Styrene-butadiene branched star-shaped asphalt modifiers: Synthesis and mechanical characterization

The synthesis and the corresponding characterization of styrene-butadiene (SB), branched, star-shaped copolymers was investigated as part of a research project on asphalt modification using polymers with precise molecular structures. The method of anionic polymerization was followed to prepare sampl...

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Bibliographic Details
Published in:Chemical engineering communications 2020-07, Vol.207 (7), p.933-945
Main Authors: Alonso-Romero, Sergio, Medina-Torres, Luis, Zitzumbo, Roberto, Nuñez-Ramirez, Diola Marina
Format: Article
Language:English
Subjects:
Anionic polymerization
Architecture
Asphalt
Asphalt modification
Asphalt pavements
Block copolymers
Butadiene
Chemical synthesis
Copolymers
Coupling (molecular)
Coupling agents
Differential scanning calorimetry
Elasticity
Investigations
Liquid chromatography
Mechanical properties
Molecular chains
Molecular structure
Molecular weight
Molecular weight distribution
NMR
Nuclear magnetic resonance
Research projects
Rheological properties
Rheology
Star-shaped
Storage modulus
Styrene-butadiene
Styrenes
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Summary:The synthesis and the corresponding characterization of styrene-butadiene (SB), branched, star-shaped copolymers was investigated as part of a research project on asphalt modification using polymers with precise molecular structures. The method of anionic polymerization was followed to prepare samples of block copolymers of SB, a synthesis method that controls chain-architecture, molecular weight distribution, monomer distribution, and the average molecular weight. The research studies are the synthesis of block copolymers including linear, three- and four-arms constructs, depending on the coupling agent used. The techniques of nuclear magnetic resonance (1NMR), differential scanning calorimetry (DSC), gel permeation chromatography (GPC), and rheology were carried out to characterize the copolymers. From the results of the 1NMR, DSC, and GPC analyses, all star-shaped copolymers investigated showed a similar block copolymer composition. Furthermore, the rheological behavior of one of the synthesized star-shaped copolymers was nearly the same as a four-branched commercial copolymer. Rheologically, the four-arm block copolymer sample had the largest storage modulus (G′) among the branched copolymers synthetized, indicating that such architecture produces a highly structured material. In regard to polymer-modified asphalt formulations, the three-branched copolymer architecture yielded better elastic behavior than the four-branch version. In summary, the findings of this investigation provide new insight about a polymer system that may offer advantages in industrial asphalt paving applications.
ISSN:0098-6445
1563-5201
DOI:10.1080/00986445.2019.1631814