Alloys of polyimides with varying degree of crosslinking through antimony salts: mechanical properties characterization

Polyimides with unique thermomechanical characteristics and film forming ca pabilities have emerged as choice material for diversified applications in advanced technologies. Wide ranging properties could be achieved for polyim ides by incorporating them with many metal salts, complexes or organic mate rials. The inadvertent crosslinking was introduced due to metal salt incorp oration and unique polyimide alloys are prepared by blending the crosslinke d and uncrosslinked polyamic acid components followed by thermal imidizatio n. The blend components were synthesized by the reaction of polyamic acid w ith varying concentrations of a crosslinker (here antimony pentachloride or APC) as high as 1.67 x 10(-2) mole/dm(3) (i.e. hypothetically calculated C ritical Crosslinker Concentration) up to lowest of 1.67 x 10(-6) mole/dm(3) . This communication delves into the synthesis and characterization of poly imide blends and alloys prepared by varying degrees of crosslinking introdu ced via APC-Amic Acid reactions. The polyimide alloys were prepared by ther mal imidization of polyamic acid blends at different curing temperature sta rting from 50 degrees to 350 degrees C. The degree of imidization, mechanic al properties and the residual solvent content for blends having varying mo le fractions of crosslinked or uncrosslinked components have been studied. The resultant APC-PI blends have exhibited synergism on mechanical properti es. The feasibility of preparing polyimide alloys with synergistic combinat ions of crosslinked and uncrosslinked polyimide components was concluded. ( C) 1999 Elsevier Science Ltd. All rights reserved.