BMI-689 (R1155) is a low viscosity, light yellow to amber liquid bismaleimide resin designed for thermoset applications. It features a non-hydrogenated dimer diamine backbone, offering excellent thermal stability, hydrophobicity, and low pH hydrolytic resistance. This resin cures via UV or free radical initiators to form tough, flexible, cross-linked polyimides with good peel strength, making it ideal for high-temperature adhesives and mixed cure systems. It is soluble in many aromatic and aliphatic solvents and recommended to be stored at 5°C or colder.