The Effect of The Addition of Alkanolamide on Poperties of Carbon Black-filled Natural Rubber (SMR-L) Compounds Cured Using Various Curing Systems
2 matches
0.9%
[49]
2 matches
0.9%
[48]
0.9%
[50]
0.9% 2 matches [47]
1.0% 2 matches [46]
[45]
3 matches
2 matches
2 matches
The effect of the addition of alkanolamide on properties of carbon-filled natural rubber (SMR-L) compounds cured using .pdf
Results of plagiarism analysis from 2017-12-06 08:20 UTC
13.8%
2 matches
0.9%
[53]
0.9%
0.9%
[52]
2 matches
0.9%
[51]
2 matches
1.0%
[44]
7 matches
1.9%
[28]
7 matches
1.8%
[27]
2.0%
[38]
1.7% 10 matches [25]
2.6% 10 matches [22]
[18]
5 matches
3 matches
3 matches
1.0%
[43]
3 matches
1.0%
[42]
1.1%
1.1%
[41]
5 matches
0.8%
[39]
4 matches
Date: 2017-12-06 08:18 UTC
[63]
0.4%
0.3% 1 matches [83]
0.3% 1 matches [82]
[80]
1 matches
2 matches
[78]
1 matches
0.4%
[77]
1 matches
0.4%
0.2%
[84]
[76]
1 matches
0.2%
[91]
1 matches
0.3%
[89]
0.2%
[86]
1 matches
0.2%
[85]
1 matches
0.2%
1 matches
0.6% 1 matches [69]
0.6% 1 matches [68]
[67]
1 matches
0.6%
[66]
0.6%
2 matches
0.7%
[65]
2 matches
[64]
2 matches
0.5%
3 matches
0.4%
0.4%
[75]
1 matches
0.3%
[74]
4 matches
[70]
[73]
2 matches
0.5%
[71]
1 matches
0.6%
1 matches
0.1%
7 pages, 4858 words PlagLevel: selected / overall 257 matches from 102 sources, of which 91 are online sources. Settings
1 matches
0.2%
[101]
1 matches
0.2%
[100]
1 matches
1 matches
0.2%
[99]
1 matches
0.1%
[98]
Data policy: Compare with web sources, Check against my documents, Check against my documents in the organization repository, Check against organization repository, Check against the Plagiarism Prevention Pool Sensitivity: Medium Bibliography: Consider text Citation detection: Reduce PlagLevel Whitelist: --
[18] e
Contents lists available at ScienceDirect
Polymer Testing
j o u h r o n m a e w l p w a w g . e c e o : l m s e / l v o i c e a r . t e / p o l y t e s t
Material properties The effect of the addition of alkanolamide on properties of carbon black-filled natural rubber (SMR-L) compounds cured using various curing systems a
b, * a Indra Surya , H. Ismail b Department of Chemical Engineering, Engineering Faculty, University of Sumatera Utara, Medan, 20155, Sumatera Utara, Indonesia School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, Engineering Campus, Nibong Tebal, 14300, Penang, Malaysia
a i r n t a f i b o c s l t e r a c t
Article history: The properties of carbon black (CB)- lled natural rubber (SMR-L) compounds, with and without thefi Received 25 November 2015 addition of Alkanolamide (ALK), based on various curing systems such as ef cient, semi-ef cient and fi fi
Accepted 12 January 2016 conventional vulcanisation systems were investigated. The ALK loading was xed at 5.0 phr. It was found fi
Available online 21 January 2016 that ALK gave improvements to the cure rate, torque difference, crosslink density, ller dispersion, rubber [27] fi efi fi ller interaction and reinforcing ef ciency of CB. ALK also enhanced the tensile modulus , hardness,
Keywords: resiliencile strength and elongation at break of CB- lled SMR-L vulcani sates for each curing sys- fi
Alkanolamide [39] tem. The degree of improvement of cure characteristics and mechanical properties depended on the level
Curing systems of sulphur and the ratio of accelerator to sulphur in each system. Scanning electron microscopy (SEM)
Carbon black proved that the CB- lled SMR-L vulcanisates with ALK for each curing system displayed a greater matrix fi
Filler dispersion tearing line and surface roughness due to greater rubber ller interaction. efi Rubber- ller interaction fi
© 2016 Elsevier Ltd. All rights reserved.
