Action Mechanism of the Improvement of Printability for Eucalypt Bleached Kraft Pulp Pretreated by Cellulase

2013 ◽  
Vol 779-780 ◽  
pp. 294-301
Author(s):  
Wan You Tang ◽  
Li Chen ◽  
Zheng Jian Zhang
Keyword(s):  
Tensile Strength ◽  
Fiber Length ◽  
Kraft Pulp ◽  
Pulp Fiber ◽  
Fiber Morphology ◽  
Strength Index ◽  
Bleached Kraft Pulp ◽  
Tear Index ◽  
Pulp Sample ◽  
The Mean

Enzymatic refining of eucalypt bleached kraft pulp with the cellulase NOV476 was studied. The effects of this cellulase on the physical properties of pulp, fiber morphology and fiber appearance of the eucalypt bleached kraft pulp in different application conditions were discussed. The results show that, with the increase in the amount of enzyme, tensile strength index, burst index and TEA index of paper are increased and then decreased; elongation and tear index of paper have been declining, Zeeil tensile strength index has been an upward trend. Without beating the pulp sample, gradually increases as the amount of enzyme, the average fiber length and the average fiber width are gradually reduced, while mean kink index substantially constant. Number of vessels in fiber overall reduced tendency reaches a minimum in the amount of enzyme 0.5μ/g, the phenomenon is most obvious. In the same conditions of beating time, gradually increases as the amount of enzyme, the average fiber length is gradually reduced, an average fiber width is gradually increased, the mean kink index reaches a maximum in the amount of enzyme is 0.5μ/g. Number of vessels in fiber overall reduced trend.

Fold cracking of coated paper: The effect of pulp fiber composition and beating

2012 ◽  
Vol 27 (2) ◽  
pp. 445-450 ◽  
Author(s):  
Hye Jung Youn ◽  
Kyujeong Sim ◽  
Kyu Deok Oh ◽  
Hak Lae Lee ◽  
Chang Sun Han ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Kraft Pulp ◽  
Low Cost ◽  
Pulp Fiber ◽  
Mixing Ratio ◽  
Pulp Fibers ◽  
Coated Paper ◽  
Mixing Ratios ◽  
Bleached Kraft Pulp ◽  
Base Paper

Abstract Fold cracking of coated papers has become important because of the increase in the coat weight and the content of low cost co-binder. The effects of base paper characteristics of coated paper were investigated to reduce fold cracking. We evaluated the fold cracking of coated paper prepared with different mixing ratios and beating degrees of pulp fibers. Hardwood bleached kraft pulp (Hw-BKP) and softwood bleached kraft pulp (Sw- BKP) were used to prepare base papers for coating. The mechanical and structural properties of base paper such as tensile strength, strain at break, short span compressive strength, and formation were measured. The fold cracking was affected by mixing ratio of pulp fibers. Base paper consisting of Hw-BKP and Sw-BKP at a 90:10 mixing ratio showed the least fold cracking. When the amount of Sw-BKP was greater than 10% or if only Hw- BKP was used, the fold cracking increased on coated paper. When the pulp was highly beaten, the mechanical strength of paper was improved, but the fold cracking was severe. An increase in the tensile strength did not reduce the fold cracking.

scholarly journals Nanostructured Films Produced from the Bleached Pinus sp. Kraft Pulp

2019 ◽  
Vol 26 (4) ◽  
Author(s):  
Lívia Cássia Viana ◽  
Graciela Ines Bolzon de Muñiz ◽  
Washington Luiz Esteves Magalhães ◽  
Alan Sulato de Andrade ◽  
Silvana Nisgoski ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Kraft Pulp ◽  
Physical And Mechanical Properties ◽  
Compact Structure ◽  
Nanostructured Films ◽  
Bleached Kraft Pulp ◽  
Lower Porosity ◽  
Density Values ◽  
Number Of Passes

ABSTRACT This study investigates the physical and mechanical properties of nanostructured films produced from Pinus sp. kraft pulp. To obtain the nanocellulose, the bleached kraft pulp was submitted to six different grinding regimes: two, five, ten, 20, 30, and 40 passes through the grinder. The influence of the number of passes was evaluated through the films’ physical and mechanical properties. The results show that the nanofibers reduced the thickness and considerably increased the density values of the fabricated films. The tensile strength increased more than 300% and the burst index was ten times higher in relation to normal papers. The more compact structure and lower porosity caused by the larger contact surface between nanofibers in the nanostructured films resulted in higher values of density, tensile strength, and burst resistance.

