Thermodynamic Parameters of Crosslinked Elastomers (BR, SBR and NBR) and Their Blends
Herein, a methodology is employed based on the Flory–Rehner equation for estimating the Flory–Huggins interaction parameter (χ<sub>12</sub>*) of crosslinked elastomer blends. For this purpose, binary elastomer blends containing polybutadiene rubber (BR), styrene–butadiene rubber (SBR) an...
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MDPI AG
2024-01-01
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| Series: | Polymers |
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| Online Access: | https://www.mdpi.com/2073-4360/16/3/351 |
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| author | César Leyva-Porras Iván A. Estrada-Moreno Claudia I. Piñón-Balderrama Sergio G. Flores-Gallardo Alfredo Márquez-Lucero |
| author_facet | César Leyva-Porras Iván A. Estrada-Moreno Claudia I. Piñón-Balderrama Sergio G. Flores-Gallardo Alfredo Márquez-Lucero |
| author_sort | César Leyva-Porras |
| collection | DOAJ |
| description | Herein, a methodology is employed based on the Flory–Rehner equation for estimating the Flory–Huggins interaction parameter (χ<sub>12</sub>*) of crosslinked elastomer blends. For this purpose, binary elastomer blends containing polybutadiene rubber (BR), styrene–butadiene rubber (SBR) and nitrile–butadiene rubber (NBR), were prepared in a mixing chamber at a temperature below the activation of the crosslinking agent. Swelling tests with benzene were employed to determine the crosslinked fraction, finding that after 20 min of thermal annealing, the BR and NBR were almost completely crosslinked, while the SBR only reached 60%. Additionally, the BR-SBR blend increased by 2–3 times its volume than its pure components; this could be explained based on the crosslink density. From the mechanical tests, a negative deviation from the rule of mixtures was observed, which suggested that the crosslinking was preferably carried out in the phases and not at the interface. Furthermore, tensile tests and swelling fraction (ϕ<sub>sw</sub>) results were employed to determine the average molecular weight between two crosslinking points (M<sub>c</sub>), and subsequently χ<sub>12</sub>*. Calculated χ<sub>12</sub>* values were slightly higher than those reported in the literature. The calculated thermodynamic parameters for the blends showed positive ΔG<sub>mix</sub> values and endothermic behavior, suggesting their immiscible nature. |
| first_indexed | 2024-03-08T03:50:21Z |
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| id | doaj.art-0137ebc11d9b4579a2aa96f5631ff6a6 |
| institution | Directory Open Access Journal |
| issn | 2073-4360 |
| language | English |
| last_indexed | 2024-03-08T03:50:21Z |
| publishDate | 2024-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Polymers |
| spelling | doaj.art-0137ebc11d9b4579a2aa96f5631ff6a62024-02-09T15:20:47ZengMDPI AGPolymers2073-43602024-01-0116335110.3390/polym16030351Thermodynamic Parameters of Crosslinked Elastomers (BR, SBR and NBR) and Their BlendsCésar Leyva-Porras0Iván A. Estrada-Moreno1Claudia I. Piñón-Balderrama2Sergio G. Flores-Gallardo3Alfredo Márquez-Lucero4Advanced Materials Research Center (CIMAV), Complejo Industrial Chihuahua, Miguel de Cervantes No. 120, Chihuahua 31136, MexicoAdvanced Materials Research Center (CIMAV), Complejo Industrial Chihuahua, Miguel de Cervantes No. 120, Chihuahua 31136, MexicoAdvanced Materials Research Center (CIMAV), Complejo Industrial Chihuahua, Miguel de Cervantes No. 120, Chihuahua 31136, MexicoAdvanced Materials Research Center (CIMAV), Complejo Industrial Chihuahua, Miguel de Cervantes No. 120, Chihuahua 31136, MexicoAdvanced Materials Research Center (CIMAV), Complejo Industrial Chihuahua, Miguel de Cervantes No. 120, Chihuahua 31136, MexicoHerein, a methodology is employed based on the Flory–Rehner equation for estimating the Flory–Huggins interaction parameter (χ<sub>12</sub>*) of crosslinked elastomer blends. For this purpose, binary elastomer blends containing polybutadiene rubber (BR), styrene–butadiene rubber (SBR) and nitrile–butadiene rubber (NBR), were prepared in a mixing chamber at a temperature below the activation of the crosslinking agent. Swelling tests with benzene were employed to determine the crosslinked fraction, finding that after 20 min of thermal annealing, the BR and NBR were almost completely crosslinked, while the SBR only reached 60%. Additionally, the BR-SBR blend increased by 2–3 times its volume than its pure components; this could be explained based on the crosslink density. From the mechanical tests, a negative deviation from the rule of mixtures was observed, which suggested that the crosslinking was preferably carried out in the phases and not at the interface. Furthermore, tensile tests and swelling fraction (ϕ<sub>sw</sub>) results were employed to determine the average molecular weight between two crosslinking points (M<sub>c</sub>), and subsequently χ<sub>12</sub>*. Calculated χ<sub>12</sub>* values were slightly higher than those reported in the literature. The calculated thermodynamic parameters for the blends showed positive ΔG<sub>mix</sub> values and endothermic behavior, suggesting their immiscible nature.https://www.mdpi.com/2073-4360/16/3/351thermodynamic parameterselastomer blendsFlory–Huggins interaction parameterswelling of crosslinked rubbers |
| spellingShingle | César Leyva-Porras Iván A. Estrada-Moreno Claudia I. Piñón-Balderrama Sergio G. Flores-Gallardo Alfredo Márquez-Lucero Thermodynamic Parameters of Crosslinked Elastomers (BR, SBR and NBR) and Their Blends Polymers thermodynamic parameters elastomer blends Flory–Huggins interaction parameter swelling of crosslinked rubbers |
| title | Thermodynamic Parameters of Crosslinked Elastomers (BR, SBR and NBR) and Their Blends |
| title_full | Thermodynamic Parameters of Crosslinked Elastomers (BR, SBR and NBR) and Their Blends |
| title_fullStr | Thermodynamic Parameters of Crosslinked Elastomers (BR, SBR and NBR) and Their Blends |
| title_full_unstemmed | Thermodynamic Parameters of Crosslinked Elastomers (BR, SBR and NBR) and Their Blends |
| title_short | Thermodynamic Parameters of Crosslinked Elastomers (BR, SBR and NBR) and Their Blends |
| title_sort | thermodynamic parameters of crosslinked elastomers br sbr and nbr and their blends |
| topic | thermodynamic parameters elastomer blends Flory–Huggins interaction parameter swelling of crosslinked rubbers |
| url | https://www.mdpi.com/2073-4360/16/3/351 |
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