1. Introduction combination form (as hybrid ller) for the purpose of achieving fi their synergistic effect in order to produce better overall mechan-
Through vulcanisation, weak and plastic raw rubbers are hard- ical properties [4] . However, at a relatively higher loading of CB or ened or cured by sulphur and converted into strong elastic rubber silica, the ller particles tend to form agglomerates and will reduce fi vulcanisates. When vulcanisation was rst discovered, the sulphur the properties of the rubber vulcanisates. Practically, to overcome
fi reaction with sulphur alone took several hours to be completed. the ller dispersion problem, special additives such as processing fi Utilisation of accelerators (organic sulphur donor ingredients), with apersant aids, etc. are utilised. [73] the combination of other ingredients such as zinc oxide and fatty In our previous work [ 5] , the preparation and application of acids, allowed the sulphur reaction to be accomplished in a shorter Alkanolamide (ALK) in silica-filled SMR-L compounds was re- time and was recognised as accelerated sulphur vulcanisation ported. The ALK enhanced the tensile properties and hardness of the silica- lled SMR-L vulcanisates. The enhancement of these
[1e3]. Based on the level of sulphur and the ratio of accelerator to fi sulphur, accelerated sulphur vulcanisation can be classi ed into properties was attributed to the improvement of silica dispersion fi three categories: ef cient (EV), semi-ef cient (semi-EV) and con- and the excelling crosslink density temmed from the incor-
fi fi [18] ventional (CV) vulcanisation or curing systems. poration of ALK. The results also indicated that ALK could function The strength and elasticity of a rubber vulcanisate can be further acelerator and internal plasticiser . [41] enhanced by the addition of reinforcing ller. Carbon black (CB) and The comparison of ALK and aminopropyltriethoxy Silane
fi silica are the most popular reinforcing llers for rubbers, and have (APTES)-silane coupling agent on the properties of silica- lled fi [18] fi been widely employed in the rubber industry. CB is commonly SMR-L compounds was also reported [ 6] . Due to its combined utilised for producing black rubber products, while silica is used in and unique function as an accelerator and internal plasticiser, ALK coloured products. Sometimes, they are also utilised in produced a higher reinforcing ef ciency than APTES at a similar
fi l . [18] A further study regarding the effect of ALK loading on properties
- * Corresponding author. of CB- lled SMR-L, epoxidised natural rubber (ENR) and styrene
fi E-mail addresses: ihana @usm.my , profhana @gmail.com (H. Ismail).
fi fi http://dx.doi.org/10.1016/j.polymertesting.2016.01.014 © 0142-9418/ 2016 Elsevier Ltd. All rights reserved. butadiene rubber (SBR) compounds revealed that ALK gave cure enhancement, better ller dispersion and greater rubber ller fi efi interaction to three different types of rubbers . ALK enhanced the [ 7]
mechanical properties, especially up to 5.0 phr of ALK in SMR-L and SBR compounds, and at 1.0 phr of ALK in ENR-25 compound.
37. The tensile strength (TS), stress at 100% elongation (M100),
) and q
1 is the initial angle of displacement (45
1 Þ (4) where q
2 Þ=ð 1 cos q
[22]
Tripsometer, according to BS 903 Part A8. The rebound resilience was calculated according to Equation . (4) % Resilience ¼ ½ ð1 cos q
stress at 300% elongation (M300) and elongation at break (EB) were determined. The hardness measurements of the samples were performed according to 691-I, using a Shore A type manual [22] durometer. The resilience was studied by using a Wallace Dunlop [99]
Tensile tre performed at a cross-head speed of 500 mm/min [83] using an Instron 3366 universal tensile machine, according to ISO
2.6. Scanning electron microscopy (SEM) analysis
2.5. Tensile, hardness and resilience properties umbbell-shaped samples were cut from the moulded sheets.
2M c (3)
1
V c ¼
[22] c of SMR- L 0. 393). The crosslink density is given by ; ¼
3 /mol), V r is the volume fraction of the rubber in the swollen specimen , Q m is the weight increase of the vulcanisate in toluene and c is the interac- tion parameter of thber network solvent ( e
¼ 106.4 cm [22]
3 ), V s is the molar volume of the toluene (V s
2 is the maximum rebound angle . [9 6]
The tensile fractured surfaces of the CB- lled SMR-L with and fi without ALK at various curing systems were examined by using a Zeiss Supra-35VP scanning electron microscope (SEM) to obtain information regarding the ller dispersion, rubber ller interac-
m
3.0
30.0
30.0
2.5 CB N330
1.5
0.8
0.8 S
1.5
2.0 MBTS
fi efi tion and to detect the possible presence of micro-defects. The Fig. 1. Molecular structure of Alkanolamide.
