Linter Pulp Research Articles

Mechanochemistry of Syringylglycerol-β-Guaiacyl Ether and Its Similarity to the Conventional Bleaching of Mechanical Pulps

Abstract Syringylalcohol (1), α-methyl syringylalcohol (2), 3, 4, 5-trime-thoxyphenyl methylcarbinol (3) were dispersed onto filter paper pulp or linter pulp, and treated, respectively, with a ceramic ball mill (CBM) or a vibration ball mill (VBM-1 or -2) under air for 1h. Mechanical treatment of VBM-2, having the more rigid surface of linter pulp, furnished the p-carbonylphenols (5), (6), and 3, 5-dimethoxy-p-benzoquinone (7). Mechanical treatments of syringylgl-ycerol-β-guaiacyl ether (4) with CBM, VBM, and a laboratory refiner provided α-(2-methoxyphenoxy)-β-hydroxypropiosyringone (8) in the highest yield and a less yield of p-quinone derivative (7) and others as shown in TABLE 2 and FIGURE 3. When treated the resultant mixture with alkaline H202, the chromophore (III) can be decomposed, but remarkable amounts of the leucochromophre (IV) are produced as shown in FIGURE 4.

Kinetics of heterogeneous cyanoethylation of cellulose

AbstractHeterogeneous sodium and potassium hydroxide‐catalysed cyanoethylation of cotton linter and viscose grade wood pulp, investigated by analysing the nitrogen content of the cyanoethylated product as a function of the time of reaction, were shown to follow a first‐order rate equation. A new procedure was elaborated and a computer program was written to estimate the number of hydroxyl groups accessible for cyanoethylation per anhydroglucose unit and the specific rate constant from the rate curves. The effect of the type of alkali, its solution‐to‐cellulose ratio, temperature of reaction, mode of agitation, and the degree of polymerisation and packing density of cellulose fibres on the kinetics of cyanoethylation reaction were investigated.

Behaviours of formaldehyde emitted from lignin to the field of mechanochemical reactions.

Treatment of both formaldehyde and creosol dispersed in linter pulp by either CBM and VBM furnished three condensation products I_??_III. Addition of creosol to pine chips, “rough pulps” (Asplund pulps), and the mill-made “1R-pulps” (TMP), followed by the treatment with laboratory refiner also afforded products I_??_III. Effect of pH of 4.0, 7.0, and 10.0 on the yields of condensation products I_??_III was also examined for “rough pulps” and “1R-pulps” by refiner treatment. The higher the pH value, the yields of reaction products I and II increased.

紙の伸縮安定性に及ぼす繊維間空げきの影響

Handsheets with different densities were prepared by TAPPI Standards, and expansivity and swelling stress of these sheets were measured. The effect of Interfiber space on the dimensional stability of papers was discussed. The results obtained are summarized below.1. Papers made from unbeaten or slightly beaten pulps containing a small amount of residual hemicellulose, such as linter pulp and alkali extracted LBKP, were rather poor in dimensional stability as compared with chemical pulps of paper making grade, but they did not increase in dimensional instability even when they were made from highly beaten pulps.2. On the contrary, papers made from chemical pulps of paper making grade greatly in-creased in dimensional instability with excessive beating of the pulp. Paper made from ground-wood pulp which contained a large amount of short fiber was also poor in dimensional stability.3. These pulps were roughly categorized into three groups according to their adsorptivities : linter pulp group, paper grade chemical pulp group and groundwood pulp group. Absorptivity depends on the chemical component of the pulps.4. For low density boards, moist-expansivity of the boards made from high C. S. freeness pulps as measured by thickness was larger than boards having the same density from low C. S. freeness pulps. But for high density boards, there were no appreciable differences in moist-expansivity among boards made from pulps of several degrees of C. S. freeness.5. A similar tendency was found in acid hydrolysis of pulps. That is, moist-expansivity of boards from unhydrolyzed pulp was larger than boards from acid hydrolyzed pulps for low density, but there were no appreciable differences in moist-expansivity among boards from these pulps for high density.6. The moist-expansivity of paper of low density was largely affected by the kind of pulp, but there was no significant difference at high densities.7. Swelling stresses due to absorbing water greatly correlated with the density of the boards and could be calculated by the following formula; y=a·xb (x : density of board, y : swelling stress) Swelling stresses of several pulps were in the following order.hardwood BKP > linter pulp, softwood BKP > softwood GP > softwood BSP8. Swelling stress of pulp was guessed to be higher than 1.5 ton/g, pulp in the case of density of 1.5, so it was very difficult to make the paper free from moist- or wet-expansion. In conclusion, it is most effective to increase interfiber space in the paper in order to make paper having high dimensional stability.

