effect of dpg on silinization
TRANSCRIPT
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Bound rubber study of silica
Effect of DPG on Effect of DPG on SilanizationSilanization Chemistry Chemistry of Silica in Rubber Processing of Silica in Rubber Processing S. Mihara*1), R.N. Datta2), A.G. Talma2), W.K. Dierkes2)
and J.W.M Noordermeer2)
1) Yokohama Rubber Co., LTD 2-1 Oiwake, Hiratsuka, Kanagawa, Japan
2) University of Twente , Faculty of Engineering Technology,
Dept. of Elastomer Technology and Engineering
P.O. Box 217, 7500 AE Enschede , the Netherlands
VKRT meeting on December 11
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1. Introduction1. Introduction
1,31,3--diphenylguanidine (DPG)diphenylguanidine (DPG)
ØØSecondary cure accelerator in silicaSecondary cure accelerator in silica--filled rubberfilled rubberØØInteraction with silica surfaceInteraction with silica surfaceØØToxic concernsToxic concernsØØNegative influence on metalNegative influence on metal--rubber adhesionrubber adhesion
NH
C
NH
NH
3
1. Introduction1. Introduction
OH OOSiSi OCOC22HH55HH55CC22OO
(CH(CH22))33
SSxx
OSi OH5C2O
(CH2)3
Sx
OSi OC2H5
(CH2)3
Sx
OH OH
SySz
SilaneSilane--RubberRubbercouplingcoupling
CrosslinkingCrosslinking reactionreaction
+ Other reactions+ Other reactions
How does DPG influence on these reactions ???How does DPG influence on these reactions ???
TESPTNH
C
NH
NH
SilanizationSilanization Silica
Typical reactions during rubber processingTypical reactions during rubber processing
Polymer
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ObjectivesObjectives
UnderstandingUnderstanding1. Influence of DPG on 1. Influence of DPG on silanesilane chemistrychemistry
2. Role of DPG during rubber processing 2. Role of DPG during rubber processing
1.1. SilanizationSilanization kineticskinetics2.2. CrosslinkingCrosslinking reaction between model olefinsreaction between model olefins3.3. Change of sulfur distribution in TESPTChange of sulfur distribution in TESPT4.4. TESPTTESPT--model olefin reactionmodel olefin reaction5.5. DPGDPG--TESPT reactionTESPT reaction
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2. Experimental2. ExperimentalMaterialsMaterials
Mixture 1 Mixture 2 Mixture 3 Mixture 4
n-decane 1.4600 1.4600 - -2,3-dimethyl-2-butene - - 0.4000 0.4000Silica 0.2000 0.2000TESPT 0.0200 0.0200 0.0320 0.0320DPG - 0.0040 - 0.0071
2,3-dimethyl-2-butene(TME)
n-decane
N-decane: (Aldrich) ; 2,3-dimehyl-2-butene: (Aldrich) ; 3-methyl-1-pentene: (Aldrich)Silica: Zeosil 1165MP (Rhodia Silices) ; TESPT: Si69 (Degussa)DPG: Perkacit DPG (Flexsys B.V)
(g)(g)
Silanization kinetics Crosslinking between model olefins
TESPT reaction with polymer or DPG
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Model olefinTESPTDPGSilicaN2 flowMelt
Reaction MixturesReaction Mixtures Reaction Mixtures
Dip into oil bath at specified temperatureDip into oil bath at specified temperature
Cool down the reaction mixture with iceCool down the reaction mixture with ice
Filtration of reaction mixture using micro pore filter
Diethyleneglycol-monobutylether
treatment
HPLCHPLC HPLC and MSHPLC and MS
Sample preparationsSample preparations
1. Silanization kinetics 2. Cross-linking products3. TESPT-model olefin complex4. TESPT-DPG complex
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HPLC conditions
Column Nucleosil 100-5 C18 HD Length of column 250 mmInternal diameter 4.6 mmMobile phaseMobile phase AcetonitrileAcetonitrile : water = 97 : 3: water = 97 : 3Flow rate 0.3 ml/minTemperature 23 CDetector UV (DAD)Wavelength 254 nm (200 to 700 nm)Injection volume 0.5 ml
S2S3
S4
S5S6 S7
Chromatographic and MS ConditionsChromatographic and MS Conditions
Chromatogram of TESPT (Mixture 1 or 2)Chromatogram of TESPT (Mixture 1 or 2)
MS ionization conditions in APCIAPCI
Flow rate 20 ml/minNebliser gas pressure 25 psiDry gas flow 3 L/minDry gas Temp. 320 CVaporise Temp. 425 C
238.9
266.9294.9
323.0
250 300 350
0
0.5
1.0
1.5
2.0
x105
Inte
nsity
[mA
U]
m/zMass to charge ratio
Retention time
Inte
nsity
APCI : Atmospheric Pressure Chemical Ionization
[ M + H] + is detected.
