The effects of carbon nanotube (CNT) in combination with carbon black (CB) on the properties of acrylonitrile butadiene rubber (NBR)/polyvinyl chloride (PVC) (70/30) were investigated. The results reveal that the maximal tensile strength of the rubber blend was obtained by the fillers ratio of CB:CNT = 39:1. At this filler ratio, the thermal stability and heat conductivity of the rubber blend were also significantly improved. The analysis of FE-SEM images and DMA diagram indicate that the dispersion of filler as well as the interaction between fillers and rubber matrix was improved by the incorporation of CNT. Keywords. NBR/PVC blends, carbon nanotube (CNT), carbon black (CB), nanocomposites

Hai, Luong Nhu

Ngoan, Nguyen Thi

Nguyen, Pham Cong

Suy, Pham Duy

The, Ngo Ke

Thuy Hang, Le Thi

Thuy, Nguyen Van

Tung, Ngo Trinh

Vietnam Academy of Science and Technology: Journals Online

  
Vietnam Journal of Chemistry, International Edition, 55(5): 627-632, 2017 
DOI: 10.15625/2525-2321.2017-00520 
627 
 
 
 
Study on the effect of carbon black, carbon nanotube on  
the properties of rubber blend acrylonitrile butadiene rubber 
(NBR)/polyvinyl chloride (PVC)  
Luong Nhu Hai
1*
, Pham Duy Suy
1
, Nguyen Thi Ngoan
1
, Nguyen Van Thuy
2
,                                                                       
Ngo Trinh Tung
3
, Pham Cong Nguyen
4,
, Le Thi Thuy Hang
5
, Ngo Ke The
2
 
1
Center for High Technology Development, Vietnam Academy of  Science and Technology 
2
Institute of Materials Science, Vietnam Academy of Science and Technology  
3
Institute of Chemistry, Vietnam Academy of Science and Technology
  
4
Institute H57 - Ministry of Public Security  
5
Hanoi University of Natural Resources and Environment 
Received 15 June 2017; Accepted for publication 18 October 2017 
 
Abstract 
The effects of carbon nanotube (CNT) in combination with carbon black (CB) on the properties of acrylonitrile 
butadiene rubber (NBR)/polyvinyl chloride (PVC) (70/30) were investigated. The results reveal that the maximal tensile 
strength of the rubber blend was obtained by the fillers ratio of CB:CNT = 39:1. At this filler ratio, the thermal stability 
and heat conductivity of the rubber blend were also significantly improved. The analysis of FE-SEM images and DMA 
diagram indicate that the dispersion of filler as well as the interaction between fillers and rubber matrix was improved 
by the incorporation of CNT. 
 Keywords. NBR/PVC blends, carbon nanotube (CNT), carbon black (CB), nanocomposites. 
 
1. INTRODUCTION 
 
One of the most interesting polymer blends in 
materials science is the rubber blend of acrylonitrile 
butadiene rubber (NBR) with polyvinyl chloride 
(PVC) [1]. The elastomeric component NBR can act 
as a permanent plasticizer for PVC applications, as 
in electrical wires and cables coatings, wrapping 
films for the food industry, conveyor belts, domestic 
appliances, etc. The presence of PVC helps improve 
the ozone and aging resistance of NBR, which 
enable the use of this blend in the automotive 
industry as gaskets, wires and cables, and in the 
manufacture of soles, footwear, artificial leather and 
others [2, 3]. To increase the applicability of rubber 
materials as well as rubber blends, these materials 
are usually reinforced with a number of reinforcing 
fillers such as carbon black, silica, clay, etc. [4, 5]. 
The reinforcement capability of the fillers depends 
on their particle size, shape, dispersion and 
interaction with the polymer. 
Carbon nanotubes (CNT) are one of the most 
popular nanoparticles which many researchers 
around the world are interested. CNT have great 
potential to be used as reinforcement in composites 
because of their unique properties such as high 
mechanical strength and high electrical as well as 
thermal conductivity [6-9]. CNT's reinforcement is 
better than common fillers (carbon black, silica, 
clay, etc.). However, CNT are difficult to disperse 
and very expensive. The rubber nanocomposites that 
use only CNT as single filler is actually not relevant 
for certain industrial purpose. This is where the idea 
of combination CNT, graphene with carbon black 
seems more practical [10, 11]. H. Ismail et al. 
studied CNT combination with carbon black (CB) 
for natural rubber. The results showed that the 
curing time of the materials decreased as the CNT 
content increased. The tensile strength, elongation at 
breaks and fatigue life of the material were greatest 
with CB/CNT ratio of 29.5/0.5. At this ratio, the 
dispersion and interaction between CB, CNT with 
the natural rubber matrix are the best [10]. 
In this study, the combination of CNT with CB 
will create a resonant effect to enhance the 
mechanical and thermal properties of the NBR/PVC 
blend. 
  
