التفاصيل البيبلوغرافية
| العنوان: |
Non-Einstein Rheology in Segmented Polyurethane Nanocomposites |
| المؤلفون: |
Hamid Reza Heydarnezhad (10230155), Naser Mohammadi (4255666), Angel Alegria (2891732) |
| سنة النشر: |
2021 |
| المجموعة: |
Smithsonian Institution: Digital Repository |
| مصطلحات موضوعية: |
Biophysics, Biochemistry, Medicine, Biotechnology, Ecology, Space Science, Biological Sciences not elsewhere classified, Chemical Sciences not elsewhere classified, nanoparticle-induced viscosity redu., C 60 nanofiller, C 60 content, microphase-mixed PUs, NPU, viscosity reduction, matrix, terminal rheological properties, wt, block copolymer-based nanocomposites, C 60 nanoparticles, length, Segmented Polyurethane Nanocomposites, HS, shear rheological behavior, SS, eff, η 0 values |
| الوصف: |
To provide a fundamental understanding regarding the potential of nanoparticle-induced viscosity reduction in segmented block copolymer-based nanocomposites, the shear rheological behavior of segmented polyurethane/C 60 nanocomposites (NPUs) was studied up to 2 wt % C 60 , and the results were complemented by several dynamic and structural probes. The same microstructural features and dynamical relaxations were revealed for each matrix (PU) and its corresponding NPUs in the absence of deformation, representing the lack of difference in their dynamical behaviors at all studied C 60 content. Under shear, however, interesting changes in the terminal rheological properties of PUs were observed in the presence of a C 60 nanofiller. An anomalous terminal shear viscosity (η 0 ) reduction was found for microphase-mixed PUs at a low C 60 content of up to 0.5 wt %. However, the microphase-mixed NPUs containing a higher C 60 content as well as the microphase-separated NPUs showed a higher η 0 than their matrices. Slippage at the polymer/C 60 interfaces was suggested as a possible mechanism behind the viscosity reduction, which appeared controllable by the degree of microphase separation, the ratio of slip length to the nanoparticle size, and the stiffness of segments. Accordingly, an effective slip length, b eff , was considered as the key factor in controlling the observed noncontinuum effects regarding the nanoparticle-induced viscosity reduction in the microphase-mixed PUs. When most C 60 nanoparticles of radius r are positioned on the hard segments (HSs) of microphase-mixed PUs, b eff / r > 1 can lead to viscosity reduction, while the localization of C 60 in the vicinity of soft segments (SSs) increased the matrix’s η 0 . A semiuniversal curve was also found to roughly estimate the η 0 values of various NPUs. |
| نوع الوثيقة: |
article in journal/newspaper |
| اللغة: |
unknown |
| العلاقة: |
https://figshare.com/articles/journal_contribution/Non-Einstein_Rheology_in_Segmented_Polyurethane_Nanocomposites/14160614Test |
| DOI: |
10.1021/acs.macromol.0c02503.s001 |
| الإتاحة: |
https://doi.org/10.1021/acs.macromol.0c02503.s001Test |
| حقوق: |
CC BY-NC 4.0 |
| رقم الانضمام: |
edsbas.6B809BA |
| قاعدة البيانات: |
BASE |
