• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.1
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• pp.39-45
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• 2014

Various approaches have been tried to reduce the emission of carbon dioxide in paper industry. One of important approaches is to use PCC manufactured from emission gas as a filler. However, it was recognized that PCC is inferior to other fillers in the paper strength properties of view. Therefore, pretreatment of PCC with pulp powder was tried to mitigate the strength reduction of paper. Pretreatment of PCC with pulp powder improved the bulk(7.4~12.9%) and air permeability(24.8~42.98%), but there is no significant change in opacity. Tensile index, burst index and stiffness were decreased by the use of pretreated PCC with pulp powder. Anionic and cationic PAM were used as a additive for PCC pretreatment in order to improve strength properties. There was no significant change in bulk in all kinds of PAM used in this study. Most strength properties were improved by the pretreatment of PCC with the anionic and cationic PAM and pulp powder, although the opacity and stiffness were more or less decreased.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.2
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• pp.53-60
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• 2015

The effects of stirring speed during filler modification by dual polymers on flocculation and reflocculation of PCC (precipitated calcium carbonate) particles and its effect on handsheet properties were elucidated. PCC surface was modified by adsorbing A-PAM (anionic polyacrylamide) and C-starch (cationic starch) in series at various stirring speeds. It was found that increasing stirring speed during filler modification decreased the initial floc size of PCC. Continuous stirring with the same speed for filler modification resulted in the decrease of a floc size, eventually reached a steady state. The variations in a floc size was influenced by the stirring speed during filler modification: the lower the stirring speed during filler modification, the larger the floc size variations. Conclusively, the stability of PCC floc could be improved by increasing the stirring speed. In addition, the stirring speed influenced the handsheet properties. The smaller the PCC floc, the lower the strength of handseet. However, too much larger floc size also deteriorated paper strength. There exists an optimum floc size in term of paper strength which shall be controlled by stirring speed during filler modification.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.43 no.3
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• pp.35-42
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• 2011

In this study, ground calcium carbonate (GCC) was modified by Layer-by-Layer (LbL) multilayering with polyelectrolytes. Cationic polyacrylamide (C-PAM) and poly sodium 4-styrene sulfonate (PSS) were used as cationic and anionic polyelectrolytes to modify GCC. The characteristics of the modified GCC were examined in terms of zeta potential and particle size with the addition level of polyelectrolyte and layer number. The GCC could form an assembly of cationic and anionic polyelectrolytes through consecutive adsorption process. The zeta potential of the modified GCC moved toward the cationicity and reached the plateau with the increase of the addition level of C-PAM. With layering of anionic PSS, the GCC had the negative charge. The particle size was dependent on the zeta potential. It was also observed by optical microscope. As the PSS was in the presence of the outermost layer, the GCC showed the better dispersability. It indicated that the surface charge and particle size can be controlled by adjusting the addition level of polyelectrolyte and the layer number.

• Journal of Forest and Environmental Science
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• v.23 no.2
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• pp.119-122
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• 2007

Actually, about 45% of total costs for wastewater treatment in a papermaking mill is spent for sludge disposal and the cost of chemicals used to improve the dewaterability of sludge takes much part of it. In order to reduce sludge disposal cost and to improve the efficiency of sludge treatment, it is necessary to minimize the amount of water contained within the sludge and hence to improve the dewaterability of the sludge. The objective of this study was to elucidate the way of improving the dewaterability of sludge. Three types of wastewater from a tissue paper mill, a printing paper mill and a newsprint mill were used and two types of high molecular weight flocculants (anionic PAM and cationic PAM) were used to treat the wastewater. Dewaterability of sludge was evaluated by measuring floc strength.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.1
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• pp.29-38
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• 2014

Guar gum is added to the pulp suspension at the suction side of the fan pump just before the sheet is formed on either a fourdrinier or cylinder machine. Guar gum replaced and supplements these hemicelluloses in paper bonding with many advantages, which include improved sheet formation with a more random distribution of pulp fibers. But, guar gum has serious storage problem. This material has easily decayed after High-temperature conditions such as summer. In this study, various properties of cotton handsheet were measured to solve the problem of deformation while storing guar gum and to improve the durability. After aging, which is one of the durability tests, cotton handsheet with 0.2% and 0.3% of A-PAM showed improved mechanical properties and bursting index and folding endurance of cotton handsheet with 0.3% of A-PAM were similar to those with guar gum. The yellowness loss of cotton handsheet with synthetic polymers was lower than those with guar gum.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.5
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• pp.440-448
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• 2016

Nonpoint sources of pollution (NPS) is defined as diffuse discharges of pollutants (e.g., nutrient, pesticide, sediment, and enteric microorganism) throughout the natural environment and they are associated with a variety of farming practices. Previous studies found that water soluble anionic polyacrylamide (PAM) is one of the highly effective measures for enhancing infiltration, reducing runoff, preventing erosion, controlling nonpoint source of pollutants, and eventually protecting soil and water environment. Potential benefits of PAM treatment in agricultural soil and water environments have been revealed by many research and they include low cost, easy and quick application, and suitability for use with other Best Management Practices (BMPs) for NPS control. This study reviews the various applications of PAM and discusses its further potentials in agricultural environment.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.11
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• pp.1024-1029
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• 2010

