Synthesis And Characterizations Of Special Cyclosiloxane Mixture

Methylsilicone oil is widely used as its excellent chemical stability, softness, hydrophobicity, bioinertia etc. One of the major development tendencies is introducing other organic groups to replace some methyl, improving some properties of methylsilicone oil, expanding the application field. Our work in the article is the synthesis and characterizations of special cyclosiloxane which is obtained by hydrolysis, cyclization reactions between dichloro silane (DDS) and other methyl chlorosilane containing other organic functional groups. This will lay the foundation for the further preparation of the modified silicone oil with uniform distribution of chain structure.The synthesis and characterization of cyclosiloxane mixture with single organic group methyl-cyclosiloxanes were studied in the first part of this thesis. With dichloro silane containing single organic groups and pure dichloro silane (DDS) as raw material, ZnO as catalyst, the monofunctional modified cyclosiloxanes were prepared via hydrolysis reaction. They were found that Si-H、Si-Ph、Si-CH2CH2CF3 had been exist in established cyclosiloxane mixture by FTIR and 1HNMR analysis. And the GC/MS also be used to separate and identify the cyclics mixture, each component was clearly defined. Meanwhile, the effect of process conditions including the hydrolysis medium, the feeding rate and the reaction temperature were also discussed. The results showed that the feeding rate had great impact on the product yield. The optimal reaction condition is the reaction temperature 35℃, the feeding rate 1 ml/min, the molar quantity of water in the reaction system is 8-10 times as much as DDS. With the methyl phenyl cyclosiloxane as raw materials, phenyl silicone oil with improved the thermal stability was prepared by ring-opening polymerization (ROP).The synthesis and characterization of cyclosiloxane mixture with multi-organic groups were studied in the second part of this thesis. With dichloro silane containing two or three even four organic groups as raw material, ZnO as catalyst, the cyclosiloxane mixture with multi-organic groups were prepared via hydrolysis reaction. The GC/MS be used to separate and identify the cyclics mixture, each component was clearly defined. And Meanwhile, with modified cyclosiloxane containing various organic groups as raw material, modified silicone oil (PAFPMS) was prepared by ROP. The results shows that the introduction of phenyl groups can improved effectively its thermal stability, the introduction of 3,3,3-trifluoropropyl group can improved effectively its surface property, the introduction of dodecyl group can improve its the compatibility with other mineral oil. And its application is promising.