The effects of kinetic factors of phase separation

such as coarsening time and quenching temperature

on the hydrophilic microporous membranes were studied via thermally induced phase separation(TIPS) process using three hydrophilic ethylene-acrylic acid co-polymers(EAA) with different co-unit contents and diphenyl ether(DPE)．The coarsening time and quenching temperature were used to influence the phase separation of the three different EAA/DPE systems

their diluent droplets growth

membrane cell size and crystalline structure．The mechanism of phase separation

liquid-liquid or solid-liquid made

was determined by the quenching temperature．For EAA／DPE systems liquid-liquid phase separation occurred when the quenching temperature was above the crystalline temperature of EAA

and solid-liquid phase separation occurred when the quenching temperature was below the crystalline temperature of EAA．The experimental results showed that the membrane pore size of the EAA/DPE systems was increased with increasing the quenching or cooling temperature．The average size of the cells was 1～3μm

3～5μm and 6～8 μm for samples with a same coarsening of time of 10 min

but differernt quenching temperatares 30℃

60℃ and 90℃

respectively．At the quenching temperature of 30℃

the droplet phase in EAA／DPE systems hardly grew because the temperature was below the crystalline temperature of EAA．The diluent droplet growth was restricted by the high viscosity of the system and the crystalline structure of EAA co-polymer．While at 90℃

it is above the crystalline temperature of EAA co-polymer

a dramatic increase of droplet size occurred with the coarsening time in the begining

and after 8 min the size kept almost unchanged．