PROPERTIES OF LINTER OXYGEN-ALKALI PULP

Crude second linter and hull linter (cf. Table 1) were purified by the oxygen•alkali method and the ordinary soda method (cf. Table 2).The linter oxygen•alkali pulp (OAP) was higher in yield, lower in Kappa no., and much higher in brightness than the linter soda pulp (AP). The polymerization degree of OAP was also somewhat higher than that of AP. COD of waste liquor of OAP was less than that of AP (cf. Table 3).Bleaching of OAP was much easier than that of AP (cf. Fig. 1 and Table 4). PC no. of the bleached OAP (BOAP) was less than that of the bleached AP (BAP) (cf. Table 5). For both BOAP and BAP, d-cellulose content was over 99% and copper no. was below 0.3 (cf. Table 5).IR absorption spectrum of unbleached OAP (UOAP) was similar to that of unbleached AP (UAP) and also to that of BOAP and BAP (cf. Fig. 2). The lateral order distribution curves showed that AP seemed to have somewhat larger fraction of high-ordered portion than OAP (cf. Fig. 3). X-ray diffractogram of OAP was similar to that of AP. However, the peak intensities in the diffractograms of BOAP and BAP were somewhat lower than those in the diffractogram of UOAP and UAP, respectively, indicating that the crystalline degree of UOAP and UAP was slightly decreased by the bleaching process (cf. Fig. 4 and 5). Specific surface area determined by the N2-adsorption method was 73.7m2/g for second UOAP and 73.1m2 /g for second UAP (Table 6). The polymerization degree distribution of BOAP was wider than that of BAP (Fig. 6 and 7). Scanning electron micrographs of the linter pulps (cf. Fig. 8_??_10) showed that there are no marked difference in morphological properties between OAP and AP.These results revealed that oxygen-alkali pulping is superior to the ordinary soda pulping in view of economical and environmental point.

Cold alkali refining of cellulosic pulps derived from Egyptian cotton and bagasse

A cotton linter pulp, a bagasse dissolving pulp and a bagasse paper pulp were subjected to cold sodium hydroxide refining and the resulting changes in their chemical, physical and submicroscopic characteristics were investigated. In the case of cotton linters the main change took place in the physical and submicroscopic properties and the refining resulted in better reactivity towards xanthation. The α-cellulose content of the paper and viscose pulps increased with alkali concentration until it reached a constant value which depends on the type of pulp and the concentration of alkali. The refining of the paper and viscose pulps impaired their reactivity towards xanthation. The presence of the more hydrophilic hemicellulose increased the swelling ability of the fibres and made them more reactive towards xanthation. The undesirable effects of drying after refining with high alkali concentration could be overcome if the DP is sufficiently lowered. In this case the resulting shorter chain macromolecules dissolve more readily during xanthation.

