Technology Details

Area of Technology:Engineering Sciences

Title of the Innovation: High Temperature Resistant Phthalonitrile Resins

Brief About Innovation

High Temperature Resistant Phthalonitrile Resins

There are many high temperature thermosetting resins which are currently being utilized in aerospace industry like epoxy, phenolics, PMRs, cyanate esters and bis-maleimides for structural and specialty applications. These resins have their own limitations and drawbacks as epoxy and phenolics have poor shelf-life at room temperature and have to be stored at sub-zero conditions and that to for a limited period. PMR and bis-maleimides have issues related to their processability while cyanate ester are highly prone to hydrolysis due to presence of labile cyanate functional group (-OCN) although they show good thermal and dielectric properties at elevated temperature. Epoxy resins are not used for high temperature applications although they have good processability due to flexible aliphatic chains present in glycidyl-ether linkage. Phenolics and PMR resins also have issues related to toxic volatiles leading to volume shrinkage so have limited processing methods for fabrication of composites. Aromatic bismaleimides although have high temperature stability and high glass transition temperature but they are difficult to process. Aliphatic bismaleimides show poor isothermal properties at elevated temperature due to decomposition of aliphatic backbone.

DMSRDE, Kanpur has developed high char yield and low dielectric constant phthalonitrile resins to overcome above concerns especially for continuous usage at high temperature, high glass transition temperature. These properties are inherently due to highly aromatic skeleton of cross-linked network.

Application of Phthalonitrile Resin

Phthalonitrile resins are potential candidates for applications where it can be used as a matrix resin for fabrication of composites structures in place of currently used phenolic and epoxy resins on account of room temperature storage of monomers, high temperature stability, high glass transition temperature, low dielectric constant and high char yield of cross-linked polymer. The resin alone can also be used for ablative coating material for surfaces on account of high char yield.