[ M + H] +[ M + H] +
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Calculation of kinetic parametersCalculation of kinetic parameters
)t(C)t(C)t(Cx
0
10 −=
][mintt
)x1ln()x1ln(k 1
01
tt1
01 −−
−−−=
x is conversion of TESPT, C(t0) and C(t1) are the amounts of unun--reacted TESPTreacted TESPTat time t0 and t1, respectively, k1 is the rate constant of silanization.
RTE)kln(kln a
01 −=
ArrheniusArrhenius equationequation
Ea is the activation energy, R is the gas constant, R is the gas constant, T is the absolute temperature.T is the absolute temperature.
Summed peak = amount of un-reacted TESPT
S2S3
S4
S5S6 S7
1/T
lnk 1
Ea
9
-5.0
-4.0
-3.0
-2.0
-1.0
0.0
0 2 4 6 8 10Time (min)
ln(1
-x)
-5.0
-4.0
-3.0
-2.0
-1.0
0.0
0 2 4 6 8 10
ln(1
-x)
Time (min)
-5.0
-4.0
-3.0
-2.0
-1.0
0.0
ln(1
-x)
0 2 4 6 8 10Time (min)
(a) 120 C (b) 140 C (c) 160 C
ØØIn the presence of DPGIn the presence of DPG conversion of TESPT conversion of TESPT increases fast at the beginning of reaction.increases fast at the beginning of reaction.
3.1 Influence of DPG on 3.1 Influence of DPG on SilanizationSilanization KineticsKineticsConversion of TESPTConversion of TESPT
with DPGwith DPG with DPGwith DPG with DPGwith DPG
without DPGwithout DPG without DPG
SiOC2H5
OC2H5
(CH2)3 S2H5C2O
OH
OH
Silica
+
TESPT
SiOC2H5
OOC2H5
(CH2)3 S2
OH2
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Mixture 1Mixture 1 Mixture 2Mixture 2without DPGwithout DPG with DPGwith DPG
Rate constant kRate constant k11 (1/min)(1/min) 0.170.17 1.091.09Activation energy EActivation energy Eaa (kJ/mol) 29.3(kJ/mol) 29.3 11.011.0
ØØkk11 of increases by a factor of six.of increases by a factor of six.ØØEEaa decreases till one third.decreases till one third.
3.1 Influence of DPG on 3.1 Influence of DPG on SilanizationSilanization KineticsKineticsCalculated kinetic parametersCalculated kinetic parameters
DPG can accelerate the DPG can accelerate the silanizationsilanization reaction.reaction.
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3.2 Influence of DPG on 3.2 Influence of DPG on crosslinkingcrosslinking reaction reaction between model olefinsbetween model olefins
Time [min]
02.0
4.0
6.0
2018 22 24 26 28
3x10
S2*S2*S3*S3*
S4**S5**
S6** S7**
S4*S4*S5*S5* S6*S6*
S2**
S3**
Inte
nsity
[mA
U]
CH2
CH3CH3
CH3 Sx CH2
CH3 CH3
CH3
S.C. Debnath, R. N. Datta, J. W. M. Noordermeer, RUBBER CHEM. TECHNOL. 76, 1311 (2002).
CrossCross--linked product of TMElinked product of TME
** TESPT
2 + Sx
Coming from TESPT
DPGDPG
12
0
50000
100000
150000
200000
250000
300000
0 10 20 30 40Reaction time (min)
Peak
are
a [m
AU
]
without DPG
with DPGwith DPG
ØØThe total peak area of The total peak area of the crossthe cross--linked products increaseslinked products increases with with increasing reaction time, increasing reaction time, even in the absence of elemental sulfureven in the absence of elemental sulfur..ØØIn the presence of DPG the increase of the crossIn the presence of DPG the increase of the cross--linked products is linked products is
much faster compared to the DPGmuch faster compared to the DPG--free system. free system.
