrylic rubber polystyrene | 220~225 220~260 195~205 195~225 195~225 194 195~220 195~200 195~200 | 200 235~240 | Similar to the polybutadiene spectrum, it can be checked according to the combustion test |
UV Spectrum of Nitrile Rubber Pyrolyzate UV Spectrum of SBR Pyrolyzate
A—28% styrene; B—50% styrene; C—60% styrene
