The effect of water‐soluble polymers on rheology of microfibrillar cellulose suspension and dynamic mechanical properties of paper sheet

Abstract

Rheological properties of fiber/polymer suspensions and dynamic mechanical analysis (DMA) of paper sheets containing the same polymers were measured. Correlations between viscoelastic properties of suspensions and strength of paper sheet are presented. Rheological properties of suspensions of microfibrillar cellulose (MFC) and a set of water soluble polymers were measured. Rheological properties of these complex fluids vary considerably depending on the added polymer. A suspension of fiber and carboxymethyl cellulose (CMC) exhibits a viscosity higher than the sum of the viscosity of the individual components in the suspension. In contrast, when cationic starch (CS) is used together with the fiber, the yielding behavior rather than the viscosity is characteristic of the suspension. Dynamic mechanical properties of paper sheets containing CMC or CS as additives were studied at different humidity levels. Different yielding behavior observed in oscillatory rheology can be correlated with straining behavior in dynamic mechanical properties.

Effect of cationic polymethacrylates on the rheology and flocculation of microfibrillated cellulose

“…2b). This is in agreement with our earlier results (Vesterinen et al 2010a), which showed that cationic polyelectrolytes strengthened MFC suspension while maintaining gel-like behavior. By contrast, the amphiphilic cationic PSMA13Q decreased the storage and loss modulus at a concentration of 0.5 wt% (Fig.…”

“…Different polymers have been mixed with MFC/ water suspension to affect the rheological properties of the suspensions (Lowys et al 2001;Vesterinen et al 2010a;Vesterinen and Seppälä 2008) or to the aggregation of the fibers (Myllytie et al 2009), but the results have not been combined. Our group (Vesterinen et al 2010a) studied the addition of carboxymethylcellulose, cationic polyacrylamide, and cationic starch to MFC suspensions.…”

“…Our group (Vesterinen et al 2010a) studied the addition of carboxymethylcellulose, cationic polyacrylamide, and cationic starch to MFC suspensions. Carboxymethylcellulose made the suspension less gel-like and reduced the shear thinning, whereas cationic polyacrylamide and starch strengthened the gel and preserved its shear thinning behavior.…”

Rheology of nanocellulose-rich aqueous suspensions: A Review

“…Related effects have been widely reported (e.g. by Guo and Ding 2006;Vesterinen et al 2010;Boluk et al 2012;Hu et al 2014;Lu et al 2014c;Ahn and Song 2016;Oguzlu et al 2016).…”

Preparation and Viscoelastic Properties of Composite Fibres Containing Cellulose Nanofibrils: Formation of a Coherent Fibrillar Network

“…Even at low concentrations, the CNF suspensions exhibit quite a complex rheological behaviour; they are shear-thinning, at least at not too high shear rates, and elastic in nature; compare, for example, [5,[26][27][28]. Both the shear viscosity and the viscoelastic parameters of the CNF suspensions are affected by additives like salts, carboxymethyl cellulose, cationic starch, and polymethacrylates [29,30]. The CNF suspensions, with a fibril content exceeding the percolation threshold, exhibit a gel-like behaviour with a yield stress, a storage modulus greater than the loss modulus, and the moduli being rather insensitive to changes in the measuring frequency, for example, [5,26], and to moderate changes in temperature, up to 80 ∘ C [5,31].…”