which is still much smaller than that of the resin filled with the
graphene sheets. For the case of natural graphite powder, the
thermal conductivity of the adhesive is 1.68 W m1 K1 at the
maximum filling load of 44.30 wt%. Thus, the thermal conductivity
of the graphene sheets in the epoxy resin at the maximum filling
load, which is about 2.15 times higher than that the graphite
nanoflake and about 2.38 times higher than the natural graphite
powder in the epoxy resin at the maximum weight filling load.
Hence, it is obvious that the graphene sheet is better than the
graphite nanoflake and natural graphite powder as the filler to
improve the thermal conductivity of the epoxy resin.
We consider that graphene sheet can improve the thermal
conductivity of epoxy adhesive, which is attributed to its own high
thermal conductivity and super thinner layer structure [32,52].
Although some part of graphene sheets may be existed to re-unit in
resin due to the super thin layer structure and stirring, from Fig. 7B
we can clearly find graphene sheets form the three-dimensional (3-
D) thermal conductivity networks in resin matrix [38]. We
considered that more graphene sheets added in resin, more 3-D
thermal conductive networks were formed due to its ultra-thin
structure, and the resin matrix also has more better of heat flow
pathways. In this study, the graphene-epoxy resin thermal
conductive adhesive reached 4.01 W m1 K1 with the maximum
weight filling load, and certainlywe cannot ignore their own higher
thermal conductivity of graphene sheet [34]. Graphite nanoflake
also has thin layer structure, but the thickness of the flakes is ~10
times than graphene sheet (Fig. 2C). Thus, the formed thermal
pathways of graphite nanoflake in epoxy are less than graphene
sheet as shown in Fig. 7D. Its thermal conductivity is only
1.86 W m1 K1 at the maximum filling load [53]. The graphite
powder filler, it is difficult to form 3-D heat conductive network
according to its layer thickness, only some contacting heat flow
pathways exist in the adhesive as shown in Fig. 7F, so it has the
lowest thermal conductivity within the three materials [15], even
when it is with the highest load (44.3%) in epoxy matrix.
Comparison of the thermal conductivities of thermal conductive
adhesives with the three kinds of graphite materials, we can find
that the thermal conductive pathwayswere formed in a resin matrix
by the thermal filler attribute to the thickness of the filler itself.
Typically, thinner fillers are helpful for heat flow pathways as indicated
in the past study [54,55]. From this study, it can be seen that
graphene sheet is preferred to improve the epoxy resin thermal
conductivity, which is due to their intrinsic high thermal conductivity,
and super thinner layer structure which can more efficiently
form 3-D thermal transport pathways in the resin matrix.
which is still much smaller than that of the resin filled with the
graphene sheets. For the case of natural graphite powder, the
thermal conductivity of the adhesive is 1.68 W m1 K1 at the
maximum filling load of 44.30 wt%. Thus, the thermal conductivity
of the graphene sheets in the epoxy resin at the maximum filling
load, which is about 2.15 times higher than that the graphite
nanoflake and about 2.38 times higher than the natural graphite
powder in the epoxy resin at the maximum weight filling load.
Hence, it is obvious that the graphene sheet is better than the
graphite nanoflake and natural graphite powder as the filler to
improve the thermal conductivity of the epoxy resin.
We consider that graphene sheet can improve the thermal
conductivity of epoxy adhesive, which is attributed to its own high
thermal conductivity and super thinner layer structure [32,52].
Although some part of graphene sheets may be existed to re-unit in
resin due to the super thin layer structure and stirring, from Fig. 7B
we can clearly find graphene sheets form the three-dimensional (3-
D) thermal conductivity networks in resin matrix [38]. We
considered that more graphene sheets added in resin, more 3-D
thermal conductive networks were formed due to its ultra-thin
structure, and the resin matrix also has more better of heat flow
pathways. In this study, the graphene-epoxy resin thermal
conductive adhesive reached 4.01 W m1 K1 with the maximum
weight filling load, and certainlywe cannot ignore their own higher
thermal conductivity of graphene sheet [34]. Graphite nanoflake
also has thin layer structure, but the thickness of the flakes is ~10
times than graphene sheet (Fig. 2C). Thus, the formed thermal
pathways of graphite nanoflake in epoxy are less than graphene
sheet as shown in Fig. 7D. Its thermal conductivity is only
1.86 W m1 K1 at the maximum filling load [53]. The graphite
powder filler, it is difficult to form 3-D heat conductive network
according to its layer thickness, only some contacting heat flow
pathways exist in the adhesive as shown in Fig. 7F, so it has the
lowest thermal conductivity within the three materials [15], even
when it is with the highest load (44.3%) in epoxy matrix.
Comparison of the thermal conductivities of thermal conductive
adhesives with the three kinds of graphite materials, we can find
that the thermal conductive pathwayswere formed in a resin matrix
by the thermal filler attribute to the thickness of the filler itself.
Typically, thinner fillers are helpful for heat flow pathways as indicated
in the past study [54,55]. From this study, it can be seen that
graphene sheet is preferred to improve the epoxy resin thermal
conductivity, which is due to their intrinsic high thermal conductivity,
and super thinner layer structure which can more efficiently
form 3-D thermal transport pathways in the resin matrix.
การแปล กรุณารอสักครู่..