DSpace at VNU: Filler Wetting in Miscible ESBR SSBR Blends and Its Effect on Mechanical Properties

Introduction “Green” passenger car PC tires were ﬁ rst introduced in the 1990s by using silane-treated silica instead of the The selective wetting behavior of silica in emulsion styre

Trang 1

Dr H H Le, Dr A Das, Dr K.-W Stöckelhuber,

Prof S Wiessner, Prof G Heinrich

Leibniz-Institut für Polymerforschung

Dresden e.V., D-01069 Dresden , Germany

E-mail: le-haihong@ipfdd.de

Dr H H Le

Institut für Polymerwerkstoffe

D-06217 Merseburg , Germany

Dr K Reincke, Prof W Grellmann, Prof H.-J Radusch

Polymer Service GmbH Merseburg

D-06217 Merseburg , Germany

Prof S Wiessner, Prof G Heinrich

Technische Universität Dresden

Institut für Werkstoffwissenschaft

D-01062 Dresden , Germany

traditional carbon black as reinforcing ﬁ ller in tread com-pounds As a result, signiﬁ cant reduction of the tire rolling resistance could be achieved [ 1–6 ] Regarding the rubber part in PC tire treads, synthetic rubbers like butadiene

1 Introduction

“Green” passenger car (PC) tires were ﬁ rst introduced in

the 1990s by using silane-treated silica instead of the

The selective wetting behavior of silica in emulsion styrene butadiene rubber (ESBR)/solution

styrene butadiene rubber (SSBR) blends is characterized by the wetting concept , which is

fur-ther developed for ﬁ lled blends based on miscible rubbers It is found that not only the

chem-ical rubber – fi ller affi nity but also the topology of the fi ller surface signifi cantly infl uences the

selective ﬁ ller wetting in rubber blends The nanopore structure of the silica surface has been recognized as the main reason for the difference in the wetting behavior of the branched ESBR molecules and linear SSBR molecules However, the effect of nanopore structure becomes more signiﬁ cant in the presence of silane It is discussed that the adsorption of silane on silica surface constricts the nanopore to some extent that hinders

effectively the space ﬁ lling of the nanopores by the branched

ESBR molecules but not by the linear SSBR mole cules As a

result, in silanized ESBR/SSBR blends the dominant wetting

of silica surface by the tightly bonded layer of SSBR molecules

causes a low-energy dissipation in the rubber–ﬁ ller

inter-phase That imparts the low rolling resistance to the blends

similar to that of a silica-ﬁ lled SSBR compound, while the

ESBR - rich matrix warrants the good tensile behavior, i.e., good

abrasion and wear resistance of the blends

Filler Wetting in Miscible ESBR/SSBR Blends and Its Effect on Mechanical Properties

Hai Hong Le ,* Katrin Reincke , Amit Das , Klaus-Werner Stöckelhuber ,

Swen Wiessner , Tung Pham , Quang Khang Do , Xuan Tung Hoang ,

Wolfgang Grellmann , Gert Heinrich , Hans-Joachim Radusch

Prof T Pham Hochschule Albstadt-Sigmaringen D-72458 Albstadt-Ebingen , Germany Prof Q K Do

Institute of Chemistry Vietnamese Academy of Science and Technology Hanoi , Vietnam

Dr X T Hoang University of Technology National University

Ho Chi Minh City , Vietnam

Trang 2

rubber (BR), emulsion styrene butadiene rubber (ESBR),

and solution styrene butadiene rubber (SSBR)

repre-sent the indispensable polymer matrix ESBR is the most

widely used rubber in the world, representing about

30% of the synthetic rubber market This kind of rubber

polymer has an excellent balance of properties and cost

performance as well as processability For tire application,

important properties like tensile strength, tear resistance,

and abrasion resistance, as well as aging resistance can

be achieved by use of ESBR Furthermore, ESBR is

typi-cally known for its broad molecular weight distribution

that makes the processing easier Its biggest

disadvan-tage is related to a very high rolling resistance and poor

ﬁ ller interaction Recently, SSBR with linear molecular

structure and narrow molecular weight was found to

give the tire tread compounds the better grip on snow

and ice as well as much lower rolling resistance [ 7,8 ]

