Chitosan polysaccharide, chitosan oligosaccaride and monolaurin were used to impart the antimicrobial properties onto paper for food products. Staphylococcus aureus(ATCC 25923) was used as test microorganism and shake flask test was carried out in order to examine the antimicrobial activity of each sample. Chitosan oligosaccaride had the greatest antimicriobial effect among them and gave the reasonable result even at the concentration of 0.005%. Its antimicrobial power was enhanced when it is used with monolaurin together. Chitosan oligosaccharide improved the tensile strength of antimicrobial paper.

The study of biodegradable low-molecular-weight aliphatic polyesters as a plasticizer for cellulose acetate(CA), with a degree of substitution(DS) of 2.5, was conducted. A series of biodegradable low-molecular-weight aliphtic polyesters (MW=670 to 2900) consisting of dicarboxylic acids and diols was synthesized in this research. The plasticized CA's were prepared first by dry blending using a high-speed mixer, and then through melt compounding by a kneader. The molecular weight effect of low-molecular-weight aliphatic polyesters as a plasticizer was not evident on mechanical properties but on melt compounding. With regard to mechanical properties poly(ethylene succinate) wa a particularly suitable plasticizer for CA although other aliphatic polyester studied in this research were also miscible with CA. The biodegradation and GPC studies of plasticized CA's indicated that the weight loss of low-molecular-weight aliphatic polyesters was much faster than that of CA.

Condebelt drying provides opportunities not only of improving the strength properties and saving of drying energy but also of reducing the basis weight or increasing the utilization of recycled furnishes. In this paper general overview of the Condebelt press drying will be described and the effects of the process variables in Condebelt press drying including drying temperature, pressure, drying time and moisture content of the sheets on the paper properties is discussed. The experiment was performed with a static rig and Korean OCC was used as a principal raw material. Significant improvement in sheet density, compression strength, tensile strength, surface smoothness, etc. was obtained when Condebelt drying was applied. Control of pressure and inlet dryness was found to be very critical in improving sheet properties. Mill experiences from Dong Il Paper Mfg. Co., Ltd is briefly described.

The reinforcement of wheat straw pulp sheets with softwood kraft was studied, with special emphasis on the impact of softwood kraft beating and the proportion softwood kraft in straw pulp. the reinforcement was evaluated by measuring the tensile stiffness sand in-plane fracture behavior of samples. the results were compared with a mechanical pulp (TMP) and with a hardwood birch kraft, both reinforced with the same softwood kraft. Wheat straw pulp forms strong interfiber bonds. Therefore, its tensile stiffness and tensile strength are larger than TMP used. In-plane tear tests showed that a pure wheat straw pulp sheet has low fracture energy and correspondingly a narrow fracture process zone. The fracture energy of the reinforced straw sheets was found to increase linearly with the proportion of both unbeaten and beaten softwood pulps.

aluminum sulfate (alum) as a representative retention aid in papermaking processes was added to pulp suspensions, and the aluminum components adsorbed on the pulp were investigated quantitatively by two types of X-ray elementary analyses with regard to simultaneous changes of their surface charges. X-ray photoelectron spectroscopy (XPS) and X-ray fluorescence analysis (XFA) were applied to determine the aluminum components retained in pulp pads up to ca. 10 nm and 100${\mu}$m depth, respectively. In other words, XPS was utilized to analyze the outermost surface layers of the samples, and XFA was available for measurement of their extensive regions. A particle charge detector (PCD) was used to monitor streaming potentials at various pHs of the pulp mixtures under moderate sharing conditions. At pH 4.5 of pulp suspensions containing alum, surface charges of pulp fibers varied from negative to slight negative (approximately neutral) according to adsorption of aluminum components onto the pulp fibers. Subsequently, when a dilute NaOH solution in limited amounts was added to pulp mixtures, both streaming potentials and surface aluminum content of the pulp fibers increased distinctly although little total aluminum retention increased. Further addition of alkali solutions brought drastic decreases of the surface charges and surface aluminum content, while total aluminum content, on the contrary, increased gradually under neutral conditions. These results indicate that residual aluminum ions remained in pulp suspensions are predominantly adsorbed on surfaces of pulp fibers by adequate alkali additions and they must sufficiently cationize the fiber surfaces with increases of somewhat cationic aluminum complexes formed on the surfaces. On the other hand, aluminum components formed in higher pH ranges have nearly no contribution to improvement of charge properties of the pulp fiber surfaces, even though aluminum retention in pulp pads increases. XPS and XFA analyses combined with streaming potential measurement using a PCD suggest close relationships between aluminum content on the pulp fiber surfaces and their charge properties.

