Chitosan and its derivatives (grafted chitosan and chitosan nanoparticles) were used as bio-based adsorbents in urea-formaldehyde (UF) resins, and accordingly, their effects on the curing behavior, resin structure, crystalline structure, and formaldehyde emission (FE) of final resin has been investigated. Synthesis of grafted chitosan and chitosan nanoparticles was confirmed by FTIR spectroscopy. Characteristics of UF resins were monitored by 13C-NMR and X-ray diffraction. This analysis showed that the free formaldehyde and crystallinity of UF resin having chitosan-based adsorbents were substantially reduced. The FE was largely decreased in the medium density fiberboard (MDF) containing chitosan nanoparticles (60%), followed by grafted chit

Lignocellulosic hydrogels are valuable bio-products that have been considered widely in recent investigations. Also, application of low value recycled fibers for high value added products can be of much interest. In this respect, current research has focused on producing hydrogel from recycled old corrugated container (OCC) resources, using 1-butyl-3-methyl-imidazolium chloride ionic liquid (IL) as a green solvent. The results indicated that the IL successfully dissolved OCC fibers, allowing the production of lignocellulosic hydrogel. Considering total water absorption amount as a main criterion for evaluation of hydrogels, the fabricated hydrogel showed promising results (up to 4700% water absorption). X-ray diffraction analysis confirmed

The use of minerals instead of expensive virgin fibers is one of the common ways to reduce production costs in papermaking. But the presence of fillers reduces the mechanical properties of produced papers. In this study, the possibility of using zeolite (an abundant mineral) as a filler along with chitosan biopolymer was investigated. Zeolite was replaced by virgin fibers at three levels of 10, 20 and 30% (based on pulp dry weight). The results showed that the presence of 1% chitosan as an additive in pulp increased the zeolite retention in printing and writing paper. But the presence of chitosan in the paper containing the filler had no effect on the mechanical properties. It seems that with increasing the amount of chitosan, the mechanica

The application of chitosan biopolymer with and without nanoparticles in the papermaking process was investigated. The effect of the chitosan’s molecular weight on its interaction with silica nanoparticles in recycled old corrugated container pulp was studied. Initially, the nanosilica particles were analyzed via atomic force microscopy and scanning electron microscopy, which confirmed the spherical shape of the silica nanoparticles with diameter less than 5 nm. Dynamic light scattering method was used to determine the zeta potential and the hydrodynamic radius of the chitosan with different molecular weights. Infrared spectroscopy was used to show the possibility of hydrogen bonding between the chitosan and the nanosilica. The results sh

Chitosan was used as environmentally friendly and bio-based scavenger for reducing the formaldehyde emission from medium density fiberboard. Using of chitosan powder showed better capacity of formaldehyde adsorption rather than the chitosan solution. Liquid 13C-NMR showed that the free formaldehyde in urea formaldehyde adhesive having chitosan powder was drastically reduced. Additionally, the observed peak at 155?ppm showed that that the chitosan powder was copolymerized with urea formaldehyde adhesive. Increasing the amount of chitosan powder was significantly reduced the emitted formaldehyde. It was shown that the formaldehyde adsorption of chitosan was strongly influenced by the pH value of adhesive composition. The pH value and the adhe

In this research, the effect of bentonite micro-particles on the performance of chitosan as a new additive system for improving the dry strengths of acidic papermaking was studied. Chitosan, an abundant carbohydrate biopolymer, in 4 dosages (0, 0.75, 1.25 and 2% based on dry weight of pulp) was applied with bentonite in 4 dosages (0, 0.3, 0.6 and 0.9% based on oven-dry weight of pulp). Although the addition of chitosan up to 0.75% (without bentonite) improved tensile index and burst index, but the addition of more chitosan decreased all mechanical properties in comparison with the control sample. The application of bentonite in combination with chitosan had a significant impact on chitosan performance in mechanical properties. The best resu

The old newsprint, as an important grade of waste papers, usually has been produced from chemical-mechanical pulp (CMP). Although the effect of paper aging on different properties of recycled pulp has been investigated from long time ago, but, few studies have been observed about the effect of this phenomenon on recycling of CMP paper. In this study, accelerated aging was applied on Hardwood CMP newspaper by 2 levels of temperature (50 and 100 o c) and 2 levels of time (24 and 48 hours). Results showed that accelerated aging applying 100 o c in 24 and 48 hours (about half of a decade and more) impose an intense reduction tensile strength, burst strength and tear strength indices as well as folding endurance strength of recycled pulp. Also,