VJC, 55(5), 2017  Luong Nhu Hai et al.  
 628 
2. EXPERIMENTAL 
 
2.1. Materials 
 
- NBR/PVC blend is type NBR7030 (LG Chem. 
LTD., Korea). 
- Carbon Nanotube (CNT) was supplied by 
Institute of Materials Science (Vietnam). The 
average diameter of CNT is between 60-80 nm, with 
a purity of 90 %. 
- Carbon black is kind N330 (China). 
- Additives: Sulfur, Sae-Kwang Chemical IND. 
No. Ltd. (Korea); zinc oxide, Zincollied (India); 
stearic acid, PT. Orindo Fine Chemical (Indonesia); 
DM and CZ accelerator; antioxidant D (China). 
- Industrial ethanol 96° (Vietnam). 
The basic ingredients in the rubber are shown in 
table 1. 
Table 1: Formulations of the compounds 
No Ingredients Content (phr) 
1 NBR/PVC (70/30) 100 
2 Zinc oxide 5.0 
3 Stearic acid 1.0 
4 Antioxidant A 1.0 
5 CZ accelerator  1.5 
6 DM accelerator 0.5 
7 Sulfur 2.0 
8 Carbon black (CB) 10 50  
9 Carbon nanotube (CNT) 0.5 3.0 
 
2.2. Preparation and characterization methods 
 
- Preparation of rubber blends nanocomposite 
+ First, disperse CNT in ethanol 96
o
 with 
stirring and ultrasonic vibration, then the solvent to 
evaporate in part to gain CNT in paste form. 
+ Then mixing CNT paste with NBR/PVC blend 
on the internal mixer (Brabender) at 100 
o
C, the 
speed of 50 rpm for 8 minutes. 
+ After that, mixing NBR/PVC/CNT with 
carbon black and other additives on a two-roll mill at 
room temperature. 
+ Finally, sheets of rubber blends were prepared 
for curing presses. The rubber blends was 
vulcanized at a pressure of 20 kG/cm
2
, temperature 
of 155 
o
C, in 20 minutes 
 
- Material Characteristics 
Tensile properties are determined according to 
Vietnam Standard TCVN 4509-2006. The 
morphological structure was studied using Hitachi's 
S-4800 field emission scanning electron microscope 
(FESEM). Thermal stability was determined by 
Thermogravimetric Analysis (TGA) on Setaram 
Labsys Evo S60/58988 (France) at a heating rate of 
10°C/min in air. Dynamic Mechanical Analysis is 
carried out on a DMA 8000 from Perkin Elmer 
(Germany) with a constant frequency of 1 Hz, a 
heating rate of 3 °C/min from -100 °C to 100 °C in 
nitrogen. The thermal conductivity of the material 
was determined according to DIN EN 993-15 on  
Linseis THB500 instrument (Germany) with a 
power heater of 60 mW; measuring current: 20 mA; 
measurement time: 180 seconds. The sample size is 
60x40x3 mm. 
 
