Search

The present work reports on the development of a pressure-affected based headspace (HS) analytical technique for the determination of calcium carbonate content in paper samples. By the acidification, the carbonate in the sample was converted to CO 2 and released into the headspace of a closed vial and then measured by gas chromatography (GC). When the amount of carbonate in the sample is significant, the pressure created by the CO 2 affects the accuracy of the method. However, the pressure also causes a change in the O 2 signal in the HS-GC measurement, which is a change that can be used as an indirect measure of the carbonate in the sample. The results show that the present method has a good precision (the relative standard deviation<2.32%), and good accuracy (the relative differences compared to a reference method was<5.76%). Coupled with the fact that the method is simple, rapid, and accurate, it is suitable for a variety of applications that call for the analysis of high carbonate content in paper samples., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Recycled paper mills produce large quantities of fibrous rejects and fines which are usually sent to landfills as solid waste. These cellulosic materials can be enzymatically hydrolyzed into sugars for the production of biofuels and biomaterials. Paper mill wastes also contain large amounts of calcium carbonate which inhibits cellulase activity. The calcium carbonate (30%, w/w) decreased 40-60% of sugar yield of unbleached softwood kraft pulp. The prime mechanisms for this are by pH variation, competitive and non-productive binding, and aggregation effect. Addition of acetic acid (pH adjustment) increased the sugar production from 19 to 22 g/L of paper mill waste fibers. Strong affinity of enzyme-calcium carbonate decreased free enzyme in solution and hindered sugar production. Electrostatic and hydrogen bond interactions are mainly possible mechanism of enzyme-calcium carbonate adsorption. The application of the nonionic surfactant Tween 80 alleviated the non-productive binding of enzyme with the higher affinity on calcium carbonate. Dissociated calcium ion also inhibited the hydrolysis by aggregation of enzyme.

Causticized calcium carbonate (CCC), a solid waste derived from kraft black recovery process, can be used as an alternative for the conventional precipitated calcium carbonate (PCC). However, the application of the CCC has been limited due to its low sizing efficiency in its filled paper. In this study, the characteristics of the CCC were studied aiming to improve the alkyl ketene dimer (AKD) sizing performances of the CCC filled papers, and the results were compared with those from PCC filled papers. The results showed that the CCC had higher pore structure, higher specific surface area, and more negative charge density than the PCC, thus leading to a higher cationic AKD adsorption onto the CCC filler. The lower AKD sizing efficiency in the CCC filled paper can be explained by the combination of higher AKD adsorption and migration, both of which resulted in preferred AKD adsorption onto/into the CCC fillers, rather than the cellulose fibers. Based on the above, the prior addition of polyamide-polyamine epichlorhydrin (PAE) resin to the CCC filler system was proposed to remedy the related issues, thus improving the sizing efficiency.

Utilized the principles of guar gum (GG) gelation and crosslinking, a novel modified precipitated calcium carbonate (MPCC) papermaking filler was prepared by using organic titanium (OT) ionic crosslinking agent. The MPCC was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). FTIR results confirmed that GG had been coated on the surface of PCC particles, XPS analysis indicated the presence of titanium atoms on MPCC particles, and SEM and XRD results showed that the modification treatment did change the surface morphology and crystal structure of PCC particles. The handsheet testing results showed that the strength properties of handsheets were obviously improved when using MPCC as papermaking filler, and the optimum preparation conditions of MPCC were obtained. This research suggests that the GG modified PCC by using OT as crosslinking agent can be used to manufacture high filler content paper products., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

A new concept of composite filler was developed by using cellulose nanofibrils (CNF), precipitated calcium carbonate (PCC) and cationic starch (C-starch). In this study, cellulose nanofibrils were utilized in two different ways: a PCC-CNF composite filler and a papermaking additive in sheet forming. The aim was to elucidate their effects on flocculation, filler retention and the strength and optical properties of handsheets. The highest filler retention was obtained by using the PCC-CNF composite filler in paper sheets. The paper filled with the composite fillers had much higher bursting and tensile strengths than conventional PCC loading. It was also found that the paper prepared with PCC-CNF composite fillers became denser with increasing the filler content of paper., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

