جستجوی مقالات مرتبط با کلیدواژه "خمیرکاغذ nssc" در نشریات گروه "صنایع چوب و کاغذ"

The objective of this study was to investigate the modification of neutral sulfite semi chemical (NSSC) pulping liquor by applying changes in the percentage of chemicals, increasing alkalinity and changing the pulping duration for the production alkali sulfite (AS). Among the pulps, the best combination was acceptable with respect to the residual alkalinity (pH> 11) and the acceptable kappa number (about 17) and the lowest amounts of so-called undercooked wood (or “rejects”) was selected. Pure AS pulp and also the mixing of different percentages of AS pulp with NSSC pulp were compared. The results showed that the overall strength of the modified pulp compared with the initial NSSC pulp increased. So that the alkali sulfite (AS) and NSSC is about 66.2 and 32.4 N.m/ g, respectively. By adding more amounts of this pulp in furnish, by increasing the required strength of the paper, the consumption of pulp from the imported long fiber could be reduced while maintaining the paper's strength properties.

In the current study, modification of NSSC pulp broke fibers was done by forming starch polymeric multilayers, using Layer-by-Layer (LbL) layering method. After fiber slushing and preparation of pulp suspension with 0.5% consistency and conductivity formation of about 437 µS/cm, adding water solution of 1 mM NaCl, the experiments of fibers treatment were conducted to build the polymeric layers (up to 5 consecutive layers). Afterward, water retention value (WRV) of fibers was calculated in samples to evaluate the influence of this method on fibers hydrophilicity. The fibers were then used to prepare standard handsheets (60±3g/m2) and the physical and strength properties of sheets were evaluated as a function of the number of layers deposited on the fibers. The results showed that the WRV index of the fibers was improved by the LbL treatment of NSSC broke pulp fibers, due to the increase in starch electrostatic absorption. Successive variation in paper apparent density increase and paper thickness decrease confirmed the construction of starch multilayers on the surface of broke fibers. Formation of such multilayers on broke fibers has led to considerable improvement in tensile index (from 13.21 N.m/g to 30.65 N.m/g) and burst index (from 1.23 kPa.m2/g to 2.36 kPa.m2/g). Also, the prepared SEM micrographs approve the sheet web compaction and paper mechanical improvement resulted due to an increase in inter-fiber bonding.