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

摘要

Polyimides with unique thermomechanical characteristics and film forming capabilities have emerged as choice material for diversified applications in advanced technologies. Wide ranging properties could be achieved for polyimides by incorporating them with many metal salts, complexes or organic materials. The inadvertent crosslinking was introduced due to metal salt incorporation and unique polyimide alloys are prepared by blending the crosslinked and uncrosslinked polyamic acid components followed by thermal imidization. The blend components were synthesized by the reaction of polyamic acid with varying concentrations of a crosslinker (here antimony pentachloride or APC) as high as 1.67 * 10~(-2) mole/dm~3 (i.e. hypothetically calculated Critical Crosslinker Concentration) up to lowest of 1.67 * 10~(-6) mole/dm~3. This communication delves into the synthesis and characterization of polyimide blends and alloys prepared by varying degrees of crosslinking introduced via APC-Amic Acid reactions. The polyimide alloys were prepared by thermal imidization of polyamic acid blends at different curing temperature starting from 50 deg to 350 deg C. The degree of imidization, mechanical properties and the residual solvent content for blends having varying mole fractions of crosslinked or uncrosslinked components have been studied. The resultant APC-PI blends have exhibited synergism on mechanical properties. The feasibility of preparing polyimide alloys with synergistic combinations of crosslinked and uncrosslinked polyimide components was concluded.