Phenyl silicone oil is a product in which some methyl groups in methyl silicone oil are replaced by phenyl groups. Compared with ordinary methyl silicone oil, phenyl silicone oil has higher viscosity-temperature coefficient, lower freezing point, flash point, and compression resistance. The viscosity changes faster under pressure, and also has good radiation resistance, oxidation stability, heat resistance, flame resistance, UV resistance and chemical resistance. It can be used as lubricating oil, heat exchange fluid, insulating oil It can also be used for insulation, lubrication, damping, shockproof, dustproof and high temperature heat carrier, etc. It is an ideal liquid damping dielectric fluid for electronic instruments.
As a functional group in phenyl silicone oil, the content of phenyl directly affects its performance. At the same time, phenyl silicone oil is composed of octamethylcyclotetrasiloxane, tetramethyldiphenyldisiloxane, methylphenyl disiloxane The hydrolyzate of ethoxysilane is obtained by telomerization in the presence of a catalyst. Therefore, there are more or less a small amount of starting materials in phenyl silicone oil, namely methylphenylsiloxane ring, mainly including methylphenylcyclotrisiloxane, methylphenylcyclotetrasiloxane and methylphenylcyclopentasiloxane. These methylphenyl rings, as impurities of phenyl silicone oil, significantly affect the physicochemical properties of phenyl silicone oil. Therefore, in order to realize the quality control of phenyl silicone oil products, it is necessary to establish a quantitative method for methyl phenyl siloxane ring and its phenyl content in phenyl silicone oil.


Although phenyl silicone oil is a polymer, and methyl phenyl ring is a small molecular compound, the polarity of the two is very weak, and the physicochemical properties are very similar. Conventional extraction methods cannot be efficiently extracted from phenyl silicone oil. Methylphenylsiloxane ring. At the same time, the boiling point of the methylphenylsiloxane ring is relatively high, and it cannot be quantified by headspace sampling gas chromatography (or GC-MS). At present, proton nuclear magnetic resonance spectroscopy is a general method for the detection of methyl phenyl rings in phenyl silicone oil, but the NMR instruments are expensive and the detection sensitivity is not high enough, which can only achieve the detection of more than 1% methyl phenyl silicone Quantification of alkane rings. Gel permeation chromatography (GPC) technology is often used for the distribution analysis of the relative molecular mass of polymers, but it uses a general-purpose parallax refractive index detector, which cannot be used for sensitive detection of compounds. At the same time, GPC technology uses pore size. The controllable cross-linked polystyrene gel particles are separated according to the relative molecular mass size distribution of the polymer, so the separation of the polymer and the small molecule is easy to achieve. This paper attempts to combine GPC technology with a high-sensitivity UV detector to conduct the separation and quantitative analysis of phenylsilicone oil and methylphenylsiloxane ring, and provide basic research for the quality control of phenylsilicone oil products.