How-ever, SSBR is more expensive and difﬁ cult to be processed

than ESBR Concerning the interest of tire manufacturers,

i.e., lowering the rolling resistance by maintaining the

wet grip and wear resistance and improving the

pro-cessability one can propose ESBR/SSBR blends ﬁ lled with

silica, which can combine the advantages of ESBR and

SSBR It is well known that the dynamic properties of tire

tread compounds are strongly inﬂ uenced by the ﬁ ller–

polymer interaction and consequently by the structure

of the polymer–ﬁ ller interphase [ 9 ] According to Heinrich

and Vilgis, [ 10 ] the differences in microstructure between

ESBR and SSBR cause differences in polymer–ﬁ ller

inter-phase, which leads to the different dynamic behavior of

their silica-ﬁ lled compounds Indeed, silica represents a

structure having pores on its surface in the nanometer

region [ 11 ] Due to its branching structure, ESBR does not

effectively penetrate the silica nanopores leading to a

weak polymer–ﬁ ller interaction The weak interlocking

might be responsible for a much larger amount of

dissi-pated energy during dynamic-mechanical excitation of

the rubber tread compound during rolling of the tire In

contrast, the easy wetting of linear SSBR inside nanopores

during mixing leads to a tight rubber–ﬁ ller interlocking

This kind of strong polymer–ﬁ ller interaction causes a

low contribution to energy dissipation during

dynamic-mechanical excitation Owing to this knowledge, the

syn-ergetic effect of the ESBR/SSBR blends can be achieved

only if a special structure of the blend is formed, i.e., a

structure comprising an SSBR-rich polymer–ﬁ ller

inter-phase and ESBR-rich matrix In our previous works we

developed a wetting concept for quantifying the selective

wetting behavior of ﬁ ller in binary and ternary blends

containing immiscible rubbers [ 12–15 ] In this work, the

wet-ting concept is further developed for characterization of

the selective silica wetting in miscible ESBR/SSBR blends

The correlation between the microstructure of ﬁ lled ESBR/

SSBR blends and mechanical properties will be discussed

2 Experimental Section

Materials and Sample Preparation : ESBR used was BUNATMSB

1500—Schkopau (Trinseo Deutschland GmbH) with a styrene content of 23.5% Mooney viscosity ML 1+4 (100 °C) is 50 MU SSBR used was SPRINTAN SLR4602 (Trinseo Deutschland GmbH) with a styrene content of 21% and vinyl content of 63% Mooney viscosity ML 1+4 (100 °C) is 65 MU Silica used was Ultrasil 7000

GR (Evonik) with speciﬁ c surface area CTAB = 160 m 2 g −1 and BET = 170 m 2 g −1 , pH-value 6.8 Bis(triethoxysilylpropyl) polysulﬁ de (TESPT) Si69 (Evonik) and 3-Octanoylthio-1-propyltriethoxysilane NXT (Crompton) were used as coupling agents

Silica-ﬁ lled SBR compounds and blends with and without silane were prepared in an internal mixer Plasticorder PL

2000 (Brabender) according to Table 1 Rotor speed of 50 rpm and

ﬁ ll factor 0.7 were chosen for all the mixtures Initial chamber temperature T A was varied and the corresponding dumping temperature T E was recorded A package of curing additives

containing stearic acid, zink oxide (ZnO), sulphur, N

-cyclohexyl-2-benzothiazole sulfenamide (CBS), and diphenylguanidine (DPG) was used in all the mixtures In all formulations, the con-tent of rubber, ﬁ ller, and ingredients was given in phr (parts per hundred rubber) Samples were taken out during the mixing pro-cess at different times for further investigation Samples taken out at 30 min mixing time were compression-molded at 150 °C

and 100 bar for t 90 to obtain a sheet used for mechanical testing

Tensile Test : Stress–strain measurements were performed according to ISO 37 using a tensile tester Z005 (Zwick/Roell) with

a cross-head speed of 200 mm min −1 at room temperature The test specimens had a thickness of 2 mm and an initial gauge length of 50 mm All data presented are the average of ﬁ ve meas-ured specimens for each sample