A new thermoporosimetry technique is described. The technique is based on the isothermal step melting of water in a porous sample. The pore size distribution (PSD) is calculated from the melting temperature depression of the imbibed water. It is shown that the pore volume and PSD of 4-300 nm nominal pore diameter porous glasses can be accurately measured with the step technique. The results indicate that pulp fibers are more complicated than porous glasses to measure with thermoporosimetry.

The distribution of anionic groups in the fibers, the fines, the colloidal fraction and the dissolved fraction, respectively, of thermomechanical pulp (TMP) suspensions was determined and peroxide bleaching of spruce TMP were also studied. Spruce TMP was extracted with hexane, treated with alkali, or bleached with peroxide. Suspensions made at pH 5.5 were fractionated into long fibres, large fines, small fines, a colloidal fraction and a dissolved fraction. The charge of the fractions was determined using polyelectrolyte titration. To determined the origin of the charges, the contents of fatty acids, resin acids and acidic units in hemicelluloses in the different fractions were determined by has chromatography. Extraction of TMP with hexane prior to fractionation increased the measured charge of the fibres. The removal of the wood resin probably uncovered some carboxyl groups on the fibre surfaces, or improved th e penetration of polybrene into the pores of the fibres. The charge of the fines and the colloidal fraction was lower when the wood resin had been removed. Alkaline treatment of the TMP increased the charge of the fibres and fines, mainly because of demethylation of pectins. Alkaline treatment increased the charge also of the dissolved fraction, because of the release the charge also of the dissolved fraction, because of the release of pectic acids into the water phase. Alkaline peroxide bleaching further increased the charge of fibres and the dissolved fraction, most likely because of lignin oxidation. The charge of the colloidal fraction, consisting mainly of wood resin, was only slightly affected by alkaline treatment and peroxide bleaching. The anionic groups in TMP suspensions were mainly free uronic acids in the hemicelluloses. The contribution from the fatty and resin acids was substantial only for the colloidal fraction.

Confocal laser Scanning Microscopy (CLSM) made it possible to investigate the inner structure of fiber walls and, using an optical sectioning technique, macro-separation in fiber walls. In particular, the optical sectioning technique was used to observe the sequence of the fiber wall delamination and the fiber wall breakage during refining. In combination with image analysis techniques, the most important thing done with the CLSM was to quantify internal fibrillation of beaten fibers. The quantification demonstrated the excellent relationships between paper properties and internal fibrillation. Furthermore, the quantification of fiber wall delamination confirmed that low intensity beating was not only a more efficient technique in deriving internal fibrillation than high intensity beating, but also the best strategy for retaining fiber length during refining. The CLSM enabled observations demonstrating that the thickness or diameter of fiber cross-sections was reduced with excessive refining, despite fiber wall swelling taking place. Measurement of fiber wall thickness after every recycling stage confirmed that hornification leading to deterioration of wet plasticity hindered fiber wall swelling.

Highly effective processes of photo-oxidation of lignocelluose materials affected by light with λ=253.7nm are found. The quantum yield of oxygen absorption ($\phi$02) and evolution of photodegradation gaseous products ($\phi$gas) exceed the unity considerably ($\phi$02=2.5-25). By comparison of $\phi$02 with the quantum yield of initiation, (∼10-3), it is concluded that chain oxidation reactions with a kinetic chain length of 104 - 105 units develop here. An effective evolution of gaseous products ( $\phi$gas 3-50), among them CO2, testifies that there takes place a deep photo-degradation of macromolecules with breaking of C-C bonds in the main polymer chain. The cellulose photo-oxidation under the natural sunlight occurs by the mechanism close to the hydroperoxide one: the length of the photo-oxidation kinetic chain reaches about 40 units.

