Search

Cellulose nanofibers isolated from unbleached pulp are characterized by different surface properties due to presence of lignin at their surface, in addition to lower cost than isolated from bleached pulp. In the current work, the effect of cellulose nanofibers isolated from unbleached neutral sulfite and bleached soda rice straw pulps (so called UBCNF and BCNF) on improving paper sheet properties of unbleached and bleached rice straw pulp (so called UBP and BP) was studied. The effect on mechanical properties (tensile strength, burst strength, and tearing resistance) and physical properties (porosity and water vapor permeability) was studied. Scanning electron microscopy (SEM) was used to assist in explaining the obtained results. The result showed that using BCNF and BP resulted in better improvement in mechanical properties and also more effective in reducing porosity of paper sheets than in case of using UBCNF and UBP. These results indicated stronger bonding between nanofibers and pulps’ fibers in case of using BCNF and BP (surfaces rich in cellulose hydroxyl groups) than in case of UBCNF and UBP (surfaces rich in lignin). Water vapor permeability of paper sheets made from unbleached or bleached pulps did not significantly affect by the addition the nanofibers.

A series of lightweight, hydrophobic, and fire retardant foams were fabricated through activation of cellulose by phosphoric acid as a primarily step. Dolomite clay was embedded onto the cellulosic suspensions with gelatin/ tannin as adhesive followed by freeze drying process. A solution of the environmentally friendly silicone rubber (RTV) was applied onto foam samples via spray-coating to improve their water repealing performance, which was explored by investigating both of water contacting angle and wettability time of the coated foam samples. Flammability characteristics, thermal decomposition, surface morphology, and chemical structure of treated and untreated foams were investigated by flammability test, thermogravimetric analysis, scanning electron microscopy, X-ray diffraction, and Fourier-transform infrared, respectively. Results showed that the foams loaded dolomite and coated RTV have high hydrophobicity as well as anti-inflammability.

The paper sheet prepared from unbleached rice straw containing different concentration of inorganic salts, that work as flame retardant additives (Lithium hydroxide one hydrate (LiOH.1H 2 O), Magnesium hydroxide (Mg (OH) 2 . 15H 2 O), aluminum sulphate (Al 2 (SO 4 ) 3 ) and calcium carbonate (CaCO 3 )) were investigated using horizontal burning test against flame retardant. Also, the prepared paper sheets were characterized using scanning electron microscope (SEM), thermal gravimetric analysis (TGA) and Infrared spectroscopy (IR). Furthermore, the water absorption was determined. In addition, the mechanical properties (breaking length, tear factor and burst factor) of the prepared paper sheet were evaluated. Correspondingly, the physical (structure and mechanical) properties of the prepared paper sheet were enhanced in terms of tensile, tear factor and water absorption. Also, delaying firing process will help in protecting the materials from burning, saving many of economic effect. So the prepared paper sheet can be used for different industrial applications especially in packaging applications.

It’s a report on a novel approach; preparation and electrochemical properties of modified lignin. Wax and starch were used as natural, green adhesives for enhancing the electrical resistivity of lignin in acidic medium, forming eco-friendly high insulator biocomposite. Scanning electron microscopy (SEM) was used to characterize the fabricated biocomposite. The modified lignin was characterized using Fourier transform infrared (FTIR), while the electrochemical behavior was examined by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The innovative approach described in this work provides a promising eco- friendly method for lignin modification with highly electrical resistivity and stability with time.

Cation exchangers from chemically modified banana leaves have been prepared. Banana leaves were treated with different molarities of KMnO4 and cross linked with epichlorohydrin and their effect on metal ion adsorption was investigated. Phosphorylation of chemically modified banana leaves was also studied. The metal ion uptake by these modified banana leaves was clarified. Effect of different varieties, e.g. activation of produced cation exchanger, concentration of metal ions was also investigated. Characterization of the prepared ion exchangers by using infrared and thermal analysis was also taken in consideration.

The pulp black liquor waste (PBL), a byproduct from paper-making, is applied as a cement admixture in two types of cement, namely Ordinary Portland cement (OPC) and Portland limestone cement (LPC). The results showed that the water of consistency of cement pastes premixed with PBL was gradually increased with the concentration of PBL while the setting times (initial and final) were decreased. So, it can be used as an accelerator. The compressive strength increased slightly during the early ages of hydration but sharply during the later ages, particularly with those premixed with PBL. The combined water content and bulk density displayed the same trend as the compressive strength, whilst the apparent porosity decreased at all curing times. The IR spectra of cement pastes showed that the intensities of the different peaks of cement pastes with PBL are higher than those of the pure samples. The SEM images proved that the incorporation of PBL with cement did not affect the chemical composition of OPC or LPC hydrates, but it only affected the physical state, shape, size, morphology and crystallinity of the formed hydrates. The 2 wt. % of PBL is the optimum concentration.