Dynamic Mechanical Analysis (DMA) : DMA was performed by

means of a mechanical spectrometer Eplexor 150 N (Gabo) Tem-perature sweep measurements were carried out from −100 to

100 °C at a heating rate of 1 K min −1 and at a frequency of 1 Hz The specimens of size 25 × 10 × 1 mm 3 were stamped out from the cross-linked samples

Fracture Toughness Characterization : The materials were

char-acterized regarding their crack toughness by using the instru-mented tensile-impact test (ITIT) Principal details on this test can be found in [ 16,17 ] The tests were carried out on double edge

notched specimens (DENT) with dimensions length L = 64 mm, width W = 10 mm, thickness B = 4 mm and initial notch depth a = 2 mm [ 18 ] The instrumented pendulum device RESIL IMPACTOR Junior (CEAST) was used with a pendulum hammer with a maximum working capacity of 7.5 J at maximum falling angle (150°), corresponding to a test speed of 3.7 m s −1 The initial gauge length was 30 mm For each vulcanizate, the

load ( F )–extension ( l ) diagrams of 10 specimens were recorded and analyzed As a result, J d values were determined, which describe the materials resistance against crack propagation

Surface Tension Measurements : Sessile drop contact angle measurements on a sheet of lightly cured rubber were con-ducted with the automatic contact angle meter OCA 40 Micro, DataPhysics Instruments GmbH, Filderstadt, Germany The sur-face energies were calculated from the results of these wetting experiments For this purpose a set of test liquids with different

Trang 3

surface tension (and polarity) was used: water, formamide,

dode-cane, and ethanol Surface energy calculations were performed

by ﬁ tting the Fowkes Equation [ 19 ]

Experimental Determination of Filler Wetting in Rubber

Com-pounds and Blends : For the investigation of the rubber–ﬁ ller gel

of the compounds and blends, 0.1 g of each raw mixture was

stored for seven days in 100 ml toluene at room temperature The

rubber–ﬁ ller gel was taken out and dried up to a constant mass

The rubber content in the gel L ESBR and L SSBR as well as L B(ESBR/SSBR)

as a measure for the wetting behavior of silica surface by ESBR

and SSBR as well as ESBR/SSBR blend, respectively, is determined

according to Equation ( 1) [ 12 ]

2 1 2

= − ⋅

The mass m 1 is corresponding to the rubber compound before

extracting m 2 is the mass of the rubber–ﬁ ller gel, which is the

sum of the undissolvable rubber part and the mass of silica c F

is the mass concentration of silica in the single rubber mixture

or binary blends For ESBR/SSBR blend the rubber layer L B(ESBR/

contributions according to Equation ( 2)

LB(ESBR/SSBR)( )t =LB(ESBR)( )t +LB(SSBR)( )t (2)

L B(ESBR) and L B(SSBR) can be determined by means of a calibration curve For creation of the calibration curve, blends with different ESBR/SSBR ratios were prepared and investigated by FTIR FTIR spectra were recorded by use of an FTIR spectrometer S2000 (Perkin Elmer) equipped with a diamond single Golden Gate

Table 1 Mixing regime of silica-ﬁ lled SBR compounds and blends

Dumping temperature T E = 90 °C

n = 50 rpm

Dumping temperature T E = 152 °C

Figure 1 a) FTIR spectra of the neat ESBR and SSBR and b) correlation between the surface ratio A ESBR(964) /A SSBR(907) and the mass ratio ESBR/ SSBR