2.0
2.0
2.0 IPPD
2.0
5.0 5. [44] Stearic acid 2 .
5.0
Ingredients a Curing system EV Semi-EV CV SMR-L 100.0 100.0 100.0
ZnO
Table 1
The SMR-L compound formulation.(2) where r is the polymer/rubber density ( r of SMR-L
1 1 þ Q
It is important to further investigate the applicability of ALK as a new rubber additive in rubber vulcanisation. Hence, through the examination of the properties of CB- lled SMR-L compounds in the
2.3. Cure characteristics The cure characteristics of the CB- lled SMR-L compounds with
) according to ISO amples of the
H dM L
) and torque difference (M
90
), cure time (t
2
fi and without ALK at various curing systems were obtained using a Monsanto Moving Die Rheometer (MDR 2000), which was employed to determine the scorch time (ts
fi ALK at various curing systems.
C. The CB- lled SMR-L fi compounds were subsequently compression-moulded using a stainless steel mould at 150
2.2. Compounding The EV, semi-EV and CV vulcanisation recipes were applied in rubber compounding. The compounding procedure was performed on a two-roll mill (Model XK-160). Table 1 displays the compound formulation of CB- lled SMR-L compounds with ALK and without
fi Bleached Deodorized Palm Stearin (RBDPS) and diethanolamine. The reaction procedures and molecular characterisations of the ALK were given in our previous report . The molecular structure of [5] ALK is presented in Fig. 1.
Malaysia . The ALK was synthesised in the laboratory using Re ned
fi supplied by Bayer Co. (M) Sdn. Bhd. , Petaling Jaya, Selangor, [18]
2.1. Materials NR grade SMR-L was used and obtained from Guthrie (M) Sdn. Bhd., Seremban, Malaysia, and N330-grade CB was supplied by the Cabot Corporation. Other compounding ingredients such as sulphur (S), zinc oxide (ZnO), stearic acid, N-isopropyl-N'-phenyl- p-phenylenediamine (IPPD), benzothiazyl disul de (MBTS) were
2. Experimental
properties of CB- lled SMR-L compounds with and without ALK, fi which were cured by EV, semi-EV and CV systems.
fi presence of ALK, the applicability of ALK in vulcanisation of CB- filled compounds with various curing systems was stud- [39] ied. This study focused on the cure characteristics and mechanical
respective compounds were tested at 150 [58]
(1) V r ¼
r
2 r
ln 1 ð V r Þ þ V r þ cV
s
V
p
c ¼
C, with a pressure of 10 MPa , and applying a laboratory hot-press based on respective curing times.
M
) b y applying the Flory Rehner equation . e [ 8]
to calculate the molecular weight between two crosslinks (M c
C [22] until constant weight was obtained. The swelling results were used
pieces (30 mm 5 m m 2 mm) were weighed using an electric balance and swollen in toluene until equilibriuch took 72 h [22] at room temperature. The samples were taken out from the liquid, the toluene was removed from the sample surfaces and the weight was determined. The samples were then dried in an oven at 60
fi [22] formed in toluene in accordance with ISO 1817. The cured test
2.4. Measurement of crosslink density Swelling tests on the CB- lled SMR-L vulcanisates were per-
30.0 ALK 0.0; 5.0 0.0; 5.0 b 0.0; 5. [25]
a parts per hundred parts of rubber .
b 5.0 phr was the optimum loading of ALK for CB- lled SMR-L compound with a fi semi-EV recipe . [7] e fractured pieces were coated with a layer of gold to eliminate electrostatic charge build-up during analysis. [ 60]
2.7. Measurement of rubber ller interaction
0.0
Fig. 3. Cure times (t 90 ) of the CB- lled SMR-L compounds at various curing systems.
fi Table 2 Torque difference properties of the CB- lled and un lled SMR-L compounds at fi fi various curing systems.