3. RESULTS AND DISCUSSION  
 
3.1. The effect of carbon black on the mechanical 
properties 
 
In this study, the technological factors as well as other 
additive components (accelerators, sulfur, stearic acid, 
...) are fixed, only varying content of carbon black 
(CB). The results of investigating the effect of CB 
content on the mechanical properties of NBR/PVC 
(70/30) blend are shown in the following figures. 
 
8
11
14
17
20
23
26
0 10 20 25 30 40 50
 CB conten (phr)
T
e
n
s
il
e
 s
tr
e
n
g
th
 (
M
P
a
)
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
A
b
ra
s
io
n
 (
c
m
3
/1
,6
1
 k
m
)
Tensile strength
Abrasion
 
Figure 1: Effect of CB content on tensile strength 
and abrasion  
The results in figure 1 show that, as the carbon 
black (CB) content increased, the tensile strength 
increased and the abrasion decreased. At 40 phr CB 
content, the tensile strength reached the maximum 
value and the abrasion reached the minimum value. 
If the CB content is greater than 40 phr, the tensile 
strength decreased and the abrasion increased. The 
variation in these values was due to the fact that the 
CB content is within the optimal range of CB 
particles forming their own network and splits the 
polymer macromolecules in all directions to form a 
hydrocarbon network. These two networks 
intertwine, forming a filler-rubber structure 
continuous that increases the mechanical properties 
of the material. As the CB content exceeds the 
  
VJC, 55(5), 2017  Study on the effect of carbon black... 
 629 
optimal content (greater than 40 phr) some CB 
particles do not join the CB network and it will form 
a separate phase. Thus, a fine dispersion of CB in 
rubber matrix is not obtained [4]. 
150
200
250
300
350
400
450
0 10 20 25 30 40 50
 CB content (phr)
E
lo
n
g
a
ti
o
n
 a
t 
b
re
a
k
 (
%
)
40
50
60
70
80
90
100
H
a
rd
n
e
s
s
 (
S
h
o
re
 A
)
Elongation at the break 
Hardness
 
Figure 2: Effect of CB content on elongation at 
break and hardness  
 
Meanwhile, the elongation at the break gradually 
decreased and the stiffness increased as the CB 
content increased. This can be explained, as the 
increase in CB content will make the rubber 
molecules less flexible, hampering the bonding 
between them leading to reduced elongation at break 
and increased hardness of the material. 
From the above results, CB content of 40 phr 
was chosen for further study. 
 
3.2. Effect of CNT combination with CB on the 
mechanical properties  
 
CNT possess high tensile strength of about 150 GPa, 
high elastic modulus of about 1200 GPa and high 
specific surface area that 500 times greater than that of 
carbon fiber. Therefore, this material has been 
considered as a research material used as a 
reinforcement material for polymers and only a small 
amount in the polymer, can improve the mechanical 
properties of materials. Carbon nanotubes also have 
the same chemical constituents as carbon atoms, so 
when combined with carbon black, they can have a 
resonant effect. Therefore, in this study, CB 
substitution by CNT was investigated into the 
mechanical properties of the material. The results 
are shown in table 2. 
 
Table 2: Effect of CNTs content combination with CB on the mechanical properties of materials 
Samples Tensile strength 
(MPa) 
Elongation at 
break (%) 
Hardness 
(Shore A) 
Abrasion 
(cm
3
/1.61km) 
NBR/PVC/40CB 24.28 328 86.0 0.261 
NBR/PVC/39.5CB/0.5CNT 25.19 342 86.3 0.243 
NBR/PVC/39.0CB/1.0CNT 27.01 353 87.0 0.226 
NBR/PVC/38.5CB/1.5CNT 25.33 338 87.4 0.229 
NBR/PVC/38.0CB/2.0CNT 24.54 323 88.0 0.236 
NBR/PVC/37.0CB/3.0CNT 23.85 317 89.2 0.241 
 