In the paper, a simple and sensitive electrochemiluminescence (ECL) DNA sensor based on graphene-modified porous Au-paper working electrode (GR/Au-PWE) and calcium carbonate/carboxymethyl chitosan (CaCO3/CMC) hybrid microspheres @ luminescent silver nanoparticles (AgNPs) composites was developed. The GR/Au-PWE with excellent conductivity was successfully prepared for the immobilization of capture probe. The CaCO3/CMC hybrid microspheres were prepared by the precipitation of calcium carbonate in an aqueous solution containing CMC. The AgNPs was synthesized by thermal reduction of silver ions in glycine matrix, taking advantage of the solid-state matrix to control the nucleation and migration of reduced silver atoms. The CaCO3/CMC@AgNPs composites exhibited 3.6 times higher ECL intensity than the pure AgNPs-labeled reporter DNA. Taking advantage of dual-amplification effects, the paper-based DNA sensor could detect the target DNA quantitatively, in the range of 4.0×10(-17)-5.0×10(-11) M, with a limit of detection as low as 8.5×10(-18) M, and perform excellent selectivity. The simple, low-cost, sensitive device could be easily applied for point-of-care testing, public health and environmental monitoring in remote regions, developing or developed countries., (Copyright © 2014 Elsevier B.V. All rights reserved.)

To mitigate the negative effect of filler addition on paper strength and improve filler retention, filler modification with hydrogen bonding polymers (e.g., starch) or their composites is an interesting research topic. Differing from previous reports, the concept related to the deposition of starch/oleic acid complexes on precipitated calcium carbonate (PCC) with the aid of calcium ions was demonstrated. The introduction of calcium ions resulted in effective starch deposition. As a result of filler modification, filler retention and the tensile strength of the filled paper were simultaneously improved essentially due to the aggregation of PCC particles in filler modification process as well as improved filler bondability. The concept demonstrated in this brief study may provide an alternative approach to filler bondability enhancement for improved papermaking performances., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

The effective treatment and utilization of biowaste have been emphasized in our society for environmental and economic concerns. Recently, the eggshell waste in the poultry industry has been highlighted because of its reclamation potential. This study presents an economical treatment process to recover useful bioproducts from eggshell waste and their utilization in commercial products. We developed the dissolved air floatation (DAF) separation unit, which successfully recovered 96% of eggshell membrane and 99% of eggshell calcium carbonate (ECC) particles from eggshell waste within 2 h of operation. The recovered ECC particles were utilized as coating pigments for ink-jet printing paper and their impact on the ink density and paper gloss were investigated. The addition of the ECC particles as coating pigments enhances the optical density of cyan, magenta and yellow inks while decreasing the black ink density and the gloss of the coated paper.

Wt% of aragonite, a CaCO(3) polymorph, increased with higher hydraulic activity ( degrees C) of limestone in precipitated calcium carbonate (PCC) from the lime-soda process (Ca(OH)(2)-NaOH-Na(2)CO(3)). Only calcite, the most stable polymorph, was crystallized at hydraulic activity under 10 degrees C, whereas aragonite also started to crystallize over 10 degrees C. The crystallization of PCC is more dependent on the hydraulic activity of limestone than CaO content, a factor commonly used to classify limestone ores according to quality. The results could be effectively applied to the determination of polymorphs in synthetic PCC for eco-friendly paper manufacture.

A laboratory aerobic incubation study was performed during 18 weeks under controlled conditions to assess the effects of applying different doses of pulp mill inorganic wastes on the physical-chemical properties of an acid Dystric Cambissol. Three different inorganic wastes were tested - wood ash, dregs and grits, and an agriculture limestone was used as reference. Results showed that increasing the dose applied of the different inorganic wastes tested always led to significant raises of soil pH at different incubation times demonstrating that its use as alternative-liming materials could be a valid and less expensive option to the use of commercial agricultural limestone. Moreover, no immediate concerns seem to be expected related to soil exchangeable sodium (Na) content, at least for the doses needed to increase soil pH until the targeted value 6.5. Particularly for wood ash a pronounced increase on soil extractable potassium and phosphorous was observed, indicating that besides the liming effect this waste can contribute to improve soil fertility by supplying significant available amounts of these nutrients. Finally, metals do not seem to be a limiting factor for the application to land of these by-products.