Curing systems Loading of ALK (phr) Torque difference properties M H , dN.m M L , dN.m M H dM L , dN.m EV
0.0
7.69
0.29
7.40
5.0
8.95
0.22
8.73 Semi EV
8.43
fi observation was in line with the data in Table 2. Torque difference
0.33 8.10 e
5.0
9.93
0.30
9.63 CV
0.0
10.55
0.20
10.35
5.0
12.64
0.19
Fig. 2. Scorch times (ts ) of the CB- lled SMR-L compounds at various curing systems.
(1) CB- lled SMR-L compounds increased the crosslink density. This
efi The rubber ller interactions were determined by swelling the efi d CB- lled SMR-L compounds in toluene, according to ISO 1817. fi
3. Results and discussion
Test pieces with dimensions of (30 mm 5 m m 2 mm) were [63] prepared from the moulded sheets . The initial weights were
recorded prior to testing. The test pieces were then immersed in toluene and conditioned at room temperature in a dark environ- ment for 72 h. After the conditioning period, the weights of the swollen test pieces were recorded. The swollen test pieces were then dried in the oven at 70
C for 15 min and were allowed to cool at room temperature for another 15 min before the nal weights fi were recorded. The Lorenz and Park's equation [9e1
1 ] was applied in this study. The swelling index was calculated according to Equation . (5)
Qf [84]
=Qg ¼ ae z
þ b (5) where the subscripts f and g d to lled and gum vulcanisates,
fi [27] respectively ; z was the ratio by weight of ller to hydrocarbon fi rubber in the vulcanisate; while a and b were constants. The lower
the Qf/Qg value, the greater the rubber ller interaction becomes. efi
In this study, the weight of the toluene uptake per gram of hy- drocarbon rubber (Q) was calculated based on Equation . (6) Q ¼ ½ Swollen Dried weight =½Initial weight
100=Formula weight (6)
3.1. The cure characteristics and crosslink density The cure characteristics of CB- lled SMR-L compounds, with
fi pounds, with and without the presence of ALK, for various curing systems. The crosslink density was determined by the Flor- y Rehner approach [Eq. ]. The addition of 5.0 phr of ALK into the e
fi and without the presence of ALK at various curing systems, are shown in and Figs. 2 and 3 Table 2. The addition of 5.0 phr of ALK into the CB- lled SMR-L compound for each curing system caused a
fi decrease in scorch and cure times and an increase of torque dif- ference. Since amine is an ingredient of accelerators and also an accelerator activator , the amine part of ALK, together with ZnO [12] and fatty acid, activated the MBTS-accelerator more pronouncedly and, consequently, improved the rate of sulphur reaction of CB- filled SMR-L compounds. The increase of torque difference value was attributed to the additional function of ALK, as an internal plasticiser agenth plasticised and sof tened the lled com-
fi [38] pounds. This resulted in reduced viscosity and improved process- [38]
ability due to the CB dispersion and SMR-L CB interaction . The e SMR-L CB interaction may be de additional physical e fi [38] crosslinks [ 13,14] and, together with sulphide crosslinks , contrib- uted to total ck density [ 15,16] of the CB- lled SMR-L com-
fi [38] pound. Degree of crosslink density of a rubber vulcanisate was
indicated by its own torque difference value [ 17 20]
e . The higher the torque difference value, the higher the degree of crosslink density.
It was also observed that the scorch times of CB- lled com- fi pounds, with and without ALK, decreased when the curing system [18] was changed from EV to Semi-EV and CV. All curing systems used
MBTS as the accelerator, and it was functionally classi ed as a fi primary accelerator which usually provides delay to a rub- [18] ber compound [ 21]. The lower the amount of MBTS, the lower was the scorch safety . This explained why the scorch times tended to
slightly decrease when the curing system was changed through the above sequence.
