Low dielectric and high performance of epoxy polymer via grafting POSS dangling chains

Polyhedral oligomeric silsesquioxane (POSS) is an ideal nano particle for epoxy polymer to reduce dielectric constant and enhance mechanical properties due to its hollow cage type organic silicon. However, the poor compatibility between POSS and epoxy resin has always been the key factor limiting the amount of addition and the improvement of performance. Herein, a modified epoxy (EGP) with POSS dangling chain is designed, that is, mercaptopropyl isobutyl POSS (POSS-SH) is grafted to diglycidyl ether of 4,4′-diallyl bisphenol-A (DADGEBA) backbone via ‘thiol-ene’ click reaction. Compared with the reported researches, thiol-ene click chemistry shows efficient and controllable, which makes the grafting efficiency of POSS-SH close to 100%. Covalent bond linking between POSS and DADGEBA constrains the aggregation and phase separation of POSS, and the content of used POSS is up to 50%. As expected, the obtained polymer (EGP-x-DDM) cured by 4,4′-diaminodiphenylmethane (DDM) presents low dielectric constant and dielectric loss, as well as tensile strength and tensile modulus are enhanced by 22.9% and 31.6%, respectively. The novel epoxy resin EGP has potential application in the electronic and electrical field.