過酢酸気相標白したＢＳＰの強度特性について

In order to elucidate the mechanical properties of bleached sulfite pulp, NUSP and LUSP were bleached with peracetic acid (PA) in vapor phase under the following conditions : Chemicals addition on pulp, 10 to 32% ; DAISERU stabilizer addition on pulp, 0.018% ; pulp consistency, 33% ; temperature, 90°C ; pH 4 ; bleaching time, 60 min for NUSP and 30 min for LUSP. Viscosity of BSP thus obtained was 4 to 16 cp, and the brightness was 86 to 94% GE. Comparison between the sheet strengths and pentosan content or viscosity of BSP prepared under above conditions was also carried out. The results are summarized as follows : 1. NUSP and LUSP were more easily bleached than NUKP or LUK1 by PA-bleaching in vapor phase. Brightness of both SP, bleached with PA in vapor phase, was 5 to 8% GE higher than that of multistage-bleached SP at the equal pulp viscosity. 2. The decrease in tensile strengh, burst factor, tear factor and folding end. of linter pulp during PA- or multistage-bleaching was attributed to decrease viscosity of the pulp in a cupri ethylenediamine solution. On the other hand, sheet strengths of PA- or multistage-beached NSP and LSP at the equal freeness increased proportionally with increasing pentosan content in the bleached pulps, except folding end. of multistage-bleached NSP sheet. 3. The ellution pattern of gel filtration of hemicellulose, isolated from NSP with 5% KOH solution, was found to unchange hardly during multistage- or PA-bleaching in vapor phase. Whereas hemicellulose in LSP was partially degraded to lower molecular part during both bleaching. The lower molecular content of hemicellose in the PA-bleached LSP was more than that in the multistage-bleached pulp. 4. Tensile strength and burst factor of PA- or multistage-bleached pulp increased proportionally with increasing sheet density of each bleached pulp at the equal f reeness. The sheet strengths of PA- or multistage bleached KP were stronger than that of BSP at the equal sheet density. From the facts described above, it is assumed that the decrease of DP of polysaccharides in BSP is reduced the sheet strengths of the BP, and also, that the strengths are greater affected by the amounts of pentosan and lower molecular part of hemicellulose in the pulps.

Thermogravimetric analysis of pulps

A differential and an integral method of kinetic analysis of the data from isothermal pyrolysis of two pulps have shown that a cotton linters pulp has a lower activation energy throughout the entire reaction than has a bleached pine kraft pulp. In all cases, the activation energy decreases with increasing conversion. The mean values obtained were 30 and 36 kcal/mole by the differential and integral methods, respectively, for pyrolysis of the cotton linters pulp and 42 and 45 kcal/mole, respectively, for pyrolysis of the bleached pine kraft pulp. Neither method of analysis used in this work requires prior determination or empirical statement of the reaction order n. This is essential to a proper analysis since it has been shown that the reaction order cannot be regarded as a constant if the complete pyrolysis reaction is studied.

GRAFT COPOLYMERIZATION OF ACRYLAMIDE ONTO MICROCRYSTALLINE CELLULOSE

Graft copolymerization of acrylamide onto microcrystalline cellulose “Avicel” was carried out using ceric salt as an initiator. It was found that the total conversion and the grafting ratio increase with increasing concentration of acrylamide, but they decrease with the increase in ceric salt concentration.The rates of both the total conversion and the grafting ratio decreased with the reaction time. The rate of consumption of ceric ion in the reaction with “Avicel” was much faster than with linter pulp and α-methyl-D-glucoside. It is supposed to be attributed to the fact that its molecular weight is low and it contains more end groups. It was also supposed that the graft copolymerization is initiated preferentially at the reducing end groups rather than hydroxyl groups in cellulose. Remarkable difference in reactivity was observed irrespective of the grain size of the sample cellulose. Namely, the reactivity was independent of the apparent surface area of the cellulose grain. Therfore, it was concluded that the reaction occurs in the inside of the cellulose grains, but the results of X-ray diffraction measurement indicated that the graft copolymerization does not occur in the crystalline region of cellulose.

STUDIES ON THE BAMBOO DISSOLVING PULP

Using the X-ray diffractometer, crystallinity index (Cr. I.) was measured on the bomboo dissolving pulp as well as linter and wood pulps. Crystallinity index, proposed by L. Segal, changed a little according to the extent of prehydorlysis and sulfate cooking, however, Cr. I. of the bamboo pulp was nearly exual to those of wood pulps.The bamboo pulp was treated with 8-18% NaOH solutions in the same way as with linter and wood pulps and regenerated with acetic acid solution. The degree of mercerization of the samples was determined quantitatively by the X-ray diffractometer using standard mixture samples of linter and its mercerized pulp. The bamboo pulp does not mercerize so easily as wood pulps, though not so hard as with linter pulp. Mercerization is retarped with temperature. This was observed on the bamboo and wood pulp, when these pulps were treated with 14% NaOH solution.The difference of behavior at mercerization between the bamboo and wood pulps with nearly equal degree of crystalligation was supposedly due to in the fine structure, especially in the lateral order.The charactaristic behavior of bamboo in mercerization should be considered our practical preparation of alkali-cellulose for viscose.

