Thermal stable composite membranes were prepared through the interfacial polymerization of m-phenylene diamine (MPD)

piperazine (PIP) and trimesoyl chloride (TMC) on poly(phthalazinone ether) ultrafiltration membrane.The effect of the proportion of PIP and MPD in aqueous phase on the chemical structure of the active layer polymer

surface morphology and separation properties of the composite membranes was studied.The results showed that the average roughness of the surface of the composite membranes increased from 17.8 nm to 71.9 nm

the rejection for NaCl solution increased from 26% to 99%

while the flux decreased from 130 L·m-2·h-1 to 12 L·m-2·h-1

as the proportion of the monomers MPD/PIP increased from 0/100 to 100/0. The flux of the membranes trebled as the operating temperature increased from 25℃ to 80℃

while the rejection kept constant

which testified the good thermal stability of the membranes.