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Hindawi Publishing CorporationInternational Journal of Polymer ScienceVolume 2013 Article ID 937284 5 pageshttpdxdoiorg1011552013937284
Research ArticleFourier Transform Infrared Spectral Analysis of Polyisoprene ofa Different Microstructure
Dongmei Chen1 Huafeng Shao2 Wei Yao2 and Baochen Huang2
1 High Performance Polymer Institute of Qingdao University of Science and Technology Qingdao 266042 China2 Key Lab of Rubber and Plastic Ministry of Education Qingdao University of Science and Technology Qingdao 266042 China
Correspondence should be addressed to Dongmei Chen cdm321126com
Received 4 April 2013 Accepted 22 May 2013
Academic Editor Zhou Yang
Copyright copy 2013 Dongmei Chen et alThis is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited
Some polyisoprene samples of differentmicrostructure contents were studied by Fourier transform infrared (FTIR) and 1HNuclearmagnetic resonance (1H NMR) On the basis of detailed analysis of FTIR spectra of polyisoprene the shift of absorption peakscaused by microstructure contentrsquos variation was discussed The contents of the polyisoprene samplesrsquo microstructure which wasdetermined by the 1H NMR was used as the standard Through the choice calculation and comparison with the correspondingabsorption peaks of FTIR a method based on the results of the analysis has been developed for the determination of themicrostructure contents of polyisoprene by FTIR
1 Introduction
As it is well known polyisoprene (PIp) is one kind of impor-tant rubbers and there are four kinds of microstructure in itsmolecular chain which are cis-14- trans-14- 12- and 34-polyisopreneThemain ingredient of nature rubber is cis-14-or trans-14-polyisoprene For example Hevea brasiliensis(the Brazilian rubber tree) is polyisoprene with more than5000 cis-14-repeat units except for the transinitiator residueof repeat units ranging from 1 to 4 depending on the plantspecies Gutta-percha Balata orMalaysian rubber is polyiso-prene with trans-14-repeat units [1ndash4] Since English chemistMichael Faraday found that the structure unit of naturerubber was C
5H8 the research of synthetic polyisoprene
keeps active [1ndash7]Except for the synthesis of high content of cis-14- or
trans-14-polyisoprene to imitate and replace nature rubberthe research on synthesis of polyisoprene with variablemicrostructure contents keeps attractive in order to obtainsome materials of special properties For example with 34-unit contentrsquos increasing the curing rate and low temperatureproperties of polyisoprene decrease but hardness and elas-ticity increase as well as tensile properties tension set and
tearing strength maintain are slightly changed Particularlythe water resistance and hermeticity of polyisoprene withhigh 34-unit content can compare with butyl rubber [8ndash11]The application of polyisoprene with high 34-unit content intread can improve the skidding resistance traction propertyand cutting growing resistance and also can decrease thegeneration of heat by friction So it is the new varieties ofrubber for a fuel-saving environmental protection and safetytire
Most of the studies on microstructure of polymers arecharacterized by nuclear magnetic resonance (NMR) spec-trophotometer and FTIR [12 13] The first extensive IRspectroscopic studies of synthetic polyisoprenes were under-taken by Binder Cornell and Koenig In comparison withother polymers much less work has been reported on poly-isoprene [14] In this paper polyisoprenes of some differ-ent microstructure content are analyzed by FTIR in de-tails Through comparison the intensity of correspondingmicrostructure characterization peak in FTIR with in NMRthe experience relation equation is founded and the methodof calculating the microstructure content of polyisoprene byFTIR is also established
2 International Journal of Polymer Science
2 Experimental
21 Materials All the polyisoprene samples with variablemicrostructure content were polymerized according to [15ndash18]
22 Characterization
221 FTIR Tensor 27 (Bruker German) has been used in theanalysis The samples are tested by ATR-FTIR with 4 cmminus1resolution and scanned 32 times
222 1H NMR AV500 (Bruker German) has been used inthe analysis 1H NMR spectra of the polyisoprene in CDCl
3
were obtained at 50013Hz and chemical shifts were referredto TMS
The 1H NMR spectrum of polyisoprene which contains14- 12- and 34-unit is shown in Figure 112057552sim5012057550sim48and 12057548sim46 peaks are ascribed to the olefinic hydrogen of14- 12- and 34-unit respectively Determining the intensityof these spectral lines then calculating 14- 12- and 34-unitcontent with formula (1) and the results are shown in Table 1
