چكيده به لاتين
Abstract:
Nano-fillers have displayed excellent mechanical properties and are widely used in different polymer matrices for high performance applications. Recently, epoxy resin modified by nano-reinforcing fillers have been developed for adhesive applications.
In this work, influence of 0.1, 0.3 and 0.5 weight percent of various Multi-walled carbon nanotubes (<8 nm, 20-30 nm and >50 nm) on mode I fracture energy for adhesive was studied. Adhesive fracture energies were obtained by double cantilever beam (DCB). The experimental results revealed that the addition of MWCNT into the adhesive increased adhesive fracture energy. The toughening mechanisms were determined using scanning electron microscopy (SEM) Observation of the fracture surfaces using SEM showed toughening mechanism such as pullout, debonding and crack bridging. Maximum increase in fracture energy for all sizes was obtained for addition of 0.3 wt% MWCNTs. However, addition of higher amount of MWCNTs caused decrease in fracture energy due to the agglomeration of multi-walled carbon nanotubes. Addition of 3.0 wt% MWCNTs with the size of less than 8 nm improved the fracture energy by 58.4% compared with the neat adhesive.
Furthermore, cohesive zone model was used for simulating the adhesive fracture behavior and for studying the effect of the particle size on the damage behavior. The traction-separation curves of each sample was obtained. According to the obtained traction-separation curves, all specimens with 0.3 wt% MWCNTs had an increase in the process zone length and decrease in 0.5 wt% particles, due to the agglomeration multi-walled carbon nanotubes.
Keywords: Adhesive polymer, Multi-wall carbon nanotubes, Fracture energy, Traction-Separation curve
