Aynaz Holakoyi; Omid Ramezani; Hossein Kermanian; Faranak Mohammad Kazemi
Abstract
Introduction: Due to the hydrophilic nature of cellulose, nanofibrillated cellulose (NFC) is supplied in low solid content and high viscosity. As a cost saving strategy, increasing the possible highest solid content is preferred, which is hardly feasible owing to the irreversible hydrogen bonding formation ...
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Introduction: Due to the hydrophilic nature of cellulose, nanofibrillated cellulose (NFC) is supplied in low solid content and high viscosity. As a cost saving strategy, increasing the possible highest solid content is preferred, which is hardly feasible owing to the irreversible hydrogen bonding formation during drying. This phenomenon known as Hornification prevents the cellulose nanofibrils to be readily dispersed in water after being dried. This research assessed an environmentally friendly procedure for the production of water-dispersible nanofibrillated cellulose powder based on carboxymethyl cellulose (CMC) absorption. Material and methods: The absorption of varying amounts of CMC (0, 20 and 40 ml to constant 100 ml NFC) on cellulose nanofibrils in different temperatures of 22 °C (ambient) and 121 °C (autoclave) was investigated using conductometric titration. As the innovative part of the project, hydrodynamic properties of the dispersed NFC suspension including viscosity, turbidity, hydrodynamic specific volume, and water uptake were explored. Besides, the size of powder particles was probed by Dynamic Light Scattering (DLS). Results and discussion: The results indicated that in the highest addition level of CMC (40 ml) and autoclaving at 121 °C for 25 min, the highest absorption was observed, which yielded maximum results in all hydrodynamic properties compared to the control and other treated samples. On the contrary, data recorded for DLS signified that Poly Dispersity Index and the hydrodynamic diameter of the treated samples were bigger than untreated NFC, which was ascribed to the aggregation and agglomeration of cellulose particles in aqueous media. Conclusion: Based on the method presented in this research, NFC powders with suitable dispersibility were obtained after oven-drying. It is concluded that the addition of adequate CMC to NFC results in increased dispersion and waster absorption capacity. The achievements of this novel method facilitates the production, handling, and storage of NFC in industrial applications.
Zahra Razmpour,; Hossein Kermanian; Omid Ramezani,; Saeed Mahdavi; Mehdi Rahmaninia
Volume 9, Issue 2 , January 2012
Abstract
Recycling is a promising approach for rescuing the earth from recoverable solid waste. Among different wastes, paper plays an important role. The effects of wastepaper recycling times on the properties of recycled paper have always been considered but less attention has been paid to semi-chemical papers. ...
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Recycling is a promising approach for rescuing the earth from recoverable solid waste. Among different wastes, paper plays an important role. The effects of wastepaper recycling times on the properties of recycled paper have always been considered but less attention has been paid to semi-chemical papers. In this study, the effect of the recycling times of NSSC wastepaper on their WRV (Water Retention Value), hornification of fibers, tensile strength index, burst strength index and tear strength index was investigated. Results indicated that successive recycling of NSSC wastepaper presents an identical behavior to successive recycling of chemical waste papers. The WRV, tensile strength index, burst strength index and tear strength index decreased and the hornification of fibers increased.