TESPT acts as a sulfur donor during processing.TESPT acts as a sulfur donor during processing.
3.2 Influence of DPG on 3.2 Influence of DPG on crosslinkingcrosslinking reaction reaction between model olefinsbetween model olefins
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Si
OC2H5
OC2H5
H5C2O (CH2)3 Sx (CH2)3 Si
OC2H5
OC2H5
OC2H5
In the presence of DPG the increase of the triIn the presence of DPG the increase of the tri--sulfide is sulfide is relatively faster compared to the DPGrelatively faster compared to the DPG--free system. free system.
0.0
0.2
0.4
0.6
0.8
0 10 20 30 40Reaction time (min)
Rat
io o
f sul
fur
rank
0.0
0.2
0.4
0.6
0.8
0 10 20 30 40Reaction time (min)
Rat
io o
f sul
fur
rank with DPGwith DPGwithout DPGwithout DPG
S3S3S3S3
3.3 Influence of DPG on sulfur distribution in TESPT3.3 Influence of DPG on sulfur distribution in TESPT
( ) : S3 ;( ) : S2 ; ( ) : S4 ; ( ) : S5 ; ( ) : S6 ; ( ) : S7
**Reaction Temperature : 140 Reaction Temperature : 140 CC
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3.4 Influence of DPG on reaction between3.4 Influence of DPG on reaction betweenTESPT and model olefinsTESPT and model olefins
12 14 16 180
1
2
3
4
5
0
12 14 16 18
1
2
3
4
5
0
0
1
2
3
0
12 14 16 180
2
4
6
0
Ion
inte
nsity
x 1
04 (m
AU
)
0 12 14 16 18Retention time (min)
(a)
(b)
(b)(c)
(d)
0 12 14 16 18
0
0 12 14 16 18
12 14 16 18 Time [min]12 14 16 18
0
1
2
3
4
5
0
1
2
3
4
5
0
1
2
3
4
5
0
1
2
3
4
5
( x 1
05 )
( x 1
05 )
( x 1
04 )
TMETME
TME+DPGTME+DPG
TME+TESPTTME+TESPT (Mixture 3)(Mixture 3)
TME+TESPTTME+TESPT+DPG (Mixture 4)+DPG (Mixture 4)
Reaction Temperature:140 ºCTime: 30 minutes
Extracted ion peak of 323 Extracted ion peak of 323 m/zm/z
Si
OC2H5
OC2H5
H5C2O (CH2)3 Sx+2
S
SiOC2H5
CH3
CH3CH
CH3
CH3
OC2H5
H5C2O
[M + H[M + H++] = 323 ] = 323 m/zm/z
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Fragmentation of 323 Fragmentation of 323 m/zm/z using the MS using the MS
Masses of 295 Masses of 295 m/zm/z, 267 , 267 m/zm/z and 239 and 239 m/zm/z coming from coming from the TESPTthe TESPT--TME complex are obtained.TME complex are obtained.
This decrease with each time 28 This decrease with each time 28 m/zm/z can be related to progressive can be related to progressive hydrolysis of the hydrolysis of the ethoxyethoxy groups of the TESPT moiety. groups of the TESPT moiety.
238.9
266.9294.9
323.0
250 300 350
0
0.5
1.0
1.5
2.0
x105In
tens
ity [m
AU
]
Mass to charge ratio
[M + H+]
3.4 Influence of DPG on reaction between3.4 Influence of DPG on reaction betweenTESPT and model olefinsTESPT and model olefins
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Possible structures of TESPTPossible structures of TESPT--Model Olefin ComplexModel Olefin Complex
S
SiOC2H5
CH3
CH3CH
CH3
CH3
OC2H5
H5C2O
S
Si
CH3
CH3CH
CH3
CH3
OHOC2H5
H5C2O
S
Si
CH3
CH3CH
CH3
CH3
OHOH
H5C2O
S
Si
CH3
CH3CH
CH3
CH3
OHOH
OH
M + H+ = 323
- C2H4
Hydrolysis- C2H4
Hydrolysis- C2H4
Hydrolysis
-28 m/z -28 m/z -28 m/z
M + H+ = 295 M + H+ = 267 M + H+ = 239
3.4 Influence of DPG on reaction between3.4 Influence of DPG on reaction betweenTESPT and model olefinsTESPT and model olefins
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3.4 Influence of DPG on reaction between3.4 Influence of DPG on reaction betweenTESPT and model olefinsTESPT and model olefins
Amount of TESPTAmount of TESPT--Model Olefin ComplexModel Olefin Complex
ØØThe total peak area of TESPTThe total peak area of TESPT--Model olefin complexModel olefin complexincreases with increasing reaction time. increases with increasing reaction time. ØØDPG is capable of accelerating the TESPTDPG is capable of accelerating the TESPT--model olefin reaction.model olefin reaction.