The results in table 2 showed that the tensile 
strength, elongation at break and abrasion resistance 
of the material reached a maximum value at 1 phr 
CNT. As the CNT content continued to increase 
(greater than 1 phr), these properties tend to 
decrease. This can be explained, as the CNT content 
exceeds the optimum value, CNT tend to bind to 
each other and reduce their ability to interact with 
the polymers matrix, leading to defects in the 
structure. The material structure leads to a reduction 
in the material properties of the material. 
The hardness of the material increased because 
the CNT have a higher hardness than the CB. From 
these results, the CNT content to replace CB was 1 phr 
was selected for further study. 
3.3. The morphological structure of the material 
 
The morphological structure of NBR/PVC blends 
with CB and CNT was determined by FESEM. 
FESEM images of broken surfaces of typical 
material samples are shown in figure 3. 
Results FESEM image shows that in NBR/PVC 
sample containing 25 phr CB, CB particles were 
relatively well dispersed in the rubber matrix. 
However, on the fracture surface of the material 
there is still agglomeration of CB particles. When 
the CB content increases to 40 phr, CB particles 
were still uniformly distributed in the rubber matrix. 
Therefore, the mechanical properties of the material 
reach the maximum value. When the CB content 
  
VJC, 55(5), 2017  Luong Nhu Hai et al.  
 630 
continues to rise (50 phr), there is more 
agglomeration of CB particles that causes the 
material defects leading to decrease the mechanical 
properties of the material. 
When replacing 1 phr CB by CNT, on the 
fracture surface of the material, carbon black 
particles disperse and interact better with rubber 
matrix. Therefore, with 1 phr CNT replacing CB has 
significantly improved the mechanical properties of 
the material. 
3.4. Dynamic Mechanical Analysis (DMA) 
Dynamic Mechanical Analysis allows to determine 
the glass temperature (Tg) of polymers, storage 
modulus (E'), loss modulus (E''). The effect of 
temperature on the storage module of samples at 1 
Hz is shown in figure 5. The E' value indicates the 
energy dissipation due to molecular motions, so E' 
represents the hardness of the material. The E' value 
depends on three factors: crosslinking density, 
dispersion filler content, dispersion particle size. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Figure 3: FE-SEM image of the fracture surface of the blend NBR/PVC with reinforcing fillers 
(a) 25CB; (b) 40CB; (c) 50CB and (d) 39CB/1CNT 
 
 Figure 4: Storage modulus diagram of the samples     
based on blends NBR/PVC 
 
The results in figure 4 show that the rubber 
blend samples have large storage modules at low 
temperatures, and then sharply decrease at the 
transition area. For two rubber blends samples with 
reinforcing filler, the storage modulus of the 
material increased significantly, especially the 
sample containing 1 phr of CNT. This proves 
reinforcement of CNT in rubber blend, especially in 
the visco-elastic zone. 
Results in figure 5 shows, NBR/PVC (70/30) 
rubber blend sample compatible well with each other 
(tan delta curve only appears a sharp peak with Tg = 
22.74 
o
C). Two rubber blends samples with 
reinforcing filler, tan delta peak intensity and glass 
temperature decreases (due to storage module E' 
increases). In these two samples, rubber blend 
sample containing CNT has tan delta peak widths 
narrower. This demonstrates, when CNTs increased 
ability that scattered fillers dispersed more evenly, 
leading to increased interoperability between fillers 
with polymers matrix, similar to the report [11]. The 
Results in table 3 show that thermal stability of the 
a c 
b d 
  
VJC, 55(5), 2017  Study on the effect of carbon black... 
 631 
NBR/PVC blend is markedly improved with 40 phr CB 
through onset decomposition temperature increases 
(from 192.33 
o
C to 196.46 
o
C) and weight loss at 
330 
o
C decreased (from 17.531 % to 13.412 %). 
Therefore, the mechanical properties of the 
material are significantly improved. 
 