When the curing system was changed from EV to Semi-EV and CV, the cure time and torque difference tended to increase. A possible explanation may be due to the effect of sulphur content of each curing system. The EV system possesses the least amount of sulphur and the CV system possesses the greatest. The higher amount of sulphur requires longer time to complete the sulphur- isation, or crosslinking reaction, hence it produces higher crosslink density. This explains why the cure time and torque difference of the CB- lled SMR-L compounds, with and without ALK, increased
fi in sequence: EV, Semi-EV and CV. Fig. 4 displays the crosslink density of CB- lled SMR-L com-
12.45 e values of CB- lled compounds with ALK were higher than those of fi [100]
CB- lled compounds without ALK. This indicated that the crosslink fi
3.4. The reinforcing ef ciency (RE) fi
L
M
H
RE ¼ ð M
fi simplest form , was given by Equation . (8) [ 6]
The degree of reinforcement provided by the ller can be fi calculated through its reinforcing ef ciency ( RE), which in its
sulphur CB interaction, and hence the better the CB dispersion and e the greater the SMR-L-CB interaction. [ 78]
f
Again, this was attributed to the sulphur content of the curing [97] system. The higher the sulphur content, the more pronounced the
The rubber- ller interaction of the lled SMR-L compounds, fi fi and without ALK, was enhanced from EV, Semi-EV and CV.
filled SMR-L compounds and, therefore, improving the CB dispersion.
efi interaction in CB- lled SMR-L systems became greater, which was fi attributed to the capability of ALK to plasticise and soften the CB-
values decreased with the addition of ALK for all various curing systems. The decreased Qf/Qg indicated that the rubber ller
fi efi teracted on Lorenz and Park's equation (Equation ), the (5) rubber ller interaction of CB- lled SMR-L compounds at various efi fi [39] curing systems is presented in . It can be seen that the Qf/Qg Fig. 6
Þ
ð M
fi as coupling bonds . The higher the sulphur content, the [25,26] higher the solubility of CB in the sulphur phase, and hence the higher the degree of CB dispersion.
Þ
fi Fig. 5.
fi Fig. 4. Crosslink density of the CB- lled SMR-L compounds at various curing systems.
fi compound A higher RE value meant greater rubber- ller interaction, which
fi (M H M L ) g ¼ difference in torque value of un lled/gu
(8) in which: (M H M L ) f ¼ difference in torque value of lled compound
g
L
H
M
H
= ðM
g
Þ
L
M
3.3. The rubber ller interaction efi Improved ller dispersion means greater rubber ller in-
fi the rubber . This is rubber- ller crosslinking which is consid- [25] fi ered as another type of crosslink to the rubber system, and de ned
density of CB- lled compounds with ALK was higher than that of fi CB- lled compounds without ALK.
r
r
], and m
Lg
/M
Lf
¼ [M
m r (7) where: h
Hf
r
. L ¼ h
3.2. The ller dispersion fi The degree of CB dispersion in SMR-L compounds using various curing systems, due to the addition of ALK, can be quantitatively determined by Equation (7) [5 7,23,24] e
ALK increased when the curing system was changed from EV to Semi-EV and CV. This was simply due to the sulphur content of each curing system. A curing system with higher sulphur content would produce a higher crosslink density . [22]
The crosslink density of the lled compounds with and without fi
fi
¼ [M
/M
fi decreased from EV to Semi-EV and CV. This meant that the degrees of CB dispersion were the lowest in EV and the highest in CV. This phenomenon was also attributed to the sulphur content, since CB reacts with sulphur during the curing process and forms CB- sulphur bonds that link the rubber chains and tie the ller onto
); and 4.85, 4.88 and 5.91 (M
fi The L values of CB- lled compounds, with and without ALK,
values of L indicated that ALK had improved the CB dispersion through its plasticisation effect in CB- lled SMR-L compounds.
fi
be seen that the L values of CB- lled compounds with ALK were fi lower than those of CB- lled compounds without ALK. The reduced
Fig. 5 presents the values of L for CB dispersion in the SMR-L [39] phase, with and without ALK, using various curing systems. It can
HG ), respectively.
LG
Hg [74]
particular CB loading, meant a better degree of CB dispersion. The cure characteristics of gum compounds of SMR-L using different curing systems (i.e. EV, Semi-EV and CV; M LG and M HG ) were 0.05, 0.07 and 0.05 (M
fi
Hg were the minimum and the maximum torques of the un lled/gum rubber compound. A lower value of L, at a
Lg and M
Hf were the minimum and maximum torques of the lled compounds, fi and M
Lf and M
]; where M
Fig. 6. The L values of CB- lled SMR-L compounds at various curing systems. The Qf/Qg values of CB- lled SMR-L compounds at various curing systems. was infl fi uenced by the degree of ller dispersion. The improved fi
fi ller dispersion provided a greater surface area for rubbere ller interactions. RE of CB on SMR-L compounds, with and without ALK, at various curing systems is shown in Fig. 7.
