Effect of carbon nanotubes on curing characteristics of low energy electron beam curing CFRPs

Abstract

Low energy electron beam (E‐Beam) curing process has been considered a promising fabrication technology in high‐efficiency and low‐cost OOA curing, but still not been widely used in industrial applications, mainly limited by the poor mechanical properties of the CFRP resulting from the poor toughness of the low‐energy E‐Beam curable resin. This paper extended the excellent effect of carbon nanotubes (CNTs) toughened resin to the E‐Beam curable resin system, and focused on the influence law and mechanism of CNTs on the curing characteristics of the resin. Theoretical analysis showed that the carboxylated CNTs affect the curing characteristics by participating in the chain transfer link of the cationic curing process. According to the DSC experimental results, the activation energy of the curing reaction of the resin were reduced from 136.2 kJ·mol−1 without adding CNTs to 123.9 kJ·mol−1, 118.3 kJ·mol−1, 112.8 kJ·mol−1 and 105.8 kJ·mol−1 at 0.25 wt.%, 0.5 wt.%, 0.75 wt.% and 1 wt.% of CNTs adding amount respectively, due to which the curing degree of the E‐Beam curable CFRPs were improved with the increase of CNTs contents. Considering the E‐Beam dose attenuation and its influence on curing characteristics, prepregs were irradiated single‐sided or both sided for efficient preparation of E‐Beam cured CFRP components subsequently, for which the curing degree along the prepreg thickness were investigated through the curing reaction kinetic models and DSC experiments. This study will provide research basis for parameter optimization of CNTs contents, and performance improvement of E‐Beam cured CNTs/CFRP.