Mechanical properties of clay-polyimide (BTDA-ODA) nanocomposites via ODA-modified organoclay

Clay-polyimide [3,3', 4,4'-benzophenone tetracarboxylic dianhydride-4,4'-ox ydianiline (BTDA-ODA)] nanocomposites were synthesized from ODA-modified mo ntmorillonite (organoclay) and poly(amic acid). The layered silicates of or ganoclay were intercalated by polyimide (BTDA-ODA), as confirmed by X-ray d iffraction and by transmission electron microscopy, and the tensile mechani cal properties of the nanocomposites were measured. It was found that the m odulus and the maximum stress of these organoclay/BTDA-ODA nanocomposites w ere much higher than those of pure BTDA-ODA: a twofold increase in the modu lus and a one-half-fold increase in the maximum stress in the case of 7/93 organoclay-BTDA-ODA. In addition, the elongation-for-break of organoclay/BT DA-ODA nanocomposites is even slightly higher than that of pure BTDA-ODA, w hich is a sharp contrast to that of conventional inorganics-filled polymer composites. (C) 2000 John Wiley & Sons, Inc.