Use of polymeric soil amendments is an emerging way to reduce soil erosion, and improve crop productivity and soil quality. Objective of this study was to evaluate the effects of anionic polyacrylamide (PAM) and synthetic biopolymer on soil erosion, crop growth and soil quality. The aqueous solutions of PAM and biopolymer at 40 kg/ha were applied to loamy soil plots (3 m width by 18 m long) having a 20% slope during radish (Raphanus sativus) cultivation. Results showed that PAM and biopolymer treatments increased aggregate stability up to 11% compared to the untreated control. Treatments of PAM and biopolymer also increased leaf length of radish but there was no significant difference in crop yield. Soil loss was decreased by up to 41% using the polymeric soil amendments; however, no difference in runoff was found, compared to the untreated control. Soil loss was logarithmically increased against an increase in rainfall intensity ($R^2=0.85$). Our findings suggest that proper use of polymeric soil amendments would be beneficial to maintain soil quality and reduce soil erosion in sloping uplands.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.6
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• pp.154-163
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• 2015

Because of acute or chronic intoxication by carbon disulfide, viscose rayon industry is strictly subjected to environment regulatory approval. Recently, non-wood fibers are frequently considered as a raw materials for the manufacture of specialty paper for the higher physical strength and functionality. Among the non-wood fibers, hemp bast fiber is one of the most widely used materials in viscose rayon yarn industries. In this study, the handsheet for manufacturing the viscose rayon yarn was prepared with wood pulp fibers and hemp bast fibers. The proper mixing ratio of wood fibers and hemp bast fibers with dry-strength agent and nano-celluloses was analysed in terms of physical and mechanical strength of sheet for viscose rayon yarn. The papermaking conditions for high mechanical strength of sheet were obtained by mixing the SwBKP and HwBKP fibers with freeness level of 200 mL CSF. The dual polymer system by controlling the addition ratio of PVAm and anionic PAM was also important. The addition of nano-cellulose into wet-end furnishes increased the physical strength of sheet, and improved the paper structure for the production of viscose rayon yarn.

• Applied Chemistry for Engineering
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• v.29 no.2
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• pp.155-161
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• 2018

For the efficient recovering of collapsed sloped soil, using a soil binder that can support the soil strongly and help the growth of plants is very important. The soil binder should also have functions of recovering the soil ecologically as well as be environmental friendly materials. In this research, optimum values of the water content and permeability and direct shear strength were searched by adding the water absorbent and coagulant into the soil binder. The polyacrylamide (PAM) with various anionic strength, super absorbent polymer (SAP) and cellulose ether (CE) were used as a soil binder, water absorbent and coagulant, respectively. Effects of the soil binder on the characteristics of soil were observed by changing the mixing ratio of PAM, SAP and CE. Experimental results showed that the soil binder increased the direct shear strength tens of times and the water content around two times, whereas decreased the water permeability. Also, the addition of CE to increase the coagulation of SAP increased more of the direct shear strength and water content.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.271-278
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• 2006

We used polymers of alternating cationic and anionic nature to build up shells on fiber surfaces, strengthen the worn-out fibers and improve paper properties made from such fibers. OCC and ONP pulps were either dipped or salted out in the cationic polyallylamine, polyacrylamide and starch solutions. After centrifugal drying, these were followed by treatments in anionic polyacrylic acid, poly-acrylamide, and starch solutions, respectively. The shell-enhanced fibers were formed into handsheets and their physical properties evaluated. The results show that building multiple shells on worn-out fiber surfaces can strengthen the fibers and paper. The simpler and more practical impregnation-centrifuging treatment provided the desired effects, whereas salting out the polymers produced somewhat superior fibers. The latter process, were impractical, however. The first pair of polymeric shells imparted marked strength improvement, whereas later layers had diminishing efficacies. Overall, the methods can improve fiber quality, attaining paper strength requirements without resorting to expensive measures. Alternate cationic polymer and filler powders were also deposited on fiber surface based on the micriparticle system in an anticipation of stiffness gains. Platy minerals, such as montmorillonite, bentonite, sericite, clay and talc were added following cationic PAM. After dewatering of polymer-pigment shelled fiber of one to 3 pairs of layers, handsheets either calendered or uncalendered were evaluated. The results indicate that regardless of calendaring, stiffness of the handsheets did not improve appreciably while certain other strength properties showed gains. We also attempted the novel starch gel filler addition method wherein tapioca starch and filers (PCC, sericite or clay) were mixed at high solids content of 50% and cooked until gelatinized. The filled handsheets were dried under various conditions and then tested for their properties. Improvements in strengths of modified filled paper were observed.