11988314-PIp
=int 12057552ndash50
int 12057552ndash50 + (int 12057550ndash48 + int 12057548ndash46) 2times 100
11988312-PIp
=int 12057550ndash482
int 12057552ndash50 + (int 12057550ndash48 + int 12057548ndash46) 2times 100
11988334-PIp
=int 12057548ndash462
int 12057552ndash50 + (int 12057550ndash48 + int 12057548ndash46) 2times 100
(1)
3 Results and Discussion
31 Analysis of FTIR Spectra of Polyisoprene Polyisoprenehas four kinds of microstructure which are cis-1 4- trans-14- 1 2- and 3 4-polyisoprene as shown in Figure 2
The characterization and attribution peaks of FTIR spec-tra of polyisoprene are listed in Table 2
It can be seen from Figure 3 and Table 2 that the differ-ence of FTIR behavior of the polyisoprene microstructuresis obvious However only 910 888 and 840 cmminus1 peakscan be used for quantitative calculation of microstructurecontent of polyisoprene It is because that the peaks forquantitatively calculation must have moderate intensity littleinterfering factors by other peaks or conditions and so onExcept for those differences shown in Table 2 Table 3 showssome frequency excursion caused by microstructure contentchanging
0
50
100
150
20051345121
4966494649004875484247394670
056
057
026
100
t1 (ppm)450500550
Figure 1 1H NMR spectrum of polyisoprene
Table 1 Microstructure contents of polyisoprene by 1H NMR
32 Quantization Calculation of Microstructure Content ofPolyisoprene by FTIR According to the Beer-Lambert lawthe integrated intensity 119860 of a characteristic band can beexpressed as follows
119860 = 119887119888int
+infin
0
120576 (]) 119889] (2)
Here 120576 is the absorption coefficient 119887 is the thickness 119888is the concentration and ] is the wavenumber
Choosing a peak which has moderate intensity and is notaffected by configuration conformation or other structurefactors as internal standard of thickness then formula (2) canbe changed to the following
[119860] =1198601
1198600
= 1198881[
[
int+infin
0120576 (1205991) 119889120599
1198880int+infin
0120576 (1205990) 119889120599
]
]
= 1198881sdot 119896 (3)
Here ldquo1rdquo means characteristic band and ldquo0rdquo meansinternal standard band ldquo119870rdquo is the correction factor and canbe calculated by 1HNMRdates As described above 910 888and 840 cmminus1 peaks can be used for quantitatively calculatingmicrostructure content of polyisoprene Table 2 shows thatthere is seldom peak which can meet the request of internalstandard peak In this paper 2727 cmminus1 is used as internalstandard peak The integrated intensity 119860 are calculated bythe software of FTIR and the integration methods are shownin Figure 4
International Journal of Polymer Science 3
CC C C
HC C
H
CH2 CH2
CH2CH2
CH3
CH2
CH3
CH2
CH2
n
n
n n
H2C
H3C
H3CCH
CH
12- 34- cis-14- trans-14-
Figure 2 The structural formula of polyisoprene
Table 2 The explanation of absorption peaks of FTIR spectrum of polyisoprene
Figure 4 Samples of absorption values of peaks of polyisoprene
12-
PIp
A910A27274 6 8 10 12 14
468
101214161820222426
(a)
0 5 10 15 20 25 30 35 400
10
20
30
40
50
60
70
34-
PIp
A888A2727
(b)
2 4 6 8 10 12 14102030405060708090
100
14-
PIp
A840A2727
(c)
Figure 5 The absorption coefficient calculation of (a) 910 cmminus1 (b)888 cmminus1 and (c) 840 cmminus1 peaks of FTIR spectra of polyisoprene
The samples shown in Table 1 are calculated with thismethod and the results are given in Figure 5
After regression of measured points of testing pointsbased on a least-squares method the formula of microstruc-ture content is shown as follows
11988312-PIp = 221[119860] 910 cmminus1 minus 610
11988334-PIp = 192[119860]888 cmminus1 minus 340
11988314-PIp = 655[119860]840 cmminus1 + 229
(4)
Because of 910 888 and 840 cmminus1 peak overlaps partlythe errors of calculated values of integrated intensity 119860 willincrease when the peakrsquos intensity is too small Therefore the
International Journal of Polymer Science 5
microstructure content shall be calculated with two higherpeaks In the 12- and 34-unit the double bond is on thebranched chain and belongs to asymmetry substitute so theirdipole momentrsquos shift is bigger than that of 14-unit As aresult the integrated intensity of 910 and 888 cmminus1 peak is farstronger than 840 cmminus1 peak when the contents of their cor-responding units are the same Therefore the calculation ofmicrostructure content of polyisoprene shall choose theformer two peaks
4 Conclusion
The change of microstructure content of polyisoprene cancause a lot of differences in FTIR spectra The describedmethod by FTIR can be used to determine themicrostructurecontent of polyisoprene 910 and 888 cmminus1 peaks of 12- or34-unit have higher absorption ability than 840 cmminus1 peaksof 14-unit therefore 910 and 888 cmminus1 peaks shall be usedfirst for the quantitative analysis of microstructure content ofpolyisopreneThe quantitative calculation formulas were alsoobtained