50
29.2 1.2 966.3
0.22
5.15
0.23
1.36
5.0
0.6 e ± ± ± ± ± ±
58.4
0.4
20.2
54
25.3 0.9 835.8
0.18
4.92
0.20
1.28
0.0
0.5 ± ± ± ± ± ± Semi EV
60.9
0.7
51
23.0
0.6
25.6 0.9 978.3
0.6 ± ± ± ± ± ±
68.8
0.9
57
20.2
0.20 29.5 1,1 799.3
6.02
0.22
1.58
5.0
61.7
65.5
0.3
51
21.2
26.4 0.9 758.3
0.17
5.56
0.18
1.39
0.0
0.8 ± ± ± ± ± ± CV
19.2
0.18
As presented in Fig. 7, ALK increased the RE of CB on SMR-L compounds. This was attributed to the combined effects of better fi fi ller dispersion and greater rubbere ller interaction.
fi fl fi vulcanisates. The ALK provided a free volume which allowed more flexibility for the SMR-L chains to move.
fi greater rubber ller interaction, and the micrographs of the tensile efi fractured surfaces were in good agreement with the graphs in
fi ( (a), (c) and (e)). This indicated better ller dispersion and Fig. 8
fi observed that the CB- lled SMR-L vulcanisates with 5.0 phr of ALK fi for each curing system (micrographs of (b), (d) and (f)) Fig. 8 exhibited greater matrix tearing lines and surface roughness compared to those of CB- lled SMR-L vulcanisates without ALK
vulcanisates of CB- lled SMR-L, with and without ALK, for various fi curing systems, taken at 300 magni cation. It can be clearly
Fig. 8 displays the SEM micrographs of fractured surfaces of the
3.6. Scanning electron microscopy (SEM ) study
fi rubber- ller interaction, and hence lowest RE. fi [ 73]
fi vulcanisates, with and without ALK, of the EV system were the lowest due to the lowest degree of ller dispersion, weakest
The mechanical properties of CB- lled SMR-L vulcanisates, with fi and without ALK, of the CV system were the greatest due to the highest degree of filler dispersion, greatest rubber- ller interaction, fi and hence highest RE. The mechanical properties of CB- lled SMR-L
fi Again, this was attributed to the function of ALK as an internal plasticiser agent which modi ed the exibility of CB- lled SMR-L
4. Conclusions From this study, the following conclusions were drawn:
The elongations at break of CB- lled SMR-L compounds with fi ALK were higher than those of CB- lled compounds without ALK.
Fig. 8 micrographs of CB- lled SMR-L vulcanisates with ALK exhibited fi greater matrix tearing lines and surface roughness. This indicated greater rubber ller interaction which altered the crack paths, efi leading to increased resistance to crack propagation, thus causing an increase in tensile strength.
fi rubber ller interaction. This explanation was in line with the efi results in and the SEM micrographs later in . The Figs. 5 7 e
The enhancement in tensile strength was attributed to a higher RE, or the combined effects of better ller dispersion and greater
Tensile modulus and hardness of a rubber vulcanisate are mainly dependent on the degree of crosslinking [27,28]. Resilience is enhanced, to some extent, as the crosslink density rises [21,29]. Hence, the enhancements of M100, M300, hardness and resilience were attributed to the enhancement of crosslink density, as dis- played in . Fig. 4
Obviously, the tensile modulus (M100 and M300 ), hardness, resil- [27] ience, tensile strength and elongation at break were signi cantly fi increased using various curing systems with the addition of ALK.
fi and without the addition of ALK, for various curing systems.
3.5. The mechanical properties Table 3 showed the mechanical properties of CB- lled SMR-L,
fi the highest degree of CB dispersion and the greatest rubber- ller fi interaction in CV.
The RE values of CB, with and without ALK, were the lowest in EV and were the highest in CV. This was due to the lowest degree of CB dispersion and the weakest rubber- ller interaction in EV, and
Figs. 5 and 6, which showed the lower L and Qf/Qg values of CB- filled SMR-L compounds with ALK. An enhancement in rupture energy, due to a greater rubber ller interaction, was responsible efi for the roughness and the matrix tearing line of the fractured sur- face. The micrographs of the tensile fractured surfaces were in good agreement with the results obtained by other researchers [30,31] who reported that an increase in rupture energy was responsible for the roughness and the matrix tearing line of the fractured surfaces.
