Enhanced durability of silanized multi-walled carbon nanotube/epoxy nanocomposites under simulated low earth orbit space environment

Silane treated carbon nanotube filled polymer nanocomposites are suggested as a new alternative to reduce the degradation of polymer matrix composites (PMCs) exposed to the low earth orbit (LEO) environment. The silanization of multiwalled carbon nanotubes (MWCNTs) is conducted using 3-aminopropyltriethoxysilane (APTES). Nanocomposites filled with MWCNTs with and without silanization were prepared by the solution mixing method using mechanical/physical approaches to homogeneously disperse the MWCNTs into the polymer matrix. The samples were exposed to an accelerated low earth orbit simulated space environment for 20 h. The synergistic environmental factors used in the ground simulation systems were high vacuum, atomic oxygen (AO), ultraviolet (UV) radiation and thermal cycling. The material properties for nanocomposites reinforced with MWCNTs with and without silanization before and after exposure to the low earth orbit space environment were evaluated by total mass loss (TML), tensile test, thermo-gravimetric analysis (TGA), thermo-mechanical analysis (TMA), and thermo-optical analysis. Surface morphologies of the exposed samples were characterized through scanning electron microscopy (SEM). The results indicated that improvement of the interfacial bonding between the nanotubes and the matrix by the silanization of MWCNTs can considerably reduce the degradation rate and enhance the thermal stability, without sacrificing the thermo-mechanical properties of nanocomposites with very low MWCNT content under LEO space environmental conditions.