References
[1] J E Puskas F Peruch A Deffieux et al ldquoBiomimetic carboca-tionic polymerizations III Investigation of isoprene polymer-ization initiated by dimethyl allyl bromiderdquo Journal of PolymerScience Part A vol 47 no 8 pp 2172ndash2180 2009
[2] J E Puskas C Peres F Peruch et al ldquoBiomimetic processes IVcarbocationic polymerization of isoprene initiated by dimethylallyl alcoholrdquo Journal of Polymer Science Part A vol 47 no 8pp 2181ndash2189 2009
[3] A Avgeropoulos S Paraskeva N Hadjichristidis and E LThomas ldquoSynthesis and microphase separation of linear tri-block terpolymers of polystyrene high 14-polybutadiene andhigh 34-polyisoprenerdquo Macromolecules vol 35 no 10 pp4030ndash4035 2002
[4] B Wang D Wang D Cui et al ldquoSynthesis of the first rareearth metal bis(alkyl)s bearing an indenyl functionalized N-heterocyclic carbenerdquoOrganometallics vol 26 no 13 pp 3167ndash3172 2007
[5] G Ricci M Battistella and L Porri ldquoChemoselectivity andstereospecificity of chromium(II) catalysts for 13-diene poly-merizationrdquo Macromolecules vol 34 no 17 pp 5766ndash57692001
[6] G Ricci DMorganti A Sommazzi R Santi and FMasi ldquoPoly-merization of 13-dienes with iron complexes based catalystsinfluence of the ligand on catalyst activity and stereospecificityrdquoJournal of Molecular Catalysis A vol 204-205 pp 287ndash2932003
[7] C Bazzini A Giarrusso L Porri B Pirozzi and R Napoli-tano ldquoSynthesis and characterization of syndiotactic 34-polyisoprene prepared with diethylbis(221015840-bipyridine)iron-MAOrdquo Polymer vol 45 no 9 pp 2871ndash2875 2004
[8] T Yu B Huang W Yao et al ldquoResearch and development of34-polyisoprene rubberrdquo China Synthetic Rubber Industry vol27 no 2 pp 122ndash126 2004
[9] W Zhang B Huang A Du et al ldquoProperties of TPIHVBRNRblendsrdquo China Rubber Industry vol 49 no 1 pp 5ndash8 2002
[10] W Zhang B Huang A Du et al ldquoProperties of TPIHVBRSBR blendsrdquo China Rubber Industry vol 49 no 2 pp 69ndash722002
[11] Z Zhao ldquoThe applied technology and properties of polyiso-prene of high 34-isomer contentrdquo China Rubber Collection ofTranslations no 2 pp 66ndash69 1996
[12] B Huang W Zhang A Du et al ldquoApplication of TPIHVBRblend to treadrdquo China Rubber Industry vol 49 no 3 pp 133ndash137 2002
[13] D Derouet S Forgeard J-C Brosse J Emery and J-Y BuzareldquoApplication of solid-state NMR (13C and29Si CPMAS NMR)spectroscopy to the characterization of alkenyltrialkoxysilaneand trialkoxysilyl-terminated polyisoprene grafting onto silicamicroparticlesrdquo Journal of Polymer Science Part A vol 36 no 3pp 437ndash453 1998
[14] V Arjunan S Subramanian and S Mohan ldquoFourier transforminfrared andRaman spectral analysis of trans-14-polyisoprenerdquoSpectrochimica Acta Part A vol 57 no 13 pp 2547ndash2554 2001
[15] B Huang J He J Song et al ldquoNew polymerization methodof high trans1 4mdashpolyisoprenerdquo CN1048257C China January2000
[16] B Huang Z ZhaoW Yao et al ldquoIndustrial productionmethodof high trans14mdashpolyisoprenerdquo CN1847272A China October2006
[17] P Wang H Shao W Yao et al ldquoPolymerization of isopreneinitiated with tetra-n-butyl titanate supported titanium catalystand triethylaluminiumrdquo China Synthetic Rubber Industry vol32 pp 284ndash284 2009
[18] R Gao T Yu L Bi et al ldquoResearch on novel Mg-Ti-Al complexand its catalysis for olefin polymerizationrdquo China SyntheticResin and Plastics vol 24 no 6 pp 25ndash28 2007
21 Materials All the polyisoprene samples with variablemicrostructure content were polymerized according to [15ndash18]
22 Characterization
221 FTIR Tensor 27 (Bruker German) has been used in theanalysis The samples are tested by ATR-FTIR with 4 cmminus1resolution and scanned 32 times
222 1H NMR AV500 (Bruker German) has been used inthe analysis 1H NMR spectra of the polyisoprene in CDCl
3
were obtained at 50013Hz and chemical shifts were referredto TMS
The 1H NMR spectrum of polyisoprene which contains14- 12- and 34-unit is shown in Figure 112057552sim5012057550sim48and 12057548sim46 peaks are ascribed to the olefinic hydrogen of14- 12- and 34-unit respectively Determining the intensityof these spectral lines then calculating 14- 12- and 34-unitcontent with formula (1) and the results are shown in Table 1
11988314-PIp
=int 12057552ndash50
int 12057552ndash50 + (int 12057550ndash48 + int 12057548ndash46) 2times 100
11988312-PIp
=int 12057550ndash482
int 12057552ndash50 + (int 12057550ndash48 + int 12057548ndash46) 2times 100
