Rheology and Processing of Polymer Nanocomposites: Theory, Practice, and New Challenges

Rheological behavior of cellulose nanocrystal suspensions in polyethylene glycol

“…Furthermore the percolation threshold, c, is much smaller for PEG/CNC nanocomposites (~ 0.15 vol%) than for PLA/CNC nanocomposites (0.5 and 2 vol%) [17,41]. Beyond the probably better nanodispersion state achieved via a good solvent solution mixing method in water and an efficient ultrasonication treatment, this lower threshold could be partially explained by the better affinity between the matrix and the filler [72], as suggested by the lower interfacial tension PEG-CNC = 3.98 mJ/m 2 (Eq. (3) and Table II) compared to PLA-CNC = 6.38 mJ/m2 (using the surface tension of PLA reported by Khoskava [51]).…”

“…This ratio characterizes the strength of the network at rest [72]. Even if for freeze-dried and spray-dried CNC, both G'p and G" max are generally larger after a strong ultrasonication treatment (E = 10,000 J/gCNC) than those after a weak ultrasonication treatment (E = 5,000 J/gCNC), in agreement with the Z-average hydrodynamic diameter measurements (Table I), the ratio G'p/G" max is similar for each fraction (for example, close to 3.5 for  = 2.2 vol%), i.e.…”

Preparation and characterization of nanocomposites based on polylactide manufactured by reactive extrusion-calendering : thermal, rheological, mechanical and fracture properties

“…Numerous studies has observed similar findings and have attributed the result to the restriction of molecular mobility due to the increase in MW and the chain extension/branching reactions resulting from the reactive process. (Al-Itry et al, 2014;Corre et al, 2011a;Dorgan et al, 1999;Mihai et al, 2010;Najafi et al, 2012a) On the contrary, the viscosity enhancement with presence of clay particles in a REX- In general, a good dispersion of filler agglomerates can be achieved when the cohesive forces of the agglomerates are exceeded by the hydrodynamic separating forces applied by the fluid polymer (Majesté, 2016). However, relying only on hydrodynamic stress is insufficient to ensure good dispersion state of nanoparticles in polymer matrix as evidenced in PLA-C.…”

“…The primary particles of fumed silica are extremely small, around 7-40 nm. They contact with each other by hydrogen bonds or van deer Waals force and build up a loose, non-isolated network (Flörke et al, 2000;Majesté, 2016). Figure 3.9 presents the TEM micrograph of a typical commercial fumed silica.…”