Pulps from Pinus pinster were obtained using classical and modified kraft processes of pulping with the aim objective of establishing whether the extractives contribute in inducing the dark colour of the unbleached pulps from this specie. The methodology adopted here was based on carrying out two set of experiments. The first one consisted on cooking extractive-free wood chips whereas the second one was devoted to the pulping of wood in the presence of a surfactant. The colour of the pulps thus obtained were compared to that of the pulps prepared from initial wood cooked without any modification. In the first set of experiments, the wood chips were submitted to extraction wit different solvent sand acetone and toluene/ethanol appeared to be the most efficient, since the pulps obtained from wood previously extracted by this solvent showed that the brightness of pulps increased by more than 12% and the kappa number decreased by about 4 points. In second set of experiment, the wood chips were cooked in the presence of non-ionic surfactants from poly(ethlene), PEG, and poly(propylene) glycol, PPG, homopolymers and copolymers with molecular weights ranging from 400 to 10000. The most promising tensio-active compounds were PEG and a block copolymer PEG-PPG-PEG with molecular weight of 1000 and 1100, respectively. The optimal concentration of the surfactants was about 4%. The kappa number of these pulps lowered significantly, i.e. from 50 for the reference to 39 for the pulps obtained by kraft 50 cooking in the presence of 4% of PEG 1000.

The surfaces of sheets added with N-chloro-polyacrylamide (N-Cl-PAM) are analyzed using X-ray photoelectron spectroscopy (XPS) to clarify the chemical bonding involved in the paper strength development induced by N-Cl-PAM. The comparison of the observed N1s chemical shift of the sheet with those of the paper strength additives and the model compound, 1-butyryl-3-propyl urea, illustrated the presence of covalent bonds of alkyl acyl urea and urethane on the fiber surfaces. Thus the formation of the covalent bonds by N-Cl-PAM themselves and by N-Cl-PAM with cellulose and hemicellulose may be an explanation for much higher effectiveness of N-Cl-PAM on the improvement of wet strength of paper than A-PAM.

The major cause of paper deterioration is the acid-catalyzed hydrolysis of cellulose in paper fibers. The deacidification of paper reduces the rate of this deterioration, and It has been reported to extend the useful life of acidic paper by three to five times [1]. It has bee recognized the need for an effective method of deacidifying large quantities of books and documents. The review of the current state of deacidification technology has been published recently [5]. The paper points to the immediate need for a cost-effective and reliable method to save the millions of books that prish every year [5]. It was tried to deacidify by the gaseous ethanolamine for solving above the problems. Acidic paper was treated with the monoethanolamine, diethanolamine, triethanolamine. In result, it was found that the rate of deacidification was in the order of the monoethanolamine > diethanolamine > triethanolamine. But treated paper caused very little brigthness and fold endurance.

The chemical composition of crops from banana (Musaaccuminata Colla) was studied. Two types of material were investigated, namely: the whole material (type I) and the outer bark material (type II), which was apparently rich in cellulose fibres. These characterisation showed that the amount of holocellulose is high enough (∼70%) to envisage the pulping of this material, despite its surprisingly high content of ashes (∼14%). It is worth noting that, as expected, the type II material was found more rich in cellulose. Soda and Soda-Anthraquinone cooking processes were carried out using mini-digestors and the optimal pulping conditions were established. In fact, it was found that the maximum of yield is obtained when the following pulping conditions are respected: alcali 18%, time of the reaction: 1 hour to reach the isothermal regime and 30 min of pulping at 120$^{\circ}C$. The kappa number of these pulps was found around 30, which is very acceptable for unbleached pulps. The use of anthraquinone was found to increase the yield of pulps very slightly. The morphology of the fibers thus obtained was determined and showed that about 80% of fibres have a length between 1.4 and 1.9 ${\mu}$m. The width of these fibres was also determined and found in the range of 10-30 ${\mu}$m. Finally, hand sheet paper with two basis weight (60 and 135 g/㎡) were made from pulps using the optimal conditions of cooking (300 g OD of crops). The yield and the kappa number of this cooking were very close to those found in mini-digestor reactions. The unbeaten pulps had a relatively high Shopper degree (59$^{\circ}$SR) and the drainage was slow when the paper sheets were made. These papers showed good physical mechanical properties. The high basis weight was submitted to test which are specific to corrugated boards and showed very interesting values of RCT, CMT and FCT.

