PNIPAAm with terminal amino groups was synthesized using 2-aminoethanethiol hydrochloride (AESH) as a chain transfer agent.It was then reacted with methacryloyl chloride to result in macromer

vinly PNIPAAm.A graft copolymer

P(AN-g-NIPAAm) was synthesized through the copolymerization of acrylonitrile (AN) and vinyl PNIPAAm.Using this graft copolymer as an additive

thermal responsive PAN-based membranes were prepared by the immersion precipitation phase inversion method (IPPI).Results from FTIR and NMR indicate that the molecular weight of PNIPAAm can be effectively modulated by changing the concentration of AESH.Then

the weight average molecular weight (Mw) was measured by laser scattering.Results of captive bubble contact angle measurements and turbidity analysis show that the graft copolymers are still thermally responsive

which is more remarkable with higher PNIPAAm content.XPS analysis proves that the PNIPAAm graft chains are enriched at the membrane surface and pore surface during the course of IPPI because of the hydrophilicity of PNIPAAm.Pure water flux at 40℃ (above the LCST of PNIPAAm) is almost twice as that at 25℃ (below the LCST of PNIPAAm)

which is due to the conformation change of PNIPAAm chains.All these results demonstrate the synthesized graft copolymers are effective additives for the preparation of thermal responsive PAN membranes.