CHEMICAL BEHAVIOR OF HIGH POLYMERS IN LIQUID SULFUR DIOXIDE

Throughout the study of chemical behavior of high polymers in liquid sulfur dioxide, it has been found that natural cellulose is soluble in liquid sulfur dioxide with addition of amines. Amines which exert a dissolving effect upon the cellulose are secondary or tertiary alkyl amines, such as diethylamine and triethylamine. In present work, diethylamine was employed as dissolving agent. The cellulose fiber such as ramie (_??_p 2, 000), linter pulp (_??_p 670) and commercial grade dissolving pulp can be dissolved rapidly at ordinary temperature in sealed reaction vessel.It is an interesting fact that there is stoichiometric relation between the amount of dissolved cellulose and amine used. The cellulose fiber can be dissolved completely with addition of 3moles of amine for each glucose unit without any decomposition or depolymerization of cellulose molecule. In other words, an equivalent amount of amine for each free hydroxyl group is enough to dissolve the cellulose completely.The obtained dope consists of cellulose-amine-SO2 and it is colored orange yellow and quite clear viscous solution. Left standing for a few days in sealed tube, no change in the above solution has been found.Cellulose disolved in liquid sulfur dioxide is easily regenerated by treatment of water or alcohols into the form of filament or film. When the solution is allowed to stand in atmosphere, sulfur dioxide gas is evaporated rapidly leaving the mixture of cellulose and amine-SO2 adduct.The cellulose is regenerated perfectly from the mixture by further treatment with water or alcohols.The mechanism of the above phenomena has not been confirmed. But a hypothesis may be assumed from following standpoints.It has been mentioned already that the dope consisted of cellulose-amine-SO2 is remarkably unstable in neutral solvents such as water or alcohols and even in atmosphere. Therefore, there is no evidence of formation of stable complex molecule between cellulose and amine or sulfur dioxide.Meanwhile, according to literatures, the characteristics of reactions in such solvent has been pointed out by many workers. From many aspects of experimental behavior such as the ability to change the color of indicator or conductivity relationships or the change of color of amine-SO2 adduct from yellow to colorless with addition of acids, these workers have emphasized the acidbase reaction theory in such solvent system.The color of amine-SO2 adducts disappeares with addition of excess cellulose.From these standpoints, the reaction scheme may be assumed as follow.R3N+SO2→R3N•SO2 (yellow)R3N•SO2+Cell-OH→R3NH++Cell-O-+SO2 (colorless)Furthermore, the molecule of sulfur dioxide may be shown as a resonance hybrid of following structures.It is not surprising that sulfur dioxide act as a splitter on cellulose fiber. The sulfur dioxide molecule may be absorbed strongly to the ionized macro-molecule of cellulose. The macro-structure of cellulose fiber may be degraded by “splitting effect” of sulfur dioxide and the splitted cellulose molecule disperses then in the solution.The formation of complex of cellulose, amine and sulfur dioxide has not yet been confirmed.

Effects of Non.bonded Area and Hemicelluloses on the Brightness of Pulp and Paper

Bleached sulfite, bisulfite and sulfate paper pulps and linter pulp were beaten by Lampen mill or TAPPI standard test beater, and their brightness drops were compared.Sulfite pulp decreases generally greater than sulfate pulp in brightness as freeness decreases by beating, and the brightness drop increases also with the hemicellulose content in the same kind of pulp (Table 1 and 2, and Fig. 1, 3 A and 4 A). This reason is due to that the pulp, which is rich in hydrophilic hemicellulose and higher in swellability, increases greater in fiber-to-fiber bonded area, namely decreases in non-bonded area, in the dried pulp sheet beaten at the same freeness, and consequently decreases the proportion of the light reflected out of the sheet.However, the brightness decreases similarly as the water retention value of the wet pulp increases and the specific scattering coefficient of dried pulp sheet decreases by beating, irrespective of the kind of pulp and the hemicellulose content (Fig. 2, 3 B and 4 B) Same tendency is observed too, when the pressure to wet pulp sheet is changed (Fig. 5).That the bleached paper grade pulps, especially high yield pulps, are generally inferior to the dissolving pulps in brightness of unbeaten pulp sheet, is mostly attributed to the richer bonded area (poorer non-bonded area) of dried sheet owing to the higher content of hydrophilic hemicellulose (Table 1, 2 and Fig. 6).It seems that the brightness is affected also with the difference of morphological fiber structure owing, to the wood species.

