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Franco M Rabagliati - One of the best experts on this subject based on the ideXlab platform.
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Styrene/substituted Styrene copolymerization by Ph2Zn-metallocene-MAO systems : homo-and copolymerization of p-methoxyStyrene with Styrene
Polymer International, 2020Co-Authors: Franco M Rabagliati, Héctor E. Muñoz, Gonzalo A Mardones, Francisco J. RodríguezAbstract:BACKGROUND: The present work is part of a general study regarding the homo- and copolymerization of Styrene using diphenylzinc–additive initiator systems, with the aim of improving the properties of commercial atactic polyStyrene. The study is focused on syndiotactic polyStyrene and/or copolymers of Styrene (S) with substituted Styrene, Styrene derivatives or various α-olefins. This research has been ongoing over the last 15 years. RESULTS: The reported experiments show that binary metallocene–methylaluminoxane (MAO) and ternary Ph2Zn–metallocene–MAO, depending on the metallocene employed, are capable of inducing both homo- and copolymerization of Styrene and p-methoxyStyrene (p-MeOS). The results indicate that for a Styrene/p-MeOS mole ratio with p-MeOS > 25% the product obtained has only a minor incorporation of Styrene units. The efficiency of the metallocenes studied follows the order bis(n-butylcyclopentadienyl)titanium dichloride ((n-BuCp)2TiCl2) > indenyltitanium trichloride (IndTiCl3) > Cp2TiCl2. CONCLUSION: Metallocenes (n-BuCp)2TiCl2, Cp2TiCl2 and IndTiCl3 in binary systems combined with MAO, as well as in ternary systems combined with Ph2Zn and MAO, induce the homopolymerization of p-MeOS and its copolymerization with Styrene. The Styrene/p-MeOS copolymer obtained was enriched in p-MeOS with respect to the initial feed, in agreement with the I+ inductive effect of the methoxy group in the para position of Styrene. As already reported, the role of Ph2Zn was nullified by its complexation with the p-MeOS comonomer. Copyright © 2008 Society of Chemical Industry
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Styrene–substituted-Styrene copolymerization using diphenylzinc–metallocene–methylaluminoxane systems
Polymer International, 2020Co-Authors: Franco M Rabagliati, Francisco J. Rodríguez, Abdel Alla, Sebastián Muñoz-guerraAbstract:Homopolymerization of disubstituted Styrenes (2,4- and 2,5-dimethylStyrene) and trisubstituted Styrene (2,4,6-trimethylStyrene) and their copolymerization with Styrene were carried out using diphenylzinc–metallocene–methylaluminoxane initiator systems for metallocene (n-BuCp)2TiCl2 and for half-metallocene CpTiCl3. The studied comonomers were found to be less reactive than p-tertbutylStyrene, p-methylStyrene and Styrene. The results indicate that, even though the methyl group has I+ inductive effect, di- and tri-methylStyrenes are reluctant to undergo either homopolymerization or copolymerization. This behavior suggests that the reactivity is regulated not only by the inductive effect of the alkyl group but also by the steric impediment caused by the crowding of the substituents on the benzene ring. Copyright © 2006 Society of Chemical Industry
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HOMO- AND COPOLYMERIZATION OF Styrene AND Styrene RELATED MONOMERS. SYNTHESIS AND CHARACTERIZATION
Journal of The Chilean Chemical Society, 2016Co-Authors: Franco M Rabagliati, Rodrigo A. Cancino, Monica A Perez, M. Verónica Cuevas, Héctor E. Muñoz, Gonzalo A Mardones, Marcela Saavedra, M. Vidal, Francisco J. Rodríguez, Lisa MuñozAbstract:Systems including diphenylzinc, metallocene, and methylaluminoxane, at various combinations has been attempted, as initiating systems for homo- and copolymerization of Styrene and various Styrene related comonomers including : substituted Styrenes, Styrene derivatives, α-olefins, dienes and more recently cycohexenes including norbornene. The used metallocenes were those containing titanium, zirconium and for comparatives reasons hafnium. The metallocene efficiency towards syndiotactic polyStyrene polymerization showed the order : titanocene > zirconocene > hafnocene. While the polymerization as well the copolymerization of Styrene with related to Styrene compounds resulted to be much influenced by both electrical and steric hindrance effect. For Styrene substituted derivative those group or element having I+ inductive effect depending its position at Styrene’s its phenyl ring favours homopolymerization as well their copolymerization with Styrene. The steric hindrance also showed a determinant influence on reactivity, so methyl and tert-butyl group, having a I+ effect, when at para -position improve activity and stereoregularity of their polymerization processes. But when placing at orto- position showed a very low capacity to polymerize. The present and previous results indicate that polymerization processes are initiated by monomer coordination to active metal species either of the binary metallocene-MAO or of the ternary Ph2Zn-metallocene-MAO.
