Engineering topics
Publications and source records attributed to Beltz, Mark W..
Offset stoichiometries and end-capping agents impart desired properties. Semicrystalline polyimides synthesized from 3,3',4,4' benzophenonetetracarboxylic dianhydride (BTDA) and 1,3-bis(4-aminophenoxy-4'-benzoyl)benzene (1,3-BABB) modified to increase melt flow. Modified versions more amenable to compression molding, processing to form adhesive bonds, and use as matrices in matrix/fiber composite materials.
The semicrystalline polyimide prepared by reaction of 3,3',4,4' benzophenonetetracarboxylic (BTDA) and 1,3-bis(4-aminophenoxy 4' benzoyl) benzene (1,3-BABB) is modified so that it can be more readily processed to form adhesive bonds, moldings, and composites. The stoichiometric ratio of the two monomers, BTDA and 1,3-BABB is controlled so that the intermediate polyamide acid is of a calculated molecular weight. A polyimide acid with excess anhydride groups is then reacted with the stoichiometrically required amount of monofunctional aromatic or aliphatic amine required for complete endcapping. The stoichiometrically offset, encapped polyimide is processed at lower temperatures and pressures than the unmodified high molecular weight polyimide with the same repeat unit, and exhibits an improved melt stability.
Polymer exhibits resistance to hydraulic fluid, excellent processability, and extremely high adhesive strength. Synthesis involves reaction of new diamine, 1,3-bis 2-ethyl ether, with 3,3',4,4'-benzophenonetetracarboxylic dianhydride to form polyamic acid and subsequent conversion to polyimide.