The pulp and paper industry uses significant amounts of water and energy for the paper production process. Closing the water cycles in this industry, therefore, promises large benefits for the environment and has the potential of huge cost savings for the industry. Closing the water cycle on the other hand also introduces problems with process water quality, quality of the end-product and scaling, owing to increased water contamination. An inline treatment system is discussed in which anaerobic-aerobic bioreactors perform a central role for removing both organic and inorganic pollutants from the process water cycle. In the proposed set-up, the organic compounds are converted to methane gas and reused for energy supply, while sulphur compounds are stripped from the process cycle and calcium carbonate is removed by precipitation. Improved control of the treatment system will direct the inorganic precipitates to a location where it does not adversely affect paper production and process water treatment. A simulation program for triggering and controlling CaCO3 precipitation was developed that takes both biological conversions and all relevant chemical equilibria in the system into account. Simulation results are in good agreement with data gathered in a full-scale "zero-emission" paper plant and indicate that control of CaCO3 precipitation can be improved, e.g. in the aerobic post-treatment. Alternatively, a separate precipitation unit could be considered.

Calcium precipitation can have a number of effects on the performance of high-rate anaerobic performance including cementing of the sludge bed, limiting diffusion, and diluting the active biomass. The aim of this study was to observe the influence of precipitation in a stable full-scale system fed with high-calcium paper factory wastewater. Granules were examined from an upflow anaerobic sludge blanket reactor (volume 1,805 m3) at a recycled paper mill with a loading rate of 5.7-6.6 kgCOD.m(-3).d(-1) and influent calcium concentration of 400-700 gCa m(-3). The granules were relatively small (1 mm), with a 200-400 microm core of calcium precipitate as observed with energy dispersive X-ray spectroscopy. Compared to other granules, Methanomicrobiales not Methanobacteriales were the dominant hydrogen or formate utilisers, and putative acidogens were filamentous. The strength of the paper mill fed granules was very high when compared to granules from other full-scale reactors, and a partial linear correlation between granule strength and calcium concentration was identified.

Deacidification is a method used to neutralize acids that can damage paper and provide a buffer to protect paper from the effects of acid from the outside. This research is related to the application of deacidification for archive paper at BBIB Singosari. BBIB Singosari is the Singosari Center for Artificial Insemination (BBIB) and is a technical implementation unit (UPT) of the Directorate General of Livestock and Animal Health. The purpose of this research is to apply the deacidification process at the BBIB Singosari Center and observe the physical factors which have an effect on preservation efforts. High acidity levels cause damage to archive paper, staining it yellow, and making it brittle. The deacidification process can change the condition of the paper to alkaline. In this experiment, the deacidification process is done by means of brushing and spraying techniques using calcium carbonate (CaCO3) and sodium carbonate (Na2CO3) solutions at 0.1% and 1%.

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This work has been conducted to investigate the effect of accelerated ageing on the filler-free (control) handsheets and the ones having Precipitated Calcium Carbonate (PCC) and Zeolite (Clinoptilolite) fillers. The diagnosis approach of this work has been based on the use of the techniques of attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray diffraction (XRD). The FT-IR technique has allowed identifying the changes in cellulose components of handsheets. Likewise, the XRD technique has provided to diagnose the changes in crystallinity of the handsheets and fillers. The results found out that PCC and Zeolite fillers could be easily added to the structure of the paper network by changing various experimental variables. The loss of C−O functional groups and the formation of carbonyl groups in handsheets has been analysed by accelerated ageing. The spectroscopy results confirmed that usage of zeolite filler has a retarding and structurally improving effect on the glycosidic linkages. Recent findings have been provided new insights into the role of the synergistic effect of the combination of PCC and zeolite fillers in the decelerating of certain ageing mechanism. [ABSTRACT FROM AUTHOR]

