Formation of polyamide 12 membranes via thermal-nonsolvent induced phase separation

The thermal-nonsolvent induced phase separation method was used for the fabrication of porous membranes from polyamide 12 (PA12), an attractive engineering polymer; the water/formic acid (FA)/PA12 ternary system is explored in detail. Scanning electron microscopy, differential scanning calorimetry, X-ray diffractometry, tensile strength analysis, and water flux were used to characterize the structure and properties of the fabricated membranes. The morphology of the membranes was found to depend on the FA content in the bath. The top surface of the membrane becomes less dense with increasing FA content in the bath. The cross section and bottom surface of all membranes exhibited a cellular morphology, except for the case of the novel procedure of dope precipitation in a cold neat solvent (FA) bath. In all cases membranes exhibited a crystallinity of ca. 38% with a melting point of ca. 179 degrees C; tensile strengths in excess of 10 MPa were found possible in some cases. (c) 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013