11988334-PIp
=int 12057548ndash462
int 12057552ndash50 + (int 12057550ndash48 + int 12057548ndash46) 2times 100
(1)
3 Results and Discussion
31 Analysis of FTIR Spectra of Polyisoprene Polyisoprenehas four kinds of microstructure which are cis-1 4- trans-14- 1 2- and 3 4-polyisoprene as shown in Figure 2
The characterization and attribution peaks of FTIR spec-tra of polyisoprene are listed in Table 2
It can be seen from Figure 3 and Table 2 that the differ-ence of FTIR behavior of the polyisoprene microstructuresis obvious However only 910 888 and 840 cmminus1 peakscan be used for quantitative calculation of microstructurecontent of polyisoprene It is because that the peaks forquantitatively calculation must have moderate intensity littleinterfering factors by other peaks or conditions and so onExcept for those differences shown in Table 2 Table 3 showssome frequency excursion caused by microstructure contentchanging
0
50
100
150
20051345121
4966494649004875484247394670
056
057
026
100
t1 (ppm)450500550
Figure 1 1H NMR spectrum of polyisoprene
Table 1 Microstructure contents of polyisoprene by 1H NMR
32 Quantization Calculation of Microstructure Content ofPolyisoprene by FTIR According to the Beer-Lambert lawthe integrated intensity 119860 of a characteristic band can beexpressed as follows
119860 = 119887119888int
+infin
0
120576 (]) 119889] (2)
Here 120576 is the absorption coefficient 119887 is the thickness 119888is the concentration and ] is the wavenumber
Choosing a peak which has moderate intensity and is notaffected by configuration conformation or other structurefactors as internal standard of thickness then formula (2) canbe changed to the following
[119860] =1198601
1198600
= 1198881[
[
int+infin
0120576 (1205991) 119889120599
1198880int+infin
0120576 (1205990) 119889120599
]
]
= 1198881sdot 119896 (3)
Here ldquo1rdquo means characteristic band and ldquo0rdquo meansinternal standard band ldquo119870rdquo is the correction factor and canbe calculated by 1HNMRdates As described above 910 888and 840 cmminus1 peaks can be used for quantitatively calculatingmicrostructure content of polyisoprene Table 2 shows thatthere is seldom peak which can meet the request of internalstandard peak In this paper 2727 cmminus1 is used as internalstandard peak The integrated intensity 119860 are calculated bythe software of FTIR and the integration methods are shownin Figure 4
International Journal of Polymer Science 3
CC C C
HC C
H
CH2 CH2
CH2CH2
CH3
CH2
CH3
CH2
CH2
n
n
n n
H2C
H3C
H3CCH
CH
12- 34- cis-14- trans-14-
Figure 2 The structural formula of polyisoprene
Table 2 The explanation of absorption peaks of FTIR spectrum of polyisoprene
Figure 4 Samples of absorption values of peaks of polyisoprene
12-
PIp
A910A27274 6 8 10 12 14
468
101214161820222426
(a)
0 5 10 15 20 25 30 35 400
10
20
30
40
50
60
70
34-
PIp
A888A2727
(b)
2 4 6 8 10 12 14102030405060708090
100
14-
PIp
A840A2727
(c)
Figure 5 The absorption coefficient calculation of (a) 910 cmminus1 (b)888 cmminus1 and (c) 840 cmminus1 peaks of FTIR spectra of polyisoprene
The samples shown in Table 1 are calculated with thismethod and the results are given in Figure 5
After regression of measured points of testing pointsbased on a least-squares method the formula of microstruc-ture content is shown as follows
11988312-PIp = 221[119860] 910 cmminus1 minus 610
11988334-PIp = 192[119860]888 cmminus1 minus 340
11988314-PIp = 655[119860]840 cmminus1 + 229
(4)
Because of 910 888 and 840 cmminus1 peak overlaps partlythe errors of calculated values of integrated intensity 119860 willincrease when the peakrsquos intensity is too small Therefore the
International Journal of Polymer Science 5
microstructure content shall be calculated with two higherpeaks In the 12- and 34-unit the double bond is on thebranched chain and belongs to asymmetry substitute so theirdipole momentrsquos shift is bigger than that of 14-unit As aresult the integrated intensity of 910 and 888 cmminus1 peak is farstronger than 840 cmminus1 peak when the contents of their cor-responding units are the same Therefore the calculation ofmicrostructure content of polyisoprene shall choose theformer two peaks
4 Conclusion
The change of microstructure content of polyisoprene cancause a lot of differences in FTIR spectra The describedmethod by FTIR can be used to determine themicrostructurecontent of polyisoprene 910 and 888 cmminus1 peaks of 12- or34-unit have higher absorption ability than 840 cmminus1 peaksof 14-unit therefore 910 and 888 cmminus1 peaks shall be usedfirst for the quantitative analysis of microstructure content ofpolyisopreneThe quantitative calculation formulas were alsoobtained