Trang 4

ATR cell (Specac) Two neat rubbers show clearly a strong peak at

964 cm −1 , which is assigned to vibration trans-1,4 butadiene unit,

and a peak at 907 cm −1 , which is attributed to vibration of

vinyl-1,2 butadiene unit (Figure 1 a) Taking a closer look at the spectra,

it is clear that the intensity of the peak at 964 cm −1 is stronger

in ESBR than in SSBR, while the peak at 907 cm −1 is weaker in

ESBR than in SSBR The difference in intensity of these two peaks

can be used for identiﬁ cation of ESBR and SSBR in their blends

The correlation between the peak area ratio A ESBR(964) /A SSBR(907)

and the given mass ratio ESBR/SSBR presented in Figure 1 b is

not described by a straight line as we often observed for other

systems containing immiscible rubber components reported

in our previous works [ 12–15 ] Thus, the ratio L B(ESBR) /L B(SSBR) in

the rubber–ﬁ ller gel can be determined manually using the

calibration curve presented in Figure 1 b

The selective wetting of silica in ESBR/SSBR blend can be

calculated according to Equation ( 3) and ( 4) :

L L

( )

( ) ( )

P P

B(ESBR)

B(SSBR)

SSBR ESBR B(ESBR) B(SSBR)

(3)

SB= SB(ESBR)( ) t + SB(SSBR)( ) t (4)

S B(ESBR) and S B(SSBR) are the silica surface fractions wetted by

ESBR and SSBR component of blend, respectively t is the mixing

time S B is the total ﬁ ller surface wetted in blend L P ESBR , L P SSBR

and L P B(ESBR/SSBR) are the saturated rubber contents in the gel

of the single compounds and blend, respectively They can be

determined from extraction experiments of the samples taken

out at 30 min mixing time

3 Results and Discussion

3.1 Theoretical Prediction and Experimental

Determina-tion of the Selective Wetting of Silica in ESBR/SSBR Blends

When silica is mixed into a rubber blend, both rubber

components compete with each other to wet silica On the

basis of the Z-model proposed in our previous work [ 20 ] the

ﬁ ller surface fraction wetted by blend components of a

binary ESBR/SSBR blend at an equilibrium state can be

pre-dicted using Equations ( 5) and ( 6)

S

2 2

eq

B(ESBR)

eq

B(SSBR) ESBR/SSBR

2

+ −

⎛

⎝⎜

⎞

⎠⎟ (5)

eq

B(ESBR)

eq B(SSBR)

S eq B(ESBR) and S eq B(SSBR) are the ﬁ ller surface fractions

wetted by each blend component at an equilibrium

state n ESBR / SSBR is the mass ratio of the rubber phase

ESBR to SSBR, respectively γ ESBR , γ SSBR , and γ F are the

sur-face tension values of the blend components and ﬁ ller,

respectively

Setting the surface tension values γ ESBR = 24.3 mN m −1

and γ SSBR = 24 mN m −1 of rubber components, which were

experimentally determined, into Equations ( 5) and ( 6)

with n ESBR / SSBR = 1 for the investigated blend, a Z -shaped

master curve demonstrating the ﬁ ller surface fraction wetted by ESBR component in dependence on the ﬁ ller surface tension can be created as seen in Figure 2 By

ﬁ tting the surface tension γ F = 73 mN m −1 of the non-modiﬁ ed silica [ 21 ] to the master curve a surface fraction

of silica wetted by ESBR phase S eq B(ESBR) = 0.517 was pre-dicted for 50/50 ESBR/SSBR blend Upon the silanization process the surface tension of silica reduces to a value

γ F = 45 mN m −1 [ 15 ] because of the hydrophobization of the silica surface Fitting this value to the master curve,

a value S eq B(ESBR) = 0.52 was determined Based on this result, it can be obviously predicted that ESBR and SSBR show the same afﬁ nity to silica surface and the same wetting behavior An addition of silane will not show any effect on the wetting behavior of both rubbers