scholarly journals Study on the effect of hybrid fiber length on tensile strength of sealing composites

2020 ◽  
Vol 15 ◽  
pp. 155892502096822
Author(s):  
Li Yuxian ◽  
Liu Meihong ◽  
Sun Junfeng ◽  
Wang Juan ◽  
Tian Shuo
Keyword(s):  
Tensile Strength ◽  
Fiber Length ◽  
Uniform Design ◽  
Cellulose Fiber ◽  
Mineral Wool ◽  
Interfacial Bonding ◽  
Wool Fiber ◽  
Pulp Fiber ◽  
Hybrid Fiber ◽  
Mineral Wool Fiber

The present paper aims at investigating the relationship between fiber length of hybrid fibers and the tensile strength of sealing composite materials. First, three kinds of fibers: cellulose fiber, aramid pulp fiber, and mineral wool fiber were sieved and their weight-average length was measured. Second, a uniform design method of U8 (43) was adopted to prepare sealing composites by the beater-addition process, and the properties of the tensile strength of the composite were examined. In the end, the relation model was concluded and verified using multi-linear regression analyzation and was further analyzed using micro mechanic theory and interfacial bonding mechanism. The results show that the regression equation can be used to estimate the tensile strength of composites with different hybrid fiber lengths. The tensile strength increased corresponding to the increase of the length of the cellulose fiber but decreased with the increase of the length of aramid pulp and mineral wool fiber. Particularly the fiber length of aramid pulp fiber had the most significant effect on tensile properties. The cases were decided by the comprehensive effects of fibers dispersion, interfacial bonding, and micromechanics.

scholarly journals MODIFIKASI PERMUKAAN SERAT LBKP DAN HASIL DEINKING DENGAN KARBOKSIMETIL SELULOSA

2016 ◽  
Vol 2 (02) ◽  
Author(s):  
Sonny Kurnia Wirawan ◽  
Nina Elyani ◽  
Jenni Rismijana
Keyword(s):  
Physical Properties ◽  
Carboxymethyl Cellulose ◽  
Kraft Pulp ◽  
Fiber Strength ◽  
Fiber Quality ◽  
Strength Properties ◽  
Sem Analysis ◽  
Tensile Index ◽  
Bleached Kraft Pulp ◽  
Tear Index

The strength properties of paper are strongly affected by fiber quality. The objective of this study was to assess the effect of modification fiber by carboxymethylation of leaf bleached kraft pulp (LBKP) and deinked pulp (DIP) by using carboxymethyl cellulose (CMC). Carboxymethylation was carried out by addition of various concentration of CMC and cationic agent of CaCl2. Handsheets with 70 gsm were made from the stock, and the physical properties were tested as the tensile index, stretch, tensile energy absorption (TEA), tearing index, and bursting index as well as SEM analysis. The results showed that the highest increase of fiber strength of LBKP and DIP was achieved by addition of 1% CMC and 9.19% CaCl2. For LBKP, the increasing of tensile index was 18.1%, stretch 27%, TEA 30.2%, tear index 7,8 % and burst index 16,7%. Whereas for DIP, the increasing of tensile index reached 29.9%, stretch 22.2%, TEA 61.2%, tear index 20.7% and burst index 63.1%. From the results of SEM analysis showed that the addition of CMC and CaCl2 increased fiber bonding.Keywords: CMC, LBKP, DIP ABSTRAK Sifat kekuatan kertas sangat dipengaruhi oleh kualitas serat. Tujuan penelitian ini adalah untuk mengetahui pengaruh modifikasi serat kraft putih kayu daun (LBKP) dan serat hasil deinking (DIP) dengan karboksimetilasi menggunakan karboksimetil selulosa (CMC). Modifikasi secara karboksimetilasi dilakukan dengan variasi penambahan CMC dan sebagai cationic agent CaCl2. Lembaran dibuat dari stok dengan gramatur 70 gsm, kemudian dilakukan pengujian fisik dengan parameter indeks tarik, regang, TEA, indeks sobek dan indeks retak. Selain itu lembaran juga diuji morfologi dan SEM. Hasil penelitian menunjukan peningkatan kekuatan lembaran tertinggi dicapai oleh LBKP maupun DIP, pada kondisi penambahan 1% CMC and 9.19% CaCl2. Untuk LBKP peningkatan indeks tarik adalah 18,1%, regang 27%, TEA 30,2%, indeks sobek 7,8 % dan indeks retak 16,7%. Sedangkan untuk DIP, peningkatan indeks tarik mencapai 29,9%, regang 22,2%, TEA 61,2%, indeks sobek 20,7% dan indeks retak 63,1%. Hasil analisa SEM menunjukan bahwa dengan penambahan CMC dan CaCl2, mengakibatkan terjadi peningkatan ikatan antar serat.Kata kunci: CMC, LBKP, DIP

