Today's KNOWLEDGE Share: BISMALEIMIDE RESIN (BMI)

Today's KNOWLEDGE Share

BISMALEIMIDE RESIN (BMI):

Bismaleimides monomers are synthesized from maleic anhydride and an aromatic diamine and then, the resulting bismaleamic acid is cyclo-dehydrated to a bismaleimide resin.BMI resins are a type of high-performance thermosetting polymer that possesses exceptional mechanical and thermal properties. These resins are characterized by their high heat resistance, flame resistance, and dimensional stability, that are suitable for a wide range of applications mainly withstanding extreme conditions.

BMI is easy processing by autoclave, platen press, and compression molding techniques,

excellent mechanical properties up to 250 °C,

good solvent resistance,

excellent performance in hot and wet conditions

superior flame and radiation resistance,

low smoke and toxicant emissions.

Processing techniques include prepregging resin transfer molding (RTM), filament winding,compression molding, powder coating and pultrusion.

The drawback of the BMI resins is Fracture toughness.This hampers its use in aerospace applications.To improve the toughness,a flexible monohydric aliphatic amine (MAA) can be added with neat BMI resins to increase the toughness of the resin.The morphology of MAA modified BMI observed via scanning electron microscopy (SEM).Various formulations tried in a few research projects over the decades,at 1% MAA adding in the formulation,the elongation at break MAA-modified BMI increased by 32.3 % when compared with neat BMI.The same way flexural strength of MAA modified BMI showed increasing 30%.This results showed increase usage in aerospace applications in the recent years.

There is a couple of research that have been taking place in adding inorganic fillers such as Nano Sio2,Carbon Nano Tube (CNT) and Graphene with the modification of BMI resin system with Carbon fiber,Kevlar,Basalt and Glass fiber.The results are breathtaking and leads to lot new more research to improve the toughening properties of BMI composite laminates.

Another research that impressed me was producing bismaleimide from renewable carbon content through multi functional phosphate(TAMPP) from clove oil.

A multi-functional phosphate (TAMPP) was synthesized from renewable eugenol through aqueous-phase synthesis, of which the renewable carbon content is as high as 100%. TAMPP was used to partly or totally replace petroleum-based 2,2′-diallylbisphenol A (DBA) for modifying 4,4′-bismaleimidodiphenylmethane (BDM), and then four bismaleimide (BMI) resins (BDTP or BTP) were developed. Compared with traditional DBA modified BDM resin (BD), BTP has better integrated properties including a higher renewable carbon content (45.0%), an approximately 70 °C higher glass transition temperature (Tg > 380 °C), excellent flame retardancy and good mechanical properties. 

Some of the leading key players are Huntsman,Evonik,Renegade Materials,Solvay, Qinyang Tianyi Chemical,Hos-Technik,Honghu Shuangma Advanced Materials,Hexcel etc.

Source:Acs publications/evonik