Synthesis Of Diblock Copolymers In High Vacuum Technique

For many yeas, block copolymers of polystyrene and polydimethylsiloxane (PS-b-PDMS) have been the object of studies due to their applicability and useful properties.In this paper, well-defined diblock copolymers of polystyrene and poly(methyl-3,3,3-trifluoropropylsiloxane) were synthesized by sequential anionic polymerization in high vacuum technique.The anionic polymerization of styrene initiated with n-BuLi is followed by the polymerization of methyl(trifluoropropyl)cyclotrisiloxane (F3) initiated by polystyryl anion formed in the preliminary stage of the reaction. The reaction results in a PS-b-PMTFPS diblock copolymers.The narrowness of their molecular weight distribution was confirmed by gel permeation chromatography (GPC). The block copolymers have been characterized by infrared (IR) and nuclear magnetic resonance (NMR) spectra. DSC measurements of the diblock copolymers show clearly the presence of two-phase materials with mechanical properties depending on the PMTFPS content. Phase-separated morphologies were identified, Their sizes were measured by transmission electron microscopy (TEM) on films obtained from solvent-cast samples.In addition, (3-(l-ethoxyethoxy)propyl) lithium containing an actal protected functional group has been readily prepared from l-chloro-3-(l-ethoxyethoxy) -propane in high yield, and was successfully used to the synthesis of polystyrene. The polymerization of methyl methacrylate was also completed using n-BuLi as initiator. The work is ready for the synthesis of poly(methyl methacrylate)-poly(methyl -3,3,3-trifluoropropylsiloxane)(PMMA-b-PMTFPS).