Controlled RAFT polymerization of MMA in confined space of various pore sizes of SBA-15

A series of mesoporous SBA-15 with various pore diameter (8, 15, 22 and 27 nm) were synthesized and used as “microreactor”. Reversible addition–fragmentation chain transfer (RAFT) polymerization of methyl methacrylate (MMA) was conducted in the channels of SBA-15 using azodiisobutyronitrile (AIBN) as initiator, ethyl xanthate ethyl propionate as chain transfer agent. The obtained PMMA/SBA-15 composites and neat PMMAs from composites were characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, nitrogen adsorption and desorption, Fourier transform infrared spectroscopy, thermogravimetry analysis, differential scanning calorimetry, hydrogen nuclear magnetic resonance. Results showed that compared with PMMA from conventional RAFT polymerization, PMMAs obtained from internal SBA-15 featured with narrower molecule weight distribution (1.34–1.55) and higher thermal stability due to confinement effects. With the increment of pore size of SBA-15, the molecular weight and glass transition temperature (T g ) of PMMA obtained from internal SBA-15 were distinctly improved whereas isotacticity of the PMMA decreased. The properties of the PMMA were managed with controllable RAFT polymerization by regulation the pore size of SBA-15.