EMULSION XANTHATION OF PULP

In the previous paper, it was found that the marcerization-resistance curve (M-W curve) obtained by varying concentrations of sodium hydroxide solution in emulsion xanthation is influenced by socalled lateral order distribution of pulp.According to O. Samuelson et a12)., “the reason why the pulp viscosity can be used as a criterion of filterbility of a viscose prepared from the pulp is that the decrease in viscosity in a given, process, e. g. the ordinary sulfite cooking, is parallel to the attack upon the fiber structure.” They added also that “experiments on emulsion xanthation can be used as a complement and be of considerable value for the comparison of similar types of the biological structure of which has been, attacked to a different degree.”It seems to be very important for estimating the value of M-W curve as an indication of reactivity of pulp, how the opinion mentioned above can be adapted in the comparison of different types, of pulps prepared from different raw materials or by different processes.In order to obtain the relation between M-W curve and average degree of polymerization of cellulose, dissolving sulfite pulp (DSP), dissolving sulfate pulp (DKP), linters pulp (Li. P) and mercerized DSP were degradated by various treatments to various degrees, and M-W curves of these samples were determined in this paper.The results obtained are as follow:The solubility of pulp in emulsion xanthation increases as average degree of polymerization of cellulose is lowered. Influence of the differences of lateral order found amoung DSP, DKP and Li. P upon the solubility in emulsion xanthation do not diminish, though each pulp has been hydrolyzed with dilute sulfuric acid solution and cellulose has been degradated as low as 300 of average degree of polymerization of cellulose. The fact shows the influence of fine structure of cellulose on M-W curve is very significant. Then M-W curves of DKP treated with dilute sulfuric acid solution, dilute ligninsulfonic acid solution or ultra violet ray, and of DSP hydrolyzed with dilute sulfuric acid solution after mercerization or aged in air after mercerization were determined. It was found also that the properties of fine structure of cellulose has more effect on M-W curve than average degree of polymerization of cellulose. For the similar type pulps degradated with similar type treatments, the solubility in emulsion xanthation is parallel to average degree of polymerization of cellulose, but for the different types of pulp, M-W curves are governed mainly by the fine structure of cellulose. This means M-W curve can not be used as a criterion of filterbillity of a viscose preparad from the different type of pulp.

FRACTIONAL DISSOLUTION CURVES OF NITRATED PULTS WITH ETHYL ACETATE-ETHANOL MIXTUTES

Ranby et al. had extracted nitrated pulp fibers with ethyl acetate-ethanol mixtures of increased ethyl acetate concentration, and found that the solubility curve thus obtained shows a level (Fig. 1). This fact means the carbohydrates are deposited in the plant fibers as two fractions differing markedly in solubility after nitration. In their investigation, two fractions were denitrated, hydrolyzed to monosaccharides and then analyzed by paper chromatography. This solvent-nonsolvent system gives a swelling of the fibers without destroying the fiber structure, until the concentration of ethyl acetate in mixture becomes about 60% (in volume). Therefore, the shape of this solubility curve can be effected not only by the amounts of easily soluble carbohydrates, but also the fiber structures, mainly outer layer of the cell wall and fine structure.The purpose of this investigation has been to establish what effect the fiber structurs and average degree of polymerization of pulp could have on the shape of the fractional dissolution curve. The following samples were prepared for determining the solubility curve:1. F-pulp fibers, which had been immersed in water, frozen and thawed, were prepared. This can be seen as destroyed of outer layer of cell wall or loosen fiber framework without the degradation of cellulose chain and the change of crystalline region.2. Acid hydrolyzed pulp fibers were prepared under the mild conditions. This can be seen as degradated of cellulose chain and as destroyed of outer layer of cell wall without any change in crystalline region.Two kinds of acid were used for hydrolysis of pulp fibers, namely sulfuric acid and lignosulfonic acid. According to the investigation by Samuelson, the latter had “screen effect”, then the outer layer of cell wall can be attacked more severely with lignosulfonic acid than with sulfuric acid.3. Mercerized pulp fibers were prepared. This can be seen as disordered of the crystalline region without degradation of cellulose chain. A part of easily soluble carbohydrates goes into solution during mercerization treatment.4. Linters pulp (Li. P), dissolving sulfite pulp (DSP), dissolving sulfate pulp (DKP), bleached paper sulfite pulp (BSP) and bleached paper sulfate pulp (BKP) were also used as original pulps.Mitchell's mixture was used for nitration of pulp fibers and the fractional dissolution was performed in the way Ranby did. The shape of solubility curve has been expressed by l, h, α and s (Fig. 1).As a result, it was found that l and α are effected by fiber structure, namely outer layer of cell wall and fine structure. When the outer layer of cell wall was destroyed or lateral order of cellulose was lowered, I decreased. In the case of DKP, the recrystallization had occured during freezing or acid hydrolysis and l increased. h shows the amounts of easily soluble carbohydrates in the fiber, and the shape s depends on the corelation between h and character of outer layer of cell wall. And the effect of average degree of polymerization of cellulose chain on the shape of fractional dissolution curve can be seen as subordinated to the fiber structure.