The kinetics of silica wetting in 50/50 ESBR/SSBR

blends was experimentally characterized by the wetting

concept according to Equations ( 3) and ( 4) According to

Equation ( 1) , the plateau values of rubber layer L P ESBR and

L P SSBR were determined from the extraction experiment for ﬁ lled ESBR and SSBR compound collected at 30 min

L P ESBR = 0.27, L P SSBR = 0.52 were determined indicating that ESBR forms a thin rubber layer on the silica surface, while SSBR presents a thick rubber layer bound to silica surface As seen in Figure 3 a the silica surface fractions

S B(ESBR) and S B(SSBR) wetted by ESBR and SSBR molecules, respectively, increase immediately after adding 50 phr silica into 50/50 ESBR/SSBR blend without silane It is clear that SSBR wets silica faster than ESBR in the ﬁ rst mixing stage (up to 15 min) The branching structure of ESBR may be the reason for its slow ﬁ ller wetting due to

Figure 2 Prediction of the selective wetting of silica by ESBR in

50/50 ESBR/SSBR blend

Trang 5

the steric hindrance In the second mixing stage from

15 to 30 min, the fraction S B(ESBR) gradually increases,

while S B(SSBR) remains unchanged and at 30 min silica is

wetted homogeneously by both blend components This

result is well corresponding to the prediction and

attrib-uted to the fact that the same chemical afﬁ nity of silica

to both rubbers is essential for ﬁ ller wetting at longer

mixing time, while the differences in rubber

microstruc-ture (branching and linear) inﬂ uence the kinetics of ﬁ ller

wetting at short mixing period It is well known that the

absorption of the non-rubber impurities of ESBR to silica

surface may contribute to the wetting behavior of silica

by rubbers However, the wetting of silica by both rubbers

investigated is the same at the end of the mixing process

that leads to the conclusion that in our investigation the

silica wetting is insigniﬁ cantly inﬂ uenced by the

non-rubber impurities of ESBR

As the compatibility between silica and rubbers is low,

a reduction of the polarity difference can commonly be

achieved by silane coupling agents such as NXT and Si69

as done in this work The effect of NXT and Si69 on the

kinetics of selective silica wetting in ESBR/SSBR blend is

obviously seen in Figure 3 b The silica surface fraction

S B(ESBR) increases and reaches a plateau value of 0.32 after

6 min mixing time, while S B(SSBR) continuously increases

up to 15 min and reached a plateau value of 0.68 A

pref-erential wetting of silica by SSBR in presence of silane

cannot be explained by taking into consideration the

chemical rubber–ﬁ ller afﬁ nity, because the chemical

afﬁ nity of silica to both rubbers is similar For explanation

of this feature, the behavior of linear chains (SSBR) and

branched chains (ESBR) in silica pores should be taken

into consideration When a polymer molecule is forced

into a small pore and the space available for the polymer

is restricted, a minimum pore size h min through which the

branched polymer is able to pass through was introduced

by Heinrich and Vilgis [ 10 ] according to Equation ( 7)

min≈ (−1)/2≡ ( −1)/2

where M ∼ N D is the mass of the branched polymer The

spectral dimension D was introduced for a natural

gen-eralization of the stretched length of a branched polymer object [ 22 ] The minimum pore size for linear polymers is independent of the molecular weight, i.e., linear polymers

( D = 1) pass through a very small pore if h min is of the order of the Kuhn segment radius For branched polymers (1 < D < 2) the minimum pore size h min becomes larger Based on the wetting behavior of silica in ESBR/SSBR blend in the absence and presence of silane, the effect of silane can be explained as illustrated in Figure 4 It can

be postulated that in the case of the absence of silane

the pore size is larger than the h min and the space ﬁ lling

by ESBR is nearly not disturbed (Figure 4 a) By addition

of silane the silica surface is covered by a thin layer of silane, which constricts the pores to an extent that the branched polymers cannot penetrate the pores as seen

in Figure 4 b In other words, the unaccessible space for ESBR becomes larger, when silane is used In contrast, the linear SSBR molecules can easily penetrate the small pores and wet silica inner surface well even in presence

of silane, i.e., the presence of silane does not enlarge the unaccessible space for SSBR As a result, the presence of silane will reduce the silica surface fraction wetted by ESBR and increase the silica surface fraction wetted by SSBR in their blends

