Location: Bioproducts ResearchTitle: Redispersion and structural change evaluation of dried microfibrillated cellulose
|SILVA, LUIZ EDUARDO - Federal University Of Lavras|
|DOS SANTOS, ALLAN DE AMORIM - Federal University Of Lavras|
|McCaffrey, Zachariah - Zach|
|Glenn, Gregory - Greg|
|SENA NETO, ALFREDO R DE - Federal University Of Lavras|
|Wood, Delilah - De|
|Orts, William - Bill|
|DAMÁSIO, RENATO AUGUSTO - Brazil University|
|TONOLI, GUSTAVO H D - Federal University Of Lavras|
Submitted to: Carbohydrate Polymers
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/24/2020
Publication Date: 9/30/2020
Citation: Silva, L., Dos Santos, A., Torres, L.F., McCaffrey, Z., Klamczynski, A.P., Glenn, G.M., Sena Neto, A., Wood, D.F., Williams, T.G., Orts, W.J., Damásio, R.P., Tonoli, G. 2020. Redispersion and structural change evaluation of dried microfibrillated cellulose. Carbohydrate Polymers. 252. Article 117165. https://doi.org/10.1016/j.carbpol.2020.117165.
Interpretive Summary: Environmentally-friendly materials have enormous potential as reinforcing agents in thin films. Microfibrillated cellulose is a nanoscale material with high surface area that can be used as a binder in copolymers. However, drying of cellulose often causes irreversible aggregation of the fibers diminishing their use in mixed polymers. Thus, proper drying techniques are needed to make useful products. The effect of temperature and redispersion cycles and on morphological, dispersion, mechanical and structural properties of microfibrillated cellulose fibers were evaluated. Aggregation increased with higher drying temperatures and numbers of redispersion cycles. Microfibrillated cellulose fibers dried at room temperature, avoiding redispersion cycles proved the best treatment to maintain favorable properties and is an important contribution for optimization of drying technologies for microfibrillated cellulose films.
Technical Abstract: Commercializing dried microfibrillated cellulose (MFC) has always been a challenge mainly due to the tendency of MFC to aggregate. In this study MFC samples were submitted to drying/redispersion cycles at different temperatures. Morphology, crystallinity and mechanical performance of films were analyzed throughout the cycles. Microscopy images, particle size and stability in water showed that aggregation happens more severely with 5 drying/redispersion cycles and at drying temperatures of 75 and 100 'C. Particles once-dried at 20 °C formed the same size and web-like structure as the MFC-control. Crystallinity and crystallite sizes increased with drying/redispersion cycles especially when dried at 75 and 100 °C, however drying/redispersion cycles also led to a reduction in mechanical performance due to aggregation. While oven-drying is not the most suitable method, milder action at room temperature once-drying led to suspension stability in water, morphology and mechanical properties close to never-dried MFC, which makes this treatment a feasible option to maintain cellulose quality.