References
[1] J E Puskas F Peruch A Deffieux et al ldquoBiomimetic carboca-tionic polymerizations III Investigation of isoprene polymer-ization initiated by dimethyl allyl bromiderdquo Journal of PolymerScience Part A vol 47 no 8 pp 2172ndash2180 2009
[2] J E Puskas C Peres F Peruch et al ldquoBiomimetic processes IVcarbocationic polymerization of isoprene initiated by dimethylallyl alcoholrdquo Journal of Polymer Science Part A vol 47 no 8pp 2181ndash2189 2009
[3] A Avgeropoulos S Paraskeva N Hadjichristidis and E LThomas ldquoSynthesis and microphase separation of linear tri-block terpolymers of polystyrene high 14-polybutadiene andhigh 34-polyisoprenerdquo Macromolecules vol 35 no 10 pp4030ndash4035 2002
[4] B Wang D Wang D Cui et al ldquoSynthesis of the first rareearth metal bis(alkyl)s bearing an indenyl functionalized N-heterocyclic carbenerdquoOrganometallics vol 26 no 13 pp 3167ndash3172 2007
[5] G Ricci M Battistella and L Porri ldquoChemoselectivity andstereospecificity of chromium(II) catalysts for 13-diene poly-merizationrdquo Macromolecules vol 34 no 17 pp 5766ndash57692001
[6] G Ricci DMorganti A Sommazzi R Santi and FMasi ldquoPoly-merization of 13-dienes with iron complexes based catalystsinfluence of the ligand on catalyst activity and stereospecificityrdquoJournal of Molecular Catalysis A vol 204-205 pp 287ndash2932003
[7] C Bazzini A Giarrusso L Porri B Pirozzi and R Napoli-tano ldquoSynthesis and characterization of syndiotactic 34-polyisoprene prepared with diethylbis(221015840-bipyridine)iron-MAOrdquo Polymer vol 45 no 9 pp 2871ndash2875 2004
[8] T Yu B Huang W Yao et al ldquoResearch and development of34-polyisoprene rubberrdquo China Synthetic Rubber Industry vol27 no 2 pp 122ndash126 2004
[9] W Zhang B Huang A Du et al ldquoProperties of TPIHVBRNRblendsrdquo China Rubber Industry vol 49 no 1 pp 5ndash8 2002
[10] W Zhang B Huang A Du et al ldquoProperties of TPIHVBRSBR blendsrdquo China Rubber Industry vol 49 no 2 pp 69ndash722002
[11] Z Zhao ldquoThe applied technology and properties of polyiso-prene of high 34-isomer contentrdquo China Rubber Collection ofTranslations no 2 pp 66ndash69 1996
[12] B Huang W Zhang A Du et al ldquoApplication of TPIHVBRblend to treadrdquo China Rubber Industry vol 49 no 3 pp 133ndash137 2002
[13] D Derouet S Forgeard J-C Brosse J Emery and J-Y BuzareldquoApplication of solid-state NMR (13C and29Si CPMAS NMR)spectroscopy to the characterization of alkenyltrialkoxysilaneand trialkoxysilyl-terminated polyisoprene grafting onto silicamicroparticlesrdquo Journal of Polymer Science Part A vol 36 no 3pp 437ndash453 1998
[14] V Arjunan S Subramanian and S Mohan ldquoFourier transforminfrared andRaman spectral analysis of trans-14-polyisoprenerdquoSpectrochimica Acta Part A vol 57 no 13 pp 2547ndash2554 2001
[15] B Huang J He J Song et al ldquoNew polymerization methodof high trans1 4mdashpolyisoprenerdquo CN1048257C China January2000
[16] B Huang Z ZhaoW Yao et al ldquoIndustrial productionmethodof high trans14mdashpolyisoprenerdquo CN1847272A China October2006
[17] P Wang H Shao W Yao et al ldquoPolymerization of isopreneinitiated with tetra-n-butyl titanate supported titanium catalystand triethylaluminiumrdquo China Synthetic Rubber Industry vol32 pp 284ndash284 2009
[18] R Gao T Yu L Bi et al ldquoResearch on novel Mg-Ti-Al complexand its catalysis for olefin polymerizationrdquo China SyntheticResin and Plastics vol 24 no 6 pp 25ndash28 2007
Figure 4 Samples of absorption values of peaks of polyisoprene
12-
PIp
A910A27274 6 8 10 12 14
468
101214161820222426
(a)
0 5 10 15 20 25 30 35 400
10
20
30
40
50
60
70
34-
PIp
A888A2727
(b)
2 4 6 8 10 12 14102030405060708090
100
14-
PIp
A840A2727
(c)
Figure 5 The absorption coefficient calculation of (a) 910 cmminus1 (b)888 cmminus1 and (c) 840 cmminus1 peaks of FTIR spectra of polyisoprene
The samples shown in Table 1 are calculated with thismethod and the results are given in Figure 5
After regression of measured points of testing pointsbased on a least-squares method the formula of microstruc-ture content is shown as follows
11988312-PIp = 221[119860] 910 cmminus1 minus 610
11988334-PIp = 192[119860]888 cmminus1 minus 340
11988314-PIp = 655[119860]840 cmminus1 + 229
(4)
Because of 910 888 and 840 cmminus1 peak overlaps partlythe errors of calculated values of integrated intensity 119860 willincrease when the peakrsquos intensity is too small Therefore the
International Journal of Polymer Science 5