Figure 5 a represents the silica surface fraction S B(ESBR)

and S B(SSBR) by variation of ESBR fraction in ESBR/SSBR blends It is obvious that in all blends the silica surface is dominantly wetted by the SSBR component The structure

of the blends investigated can be illustrated in Figure 5 b showing morphology with a SSBR-rich interphase and ESBR-rich matrix

DMA of silica-ﬁ lled ESBR/SSBR blends with varied blend ratios was performed The tan δ -temperature curves of different blends with NXT are presented in Figure 6 a ESBR shows a glass transition at the

tempera-ture T G = −41 °C and SSBR at T G = −11 °C All ESBR/SSBR blends show only one transition peak that indicates the

Figure 3 Kinetics of silica wetting in 50/50 ESBR/SSBR blend in a) absence and b) presence of silane.

Trang 6

miscibility of them in molecular level The tan δ value at

0 °C, which is a measure for wet grip of a tire, is

deter-mined by the glass temperature of the matrix The tan δ at

0 °C of all the blends lies between those of ESBR and SSBR

component

The tan δ at 60 °C is considered as a measure for the

rolling resistance of a tire and is mainly determined

by the internal friction caused in the polymer–filler

interphase This discussion is related to hindered

dynamics of polymer segments in the vicinity of filler

surfaces, leading to the formation of a coating layer

of immobilized glassy polymer [ 23–28 ] Gusev [ 9 ] used a

finite element method and showed that both storage

and dissipation energies are strongly localized in these coating layers Wang et al [ 29 ] also stated that the tan δ strongly depends on the interfacial layer Due to the loose interlocking between branched ESBR molecules and silica surface a high internal friction is generated

in the rubber–filler interphase during cyclic deforma-tion that leads to a high value of the tan δ at 60 °C as seen in Figure 6 a [ 10 ] The tight interlocking between linear SSBR and silica surface is the reason for the low value of tan δ at 60 °C and internal friction of silica-filled SSBR compound (Figure 6 a) With increasing ESBR fraction in the blend up to a fraction of 0.4, the value of tan δ at 60 °C of blends remains unchanged at the level

Figure 5 a) S B(ESBR) and S B(SSBR) in dependence on the ESBR fraction in blends and b) the suggested morphology of silica-ﬁ lled ESBR/SSBR blends showing an SSBR-rich interphase and ESBR-rich matrix

Figure 4 Illustration of the wetting of silica pores by ESBR and SSBR molecules a) without and b) with silane.

Trang 7

of that of the SSBR single compound (Figure 6 b) That

is related to the fact that the silica surface is mainly

wetted by the SSBR with a tight interlocking Passing

the ESBR fraction of 0.4, the silica surface fraction

S B(ESBR) wetted by ESBR starts to increase and contribute

markedly to the increase of tan δ at 60 °C Both silanes

used, NXT and Si 69, show the similar effect on the tan δ

at 60 °C, however, the extent made by Si69 is stronger

than that of NXT Without silane, ESBR and SSBR

com-pound present higher values of tan δ at 60 °C The tan δ

at 60 °C of unmodified 50/50 ESBR/SSBR blend is the

average value of those of ESBR and SSBR compound

(Figure 6 b), i.e., no synergetic effect was achieved in the

absence of silane According to Figure 3 a, in this blend,

silica is wetted homogeneously by ESBR and SSBR

Thus, the internal friction generated in the rubber–

filler interphase results from contributions by both

rubbers This finding again emphasizes the role of the

interfacial phenomena and the selective wetting of the

filler surface in the dynamic properties of filler rubber

compounds

The tensile behavior of ESBR and SSBR compounds

as well as of the 50/50 ESBR/SSBR blend is presented

in Figure 7 a The stress and strain at break of the SSBR compound are much lower than those of the ESBR com-pound The result is related to the narrow molecular weight distribution of linear SSBR compared to the broad molecular weight distribution of branched ESBR The 50/50 ESBR/SSBR blend presents a tensile behavior, which approaches the level of ESBR and much better than that of SSBR The stress at break and strain at break

