rubber MWCNT composite using solution casting [62]. Purified Halloysite (aluminosilicate nanotube) is mixed with NR (ISNR-20) in the proportion 1:10 using
toluene as a solvent at an elevated temperature. Lima et al. fabricated thermoplastic
polyurethane (TPU)/MWCNT composites by spray coating [63] after taking exact
amounts of the constituents suspended in DMF. The solution was sprayed on to a
stainless steel substrate and a solvent evaporation was carried out at 60
C. Guo
et al. have prepared isophoronediisocyanate (IPDI) and poly(diethylene adipate)
(PDA) based polyurethane (PU)/MWCNT composites in methyl ethyl ketone
(MEK) at 75
C for 3 h to synthesize NCO-terminated pre-polymer [64]. Chain
extender was slowly charged into the system followed by the addition of MWCNTs
dispersed in DMF and the reaction condition was maintained at 50
C for 2.5 h. Sui
et al. fabricated NR/CNT nanocomposites prepared through the solution route
followed by processing in two-roll mill in presence of ingredients including vulcanizing agent [65]. Thomas et al. made a blend of epoxy resin and acrylonitrilebutadiene-styrene (ABS) containing 3.6 wt% ABS and mixed with dispersed
MWCNTs. Subsequently, the mixture was cured at 180
C using 4,4
/
-diaminodiphenylsulfone (DDS) [66].
4.1.2 Melt Mixing Method
Melt mixing is an economic and industrially viable method for composite preparation. However, good dispersion in the composite is essential for satisfactory and
uniform properties and homogeneous dispersion is usually obtained at a high shear
condition [67, 68], usually true for other thermoplastics or using compatibilizers
[69]. CNFs and CNTs have enough functional groups which can act as grafting sites
and thereafter suitable for their dispersion considerably [70]. Kong et al. explained
extrusion as a high volume manufacturing process for fabricating parts with thermoplastic elastomers [71]. Pedroni et al. prepared nanocomposites of styrenebutadiene-styrene (SBS) and MWCNT through melt mixing using a mini-extruder
processed at 150
C and 90 rpm [72]. Nanocomposites of elastomers can also be
prepared using open two-roll mill at room temperature [73]. Siengchin
et al. reported the water-assisted melt compounding method [74] where nanofillers
have been used in the form of water slurry for better dispersion.
4.2 Dispersion in Nanocomposites
The properties of the nanocomposites depend on the level of dispersion of nanoparticle in the elastomer matrices. The dispersion of the nanoparticle can be
checked through electron microscope (transmission electron microscope (TEM),
scanning electron microscope (SEM)) or atomic force microscopy). Figure 1A
shows the TEM bright field images of NR nanocomposites with different concentration (5–16 wt%) of MWCNTs of mean diameter ~13 nm and length of ~20 μm
20
K.K. Jana et al.
toluene as a solvent at an elevated temperature. Lima et al. fabricated thermoplastic
polyurethane (TPU)/MWCNT composites by spray coating [63] after taking exact
amounts of the constituents suspended in DMF. The solution was sprayed on to a
stainless steel substrate and a solvent evaporation was carried out at 60
C. Guo
et al. have prepared isophoronediisocyanate (IPDI) and poly(diethylene adipate)
(PDA) based polyurethane (PU)/MWCNT composites in methyl ethyl ketone
(MEK) at 75
C for 3 h to synthesize NCO-terminated pre-polymer [64]. Chain
extender was slowly charged into the system followed by the addition of MWCNTs
dispersed in DMF and the reaction condition was maintained at 50
C for 2.5 h. Sui
et al. fabricated NR/CNT nanocomposites prepared through the solution route
followed by processing in two-roll mill in presence of ingredients including vulcanizing agent [65]. Thomas et al. made a blend of epoxy resin and acrylonitrilebutadiene-styrene (ABS) containing 3.6 wt% ABS and mixed with dispersed
MWCNTs. Subsequently, the mixture was cured at 180
C using 4,4
/
-diaminodiphenylsulfone (DDS) [66].
4.1.2 Melt Mixing Method
Melt mixing is an economic and industrially viable method for composite preparation. However, good dispersion in the composite is essential for satisfactory and
uniform properties and homogeneous dispersion is usually obtained at a high shear
condition [67, 68], usually true for other thermoplastics or using compatibilizers
[69]. CNFs and CNTs have enough functional groups which can act as grafting sites
and thereafter suitable for their dispersion considerably [70]. Kong et al. explained
extrusion as a high volume manufacturing process for fabricating parts with thermoplastic elastomers [71]. Pedroni et al. prepared nanocomposites of styrenebutadiene-styrene (SBS) and MWCNT through melt mixing using a mini-extruder
processed at 150
C and 90 rpm [72]. Nanocomposites of elastomers can also be
prepared using open two-roll mill at room temperature [73]. Siengchin
et al. reported the water-assisted melt compounding method [74] where nanofillers
have been used in the form of water slurry for better dispersion.
4.2 Dispersion in Nanocomposites
The properties of the nanocomposites depend on the level of dispersion of nanoparticle in the elastomer matrices. The dispersion of the nanoparticle can be
checked through electron microscope (transmission electron microscope (TEM),
scanning electron microscope (SEM)) or atomic force microscopy). Figure 1A
shows the TEM bright field images of NR nanocomposites with different concentration (5–16 wt%) of MWCNTs of mean diameter ~13 nm and length of ~20 μm
20
K.K. Jana et al.