1. Alkanolamide increased the cure rate, torque difference value, crosslink density, degree of ller dispersion, rubber ller fi efi interaction and reinforcing ef ciency of ef cient, semi-ef cient
4.88
0.16
0.10
1.22
5.0
0.5 ± ± ± ± ± ±
55.1
0.4
48
19.5
23.8 0.7 880.4
4.28
fi fi fi and conventional curing systems of carbon black- lled natural fi rubber (SMR-L) compounds.
0.19
1.12
0.0
fi Curing systems Loading of ALK (phr) Mechanical properties M100 (MPa) M300 (MPa) TS (MPa) EB (%) Hardness (Shore A) Resilience (%) EV
Table 3 The mechanical properties of CB- lled SMR-L compounds at various curing systems.
Fig. 7. Reinforcing ef ciency of the CB- lled SMR-L compounds at various curing fi fi systems.
L) compounds with Alkanolamide depended on the curing
3. Degree of improvement of the cure characteristics and me- chanical properties of carbon black- lled natural rubber (SMR- fi
fi black- lled natural rubber (SMR-L) compounds. fi
2. Alkanolamide also improved the tensile modulus, hardness, resilience, tensile strength and elongation at break of the ef - fi cient, semi-ef cient and conventional curing systems of carbon
0.7 ± ± ± ± ± ± e
Fig. 8. SEM micrographs of the failed fracture of CB- lled SMR-L vulcanisate at a magni cation of 300 ; (a) 0.0 phr ALK (EV), (b) 5.0 phr ALK (EV), (c) 0.0 phr ALK (semi-EV), (d)
fi fi d d d 5.0 phr ALK (semi-EV), (e) 0.0 phr ALK (CV), (f) 5.0 phr ALK (CV). d d d [8] P.J. Flory, J. Rehner Jr., Statistical mechanics of crosslinked polymer networkssystem, especially the level of sulphur and ratio of accelerator to II. Swelling, J. Chem. Phys. 11 (121. ur of each curing system. [69] [27]
[9] O. Lorenz, C. Parks, The crosslinking ef ciency of some vulcanizing agents in fi
4. Morphological studies of the tensile fractured surfaces of carbon natural rubber , J. Polym. Sci. 50 (1961) 299 312 . e
black- lled natural rubber (SMR-L) vulcanisates of each curing fi [10] H. Ismail, M. Nasaruddin, U. Ishiaku, White rice husk ash lled natural rubber fi compounds: the effect of multifunctional additive and silane coupling agents, system with Alkanolamide exhibited a greater matrix tearing Polym. Test. 18 (1999) 287 298 . e line and surface roughness due to greater rubber ller [41] efi
[11] H. Ismail, S. Shaari, N. Othman, The effect of chitosan loading on the curing interaction. characteristics, mechanical and morphological properties of chitosan- lled
fi natural rubber (NR), epoxidised natural rubber (ENR) and styrene-butadiene [ 43] rubber (SBR) compounds , Polym. Test. 30 (2011) 784 790 . e
Acknowledgements [12] H. Long, Basic Compounding and Processing of Rubber, Rubber Division,
American Chemical Society Inc. The University of Akron, Ohio, USA, 1985.[13] B. Boonstra, G. Taylor, Swelling of lled rubber vulcanizates, Rubber Chem.
fi The authors would like to thank Universiti Sains Malaysia for Technol. 38 (1965) 943 960 . [92] e
providing the research facilities for carrying out the experiment [14] R. Nunes, J. Fonseca, M. Pereira, P ller interactions and mechanical
[91] fi properties of a polyurethane elastomer , Polym.Test. 19 (2000) 93e103. and for making this research work possible. One of the authors &
[15] G. Kraus, Reinforcement of Elastomers, John Wiley Sons Inc., New York, (Indra Surya) is grateful to the Directorate General of Higher Edu- 1965. [89]
cation (DIKTI) Tahun Anggaran 2011, Ministry of Education and [16] K. Polmanteer, C. Lentz, Reinforcement studies-effect of silica structure on
properties and crosslink density , Rubber Chem. Technol. 48 (1975) 7Culture (Kemdikbud) of the Republic of Indonesia, for the award of [69] [17] B. Boonstra, H. Cochrane, E. Dannenberg, Reinforcement of silicone rubber by a scholarship under the fth batch of the Overseas Postgraduate fi particulate silica , Rubber Chem. Technol. 48 (1975) 558 576 . e Scholarship Program.
