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Strong natural bast fibers, especially flax fibers, can be used to replace glass fibers in reinforced composites. The properties of natural fibers depend largely on maturity, retting and processing. Two chemical treatments were applied to retted and semiretted flax fibers to create better fiber to resin bonding and to show the effect of retting degree and successive purification processes on the mechanical properties of natural composite materials. Retted and semiretted flax fibers have been scoured and bleached with the objective of removing surface impurities and developing finer structure. To investigate the effect of adhesion promoter on the mechanical properties of natural fiber composite, a composite sample was prepared from bleached retted flax pretreated with adhesion promoter Isostearoyltitanate (ISTT). After treatments the fibers got cleaner and the measurements showed that the fiber fineness as well as the surface free energy increased. The treatments were accompanied by decrease in the fiber tenacity but it has been found not to be reflected to the final mechanical properties of the composite. No improvement was remarked by using Isostearoyltitanate for surface modification. [ABSTRACT FROM AUTHOR]

Bifunctional starch composites were prepared by γ-induced grafting of acrylamide (Aam) and acrylic acid (AA) onto maize starch. The prepared composites were characterized by FTIR spectroscopy and scanning electron microscope (SEM). The feasibility of these composites to remove anionic dyes, direct blue 21 (D. Blue 21) and direct brown 2 (D. Brown 2) and a cationic dye, methylene blue (MB) were examined. Factors affecting adsorption of anionic and cationic dyes onto these starch composites were studied. These factors were radiation dose, agitation time, adsorbent and adsorbate concentrations. Prepared composites were effectively used in adsorption of D. Blue 2, D. Brown 2 and MB from aqueous solutions. The Adsorption data of both D. Blue 21 and D. Brown 2 complied with the Langmuir and Freundlich isotherms. [ABSTRACT FROM AUTHOR]

A new adsorbent was prepared from wood pulp (WP) after reaction with epichlorohydrin and dimethylamine in the presence of pyridine and N,N-dimethylformamide (DMF). The adsorption of Cr (VI) from aqueous solutions by the so-prepared wood pulp adsorbent (WP-A) was investigated. Various factors affecting adsorption, such as pH, adsorbent concentration (1–5 g/L), agitation time (5–60 min), and Cr (VI) concentration (50–700), were taken into consideration. The adsorption of Cr (VI) onto (WP-A) was found to be pH-dependent and maximum adsorption was obtained at pH 3. The adsorption data obeyed Langmuir and Freundlich adsorption isotherms. The Langmuir adsorption capacity (Q max ) was found to be 588.24 mg/g. Freundlich constants, K F and n, were found to be 55.03 and 2.835, respectively. [ABSTRACT FROM AUTHOR]