Coprinus cinereus 2249 that is a kind of basidiomycetes constitutively produced alkaline carboxymethyl cellulase (CMCase), filter paper cellulase (FPase) and xylanase. Crude enzymes prepared with optimal conditions showed higher FPase activity than CMCase activity. The FPase was most active at pH 9 at 50$^{\circ}C$. When applied on deinking of the old newsprint (ONP), it increases the freeness and brightness due to effect of hydrolysis at 0.1% enzyme concentration. Also, The physical properties of deinked pulp were improved.

Different papers such as toilet and towel tissue, newsprint and copy paper made from reclaimed fibres were characterized using UV-VIS reflectance and fluorescence spectroscopy. The emission properties of the extracts of the papers were also evaluated. Photochemical irradiation at ambient temperatures, and thermal aging of the copy papers at 105$^{\circ}C$ and 150$^{\circ}C$ were performed. Post-colour numbers (PC) were calculated from the reflectance values measured from the corresponding UV-VIS reflectance spectra. Light absorption coefficient spectra were calculated before and after irradiation, and the changes in absorption coefficient were related to the content of chromophores in the papers. Photochemical and thermal discolouration of the copy papers, similar to that of virgin fibres, was readily observed. The influence of changes in the concentrations of fluorescent brightening agents and dyes on the spectral properties was also assessed. Photostabilization studies of the copy papers were performed with the use of polymer additives polyethylene glycol (PEG) and polytetrahydrofuran (PTHF).

Is spent bleaching of unbleached kraft cellulose by Bratsk forest-industry complex under the traditional multistep scheme with use on hypochlorite stage as stabilizers of an yield of fibrous mass of the various additives of organic individual compounds. Is shown, that alternative many expensive compound scan be a product of updating wasted lignin by nitrous acid-nitrosolignin.

New express technique of the analysis paper compositions is offered. Based on one of lignin colour reactions - reaction of nitrosition by nitrous acid. The basic laws of the given reaction are investigated and optimum conditions of treatment of lignocellulosic materials by nitrous acid in vivo for realization of the analysis of various papers are developed. Is shown, that the offered technique does not concede on the accuracy to an earlier offered technique of the analysis with use barbituric acids.

With a view to seek the influence of hollow sphere pigments of latex upon the printed color on coated paper surface, the hollow sphere pigments were compared with filled ones in a variety of experimental approaches. Colloidal properties of latices were determined by measuring zeta potential and particle size distribution. For the amphoteric filled sphere pigment of latex, the polarity was reversed from the negative side to the positive side with decreasing pH. An extraordinarily high peak in the particle size distribution of the amphoteric filled evidenced aggregation between latex particles near the isoelectric point, depending on the electrolyte concentration and pH of the suspending medium. Coated papers containing the hollow sphere pigment in their coating improved optical properties like gloss and brightness. Optical parameters solely of the coating could account for this finding. An equation derived from the Kubelka-Munk equation calculated them fro twice measurements of reflectance of a coated paper over two substrates of different reflectances. This method permitted to predict brightness of coated paper of which coat weight would be different fro the actual one. The colorimetric parameters of solid-printed surfaces of the coated papers closely related to optical and structural properties of the coated papers. The color of the printed surfaces was dominated by the brightness and the smoothness of the coated papers. The hollow sphere pigments were proved to improve optical properties of coated paper and to control minutely colorimetric parameters of printed surfaces.

A kind of image analysis system is used to investigate the structural features of the traditional handmade papers made from Kenaf and Abutilon. The screen mark on the paper was identified and analyzed. The dusts, shives and fiber bundles were manifested and calculated. The relationship between basis weight of the traditional paper and mean gray level of the image was discussed in detail. Some methods to express the formation of traditional handmade paper were studied.