[18] H. Cochrane, C. Lin, The in uence of fumed silica properties on the processing, fl curing, and reinforcement properties of silicone rubber, Rubber Chem. Tech- nol. 66 (1993) 48 60 . e [19] H. Ismail, C. Ng, Palm oil fatty acid additives (POFA's): preparation and
References application, J. Elastom. Plast. 30 (1998) 308 327 . e [25] [20] P. Teh, Z. Mohd Ishak, A. Hashim, J. Karger-Kocsis, U. Ishiaku, Effects of
[1] M. Morton, Introduction to Rubber Technology, Reinhold Pub. Corp., New epoxidized natural rubber as a compatibilizer in melt compounded natural York, 1959. rubber organoclay nanocomposites, Eur. Polym. J. 40 (2004) 2513 2521 . e e
[2] M. Morton, Rubber Technology, Van Nostrand Reinhold Company, New York, [21] B. Rodgers, Rubber Compounding: Chemistry and Applications, CRC, New 1987. [25] York, 2004. [3] M. Akiba, A. Hashim, Vulcanization and crosslinking in elastomers , Prog.
[. Ismail, I. Salmiah, Y. Tsukahara, Palm oil fatty acid as an activator in carbon Polym. Sci. 22 (1997) 475 521 . e [22] black lled natural rubber compounds: effect of vulcanization system, Polym.
fi [4] N. Rattanasom, T. Saowapark, C. Deeprasertkul, Reinforcement of natural Int. 44 (123 529 . e rubber with silica/carbon black hybrid ller, Polym. Test. 26 (2007) 369 377 .
fi e [66] [23] B. Lee, Reinforcement of uncured and cured rubber composites and its rela- [5] I. Surya, H. Ismail, A. Azura, Alkanolamide as an accelerator, ller-dispersant
fi tionship to dispersive mixing-an interpretation of cure meter rheographs of and a plasticizer in silica- lled natural rubber compounds, Polym. Test. 32 fi carbon black loaded SBR and cis-polybutadiene compounds , Rubber Chem.
(2013) 1313 1321 . e [85] Technol. 52 (1979) 1019 1029 . e [6] I. Surya, H. Ismail, A. Azura, The comparison of alkanolamide and silane [24] P. Pal, S. De, Effect of reinforcing silica on vulcanization, network structure, coupling agent on the properties of silica- lled natural rubber (SMR-L) com- fi and technical properties of natural rubber, Rubber Chem. Technol. 55 (1982) pounds, Polym. Test. 40 (2014) 24 32 . [45] e 1370 1388 e . [7] I. Surya, H. Ismail, A. Azura, The effect of alkanolamide loading on properties of [25] M.Q. Fetterman, The unique properties of precipitated silica in the design of carbon black- lled natural rubber (SMR-L), epoxidised natural rubber (ENR),
fi high performance rubber, Elastomerics 116 (1984) 18 31 e . and styrene-butadiene rubber (SBR) compounds , Polym. Test. 42 (2015)
[26] M. Fetterman, Precipitated silica coming of age, Rubber World 194 (1986) e 208 214 .
38 40 e . [27] D.L. Hertz Jr., S.E. INC, Theory practice of vulcanization, Elastomerics & (November 1984) 1 7 [25] e . [28] H. Ismail, H. Chia, The effects of multifunctional additive and epoxidation in silica lled natural rubber compounds , Polym. Test. 17 (1998) 199 210 fi e
. [29] W. Hofmann, F. Bayer, Vulcanization and vulcanizing agents, Maclaren (1967) 143 147 e . [28] [30] H. Ismail, M. Mathialagan, Comparative study on the effect of partial replacement of silica or calcium carbonate by bentonite on the properties of EPDM composites , Polym. Test. 31 (2012) 199 208 [28] e .
[31] H. Nabil, H. Ismail, A. Azura, Compounding, mechanical and morphological properties of carbon-black- lled natural rubber/recycled ethylene-propylene-
fi diene-monomer ( NR/R-EPDM) blends , Polym. Test. 32 (2013) 385 393 e . e