Synthesis and properties of double methyl oleate terminated polysiloxane

Double methyl oleate (MO) capping agent (MO-MM-MO) was prepared by hydrosilylation, from MO and tetramethyldisiloxane (HMMH). The structure was characterized by IR spectrum. By investigating the effects of different catalysts and reaction conditions on the hydrosilylation conversion, the H2PtCl6·6H2O/isopropanol solutions was selected as catalyst, and the optimal reaction conditions were determined. The double MO-terminated polysiloxane (MOM-Dn-MMO) with different degree of polymerization (DP) was prepared via octamethylcyclotetrasiloxane (D4) ring opening polymerization, with MO-MM-MO terminated. The effects of DP on the performance of MOM-Dn-MMO were studied. With the increase in DP, the viscosity–temperature performance of product gradually increases, and it remained basically unchanged, when the DP was 60 or more. For the lubrication performance, as the DP increased, the product lubrication performance improved gradually, and compared with polydimethylsiloxane (M-Dn-M), the lubrication performance of MOM-Dn-MMO was also more excellent. The products with large DP had good thermal stability, also. In addition, the effects of product on the mineral oil performance were also investigated. The MOM-D40-MMO was good compatible with mineral oil, and the lubrication performance of mineral oil with MOM-D40-MMO was also improved, due to the presence of MO.