microstructure content shall be calculated with two higherpeaks In the 12- and 34-unit the double bond is on thebranched chain and belongs to asymmetry substitute so theirdipole momentrsquos shift is bigger than that of 14-unit As aresult the integrated intensity of 910 and 888 cmminus1 peak is farstronger than 840 cmminus1 peak when the contents of their cor-responding units are the same Therefore the calculation ofmicrostructure content of polyisoprene shall choose theformer two peaks
4 Conclusion
The change of microstructure content of polyisoprene cancause a lot of differences in FTIR spectra The describedmethod by FTIR can be used to determine themicrostructurecontent of polyisoprene 910 and 888 cmminus1 peaks of 12- or34-unit have higher absorption ability than 840 cmminus1 peaksof 14-unit therefore 910 and 888 cmminus1 peaks shall be usedfirst for the quantitative analysis of microstructure content ofpolyisopreneThe quantitative calculation formulas were alsoobtained
References
[1] J E Puskas F Peruch A Deffieux et al ldquoBiomimetic carboca-tionic polymerizations III Investigation of isoprene polymer-ization initiated by dimethyl allyl bromiderdquo Journal of PolymerScience Part A vol 47 no 8 pp 2172ndash2180 2009
[2] J E Puskas C Peres F Peruch et al ldquoBiomimetic processes IVcarbocationic polymerization of isoprene initiated by dimethylallyl alcoholrdquo Journal of Polymer Science Part A vol 47 no 8pp 2181ndash2189 2009
[3] A Avgeropoulos S Paraskeva N Hadjichristidis and E LThomas ldquoSynthesis and microphase separation of linear tri-block terpolymers of polystyrene high 14-polybutadiene andhigh 34-polyisoprenerdquo Macromolecules vol 35 no 10 pp4030ndash4035 2002
[4] B Wang D Wang D Cui et al ldquoSynthesis of the first rareearth metal bis(alkyl)s bearing an indenyl functionalized N-heterocyclic carbenerdquoOrganometallics vol 26 no 13 pp 3167ndash3172 2007
[5] G Ricci M Battistella and L Porri ldquoChemoselectivity andstereospecificity of chromium(II) catalysts for 13-diene poly-merizationrdquo Macromolecules vol 34 no 17 pp 5766ndash57692001
[6] G Ricci DMorganti A Sommazzi R Santi and FMasi ldquoPoly-merization of 13-dienes with iron complexes based catalystsinfluence of the ligand on catalyst activity and stereospecificityrdquoJournal of Molecular Catalysis A vol 204-205 pp 287ndash2932003
[7] C Bazzini A Giarrusso L Porri B Pirozzi and R Napoli-tano ldquoSynthesis and characterization of syndiotactic 34-polyisoprene prepared with diethylbis(221015840-bipyridine)iron-MAOrdquo Polymer vol 45 no 9 pp 2871ndash2875 2004
[8] T Yu B Huang W Yao et al ldquoResearch and development of34-polyisoprene rubberrdquo China Synthetic Rubber Industry vol27 no 2 pp 122ndash126 2004
[9] W Zhang B Huang A Du et al ldquoProperties of TPIHVBRNRblendsrdquo China Rubber Industry vol 49 no 1 pp 5ndash8 2002
[10] W Zhang B Huang A Du et al ldquoProperties of TPIHVBRSBR blendsrdquo China Rubber Industry vol 49 no 2 pp 69ndash722002
[11] Z Zhao ldquoThe applied technology and properties of polyiso-prene of high 34-isomer contentrdquo China Rubber Collection ofTranslations no 2 pp 66ndash69 1996
[12] B Huang W Zhang A Du et al ldquoApplication of TPIHVBRblend to treadrdquo China Rubber Industry vol 49 no 3 pp 133ndash137 2002
[13] D Derouet S Forgeard J-C Brosse J Emery and J-Y BuzareldquoApplication of solid-state NMR (13C and29Si CPMAS NMR)spectroscopy to the characterization of alkenyltrialkoxysilaneand trialkoxysilyl-terminated polyisoprene grafting onto silicamicroparticlesrdquo Journal of Polymer Science Part A vol 36 no 3pp 437ndash453 1998
[14] V Arjunan S Subramanian and S Mohan ldquoFourier transforminfrared andRaman spectral analysis of trans-14-polyisoprenerdquoSpectrochimica Acta Part A vol 57 no 13 pp 2547ndash2554 2001
[15] B Huang J He J Song et al ldquoNew polymerization methodof high trans1 4mdashpolyisoprenerdquo CN1048257C China January2000
[16] B Huang Z ZhaoW Yao et al ldquoIndustrial productionmethodof high trans14mdashpolyisoprenerdquo CN1847272A China October2006
[17] P Wang H Shao W Yao et al ldquoPolymerization of isopreneinitiated with tetra-n-butyl titanate supported titanium catalystand triethylaluminiumrdquo China Synthetic Rubber Industry vol32 pp 284ndash284 2009
[18] R Gao T Yu L Bi et al ldquoResearch on novel Mg-Ti-Al complexand its catalysis for olefin polymerizationrdquo China SyntheticResin and Plastics vol 24 no 6 pp 25ndash28 2007
Figure 4 Samples of absorption values of peaks of polyisoprene
12-
PIp
A910A27274 6 8 10 12 14
468
101214161820222426
(a)
0 5 10 15 20 25 30 35 400
10
20
30
40
50
60
70
34-
PIp
A888A2727
(b)
2 4 6 8 10 12 14102030405060708090
100
14-
PIp
A840A2727
(c)
Figure 5 The absorption coefficient calculation of (a) 910 cmminus1 (b)888 cmminus1 and (c) 840 cmminus1 peaks of FTIR spectra of polyisoprene
The samples shown in Table 1 are calculated with thismethod and the results are given in Figure 5