The focus of this research is the stabilisation of paper with Verdigris, a green copper pigment. Due to its corrosive effects on paper, many important documents, paintings and maps are in danger. The efficiency of several commercially available deacidification agents on paper samples with Verdigris was tested, including magnesium-based Bookkeeper® dispersion, nano calcium hydroxide containing Nanorestore® and CaLoSiL® dispersions as well as a recently developed dispersion of nano calcium carbonate. The antioxidant tetrabutylammonium bromide was tested either alone or in combination with nano calcium based deacidification agents. The effect of the treatments was evaluated using colour, tensile strength, degree of polymerization and pH measurements. The results indicate that acidic degradation does not play a major role during accelerated degradation of paper containing Verdigris with moderately acidic pH value and that oxidative decay could be the main culprit of the decay. The method described, which involves the use of antioxidant tetrabutylammonium bromide in combination with calcium carbonate based deacidification dispersion, was proved to have a superior effect against degradation of paper with Verdigris in comparison to the treatments which involve deacidification agents only. Nano calcium hydroxide based deacidification agents result in high pH values of the paper samples and therefore cannot be advised for use on paper documents. [ABSTRACT FROM AUTHOR]

Strongly degraded cellulosic artworks usually need deacidification and consolidation. Alkaline nanoparticles are known to be effective in neutralizing the acidity, while cellulose nanocrystals have the potential to be used as compatible and effective strengthening agents. We have grafted cellulose nanocrystals with oleic acid using a 1′1-carbonyldiimidazole-mediated procedure, to increase their dispersibility in organic solvents, and synthesized Ca(OH) 2 or CaCO 3 nanoparticles via a solvothermal process. Grafted nanocellulose and alkaline nanoparticles were used to prepare ethanol-based "hybrids". Prior to the application, the physico-chemical properties of nanocellulose dispersions and "hybrids" were studied by rheology and small-angle X-ray scattering. Cellulose nanocrystals were effectively grafted and stably dispersed in ethanol. It was shown that the use of ethanol as a dispersing medium, and the addition of alkaline nanoparticles act in a synergistic way, increasing the interactions between grafted cellulose nanocrystals, leading to the formation of clusters. These dispersions are thixotropic, a behavior particularly appealing to conservation purposes, since they can be applied in the liquid state, or, when a more confined application is required, they can be applied in a gel-like state. As a result of the application, an improvement in the mechanical properties of paper and an increase of pH were obtained. [ABSTRACT FROM AUTHOR]

A composite filler was developed by pre-flocculation of fiber fines and precipitated calcium carbonate (PCC) particles with flocculants such as cationic polyacrylamide (cPAM) and bentonite. The composite filler was compared with a conventional loading method in terms of physical properties of handsheet and filler retention. The handsheets using the composite filler showed higher strength properties than that using a conventional loading at a similar paper ash content level, implying that paper ash content can be increased maintaining same level of paper strength. Optical properties such as opacity and brightness of the paper with the composite were quite similar with the paper with the conventional loading. Filler retention of the composite filler was slightly higher than that of the conventional loading even though retention aids were not used for the composite filler. Paper formation of the composite filler was better than the case of the conventional loading. However, the sheet with the composite filler showed lower bulk than that with the conventional loading. Conclusively, the composite filler technology by pre-flocculation of fines and filler has a potential to be utilized to produce a high loaded paper. [ABSTRACT FROM AUTHOR]

Precipitated calcium carbonate (PCC) is a filler that is widely used for papermaking, and lime sludge is a special type of PCC recovered from the black liquor from kraft pulping. There has been some concern that lime sludge may interfere with the development of paper’s hydrophobicity in comparison with commercial PCC and ground calcium carbonate (GCC) due to the presence of impurities when alkyl ketene dimer (AKD) is used as the sizing additive. In this work, fillers with different particle size distributions were prepared, and the effects of particle composition on surface chemistry of fillers, adsorption for AKD, sizing degree of final paper sheets, and retention behavior of fillers were evaluated. The results showed that, through matching different particle size distributions for lime sludge fillers, the negative zeta potential decreased from -26.2 mV to -20.8 mV, the specific surface area decreased from 15.0 m2/g to 9.1 m2/g, and total pore volume decreased from 0.037 cm3/g to 0.026 cm3/g, which was favorable for the low adsorption for AKD. Consequently the sizing effect of filled paper was improved. Moreover, the retention rate also was increased by changing the particle size distribution of lime sludge.