Zeolite has been widely applied to practical processes in various industrial fields as a desiccant, an adsorbent, a molecular sieve, an ion exchanger, a catalyst and so on. It has been generally used in the form of beads or pellets. However, these ways of utilization have some fatal disadvantages such as powdering of zeolite itself by rubbing each other and remarkable pressure losses in reaction tower with increasing speed of gas. At first, therefore, the optimum conditions for the preparation of zeolite composite sheets were investigated by the use of paper making technique intending the manufacture of their honeycomb structures. Zeolite sheets, which consisted of 10% pulp, about 30% ceramic fiber and 60% zeolite were easily prepared. The sheets were ignited up at $700^{\circ}C$ to remove pulps, but they were fragile and brittle. For improvement of the zeolite sheet strength, the alumina sol was used as the binders. Although considerably high retention of sol was achieved by the internal addition method with polymer retention aids, the improvement of sheet strength was not satisfactory. In this case, the alumina sol added seemed to be located mainly on the outermost surfaces of sheet because the retention of alumina sol occurred by the filtration effects. On the other hand, soaking treatment of zeolite sheets in the alumina sol increased the sheet strength remarkably. These results indicated that the alumina sol was distributed in the whole sheets and formed the tight network structure between particles. These procedures are expected to prepare useful zeolite products, which have the possibility of new various uses.

Hanji is a traditional Korean handmade paper, which has been known in ancient Far East as excellent quality calligraphic paper for more than 1,500 year. Hanji is mostly made of Korean paper mulberry bast fibers, and if properly processed, normally lasts for more than 1,000 years with significant strength and still recognizable calligraphic writings or drawings on it. We measured the viscosity of the dissolved celluloses of the paper mulberry bast fibers of different levels of artificial aging to know the cellulose molecular weight changes. Cellulose dissolution was made by CED method. The viscosities of the Hanjis that experienced the artificial aging were compared to those of the Hanjis that were made hundreds years ago. We could interpolate the viscosities of the time-aged Hanjis in the our artificial aging curve. Dochim is a special way of Hanji calendering, but is turned out to be quite different from modern calendering (machine calendering) in several aspects. Compared to the modern calendering, Dochim increased paper gloss much more, but paper smoothness much less. In Dochim process, mechanical impact were applied vertically to the surface of papers. By the process, densification occurred and the degree of densification was very much dependent upon fiber sources.

Sizing development and retention mechanism in rosin soap size-alum systems were studied. Rosin size and aluminum contents in handsheets, which were prepared under various conditions, were determined by X-ray fluorescence analysis ad pyrolysis-gas chromatography, respectively. 13C-labeled palmitic acid potassium salt was used as a model of rosin soap size, and chemical structures of size components in handsheets were analyzed by soild-state 13C-NMR. The relationship among sizing degree, size retention and aluminum content in handsheets were obtained in terms of various handsheet-making conditions. Especially, most aluminum compound originating from alum added to pulp suspensions are immediately adsorbed on pulp fibers and form cationic sites. Anionic rosin size components are then adsorbed on the cationic sites. When the 13C-labled palmitic acid soap size was used in handsheet-making, calcium palmitate was present as a major component in the handsheets. Molecules of free palmitic acid and aluminum palmitate were present as minor components. Formation of aluminum palmitate must be significant for size retention at the wet-end. However, it is not plausible that only aluminum palmitate molecules present in the handsheets as a quite minor component govern overall sizing performance. Molecules of calcium palmitate and free palmitic acid as well as aluminum palmitate probably behave as hydrophobic compounds in the handsheets, and contribute to sizing performance.

It has been proven in previous work that rosin sizing agents are distributed relatively homogeneously on the outer surface of paper. Therefore, rosin sizing agents on paper surfaces can be characterized by macro domain measurement techniques with very thin layer from the surface. In this work, the role of rosin sizing agents on paper surface was investigated by comparing wettability from contact angle measurement with the chemical state of the outermost surface by the ESCA. Furthermore, the role of rosin on the surface of paper was discussed by the quantity of hydroxyl groups obtained from chemical modification with the TFAA-ESCA technique. It was found from the ESCA data that the fixing mechanism with soap-type rosin sizing is different from that with emulsion-type rosin sizing.

Presence of small amount of old newspapers printed with waterbased flexographic inks leads to a significant loss of brightness of the deinked pulp by flotation process. Recently there has been an increased interests in employing neutral deinking processes to solve the problems associated with waterbased flexo ink. A comparative experimental study was performed to evaluate the efficiency of neutral deinking and conventional alkaline deinking for ONP furnishes contaminated with flexo ink. Effects of the deinking processes on pulp quality and white water characteristics were examined. It was shown that neutral deinking would provide significant improvement in brightness, yield, and freeness as compared with conventional alkaline deinking. Three was no increase change in brightness when OMG was added in the furnish up to 20%, and it was attributed to the redeposition of flexo inks on chemical pulp fibers.