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Styrene copolymerization using a metallocene-MAO initiator system. Homo- and copolymerization of Styrene with some cycloalkenes
Polymer Bulletin, 2013Co-Authors: Franco M Rabagliati, Raul Quijada, Daniela E. Yañez, Daniel Canales, Paula A. ZapataAbstract:The copolymerization of Styrene with cyclohexene, 1-methyl-1-cyclohexene, and norbornene using ethenylbisindenylzirconium dichloride and methylaluminoxane, Et(Ind)_2ZrCl_2-MAO, initiating systems has been tested. The results obtained with each Styrene-cycloalkene couple, except Styrene/norbornene, indicate a less effective polymerization process compared to Styrene homopolymerization, in agreement with the electronic and steric effects present in each comonomer. The electronic I+ effects of substituent groups, depending on their placement, largely improve the polymerization process, while bulky groups on or near the vinyl carbon double bond of Styrene decrease its effectiveness. The present study shows that the copolymers obtained are amorphous and their composition showed a lower abundance of comonomer units with respect to the initial feed. For comparison, the results of the copolymerization of Styrene/(1-octadecene) using the same initiator system and polymerization process are included, a polymerization that indicates a more reactive process, and as the proportion of octadecene in the initial feed increases, it showed a crystalline fusion temperature as well as a Tg in the Styrene region which can be attributed to the formation of block Styrene/octadecene copolymers.
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Styrene substituted Styrene copolymerization using diphenylzinc metallocene methylaluminoxane systems
Polymer International, 2006Co-Authors: Franco M Rabagliati, Francisco J. Rodríguez, Abdel Alla, Sebastian MunozguerraAbstract:Homopolymerization of disubstituted Styrenes (2,4- and 2,5-dimethylStyrene) and trisubstituted Styrene (2,4,6-trimethylStyrene) and their copolymerization with Styrene were carried out using diphenylzinc–metallocene–methylaluminoxane initiator systems for metallocene (n-BuCp)2TiCl2 and for half-metallocene CpTiCl3. The studied comonomers were found to be less reactive than p-tertbutylStyrene, p-methylStyrene and Styrene. The results indicate that, even though the methyl group has I+ inductive effect, di- and tri-methylStyrenes are reluctant to undergo either homopolymerization or copolymerization. This behavior suggests that the reactivity is regulated not only by the inductive effect of the alkyl group but also by the steric impediment caused by the crowding of the substituents on the benzene ring. Copyright © 2006 Society of Chemical Industry
Francisco J. Rodríguez - One of the best experts on this subject based on the ideXlab platform.
