Synthesis of 4-arms hydroxy-functionalized PMMA-b-PE through combining free radical polymerization with coordination polymerization

The 4-arms hydroxy-functionalized PMMA-b-PE was synthesized via radical polymerization and coordination polymerization strategies. MMA radical polymerization was carried out firstly in the presence of initiator tetra(2,3-epoxy propoxy)silane to form 4-arms PMMA. The polyethylene block segments were promoted by Cp2TiCl2 through coordination polymerization. [Display omitted] •We synthesized the 4-arms hydroxy-functionalized PMMA-b-PE.•We synthesized it via radical polymerization and coordination polymerization. MMA radical polymerization was carried out firstly in the presence of initiator.•The initiator was tetra(2,3-epoxy propoxy)silane.•The PE segment was promoted by Cp2TiCl2 through coordination polymerization. The copolymerization of MMA with ethylene was promoted by metallocene complex in the presence of initiator tetra(2,3-epoxy propoxy)silane (Is), reducing agent Zn and cocatalyst MAO, combining free radical polymerization with coordination polymerization via sequential monomer addition strategy in one-pot to produce 4-arms hydroxy-functionalized PMMA-b-PE. The effects of polymerization conditions such as temperature, time, ethylene pressure and Al/Ti molar ratio on the polymerization performance were investigated. 4-Arms hydroxy-functionalized PMMA-b-PE was obtained by solvent extraction and determined by GPC, MALLS, DSC, FT-IR, WAXD and 1H(13C) NMR. The DSC result indicated that the 4-arms hydroxy-functionalized PMMA-b-PE had one Tg at 87.0°C and one Tm at 117.0°C which attributed to Tg of PMMA segment and Tm of PE segment, respectively. The microstructure of 4-arms hydroxy-functionalized PMMA-b-PE was further confirmed by WAXD, FT-IR, and 13C NMR analysis. These results demonstrated that the obtained 4-arms block copolymer consisted of PMMA segment and crystalline PE segment.