STUDIES ON THE DETERMINATION OF PENTOSANS BY ULTRA-VIOLET ABSORPTION SPECTRUM

The effects of the accessibility of cellulosic materials on the pentosan values are studied.Colorimetric method with aniline acetate, Smith's method with UV Absorption spectrum and the multi-points method previously suggested by the authors are used for determination of pentosan content of the following six samples; linter pulp, sulphite pulp, viscose rayon and dissolved samples of each in 42% HCl solutions. The following results are obtained experimentally.1. In the case of colorimetric method and Smith's method, the pentosan value obtained is affected by the accessibility of cellulosic material, especially the latter. Therefore these two methods are applied only to the samples such as pulps, which have low accessibility, are not generally applied to samples such as rayon.2. Contrary to above, the multi-points method is not affected by the accessibility of samples, but can determine the furfural formed from pentosan selectively. Therefore this method can be applied for the determination of pentosans in cellulosic materials regardless of its accessibility.

A Phase Transition Study on the Mercerization of Cellulose

Abstract The phase transition ranges were obtained at 20°C and 45°C for the linters pulp, the sulfate pulp and the sulfite pulp. It was concluded that the resistance of the linters pulp against the mercerization is higher than those of the wood pulp, where as no difference is observed between the sulfate and the sulfite pulp. It was suggested also that the visual estimation of the X-ray diffraction diagrams may transition range.

Effects of Mercerization on the Lateral Order Distribution of Cellulose

Abstract Lateral order distributions of native and mercerized celluloses were compared and then the variation of distribution in the process of mercerization was investigated. It was concluded that mercerization generally induces broadening of distribution, and cotton linters pulp shows almost the same lateral order distribution after mercerization as those of wood pulps. The authors are grateful to Dr. K. Hoshina for permitting this publication.

ON ALKALI SOLUBILITY CURVE OF PULP

In order to investigate the influence of fine structure on the alkali solubility curve of pulp, the hydrolized residues (crystalline region and crystalline region containning mesomorphous region) were prepared from linter pulp, rayon wood pulp and bleached sulfite paper pulp, by dilute acid hydrolysis for 30 minutes and 3 hours respectively, and their alkali solubilities were determined.The degraded cellulose samples were prepared from linter pulp and rayon pulp by irradiation of ultra violet rays, and their alkali solubilities were also determined.From the results obtained the influence of fine structure and degree of polymerization of pulp on the alkali solubility curve of pulp are discussed.

THE BEHAVIORS OF MERCERIZED CELLULOSE DURING EMULSION XANTHATION

In order to investigate the behaviors of mercerized cellulose in a course of emulsion xanthation, linter and rayon wood pulps and their mercerised pulps were emulsion xanthated under the conditions that merecrized pulps would show the most peculiar behaviors in the reaction. The solubilities of pulp, γ-values of undissolved part of pulp and viscose were determined at various reaction times.The findings (Fig. 1_??_14) on the bebaviors of four kinds of pulps are discussed.

ON ALKALI SOLUBILITY CURVE OF PULP

In the previous paper the influence of fine structure of cellulose on the alkali solubility curve of pulp were reported. In the present paper linter pulp and rayon wood pulp were nitrated with two kinds of acid mixtures and then denitrated so that the degree of polymerization of cellulose falls little, and the alkali solubilities and distributions of lateral order were determined on the samples thus obtained.From the results obtained further discussions are made on the influence of fine structure of the alkali solubility curve of pulp.