The goal of this study was to analyze the effects of cellulose fibers loading by precipitation in-situ of calcium carbonate over the properties of printing paper obtained from mixtures of the softwood and hardwood fibers. The effects of fibers with in-situ loading were analyzed comparatively with conventional paper loading respectively, by adding precipitated calcium carbonate into fiber stock. The effectiveness of the methods was evaluated by various analyses and investigations: calcium carbonate content, Scanning electron microscope (SEM) images, X-ray diffraction, optical and mechanical properties of the paper sheets. The evaluation of the effects on paper properties led to the conclusion that, at the same filler content, the in-situ loading method gives higher opacity and brightness than conventional methods. The utilization of cellulose fibers with in-situ loading as additive, shown as a modification of the ratio between fibers with in-situ loading and fibers without loading, regardless of whether they are softwood or hardwood fibers, allowed us to optimize printing paper properties, especially regarding the relationship between optical and strength properties.

This article presents a novel method for integrating native corn starch and calcium carbonate (CaCO 3 ) into a hybrid pigment, which can be applied in papermaking to increase the amount of starch in paper and improve sheet bonding without impairing dewatering. Starch was first thermally treated to partially gelatinize and swell the granules. The aim of the treatment was to change the surface properties of starch and thus to improve the interaction with CaCO 3 particles. CaCO 3 shell was precipitated around the swollen granules and the encapsulated starch was then cooked to achieve complete gelatinization. When the granules were cooked, the starch became active for bonding, but its solubility was very limited due to the encapsulation. Particle size measurement and scanning electron microscopy were used to analyze the sample properties during the preparation. The hybrid pigment was added to paper sheets and its effect on the paper properties was examined. Starch was shown to be effectively bound to the pigment structure. The hybrid pigment allowed a large amount of native corn starch to be added to paper without interfering with the papermaking process. Furthermore, it gave excellent mechanical paper properties. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the feasibility of using highly filled powders with 100 parts per weight of calcium carbonate and 10 parts per weight of polymer, acting as binder, as electrostatically applied paper coatings. Such powders prepared by different methods were evaluated as being suitable for electrostatic coating. Powders compacted at elevated temperatures demonstrated cohesion superior to that of calcium carbonate, and at best similar to that of aqueous coatings. Cohesion, porosity and thus absorption properties of compacted powders were affected by the powder preparation method, compaction process, and powder composition. Powders containing semicrystalline polymer turned out to be the most interesting for further testing. [ABSTRACT FROM AUTHOR]

Abstract: The commercially available copy papers and pure papers have been adopted to synthesize carbon nanomaterials. It is found that carbon nanocoils (CNCs) are efficiently synthesized on the copy paper substrates using Fe2(SO4)3/SnCl2 catalyst by a thermal chemical vapor deposition method, while only carbon nanotubes (CNTs) are obtained on the pure paper substrate using the same process. It is evidenced that the particles of calcium carbonate existing in copy paper aggregate catalyst and adsorb more sulfur elements which promote the growth of CNCs. In addition, CNCs can successfully grow out from the pure paper by adding calcium carbonate. [Copyright &y& Elsevier]

The goal of this study was to analyze the effects of cellulose fibers loading by precipitation in-situ of calcium carbonate over the properties of printing paper obtained from mixtures of the softwood and hardwood fibers. The effects of fibers with in-situ loading were analyzed comparatively with conventional paper loading respectively, by adding precipitated calcium carbonate into fiber stock. The effectiveness of the methods was evaluated by various analyses and investigations: calcium carbonate content, Scanning electron microscope (SEM) images, X-ray diffraction, optical and mechanical properties of the paper sheets. The evaluation of the effects on paper properties led to the conclusion that, at the same filler content, the in-situ loading method gives higher opacity and brightness than conventional methods. The utilization of cellulose fibers with in-situ loading as additive, shown as a modification of the ratio between fibers with in-situ loading and fibers without loading, regardless of whether they are softwood or hardwood fibers, allowed us to optimize printing paper properties, especially regarding the relationship between optical and strength properties. [ABSTRACT FROM AUTHOR]