The handsheets were prepared from softwood bleached sulfate pulp added with a soap-type rosin sizing agent. The rosin sizing agents on the surface of the handsheets were chemically modified with OsO4 vapor. The rosin existing in the surfaced layer of the depth of 10nm and 1nm were characterized by using ESCA and TOF-SIMS, respectively. The results show that the rosin sizing agents in the very thin surface layer were well characterized by Os4f peak intensities in ESCA. Os4f peak intensities increased with the increase in the added amount of rosin. However, the secondary negative ion intensity were not properly characterized in TOF-SIMS, because the secondary OsOx ions intensity had a minimum with the increase in the added amount of rosin. The positive ion intensity originated from the other site than Os atom showed a proper characterization.

Activated carbon is a porous material made by activation of carbon materials, such as coal, by steam or carbon dioxide gas to form numerous micropores on the surface which gives the material high adsorption characteristics and it is widely used as a purifier for water and air. In this research, to develop a new use for waste paper, activated carbon was prepared from waste newspaper and its adsorption characteristics were measured. As a result, activated carbon with an iodine adsorption capacity of 810 mg/g, a methylene blue adsorption capacity of 220 mg/g and a specific surface area of 1000㎡/g was obtained. These adsorption capacities were almost the same as ordinary activated carbon on the market.

This study examined the effects of multiple recycling on deinkability and properties of recycled paper from laser computer printout (LCPO). First, alkaline paper with a 20% printed area was disintegrated by TAPPI standard disintegrator at room temperature. After dewatering, the pulp was flotated and dried in oven at80$^{\circ}C$ for 24 hrs. A sequence of wetting, disintegrating, flotating and drying was one recycling cycle and this cyclic treatment was repeated from zero to five times. The recycled handsheet dropped to 90% of the original brightness after five cycles, and lost the most brightness after five cycles, and lost the most brightness in the first two cycles. However, it had a gain of 10% in opacity after five cycles as the same as the case of nonprinting. And, in this study, the method for determining residual ink(toner) content in recycled handsheets ere established by means of SEM-EDX and Py-GC. The change of residual ink percentage on recycled paper showed the effect of recycling numbers on deinkability of waste paper. A slight decrease in deinkability was noted for the recycled handsheets, which may be due to the change of fiber surface free energy connected with fiber swelling.

A method for the determination of alkenyl succinic anhydride (ASA) in pulp, paper and water samples is presented. The method, based on gas chromatography (GC), enables the determination of ASA in its different forms, that is fiber-bound ASA and unbound ASA. The latter normally comprises metal soaps of alkenyl succinic acid. In order to distinguish between bound and unbound ASA, the unbound ASA must first be extracted from the sample. In this study, were have shown that unbound ASA can be efficiently extracted from paper either with acidic acetone or acetone in the presence of KH2OP. Acetone alone is not the proper solvent, since unbound ASA in paper often occurs as Ca-soaps which are not very soluble in acetone. For GC analysis, derivatization of the extracted components is necessary. Regarding determination of bound ASA, acid methanolysis on one hand, and alkaline hydrolysis followed by methylation with diazomethane on the other, gave similar recoveries of bound ASA. The different derivatization methods evaluated here, namely silylation, methylation with diazomethane, and methylation during acid methanolysis, all resulted in similar amounts of detected ASA. Resin acids may severely interfere with the quantification of ASA due to overlapping in GC analysis. This is especially true for wood-containing or rosin-sized paper grades, where resin acids are abundant. For reliable quantification, GC-MS used in selected-ion-monitoring (SIM) mode is recommended.

The objective of this study is to assess the possibility of ozone as an environmentally friendly new deinking alternative for conventional deinking method. Ozonization could removed the ink particles above 300 microns and improved the ink removal efficiency. Ozonization also improved the WRV of recycled fiber and apparent density, scott bond strength, breaking length, double fold and tear index. Thus, we believe that ozonization could be used as a deinking means of white ledger instead of conventional deinking method.