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Styrene/substituted Styrene copolymerization by Ph2Zn-metallocene-MAO systems : homo-and copolymerization of p-methoxyStyrene with Styrene
Polymer International, 2020Co-Authors: Franco M Rabagliati, Héctor E. Muñoz, Gonzalo A Mardones, Francisco J. RodríguezAbstract:BACKGROUND: The present work is part of a general study regarding the homo- and copolymerization of Styrene using diphenylzinc–additive initiator systems, with the aim of improving the properties of commercial atactic polyStyrene. The study is focused on syndiotactic polyStyrene and/or copolymers of Styrene (S) with substituted Styrene, Styrene derivatives or various α-olefins. This research has been ongoing over the last 15 years. RESULTS: The reported experiments show that binary metallocene–methylaluminoxane (MAO) and ternary Ph2Zn–metallocene–MAO, depending on the metallocene employed, are capable of inducing both homo- and copolymerization of Styrene and p-methoxyStyrene (p-MeOS). The results indicate that for a Styrene/p-MeOS mole ratio with p-MeOS > 25% the product obtained has only a minor incorporation of Styrene units. The efficiency of the metallocenes studied follows the order bis(n-butylcyclopentadienyl)titanium dichloride ((n-BuCp)2TiCl2) > indenyltitanium trichloride (IndTiCl3) > Cp2TiCl2. CONCLUSION: Metallocenes (n-BuCp)2TiCl2, Cp2TiCl2 and IndTiCl3 in binary systems combined with MAO, as well as in ternary systems combined with Ph2Zn and MAO, induce the homopolymerization of p-MeOS and its copolymerization with Styrene. The Styrene/p-MeOS copolymer obtained was enriched in p-MeOS with respect to the initial feed, in agreement with the I+ inductive effect of the methoxy group in the para position of Styrene. As already reported, the role of Ph2Zn was nullified by its complexation with the p-MeOS comonomer. Copyright © 2008 Society of Chemical Industry
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Styrene–substituted-Styrene copolymerization using diphenylzinc–metallocene–methylaluminoxane systems
Polymer International, 2020Co-Authors: Franco M Rabagliati, Francisco J. Rodríguez, Abdel Alla, Sebastián Muñoz-guerraAbstract:Homopolymerization of disubstituted Styrenes (2,4- and 2,5-dimethylStyrene) and trisubstituted Styrene (2,4,6-trimethylStyrene) and their copolymerization with Styrene were carried out using diphenylzinc–metallocene–methylaluminoxane initiator systems for metallocene (n-BuCp)2TiCl2 and for half-metallocene CpTiCl3. The studied comonomers were found to be less reactive than p-tertbutylStyrene, p-methylStyrene and Styrene. The results indicate that, even though the methyl group has I+ inductive effect, di- and tri-methylStyrenes are reluctant to undergo either homopolymerization or copolymerization. This behavior suggests that the reactivity is regulated not only by the inductive effect of the alkyl group but also by the steric impediment caused by the crowding of the substituents on the benzene ring. Copyright © 2006 Society of Chemical Industry
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HOMO- AND COPOLYMERIZATION OF Styrene AND Styrene RELATED MONOMERS. SYNTHESIS AND CHARACTERIZATION
Journal of The Chilean Chemical Society, 2016Co-Authors: Franco M Rabagliati, Rodrigo A. Cancino, Monica A Perez, M. Verónica Cuevas, Héctor E. Muñoz, Gonzalo A Mardones, Marcela Saavedra, M. Vidal, Francisco J. Rodríguez, Lisa MuñozAbstract:Systems including diphenylzinc, metallocene, and methylaluminoxane, at various combinations has been attempted, as initiating systems for homo- and copolymerization of Styrene and various Styrene related comonomers including : substituted Styrenes, Styrene derivatives, α-olefins, dienes and more recently cycohexenes including norbornene. The used metallocenes were those containing titanium, zirconium and for comparatives reasons hafnium. The metallocene efficiency towards syndiotactic polyStyrene polymerization showed the order : titanocene > zirconocene > hafnocene. While the polymerization as well the copolymerization of Styrene with related to Styrene compounds resulted to be much influenced by both electrical and steric hindrance effect. For Styrene substituted derivative those group or element having I+ inductive effect depending its position at Styrene’s its phenyl ring favours homopolymerization as well their copolymerization with Styrene. The steric hindrance also showed a determinant influence on reactivity, so methyl and tert-butyl group, having a I+ effect, when at para -position improve activity and stereoregularity of their polymerization processes. But when placing at orto- position showed a very low capacity to polymerize. The present and previous results indicate that polymerization processes are initiated by monomer coordination to active metal species either of the binary metallocene-MAO or of the ternary Ph2Zn-metallocene-MAO.