0
2000000
4000000
6000000
8000000
10000000
12000000
0 10 20 30 40Reaction time (min)
Peak
are
a [m
AU
] with DPGwith DPG
without DPGwithout DPG
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(a)
(b)
Inte
nsity
x 10
5[m
AU
]
14 16
Retention time [min]
00
1
2
3
4
5
14 160
0
1
2
3
4
5
Extracted ion chromatograms of 530 Extracted ion chromatograms of 530 m/zm/z
In the presence of DPG and TESPT In the presence of DPG and TESPT an extracted ion peak of 530 an extracted ion peak of 530 m/zm/z can be seen. can be seen.
3.5 Reaction of TESPT with DPG3.5 Reaction of TESPT with DPG
TME + TESPT (Mixture 3)TME + TESPT (Mixture 3)
TME + TME + TESPT + DPG TESPT + DPG (Mixture 4)(Mixture 4)
Reaction Temperature:140 ºCTime: 30 minutes
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Inte
nsity
[mA
U]
(a)530
528 530 5320
1
2
x 102 (b)498.5
496 498 500
1
x 102 (c)466
464 466
1.0
1.2
454
x 102
Mass to charge ratio (m/z) Mass to charge ratio (m/z) Mass to charge ratio (m/z)
NH N
Sx
H5C2O
H5C2O
SiOC2H5
(a) X=4 Mw = 530 m/z(b) X=3 Mw = 498 m/z(c) X=2 Mw = 466 m/z
Fragments of TESPT Fragments of TESPT –– DPG complex due to elimination of sulfur DPG complex due to elimination of sulfur
A decrease with 32 A decrease with 32 m/zm/z each is observed, each is observed, corresponding to elimination of sulfur corresponding to elimination of sulfur atoms from DPGatoms from DPG--TESPT complex TESPT complex
3.5 Reaction of TESPT with DPG3.5 Reaction of TESPT with DPG
-32 -32
20
The total peak area of the DPGThe total peak area of the DPG--TESPT complex slowly increases at the TESPT complex slowly increases at the beginning of the reaction and then increases very fast. beginning of the reaction and then increases very fast.
3.5 Reaction of TESPT with DPG3.5 Reaction of TESPT with DPG
Mw=530 g/mol2
4
6
8
10
12
14
16
18
0 10 20 30 40
Reaction time (min)
Peak
are
a x
106
[mA
U]
0
21
Therefore, significant amounts of DPG could be consumed Therefore, significant amounts of DPG could be consumed during processing due to this mutual TESPTduring processing due to this mutual TESPT--DPG reaction.DPG reaction.
1. The 1. The silanizationsilanization reaction is promoted:reaction is promoted:
> Reaction Rate Constant of TESPT : Increasing by a factor of s> Reaction Rate Constant of TESPT : Increasing by a factor of sixix> Activation Energy> Activation Energy : Decreasing till one third: Decreasing till one third
2. The tri2. The tri--sulfide isomer in TESPT increases. sulfide isomer in TESPT increases. > This tri-sulfide can possibly act as a sulfur donor during processing.
4. TESPT can itself react with the model olefin or DPG.4. TESPT can itself react with the model olefin or DPG.
3. The amount of cross3. The amount of cross--linked products increases.linked products increases.
Due to the presence of DPG in reaction mixtureDue to the presence of DPG in reaction mixture……
4. Conclusions4. Conclusions
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This project was financially supported by This project was financially supported by YOKOHAMA RUBBER CO., LTD. YOKOHAMA RUBBER CO., LTD.
Thank you for your attention.Thank you for your attention.
5. Acknowledgement5. Acknowledgement