Abstract:

Coupling agent γ-aminopropyltrimethoxysilane(AMPS) was firstly bond onto the surface of silica gel particles forming modified AMPS-SiO2 particles. With the presence of ammonium persulphate in the solution, a redox initiating system was then achieved and allowed the surface-initiated graft polymerization of methacrylic acid(MAA) on the silica gel particles with a high grafting degree(0.30 g/g). The effects of different factors on the whole process were investigated in depth. The experimental results show that an optimal temperature for the surface-initiated graft polymerization system is 40 ℃. At higher temperature, the graft degree will decline due to the heat decomposition of ammonium persulphate. In addition, the grafted polymer layer hinders further polymerization. The appropriate reaction conditions are: 1.1% of the initiator and nearly 5% of the monomer concentration.

Key words: methacrylic acid, silica gel, redox initiating system, surface-initiated graft polymerization, grafting degree