of ESBR/SSBR blends with different blend ratios are pre-sented in dependence on ESBR fraction in Figure 7 b With increasing ESBR fraction up to 0.5, the stress at break of blends increases strongly and reaches the level of ESBR

at an ESBR fraction of 0.5 After that the stress at break remains unchanged with increasing ESBR fraction The

J d -values, which are a measure of the crack resistance

of the investigated blends, are presented in Figure 8 in dependence on the ESBR fraction For both blend series

modiﬁ ed with NXT and Si69, respectively, J d increases with increasing ESBR fraction and it reaches the high

Figure 6 Temperature dependence of a) tan δ of blends with different ESBR/SSBR mass ratio in presence of NXT and b) tan δ at 60 °C in dependence on the ESBR fraction in blend

Figure 7 a) Stress–strain curves of silica-ﬁ lled ESBR and SSBR compound as well as 50/50 ESBR/SSBR blend, and b) stress and strain at break

of ESBR/SSBR blends with varied blend ratios

Trang 8

level of the ESBR compound at a ESBR fraction of 0.5 The

similar dependence of the fracture behavior of blends on

the blend mass ratio when compared with the tensile

results would lead to a conclusion that the tensile and

fracture properties of the ﬁ lled blends are determined

mainly by the matrix, while the dynamic properties are

signifi cantly infl uenced by the rubber–fi ller interphase

The tensile and fracture behavior is strongly connected

also to other important properties for such as tearing

and wear resistance as well as abrasion resistance

Therefore, a combination of high strength and high

crack toughness should be given as for such materials as

a pre-condition for the use in tire treads

4 Conclusions

In this work, the wetting concept was further developed

for experimental determination of the selective

wet-ting behavior of silica in miscible rubber blends It was

found that in non-silanized miscible blends made up by

ESBR and SSBR the silica surface is wetted by the linear

SSBR molecules faster than ESBR molecules as a result

of the branching structure of ESBR molecules However,

after long mixing time both rubbers wet silica surface in

the same extent In this case, the nanostructure of silica

surface with nanopores inﬂ uences only the kinetics of

rubber wetting in the early state of mixing but not the

end state In contrast, in silanized blends the adsorption

of silane on silica surface constricts the nanopores, thus

their space ﬁ lling by ESBR is signiﬁ cantly hindered due

to its branching structure The dominant wetting of silica

surface by the tightly bonded SSBR molecules imparts the

blends the low rolling resistance compared to silica-ﬁ lled

SSBR compound, while the ESBR - rich matrix warrants

the good tensile behavior, i.e., good abrasion and tearing resistance of the blends

Acknowledgements: The authors wish to thank the Deutsche Forschungsgemeinschaft (DFG) (Project Nr LE 3202/1–1) and Vietnam National Foundation for Science and Technology Development (Nafosted) (Grant number 104.02–2014.90) for the

ﬁ nancial support

Received: September 9, 2015 ; Revised: November 9, 2015; Published online: January 29, 2016; DOI: 10.1002/mame.201500325 Keywords: mechanical properties; rubber blends; selective ﬁ ller wetting

[1] B T Poh , H Ismail , K S Tan , Polym Test 2002 , 21 , 801

[2] P Sae-oui , Ch Sirisinha , T Wantana , K Hatthapanit , J Appl

Polym Sci 2007 , 104 , 3478 [3] H Ismail , B T Poh , K S Tan , M Moorthy , Polym Int 2003 ,