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Styrene substituted Styrene copolymerization using diphenylzinc metallocene methylaluminoxane systems
Polymer International, 2006Co-Authors: Franco M Rabagliati, Francisco J. Rodríguez, Abdel Alla, Sebastian MunozguerraAbstract:Homopolymerization of disubstituted Styrenes (2,4- and 2,5-dimethylStyrene) and trisubstituted Styrene (2,4,6-trimethylStyrene) and their copolymerization with Styrene were carried out using diphenylzinc–metallocene–methylaluminoxane initiator systems for metallocene (n-BuCp)2TiCl2 and for half-metallocene CpTiCl3. The studied comonomers were found to be less reactive than p-tertbutylStyrene, p-methylStyrene and Styrene. The results indicate that, even though the methyl group has I+ inductive effect, di- and tri-methylStyrenes are reluctant to undergo either homopolymerization or copolymerization. This behavior suggests that the reactivity is regulated not only by the inductive effect of the alkyl group but also by the steric impediment caused by the crowding of the substituents on the benzene ring. Copyright © 2006 Society of Chemical Industry
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further studies on Styrene Styrene derivative copolymerizations using combined diphenylzinc additive initiator systems
Polymer International, 2005Co-Authors: Franco M Rabagliati, Monica A Perez, Carlos J Caro, Francisco J. Rodríguez, Nicolas CrispelAbstract:A combination of diphenylzinc, a metallocene and methylaluminoxane (Ph2Zn-metallocene-MAO) is a suitable initiator system for the polymerization of Styrene and for its copolymerization with para-alkyl substituted Styrenes. This paper reports new experimental results which reinforce our previous findings indicating that polymerization processes are initiated by monomer coordination to active species resulting from these particular combined systems. Polymerization propagates by a cationic pathway. Further to our previous observation that the I+ inductive effect of para-substituents in Styrene improves conversion to polymer, we now find that methyl substitution on the vinyl double bond of Styrene, in spite of the I+ inductive effect and as a result of increased steric hindrance, makes the polymerization process difficult. On the other hand, the replacement of titanocenes by zirconocenes or hafnocenes generates Ph2Zn-metallocene-MAO initiator systems which are also able to induce homo- and copolymerization, but with lower yields and producing practically amorphous polymers. The efficiency of our Ph2Zn-metallocene-MAO initiator systems follows the order titanocene > zirconocene > hafnocene, at least for the studied metallocenes. Copyright © 2004 Society of Chemical Industry
Hiroyuki Koshino - One of the best experts on this subject based on the ideXlab platform.
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scandium catalyzed cyclocopolymerization of 1 5 hexadiene with Styrene and ethylene efficient synthesis of cyclopolyolefins containing syndiotactic Styrene Styrene sequences and methylene 1 3 cyclopentane units
Macromolecules, 2011Co-Authors: Masayoshi Nishiura, Hiroyuki KoshinoAbstract:The polymerization of 1,5-hexadiene (HD) and its copolymerization with Styrene and ethylene by a series of half-sandwich scandium dialkyl complexes bearing various auxiliary ligands have been examined. Significant ligand influence on the catalytic activity and selectivity has been observed. The THF-free aminobenzyl scandium complex with a sterically demanding ligand, such as (C5Me4SiMe3)Sc(CH2C6H4NMe2-o)2 (4e), in combination with an equivalent of [Ph3C][B(C6F5)4], serves as an excellent catalyst for the cyclocopolymerization of HD with Styrene to afford a new family of polymer materials containing methylene-1,3-cyclopentane (MCP) units, vinyltetramethylene (VTM) units, and unique syndiotactic Styrene–Styrene sequences. By use of this catalyst, the terpolymerization of HD, Styrene, and ethylene has also be achieved for the first time to afford novel cyclopolymer materials containing the five-member ring MCP units, ethylene–ethylene blocks, and syndiotactic Styrene–Styrene sequences. The composition of the...
Monica A Perez - One of the best experts on this subject based on the ideXlab platform.
