Targeted kinetic strategy for improving the thermal conductivity of epoxy composite containing percolating multi-layer graphene oxide chains

Abstract

Abstract. By adding 2 wt% multi-layer graphene oxide (MGO) to an epoxy resin, the thermal conductivity of the composite reached a maximum, 2.03 times that of the epoxy. The presence of 2 wt%MGO percolating chains leads to an unprecedentedly sharp rise in energy barrier at final curing stage, but an increased epoxy curing degree (! IR ) is observed; however, this ! IR difference nearly disappears after aging or thermal annealing. These results suggest that the steep concentration gradient of -OH, originated from the 2 wt%MGO percolating chains, exerts the vital driving force on the residual isolated/ trapped epoxy to conquer barrier for epoxy-MGO reaction. A modified Shrinking Core Model customized for the special layered-structure of MGO sheet was proposed to understand the resistance variation during the intercalative epoxy-MGO reaction. It shows that the promoted intercalative crosslinking is highly desirable for further improving the thermal conductivity of the composite, but it meets with increased resistance. Guided by the kinetic studies, targeted optimization on the cure processing strategy was accordingly proposed to promote the intercalative crosslinking, a thermal conductivity, 2.96 times that of the epoxy, was got with only a small amount (30°C) increase of the post-heating temperature.

Photocurable acrylate-based composites with enhanced thermal conductivity containing boron and silicon nitrides

“…However, the heat diffusivity and conductivity values of Si 3 N 4 -containing composites are about twice as high as these of BN-containing composites. The maximum values of the discussed thermal parameters are reached at about 2 wt% of the filler content in the case of Si 3 N 4 and only at about 0.5 wt% for BN composites (a similar behavior was observed for an epoxy resin filled with graphene oxide [63]). The relative increase of the both parameters (as compared to the matrix) is quite high, about 4 times for Si 3 N 4 and about 2.5 times for BN indicating essential improvement of thermal properties.…”

Two-Dimensional Nanomaterials-Based Polymer Composites: Fabrication and Energy Storage Applications

“…Here, we will use the GO/epoxy resin as an example. By using the in situ polymerization method, the resultant GO/epoxy composite showed an increase of 103% in thermal conductivity as compared with the neat epoxy (0.25 Wm −1 K −1 ), with a loading of 2 wt% GO [84]. Similar enhancement was presented in another experiment but even with lower loading of GO [48] by using the tetraethylenepentamine (TEPA) to modify the GO sheets.…”

Graphene-Based Nanocomposites: Synthesis, Mechanical Properties, and Characterizations

“…The variation in thermal conductivity with different forms of graphene and graphite nanocomposites is reviewed in Table 2 [ 230 , 231 , 232 , 233 , 234 , 235 , 236 , 237 , 238 , 239 , 240 ]. The remarkable improvement in thermal conductivity was noted in the case of XGnP compared to other fillers.…”

“…In addition to filler type, enhancement in thermal conductivity depends on other factors including the processing method and the polymer matrix. For example, Zhou et al prepared a composite by adding 2 wt.% multi-layer graphene oxide (MGO) to an epoxy resin, and the thermal conductivity of the composite reached a maximum 2.03 times that of the epoxy [ 230 ]. The presence of 2 wt.% MGO percolating chains leads to a sharp rise in the energy barrier.…”