52 , 685 [4] L Qu , G Yu , L Wang , Ch Li , Q Zhao , J Li , J Appl Polym Sci

2012 , 126 , 116

[5] Y C Ou , Z Z Yu , A Vidal , J B Donnet , Rubber Chem Technol

1994 , 67 , 834

[6] N Suzuki , M Ito , F Yatsuyanagi , Polymer 2005 , 46 , 193

[7] S Thiele , S Rulhoff, (Styron Europe GmbH), W O Patent

No 2011/079922A1, 2011 [8] S Thiele , S Knoll , S Rulhoff , (Styron Europe GmbH),

W O Patent No 2011/076377A1, 2011

[9] A A Gusev , Macromolecules 2006 , 39 , 5960 [10] G Heinrich , T A Vilgis , Kautsch Gummi Kunstst 2008 , 61 ,

368

[11] U Görl , R Rausch , H Esch , R Kuhlmann , Kautsch Gummi

Kunstst 1995 , 48 , 407

[12] H H Le , S Ilisch , D Heidenreich , A Wutzler , H.-J Radusch ,

Polym Compos 2010 , 31 , 1701

[13] H H Le , X T Hoang , K Oßwald , S Ilisch , G Heinrich ,

H.-J Radusch , J Mater Sci 2012 , 47 , 4270

[14] H H Le , K Oßwald , S Ilisch , T Pham , K.-W Stöckelhuber ,

G Heinrich , H.-J Radusch , Macromol Mater Eng 2012 , 297 , 464

[15] H H Le , M Keller , M Hristov , S Ilisch , X T Hoang , Q K Do ,

T Pham , K.-W Stöckelhuber , G Heinrich , H.-J Radusch ,

Macro mol Mater Eng 2013 , 298 , 1085

[16] W Grellmann , K Reincke , in Fracture Mechanics and Statistical Mechanics of Reinforced Elastomeric Blends

(Eds: W Grellmann , G Heinrich , M Kaliske , M Klüppel ,

K Schneider , T Vilgis) , Springer-Verlag , Berlin 2013 , S 227

[17] K Reincke , W Grellmann in Rubber-Clay Nanocomposites: Sci-ence, Technology and Applications , 1st ed (Ed: M Galimberti ),

John Wiley & Sons , Hoboken, NJ, 2011 pp 305

[18] W Grellmann , C Bierögel , K Reincke , DENT-Prüfkörper Wiki

“Lexikon Kunststoffprüfung und Diagnostik” , http://wiki

polymerservice-merseburg.de (accessed: May 2015 )

[19] F M Fowkes , J Phys Chem 1963 , 67 , 2538

[20] H H Le , K Oßwald , S Wießner , A Das , K.-W Stöckelhuber ,

R Boldt , G Gupta , G Heinrich , H.-J Radusch , Polymer 2013 ,

54 , 7009

[21] U Jönsson , M Malmqvist , I Ronberg , Biochem J 1985 , 227 ,

363

[22] P G De Gennes , Adv Polym Sci 1999 , 138 , 91

Figure 8 J d values of silica-ﬁ lled ESBR/SSBR blends with varied

blend ratios

Trang 9

[23] G Heinrich , M Klüppel , Adv Polym Sci 2002 , 160 , 1

[24] G Heinrich , M Klüppel , T A Vilgis , Curr Opin Solid State

Mater Sci 2002 , 6 , 195

[25] L C E Struik , Physical Aging in Amorphous Polymers and

other Materials , Elsevier , Amsterdam 1978

[26] W M Litvinov , P A M Steeman , Macromolecules 1999 , 32 , 8476

[27] J Berriot , H Montes , F Lequeux , D Long , P Sotta ,

Macromole cules 2002 , 35 , 9756 [28] H Montes , F Lequeux , J Berriot , Macromolecules 2003 , 36 ,

8107

[29] M J Wang , S Wolff , E H Tan , Rubber Chem Technol 1993 ,

66 , 178

Định dạng
Số trang	9
Dung lượng	1,21 MB