After regression of measured points of testing pointsbased on a least-squares method the formula of microstruc-ture content is shown as follows
11988312-PIp = 221[119860] 910 cmminus1 minus 610
11988334-PIp = 192[119860]888 cmminus1 minus 340
11988314-PIp = 655[119860]840 cmminus1 + 229
(4)
Because of 910 888 and 840 cmminus1 peak overlaps partlythe errors of calculated values of integrated intensity 119860 willincrease when the peakrsquos intensity is too small Therefore the
International Journal of Polymer Science 5
microstructure content shall be calculated with two higherpeaks In the 12- and 34-unit the double bond is on thebranched chain and belongs to asymmetry substitute so theirdipole momentrsquos shift is bigger than that of 14-unit As aresult the integrated intensity of 910 and 888 cmminus1 peak is farstronger than 840 cmminus1 peak when the contents of their cor-responding units are the same Therefore the calculation ofmicrostructure content of polyisoprene shall choose theformer two peaks
4 Conclusion
The change of microstructure content of polyisoprene cancause a lot of differences in FTIR spectra The describedmethod by FTIR can be used to determine themicrostructurecontent of polyisoprene 910 and 888 cmminus1 peaks of 12- or34-unit have higher absorption ability than 840 cmminus1 peaksof 14-unit therefore 910 and 888 cmminus1 peaks shall be usedfirst for the quantitative analysis of microstructure content ofpolyisopreneThe quantitative calculation formulas were alsoobtained
References
[1] J E Puskas F Peruch A Deffieux et al ldquoBiomimetic carboca-tionic polymerizations III Investigation of isoprene polymer-ization initiated by dimethyl allyl bromiderdquo Journal of PolymerScience Part A vol 47 no 8 pp 2172ndash2180 2009
[2] J E Puskas C Peres F Peruch et al ldquoBiomimetic processes IVcarbocationic polymerization of isoprene initiated by dimethylallyl alcoholrdquo Journal of Polymer Science Part A vol 47 no 8pp 2181ndash2189 2009
[3] A Avgeropoulos S Paraskeva N Hadjichristidis and E LThomas ldquoSynthesis and microphase separation of linear tri-block terpolymers of polystyrene high 14-polybutadiene andhigh 34-polyisoprenerdquo Macromolecules vol 35 no 10 pp4030ndash4035 2002
[4] B Wang D Wang D Cui et al ldquoSynthesis of the first rareearth metal bis(alkyl)s bearing an indenyl functionalized N-heterocyclic carbenerdquoOrganometallics vol 26 no 13 pp 3167ndash3172 2007
[5] G Ricci M Battistella and L Porri ldquoChemoselectivity andstereospecificity of chromium(II) catalysts for 13-diene poly-merizationrdquo Macromolecules vol 34 no 17 pp 5766ndash57692001
[6] G Ricci DMorganti A Sommazzi R Santi and FMasi ldquoPoly-merization of 13-dienes with iron complexes based catalystsinfluence of the ligand on catalyst activity and stereospecificityrdquoJournal of Molecular Catalysis A vol 204-205 pp 287ndash2932003
[7] C Bazzini A Giarrusso L Porri B Pirozzi and R Napoli-tano ldquoSynthesis and characterization of syndiotactic 34-polyisoprene prepared with diethylbis(221015840-bipyridine)iron-MAOrdquo Polymer vol 45 no 9 pp 2871ndash2875 2004
[8] T Yu B Huang W Yao et al ldquoResearch and development of34-polyisoprene rubberrdquo China Synthetic Rubber Industry vol27 no 2 pp 122ndash126 2004
[9] W Zhang B Huang A Du et al ldquoProperties of TPIHVBRNRblendsrdquo China Rubber Industry vol 49 no 1 pp 5ndash8 2002
[10] W Zhang B Huang A Du et al ldquoProperties of TPIHVBRSBR blendsrdquo China Rubber Industry vol 49 no 2 pp 69ndash722002
[11] Z Zhao ldquoThe applied technology and properties of polyiso-prene of high 34-isomer contentrdquo China Rubber Collection ofTranslations no 2 pp 66ndash69 1996
[12] B Huang W Zhang A Du et al ldquoApplication of TPIHVBRblend to treadrdquo China Rubber Industry vol 49 no 3 pp 133ndash137 2002
[13] D Derouet S Forgeard J-C Brosse J Emery and J-Y BuzareldquoApplication of solid-state NMR (13C and29Si CPMAS NMR)spectroscopy to the characterization of alkenyltrialkoxysilaneand trialkoxysilyl-terminated polyisoprene grafting onto silicamicroparticlesrdquo Journal of Polymer Science Part A vol 36 no 3pp 437ndash453 1998
[14] V Arjunan S Subramanian and S Mohan ldquoFourier transforminfrared andRaman spectral analysis of trans-14-polyisoprenerdquoSpectrochimica Acta Part A vol 57 no 13 pp 2547ndash2554 2001
[15] B Huang J He J Song et al ldquoNew polymerization methodof high trans1 4mdashpolyisoprenerdquo CN1048257C China January2000
[16] B Huang Z ZhaoW Yao et al ldquoIndustrial productionmethodof high trans14mdashpolyisoprenerdquo CN1847272A China October2006
[17] P Wang H Shao W Yao et al ldquoPolymerization of isopreneinitiated with tetra-n-butyl titanate supported titanium catalystand triethylaluminiumrdquo China Synthetic Rubber Industry vol32 pp 284ndash284 2009