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HOMO- AND COPOLYMERIZATION OF Styrene AND Styrene RELATED MONOMERS. SYNTHESIS AND CHARACTERIZATION
Journal of The Chilean Chemical Society, 2016Co-Authors: Franco M Rabagliati, Rodrigo A. Cancino, Monica A Perez, M. Verónica Cuevas, Héctor E. Muñoz, Gonzalo A Mardones, Marcela Saavedra, M. Vidal, Francisco J. Rodríguez, Lisa MuñozAbstract:Systems including diphenylzinc, metallocene, and methylaluminoxane, at various combinations has been attempted, as initiating systems for homo- and copolymerization of Styrene and various Styrene related comonomers including : substituted Styrenes, Styrene derivatives, α-olefins, dienes and more recently cycohexenes including norbornene. The used metallocenes were those containing titanium, zirconium and for comparatives reasons hafnium. The metallocene efficiency towards syndiotactic polyStyrene polymerization showed the order : titanocene > zirconocene > hafnocene. While the polymerization as well the copolymerization of Styrene with related to Styrene compounds resulted to be much influenced by both electrical and steric hindrance effect. For Styrene substituted derivative those group or element having I+ inductive effect depending its position at Styrene’s its phenyl ring favours homopolymerization as well their copolymerization with Styrene. The steric hindrance also showed a determinant influence on reactivity, so methyl and tert-butyl group, having a I+ effect, when at para -position improve activity and stereoregularity of their polymerization processes. But when placing at orto- position showed a very low capacity to polymerize. The present and previous results indicate that polymerization processes are initiated by monomer coordination to active metal species either of the binary metallocene-MAO or of the ternary Ph2Zn-metallocene-MAO.
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further studies on Styrene Styrene derivative copolymerizations using combined diphenylzinc additive initiator systems
Polymer International, 2005Co-Authors: Franco M Rabagliati, Monica A Perez, Carlos J Caro, Francisco J. Rodríguez, Nicolas CrispelAbstract:A combination of diphenylzinc, a metallocene and methylaluminoxane (Ph2Zn-metallocene-MAO) is a suitable initiator system for the polymerization of Styrene and for its copolymerization with para-alkyl substituted Styrenes. This paper reports new experimental results which reinforce our previous findings indicating that polymerization processes are initiated by monomer coordination to active species resulting from these particular combined systems. Polymerization propagates by a cationic pathway. Further to our previous observation that the I+ inductive effect of para-substituents in Styrene improves conversion to polymer, we now find that methyl substitution on the vinyl double bond of Styrene, in spite of the I+ inductive effect and as a result of increased steric hindrance, makes the polymerization process difficult. On the other hand, the replacement of titanocenes by zirconocenes or hafnocenes generates Ph2Zn-metallocene-MAO initiator systems which are also able to induce homo- and copolymerization, but with lower yields and producing practically amorphous polymers. The efficiency of our Ph2Zn-metallocene-MAO initiator systems follows the order titanocene > zirconocene > hafnocene, at least for the studied metallocenes. Copyright © 2004 Society of Chemical Industry
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Further studies on Styrene/Styrene derivative copolymerizations using combined diphenylzinc-additive initiator systems †
Polymer International, 2004Co-Authors: Franco M Rabagliati, Monica A Perez, Carlos J Caro, Francisco J. Rodríguez, Nicolas CrispelAbstract:A combination of diphenylzinc, a metallocene and methylaluminoxane (Ph2Zn-metallocene-MAO) is a suitable initiator system for the polymerization of Styrene and for its copolymerization with para-alkyl substituted Styrenes. This paper reports new experimental results which reinforce our previous findings indicating that polymerization processes are initiated by monomer coordination to active species resulting from these particular combined systems. Polymerization propagates by a cationic pathway. Further to our previous observation that the I+ inductive effect of para-substituents in Styrene improves conversion to polymer, we now find that methyl substitution on the vinyl double bond of Styrene, in spite of the I+ inductive effect and as a result of increased steric hindrance, makes the polymerization process difficult. On the other hand, the replacement of titanocenes by zirconocenes or hafnocenes generates Ph2Zn-metallocene-MAO initiator systems which are also able to induce homo- and copolymerization, but with lower yields and producing practically amorphous polymers. The efficiency of our Ph2Zn-metallocene-MAO initiator systems follows the order titanocene > zirconocene > hafnocene, at least for the studied metallocenes. Copyright © 2004 Society of Chemical Industry