In order to improve the optical properties of high yield pulp, bleached chemi-thermo-mechanical pulp (BCTMP) was produced from CTMP of Betula maximowicziana Regel by two staged ozone-hydrogen peroxide bleaching. This pulp was used for the evaluation of the improvement of optical properties, chemical characteristics of lignin in fiber, and the relationship between lignin and optical properties in fiber cell wall. By hydrogen peroxide treatment, the brightness was improved, but the post color number (PC No.) was not. There was little improvement on optical properties by ozone treatment, but his could be solved by using two staged ozone-hydrogen peroxide bleaching. The hydrogen peroxide treatment did not make nay change on chemical characteristics of lignin in cell wall, but by ozone treatment, it was found that the non-aromatic conjugated structure was existed in the surface of cell wall, but this could be removed by hydrogen peroxide treatment in two staged ozone-hydrogen peroxide treatment. Therefore, the optical properties was significantly improved due to the removal of non-aromatic conjugated structure.

To investigate the influence of the design and operating parameters of the headbox on hydrodynamics, a pilot headbox system and pressure monitoring apparatus were constructed. The pilot headbox system consisted of a circulating water reservoir, centrifugal pump, distributor, step diffusor and slice. The distributor was designed to function as a pressure attenuator. Flow rate to the headbox and MD and CD velocity profiles in the slice zone were monitored using an ultrasonic flowmeter and Pitot tubes, respectively. As the distance from the step diffusor increased, evener CD velocity profile was observed. Wall effect increased with the increase of the velocity. Flow stability in the headbox was evaluated by injecting a dye at the outlet of the distributor. Application of theoretical analysis based on CFD in designing headboxes is briefly discussed.

Amphoteric polymers have brought to papermakers' attention gradually. In this paper, a series of amphoteric starches with different cationic and anionic degree of substitution (DS) are prepared. Better product has been selected and used under different condition. As retention and drainage aids, amphoteric starches were used in shorter fiber length, weak strength and poor drainage bleached AQ-Soda wheat straw pulp. In neutral and alkaline papermaking system, when amphoteric starches contain 0.024-0.026 anionic degree of substitution (DS), it is shown that the higher the cationic degree of substitution (DS) in amphoteric starches, the better the filler retention. The filler retention is improved 12.5%, 30.3%, and 35.1% and 32.5% respectively by adding 1% amphoteric starch LS-L2 -1 (0.034), LS-L2-2 (0.040), LS-L2-3 (0.047) and LS-L2-4 (0.052). But the strength of handsheets if affected a little. By adding 2% Al2 (SO4)3 and 1.5% LS-L2-3 at pH 7.5, filler retention can be improved from 38% to 80%, and breaking length of sheet only decreases 3.2%. As dry strengthening aids, amphoteric starches were used in eucalyptus APMP. Amphoteric starches are used in eucalyptus APMP. The amphoteric starch LS-L2-2 is better dry strength aid. Adding 1% LS-L2-2 can improve breaking length 24.5%, burst index 42.9%, tear index 38.8%, folding endurance and density of the handsheets.

In this paper, a series of PAC (polyaluminum chloride) samples were prepared for rosin neutral sizing system. Some characters of PAC were discussed in detail. The experimental results show that it is possible to achieve neutral sizing when PAC is compounded with DRS (dispersed rosin size) instead of alum (aluminum sulfate).

The relation between the paper formation analyzer by image process system and smoothness, compressibility uniform of ink absorption is studied. There results indicate that the paper with bad formation has higher apparent bulk than the paper with good formation. The bad formation of paper results in the nonuniform calendering and decrease of the compressibility. The bad formation of paper also results in deformation and omission of printing dots, which affects the reproduction of the printing images.

In the present work, cationic polymer microparticles (CPM) and cationic inorganic microparticles (colloidal alumina) have been used as mineral filler flocculants or retention aids in conjunction with anionic polymers. The CPM with well-defined structures was prepared via copolymerisation of styrene with three types of cationic monomer prepared in emulsifier-free emulsion polymerisation. Dynamic flocculation experiments showed that the performance of CPM depends on the particle size and the charge density of CPM. By contrast, the cationic inorganic microparticles appear to be less sensitive to the particle size and the charge density. A strong synergetic effect between CPM and anionic polyacrylamide with low charge density was observed. This significantly reduced for effective filler retention or flocculation.