[18] R Gao T Yu L Bi et al ldquoResearch on novel Mg-Ti-Al complexand its catalysis for olefin polymerizationrdquo China SyntheticResin and Plastics vol 24 no 6 pp 25ndash28 2007
microstructure content shall be calculated with two higherpeaks In the 12- and 34-unit the double bond is on thebranched chain and belongs to asymmetry substitute so theirdipole momentrsquos shift is bigger than that of 14-unit As aresult the integrated intensity of 910 and 888 cmminus1 peak is farstronger than 840 cmminus1 peak when the contents of their cor-responding units are the same Therefore the calculation ofmicrostructure content of polyisoprene shall choose theformer two peaks
4 Conclusion
The change of microstructure content of polyisoprene cancause a lot of differences in FTIR spectra The describedmethod by FTIR can be used to determine themicrostructurecontent of polyisoprene 910 and 888 cmminus1 peaks of 12- or34-unit have higher absorption ability than 840 cmminus1 peaksof 14-unit therefore 910 and 888 cmminus1 peaks shall be usedfirst for the quantitative analysis of microstructure content ofpolyisopreneThe quantitative calculation formulas were alsoobtained
References
[1] J E Puskas F Peruch A Deffieux et al ldquoBiomimetic carboca-tionic polymerizations III Investigation of isoprene polymer-ization initiated by dimethyl allyl bromiderdquo Journal of PolymerScience Part A vol 47 no 8 pp 2172ndash2180 2009
[2] J E Puskas C Peres F Peruch et al ldquoBiomimetic processes IVcarbocationic polymerization of isoprene initiated by dimethylallyl alcoholrdquo Journal of Polymer Science Part A vol 47 no 8pp 2181ndash2189 2009
[3] A Avgeropoulos S Paraskeva N Hadjichristidis and E LThomas ldquoSynthesis and microphase separation of linear tri-block terpolymers of polystyrene high 14-polybutadiene andhigh 34-polyisoprenerdquo Macromolecules vol 35 no 10 pp4030ndash4035 2002
[4] B Wang D Wang D Cui et al ldquoSynthesis of the first rareearth metal bis(alkyl)s bearing an indenyl functionalized N-heterocyclic carbenerdquoOrganometallics vol 26 no 13 pp 3167ndash3172 2007
[5] G Ricci M Battistella and L Porri ldquoChemoselectivity andstereospecificity of chromium(II) catalysts for 13-diene poly-merizationrdquo Macromolecules vol 34 no 17 pp 5766ndash57692001
[6] G Ricci DMorganti A Sommazzi R Santi and FMasi ldquoPoly-merization of 13-dienes with iron complexes based catalystsinfluence of the ligand on catalyst activity and stereospecificityrdquoJournal of Molecular Catalysis A vol 204-205 pp 287ndash2932003
[7] C Bazzini A Giarrusso L Porri B Pirozzi and R Napoli-tano ldquoSynthesis and characterization of syndiotactic 34-polyisoprene prepared with diethylbis(221015840-bipyridine)iron-MAOrdquo Polymer vol 45 no 9 pp 2871ndash2875 2004
[8] T Yu B Huang W Yao et al ldquoResearch and development of34-polyisoprene rubberrdquo China Synthetic Rubber Industry vol27 no 2 pp 122ndash126 2004
[9] W Zhang B Huang A Du et al ldquoProperties of TPIHVBRNRblendsrdquo China Rubber Industry vol 49 no 1 pp 5ndash8 2002
[10] W Zhang B Huang A Du et al ldquoProperties of TPIHVBRSBR blendsrdquo China Rubber Industry vol 49 no 2 pp 69ndash722002
[11] Z Zhao ldquoThe applied technology and properties of polyiso-prene of high 34-isomer contentrdquo China Rubber Collection ofTranslations no 2 pp 66ndash69 1996
[12] B Huang W Zhang A Du et al ldquoApplication of TPIHVBRblend to treadrdquo China Rubber Industry vol 49 no 3 pp 133ndash137 2002
[13] D Derouet S Forgeard J-C Brosse J Emery and J-Y BuzareldquoApplication of solid-state NMR (13C and29Si CPMAS NMR)spectroscopy to the characterization of alkenyltrialkoxysilaneand trialkoxysilyl-terminated polyisoprene grafting onto silicamicroparticlesrdquo Journal of Polymer Science Part A vol 36 no 3pp 437ndash453 1998
[14] V Arjunan S Subramanian and S Mohan ldquoFourier transforminfrared andRaman spectral analysis of trans-14-polyisoprenerdquoSpectrochimica Acta Part A vol 57 no 13 pp 2547ndash2554 2001
[15] B Huang J He J Song et al ldquoNew polymerization methodof high trans1 4mdashpolyisoprenerdquo CN1048257C China January2000
[16] B Huang Z ZhaoW Yao et al ldquoIndustrial productionmethodof high trans14mdashpolyisoprenerdquo CN1847272A China October2006
[17] P Wang H Shao W Yao et al ldquoPolymerization of isopreneinitiated with tetra-n-butyl titanate supported titanium catalystand triethylaluminiumrdquo China Synthetic Rubber Industry vol32 pp 284ndash284 2009
[18] R Gao T Yu L Bi et al ldquoResearch on novel Mg-Ti-Al complexand its catalysis for olefin polymerizationrdquo China SyntheticResin and Plastics vol 24 no 6 pp 25ndash28 2007