TY - JOUR
T1 - Effects of Amide-Based modifiers on surface activation and devulcanization of rubber
AU - Faisal Kabirb, Sk
AU - Zakertabrizi, Mohammad
AU - Hosseini, Ehsan
AU - Fini, Elham H.
N1 - Funding Information:
The authors acknowledge the support of the U.S. National Science Foundation (award #1928795) which enabled production and characterization of the bio-binder and laboratory experiments. We are also grateful for the helpful support of the Centre for High Performance Computing of the Republic of South Africa in providing computational resources.
Publisher Copyright:
© 2020 Elsevier B.V.
PY - 2021/2/15
Y1 - 2021/2/15
N2 - This paper examines the mechanisms of interaction between two modifiers in asphalt binder: an amide-based bio-modifier, and natural rubber vulcanized by sulfur crosslinks. The amide-rich bio-modifier surface-activates the rubber, cleaving the disulfide bonds and leading to partial surface devulcanization. Computational modeling and laboratory experiments were used to evaluate the devulcanization mechanism and its effects. Results show that non-covalent interaction between the –NH2 site of the bio-modifier and the S–S crosslink of the rubber is stronger than with the C–S part of the rubber, which can potentially induce partial devulcanization. This phenomenon is reflected in the empirical results: a reduction in viscosity, due to devulcanization; and an increased resistance to fatigue, due to improved interaction between rubber and bitumen. This study provides an in-depth understanding of the surface devulcanization mechanism of rubber, in addition to insights into the complex devulcanization process happening inside a bio-modified mixture of rubber and asphalt binder. The results of this study help expand the knowledge of bio-modifiers and present a new approach for devulcanization.
AB - This paper examines the mechanisms of interaction between two modifiers in asphalt binder: an amide-based bio-modifier, and natural rubber vulcanized by sulfur crosslinks. The amide-rich bio-modifier surface-activates the rubber, cleaving the disulfide bonds and leading to partial surface devulcanization. Computational modeling and laboratory experiments were used to evaluate the devulcanization mechanism and its effects. Results show that non-covalent interaction between the –NH2 site of the bio-modifier and the S–S crosslink of the rubber is stronger than with the C–S part of the rubber, which can potentially induce partial devulcanization. This phenomenon is reflected in the empirical results: a reduction in viscosity, due to devulcanization; and an increased resistance to fatigue, due to improved interaction between rubber and bitumen. This study provides an in-depth understanding of the surface devulcanization mechanism of rubber, in addition to insights into the complex devulcanization process happening inside a bio-modified mixture of rubber and asphalt binder. The results of this study help expand the knowledge of bio-modifiers and present a new approach for devulcanization.
KW - Amide-based bio-binders (BB)
KW - Atoms in molecules (AIM)
KW - Density functional theory (DFT)
KW - Natural bond orbital (NBO) analysis
KW - Natural rubber (NR)
KW - Sulfur devulcanization
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U2 - 10.1016/j.commatsci.2020.110175
DO - 10.1016/j.commatsci.2020.110175
M3 - Article
AN - SCOPUS:85097794978
SN - 0927-0256
VL - 188
JO - Computational Materials Science
JF - Computational Materials Science
M1 - 110175
ER -