Gel structure phase behavior in micro nanofibrillated cellulose containing in situ precipitated calcium carbonate

Abstract

Speciality high‐strength board, packaging grades, and novel cellulose‐based nanocomposites may incorporate microcellulosic nanofibrillated materials (MNFC), although the rheological properties of such strongly water sorbing structures are challenging for processing technologies. This study introduces rheological methods for the evaluation of dewatering and flow behavior of such high consistency furnishes to exemplify the effect of energy input on microfibrillar material (MFC), as produced by a combination of enzymatic pretreatment and increased levels of fluidization. The large number of fibril contact points act to entrap water, held both on the fibril surface as immobilized water and in the interfibril spacing forming the gel structure. Tuning of the rheological and dewatering properties has been enabled by in situ precipitation of calcium carbonate filler (in situ PCC) on the MFC, which results in the production of a more uniform furnish. Such in situ PCC coated MFC fibrils incorporated into furnish were seen to increase dewatering rate over that of the furnish mix without the in situ precipitated filler primarily because of the reduction in total surface area of the fibers and fibrils when the pigment is present on the fibrillary surface. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43486.

Acid dissociation of surface bound water on cellulose nanofibrils in aqueous micro nanofibrillated cellulose (MNFC) gel revealed by adsorption of calcium carbonate nanoparticles under the application of ultralow shear

“…The resulting suspension was placed in a cold storage to be cooled to less than 4 °C, at which temperature the enzyme was deactivated, and then the material was refined in a Valley Hollander for 30 min and subsequently fed two times through a microfluidiser (model M-110P, Microfluidics, USA) in order to obtain MNFC with favourable particle size and morphology. The pressure in the fluidiser was controlled at 2 000 bar and the flow gap set to 100 um [12]. The pulp was checked after 2 weeks to ensure that the enzyme did not continue the hydrolysis under these conditions, and the effect of the residual enzyme on MNFC properties can therefore be considered negligible.…”

Novel In-situ Precipitation Process to Engineer Low Permeability Porous Composite

“…A good deal of work has been done in CaCO 3 and cellulose composites for applications such as increasing brightness of paper or board, ply board, etc 11 – 13 . A few precipitation methods have been reported, including the precipitation of CaCO 3 onto cellulose nanofibres in suspension to coat fibres and reduce their water uptake 3 , or using nanomaterials in suspension to control the pore sizes in which nanoparticles nucleate and grow 5 , 14 – 16 . The technique reported in this paper is different in that nanoparticles are nucleated within a preformed web used as absorbing template; the size distribution of nanoparticles matches that of the porous substrate.…”

Enhancing the Stability of Aqueous Dispersions and Foams Comprising Cellulose Nanofibrils (CNF) with CaCO3 Particles

“…Mineral filler particles are often used to enhance the stiffness, rigidity and impact strength of polymeric composite materials. Recently, Dimic-Misic et al (2016) introduced an approach involving the inclusion of in situ CaCO 3 precipitation in order to prepare uniform nanocellulose-based inorganic-organic composites [ 14 ]. To achieve enhanced solid nanocomposite properties derived from the mineral inclusion, it is necessary to ensure full dispersion of both constituents, nanocellulose component and inorganic component, and to induce dispersion compatibility between the nanofibrils and the inorganic particles.…”