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Styrene Styrene derivative and Styrene 1 alkene copolymerization using ph2zn additive initiator systems
Macromolecular Symposia, 2004Co-Authors: Franco M Rabagliati, Rodrigo A. Cancino, Monica A Perez, Francisco J. RodríguezAbstract:Diphenylzinc-metallocene-MAO initiator systems have proven to be effective initiator systems for Styrene and for substituted Styrenes as well as for their Styrene/(Styrene-derivative) copolymerization. Titanocene produced almost pure syndiotactic polymers while zirconocenes gave atactic polyStyrene together with a low content, less than 20%, of syndiotactic polyStyrene. Systems including a zirconocene, particularly ethenyl(bisindenyl)zirconium dichloride were effective initiators of 1-alkene polymerization and of Styrene/1-alkene copolymerization. Conversion to polymer increases with the molecular size of 1-alkene. Styrene derivative and Styrene/(Styrene derivative) polymerization was greatly influenced by the inductive effect of substituent and by steric hindrance due to the monomer.
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Styrene/(Styrene Derivative) and Styrene/(1‐Alkene) Copolymerization using Ph2Zn‐Additive Initiator Systems
Macromolecular Symposia, 2004Co-Authors: Franco M Rabagliati, Rodrigo A. Cancino, Monica A Perez, Francisco J. RodríguezAbstract:Diphenylzinc-metallocene-MAO initiator systems have proven to be effective initiator systems for Styrene and for substituted Styrenes as well as for their Styrene/(Styrene-derivative) copolymerization. Titanocene produced almost pure syndiotactic polymers while zirconocenes gave atactic polyStyrene together with a low content, less than 20%, of syndiotactic polyStyrene. Systems including a zirconocene, particularly ethenyl(bisindenyl)zirconium dichloride were effective initiators of 1-alkene polymerization and of Styrene/1-alkene copolymerization. Conversion to polymer increases with the molecular size of 1-alkene. Styrene derivative and Styrene/(Styrene derivative) polymerization was greatly influenced by the inductive effect of substituent and by steric hindrance due to the monomer.
Guozhi Nan - One of the best experts on this subject based on the ideXlab platform.
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thermo rheological behavior and compatibility of modified asphalt with various Styrene butadiene structures in sbs copolymers
Materials & Design, 2015Co-Authors: Ming Liang, Peng Liang, Weiyu Fan, Chengduo Qian, Xue Xin, Jingtao Shi, Guozhi NanAbstract:Abstract The knowledge of the morphological structure or effect of polymer structure on the performance of polymer-modified asphalt (PMA) is not systematic and completed yet. In this paper, SBS-modified asphalts were prepared by asphalts with different compositions and Styrene–butadiene–Styrene (SBS) copolymers with various Styrene–butadiene structures, which in turn were subjected to frequency sweep tests, viscous measurements and fluorescence microscopy. The results revealed that the SBS-modified asphalt containing 30 wt.% Styrene had the optimal viscoelastic functions and the highest viscosity, indicating enhanced viscoelastic characteristics and less sensitivity to temperature changes. Furthermore, it is less susceptible to shear forces for asphalts as the increase of Styrene content because larger and stronger aggregated polyStyrene domains can render deformation and movement more difficult. For system studied, the compatibility becomes poorer as the increase of Styrene contents and polymer phase sizes decrease with the enhancement of Styrene contents as well as their volume proportions. The scope of distribution curves becomes narrower and the swelling degree is lower as the increase of Styrene contents by image analysis. As a conclusion, there is a moderate Styrene content for SBS to acquire equilibrium between the compatibility and viscoelastic characteristics.