The paper has always been and it remains to be the primary information carrier though only 0.1% of the total information is recorded on this media. The paper production industry has a great impact on the environment which is mostly due to the use of raw materials (wood of conifers and deciduous trees), fillers (CaCO3), additional materials (dyes, glue, binders, retention aids), and chemicals (acids and bases). However, the greatest impact on the environment is caused by the extensive water consumption. To produce 1 ton of paper up to 60 m3 of fresh water are necessary. The water is not the only resource needed in the production cycle. Besides, the consumption of electrical energy (approximately 10,000 MJ/tpap), waste paper (paper represents 35 % of waste), and air pollution (paper production and transport) should be taken into consideration. In spite of the above mentioned environmental threats the paper still remains an important element of the everyday life and the use of modern information technology (personal computers, telefax, Internet) has increased its demand and consumption. It is important that the paper is produced from natural materials which are later released into environment without significant environmental consequences. The technology of paper recycling and re-use is widely known and a must of any responsible and professional social environment. Digitisation has increased the consumption of electrical energy as a consequence of production, use and reprocessing of different devices. Unlike a written record, a digital record has no permanent value and the electromagnetic field has a negative effect on the digital records. Digital records have to be constantly updated and adjusted to the computer software and hardware. A book and its content represent a treasure and an invaluable part of the cultural heritage. To use a book it is necessary to learn the alphabet whereas to read digital records we need to be computer and information literate. Negative effects of digitisation have affected the production of paper as the demand for graphic paper (newsprint, writing, printing paper) has decreased. The demand for raw materials, products and semi-manufactured products has decreased, too. Consequently, the level of investments in modernisation of equipment and in new production lines has been equally reduced. The proportion of employees directly or indirectly involved in the paper making and paper processing industry has been diminished. In the European Union paper and paper processing industry employ 1.9 million people in 200,000 enterprises representing 6.5 % of turnover in the production sector or 80 billion EUR or 16 billion EUR of the value added per year. The EU is expected to prevent the decline of paper and paper related industry (graphic, construction, logistic) which would endanger the production -- consumption cycle. After all, dismissals can ruin the social equilibrium. However, the paper production is faced with a difficult situation caused by digitisation. The competitiveness of the global market has an impact on the labour force costs, raw materials and energy products. Besides, production costs within the European Union are not competitive because of the EU Regulations and Directives which affect the price of raw materials, semi products and energy products. All these facts led to the decrease of workforce and the loss of market leading position and competitiveness. [ABSTRACT FROM AUTHOR]

The penetration of ink into paper affects the final appearance of printing and the amount of ink usage. In this work, UV-curing fluorescent rose ink was used to investigate the penetration and distribution of the ink pigments as well as their correlation with the surface topography of paper. The ink penetration and distribution were characterized with Confocal Laser Scanning Microscopy (CLSM), whereas the microstructure of the paper surface was observed using Atomic Force Microscopy (AFM). The AFM results showed that the surface of the paper coated with kaolin layer was the smoothest among the samples. Also the pore size of the calcium carbonate coating layer was smaller than that of the kaolin coating layer. Meanwhile, the pore size distribution of the calcium carbonate coating layer appeared to be relatively narrow, compared with other samples. The results of CLSM images indicated that the depth, size, and arrangement of pores affected the penetration depth and distribution of ink pigment on coated paper. The large pores led to deeper penetration of ink pigments, and uniform ink absorption occurred when the pore distribution was uniform. The UV-curing ink pigments not only set on the surface of the uncoated paper, but also they penetrated into the paper interior and adhered to the fiber surface. [ABSTRACT FROM AUTHOR]

