Projects per year
The aging behavior of TEMPO-CNF suspensions is investigated using rheological measurements and experiments involving the free-falling solid sphere. The properties of CNF suspensions, which are formed of water and cellulose fibers with a large aspect ratio, are fundamentally different from those commonly known as model low-density gels. We characterize their aging utilizing SAOS rheometry following a period of shear rejuvenation, measuring the effect of aging time on the observed stress overshoot, and additionally measure the rheological hysteresis under continuous shear. In addition to such tests, which probe the sample at the bulk level, we study their local aging behavior via the Stokes' experiment. During SAOS, the aging of the material results in a logarithmic growth of the elastic modulus over the first 50 minutes. In the Stokes' experiment, depending on the sphere size, we find a systematic decrease in the sphere velocity with aging times up to 16 days and identify a range of intermittent particle motion. Based on our experimental evidence, we propose that the aging effect within the TEMPO-CNFs occurs due to the restructuring of fibrous elements by Brownian diffusion and that the aging of the system does not develop homogeneously across the whole sample as a consequence of the wide size distribution of CNFs. Finally, we note that this may be one of the primary reasons why the rheological data on even the same batch of CNFs show a large scatter.
|Number of pages||14|
|Early online date||25 Oct 2022|
|Publication status||Published - Jan 2023|
|MoE publication type||A1 Journal article-refereed|
- Sphere settling
- RHEOLOGICAL PROPERTIES
- AQUEOUS SUSPENSIONS
FingerprintDive into the research topics of 'Local time-dependent microstructure of aging TEMPO nanofibrillated cellulose gel'. Together they form a unique fingerprint.
- 2 Finished
Foam Wood: Manufacturing novel bio-based Wood-like foams by a continuous forming process
Alava, M., Puisto, A., Olsio, S., Coffeng, M., Karjalainen, A., Mohammed, A., Mäkinen, T., Ranta, R., Koivisto, J., Hu, H. & Jannuzzi Fonseca, L.
01/01/2021 → 31/05/2022
Project: Business Finland: New business from research ideas (TUTLI)
Alava, M., Koivisto, J., Miranda Valdez, I., Lahikainen, J., Rabensteiner, S. & Mac Intyre, J.
01/01/2020 → 31/12/2021
Project: Academy of Finland: Other research funding