New Structural Adhesives Functionalized With End Groups of Controlled Reactivity

摘要

Acetylene terminated polyimide oligomers were successfully prepared with controlled molecular weight, fully imidized structure and complete endcapping. Structural adhesives based upon this system were characterized as secondary bonding adhesives for titanium. Thermal curing at 250°C-280°C produced excellent lap shear values. Lower molecular weight oligomers exhibit lower Tg and curing temperatures, and the cured materials show much higher Tg, higher gel fractions but lower toughness. The thermal stability of cured material appears to be similar to the analogous phenyl acetylene terminated systems. They are both comparable to the thermoplastic control.