Figure 5: Tan delta diagram of of the samples                
based on blends NBR/PVC 
 
3.5. Thermal properties of the material 
 
3.5.1. Thermal stability 
 
The thermal stability of the material is evaluated by 
Thermogravimetric Analysis (TGA). The results of 
TGA analysis of material samples based on NBR/PVC 
blend are shown in figures 6-8 and table 3. 
When replacing 1 phr CB by CNT, thermal 
stability of the rubber blend continues to rise (onset 
decomposition temperature increased by nearly 
10°C). This can be explained, on one hand by the 
CNT heat resistance than CB, on the other hand due 
to the structure of the material is tighter (because 
CNT interacts well with the component polymers). 
Therefore, the thermal stability of the material is 
significantly improved. 
 
Figure 6: TGA diagram of NBR/PVC blend 
 
 
Figure 7: TGA diagram of NBR/PVC/40CB blend 
 
 
Figure 8: TGA diagram of NBR/PVC/39CB/1CNT 
blend
Table 3: Results of TGA analysis of the samples based on NBR/PVC blends 
Samples Tonset (
o
C) Tmax 1 (
o
C) Tmax 2 (
o
C)  Weight loss at 330 
o
C (%) 
NBR/PVC 192.33 266.33 430.09 17.531 
NBR/PVC/40CB 196.46 267.30 436.70 13.412 
NBR/PVC/39CB/1CNT 206.30 268.30 434.40 13.045 
 
3.5.2. Thermal conductivity 
 
To study the effect of CB and CNT on the thermal 
conductivity of the material, the samples thermal 
conductivity was determined on the Linseis THB 500. 
The thermal conductivity of the samples on based 
NBR/PVC blend is shown in figure 9. 
The results show that the thermal conductivity 
of NBR/PVC blend is unchanged with increasing 
temperature. In contrast, the thermal conductivity of 
  
VJC, 55(5), 2017  Luong Nhu Hai et al.  
 632 
NBR/PVC filled with CB increased with increasing 
temperature. The effect of CNT on the thermal 
conductivity of NBR/PVC filled with CB and CNT 
was significant, especially at high temperature. By 
this sample, the thermal conductivity increases from 
0.691 to 0.747 W/mK. The reason is due to the high 
thermal conductivity of CNT. 
0.4
0.5
0.6
0.7
0.8
20 30 40 50 60 70
Temperature (
o
C)
T
h
e
rm
a
l 
c
o
n
d
u
c
ti
v
it
y
 (
W
/m
.K
)
NBR/PVC
NBR/PVC/40CB
NBR/PVC/39CB/1CNT
 
Figure 9: Thermal conductivity of NBR/PVC blends 
with temperatures 
 
4. CONCLUSIONS 
 
- The optimal CB content for NBR/PVC (70/30) 
blend is 40 phr. At this content, the tensile strength 
of the material increased by 47.1 % compared to the 
original sample. With greater contents of CB (50 
phr), carbon black particles tend to agglomerate as 
tight structure of the material breaks down, leading 
to the mechanical properties of the material 
decreases.  
- The appropriate CNT content to replace CB is 
1 phr. With CB/CNTs ratio (39/1), the material is 
structurally tighter. The mechanical properties, 
thermal stability and heat conductivity of the 
NBR/PVC blend are significantly improved. 
Rubber blend NBR/PVC/39CB/1CNT 
nanocomposite with high mechanical and technical 
properties can be used to manufacture technical 
rubber products, especially rubber products with 
abrasion resistance and high friction. 
 
Acknowledgment. The authors acknowledge the 
financial support from the Vietnam Academy of 
Science and Technology (VAST.HTQT. HUNGARY 
01/16-17). 
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Corresponding author: Luong Nhu Hai  
Center for High Technology Development 
Vietnam Academy of Science and Technology 
18 Hoang Quoc Viet, Cau Giay Ha Noi 
E-mail: luonghai76@gmail.com; Telephone: 0914322532. 


Study on the effect of carbon black, carbon nanotube on the properties of rubber blend acrylonitrile butadiene rubber (NBR)/polyvinyl chloride (PVC)

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Study on the effect of carbon black, carbon nanotube on the properties of rubber blend acrylonitrile butadiene rubber (NBR)/polyvinyl chloride (PVC)

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