Patent ID: 10882967

Abstract:
The invention discloses a preparation method of a polyimide film having a low dielectric constant and high fracture toughness; in the method an aromatic diamine solution is firstly prepared, and then a poly(5-norbornene-2,3-dicarboxylic anhydride-alt-maleimide isobutyl polyhedral oligomeric silsesquioxane) and aromatic dianhydride are ground, uniformly mixed, added to the aromatic diamine solution, and stirred to obtain a poly(5-norbornene-2,3-dicarboxylic anhydride-alt-maleimide isobutyl polyhedral oligomeric silsesquioxane)/polyamic acid solution; the solution is uniformly applied on a clean glass sheet, then placed in a vacuum drying oven, cooled to room temperature, and then a film is peeled off in water by ultrasonic and dried under vacuum to obtain the desired product. The dielectric constant of the film obtained by the invention is reduced to 2.2, and the elongation at break is increased by 272%, the tensile breaking energy is increased by 285%, showing greatly improved elongation at break and fracture energy, and good fracture toughness.