Preparation of Poly(4-methyl-1-pentene) Membranes by Low- Temperature Thermally Induced Phase Separation

As a widely used method for the preparation of membranes, thermally induced phase separation (TIPS) is usually performed at high temperatures (200-260 degrees C) and has the disadvantages of high energy consumption, usage of large amounts of solvents, and easy decomposition of polymers. To solve these problems, this article presents a low-temperature thermally induced phase separation (LT-TIPS) method for the preparation of porous poly(4-methyl-1-pentene) (PMP) membranes at 70 degrees C. The PMP/ cyclohexane solution was cast on a glass plate and quenched in water for a few minutes, and then the solvent was recovered by vacuum evaporation and condensation. The effects of quenching medium, quenching temperature, time, wet membrane thickness, and polymer concentration on the membrane porosity and air permeability were studied. The results showed that the elevated quenching temperature and extended quenching time in water favor the increase of air permeability. The increase of wet membrane thickness and polymer concentration results in reduced air permeability. The method displays convenience in process control, low energy consumption, less solvent usage, easy recovery of solvent, and environmental for the of membranes.