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The present study has been carried out to consider the effect of acetylation conditions and type of bleached pulps [Kraft and SO 2-ethanol-water (SEW) pulps] on the properties of obtained cellulose acetates (CA) and their films. The acetylation reaction in the absence of solvent was performed by using acetic anhydride and iodine as a catalyst. The efficiency of acetylation and the degree of substitution, crystallinity, transparency, tensile strength, young modulus, differential scanning calorimetry, water vapor permeability (WVP), scanning electron microscope and atomic force microscopy images were studied. The results showed that the while the Young's modulus and transparency increased by up to 8% of the catalyst due to the increase in iodine charge; higher iodine levels led to embrittlement of the film. The increase in the ratio of acetic anhydride to pulp (A:P) from 10:1 to 20:1 with 4% catalyst led to a reduction of the DS by 8-10%, the crystallinity by 25%, the Young's modulus by 13-25%, and transparency by 1-34% of a CA obtained from SEW and Kraft pulp, respectively. With the use of higher amounts of the catalyst (8%) and a ratio of A:P equal to 20:1, all properties of CA were suitable for film preparation. WVP of films from Kraft pulp and SEW pulp showed a decrease of about 8.5% and 18% respectively when increasing the iodine amount from 4 to 8% in acetylation. The tensile strength of CA films was initially increased by enhancing the amount of iodine, but then reduced in a similar way to other properties. The condition of acetylation can be adjusted to produce a high-quality CA film according to the characteristics of the pulp used as raw material.

Papermaking sludge (PS), a waste residue from the pulp and paper processing, has brought great pressure on the environment because of large quantities that are produced in paper mills. This work was carried out to explore the possibility of making PS/cement composite products using solid waste of PS. Boards measuring 350 × 270 × 12 mm3 were manufactured using PS contents of 40, 50, and 60 wt%, adhesive dosages of 0, 10, and 15 wt%, and 0 and 5 wt% of calcium chloride as an accelerator. At least three replications were fabricated for each treatment, and some mechanical and physical properties of the boards were evaluated. Test results showed that the bending and internal strengths of the specimens decreased with an increase in the PS content, and the maximum values were obtained at PS loading of 40 wt%. The negative influence of PS content on the mechanical properties can be explained by the reduced bonding ability because of weaker PS compared with cement. Screw withdrawal values were up to 22.7 kPa. Water absorption and thickness swelling of cement mortar considerably increased with increased content of PS, with a corresponding reduction of bulk density. In general, all properties of the boards were improved when the adhesive and calcium chloride contents were increased. The results showed that an increase in board density improved the mechanical and physical properties. Finally, results showed that PS has good potential for recycling and utilization in developing value‐added building components. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers

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