Inorganic fillers are inexpensive materials used to increase the density, smoothness and other properties of paper that are important for printing. In the current study, the adhesion of pressure-sensitive adhesives (PSAs), a common type of adhesive used in labels and tapes, to papers containing varying amounts and types of fillers is investigated. Papers with three types of fillers, precipitated calcium carbonate (PCC), ground calcium carbonate (GCC) and kaolin clay, were investigated. The compositions of the papers were examined with SEM/EDX, while peel and double cantilever beam (DCB) tests were used to assess PSA-paper adhesion. The results indicate that fillers enhance the adhesion between PSA and paper. In the case of the peel tests, a combination of inter-fiber bond strength and PSA-paper adhesion determines the peel strength. While in the DCB tests, failure is isolated to the PSA-paper interface, thus allowing measurements of pure interfacial failure. [ABSTRACT FROM AUTHOR]

Abstract: Nanoscaled surface roughness with a hydrophobically modified surface has been widely used for preparation of superhydrophobic materials. However, the complicated procedure, high cost and harmful compounds used in most superhydrophobic surface modifications limited their applications. This research aims at fabricating superhydrophobic cellulosic or semi-superhydrophobic papers with low cost and nontoxic materials. Commercial PCC (precipitated calcium carbonate) particles, hydrophobic stearic acid and polymer latex particles were used for surface roughness control, surface hydrophobic modification agent, and polymer binder, respectively. A simple coating or dipping method was used to produce high contact angle and high water resistance papers. It was found that the surface pretreatment of PCC with fatty acid salt prior mixing with polymer binder plays important role for improving the water contact angle (WCA). The combination of surface coating with dipping treatment will further increase the water contact angle and water resistance of the paper. A WCA near 150° over modified paper surface has been achieved. At the same degree of water resistance, the total cost of the paper can be significantly reduced by our method. [Copyright &y& Elsevier]

The article presents an experimental research on the process to produce high-quality precipitated calcium carbonate (PCC) by the causticizing process in a kraft pulp mill. It states that the purpose of this study is that rotary lime-kiln operation could also be cut down or avoided, and the consumption of fuel oil and consequent discharge of carbon dioxide gas could be decreased. PCC, which is produced mainly by the carbonation process, has been used widely as a paper filler due to its brightness and opaqueness effects, and its low cost. Included also are the experimental procedures, schematics of the causticizing process, photographic views of the various shapes of causticizing calcium carbonate, and the derived results and discussions.

The article discusses the study on the effect of precipitated calcium carbonate (PCC) paper filler on water removal from pine, eucalyptus and birch kraft pulps in the vacuum filtration process. The study was done through the measurement of average specific filtration resistances (SFR). The PCC particles can improve dewatering efficiency by attaching to the fibers by electrostatic attraction and reducing total surface area. It has been found out that the deposition reduces the total surface area of the stock and increases the dewatering efficiency, thereby reducing the SFR the suspension. In addition, when the anionic charge of the fibers increases, the deposition of PCC particles increases and filtration resistance decreases.

The controlled combustion of paper is normally used to determine the filler content of paper. It can also be a valuable tool, to isolate the mineral particles for extra characterization or additional applications. However, the ashing temperature greatly affects the filler particles. The main goal of this study was to analyze the effects of paper calcinations on the intrinsic properties of precipitated calcium carbonate filler (PCC) at distinct temperatures, from 400°C up to 1000°C. We characterized the size, density, surface area, porosity, chemical composition, color, and electrostatic charge of the original PCC particles and the ash. The experimental results revealed that for a calcination temperature of 400°C, the size, specific surface area, and porosity of the ash are similar to those of the PCC filler before being incorporated in paper. Other important filler properties, such as color and electrical charge, are much different. To overcome this disadvantage, higher ashing temperatures need to be used. This study has demonstrated that 600°C is the optimum temperature for isolating the paper fillers, without the collapse of the PCC structure, so that their physical, chemical, optical, and electrical characteristics are adequately balanced and not too different from those of the original particles. Application: This study demonstrates the effects of thermal treatment on the structure of PCC particles and evaluates the potential of the ashing method to isolate these particles from filled papers. [ABSTRACT FROM AUTHOR]