Effect of ultraviolet irradiation on the thermal stability of bleached eucalyptus kraft pulp

TAPPI Journal ◽  
2012 ◽  
Vol 11 (2) ◽  
pp. 69-74
Author(s):  
VAGNER ROBERTO BOTARO ◽  
KÁTIA MONTEIRO NOVACK ◽  
JORGE LUIZ COLODETTE ◽  
LEONARDO SOUZA DE CAUX
Keyword(s):  
Thermal Stability ◽  
Ultraviolet Irradiation ◽  
Kraft Pulp ◽  
Cellulose Oxidation ◽  
Cellulosic Fibers ◽  
Bleached Kraft Pulp ◽  
Elemental Chlorine ◽  
Eucalyptus Kraft Pulp ◽  
Pulp Sample ◽  
Ultraviolet Treatment

The changes occurring on cellulosic fibers caused by ultraviolet irradiation at 360 nm for 24 h and 48 h were investigated. A never-dried industrial Eucalyptus urograndis elemental chlorine free–bleached kraft pulp sample (O/OD[EP]DP sequence) was used throughout the work. After irradiation, the cellulosic fibers were analyzed for polymerization degree changes, extractive and pentosan content, ultraviolet and visible spectrometric changes of water leachate from the fibers and thermal analysis (TGA/DTA). The ultraviolet treatment had no effect on the degree of cellulose polymerization. The water extracted from ultraviolet-treated fibers revealed cellulose oxidation, with increasing absorbance signals for carbonyl and carboxyl groups. Those oxidations influenced fiber thermal stability.

First characterization of the development of bleached kraft softwood pulp fiber interfaces during drying and rewetting using FRET microscopy

Holzforschung ◽  
2008 ◽  
Vol 62 (4) ◽  
Author(s):  
Cameron I. Thomson ◽  
Robert M. Lowe ◽  
Arthur J. Ragauskas
Keyword(s):  
Kraft Pulp ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Pulp Fiber ◽  
Cellulosic Fibers ◽  
Bleached Kraft Pulp ◽  
Microscopy Technique ◽  
Wet Pressing ◽  
Fiber Components ◽  
Solids Content

Abstract Cellulosic fiber interfaces are critical to the material properties of paper. Likewise, the presence of water in a paper sheet is an important property, because paper is a wet-laid structure and the cellulosic fibers that compose it are hygroscopic. This work uses a fluorescence microscopy technique established by the authors to study the development of individual bleached kraft pulp fiber crossings in situ during drying and through a cycle of rewetting and wet pressing. The results indicate that coalescence of the fiber-fiber interface occurs during drying and that the fluorescence resonance energy transfer (FRET) response, which is proportional to the distance between fiber components, increases logarithmically with time. The FRET signal of once-dried fiber crossings increases dramatically after rewetting and wet pressing for a second time. This indicates that fiber bonds are still compliant after a single drying cycle and that the interactions between fiber components are likely reversible at the solids content present in bleached kraft pulp fiber crossings dried at 25°C and 50% relative humidity.

Significant contribution of fibrils on pulp fiber surface to water retention value

2020 ◽  
Vol 35 (1) ◽  
pp. 96-105
Author(s):  
Minoru Kimura ◽  
Takashi Ishida ◽  
Yuko Ono ◽  
Miyuki Takeuchi ◽  
Akira Isogai
Keyword(s):  
Cell Walls ◽  
Kraft Pulp ◽  
Water Retention ◽  
Structural Changes ◽  
Significant Contribution ◽  
Fiber Surface ◽  
Pulp Fiber ◽  
Pulp Fibers ◽  
Bleached Kraft Pulp ◽  
Two Factors

AbstractThe contribution of structural changes of softwood bleached kraft pulp (SBKP) fibers and partly dried SBKP handsheets to their water retention values (WRVs) was studied. Two factors related to mesopores and macropores, which were determined for super critical point (SCP)-dried SBKP sheet samples, should participate in the WRVs determined for wet SBKP sheet samples. The mesopores are formed during pulping/bleaching to remove lignin and a part of hemicelluloses that are present originally in wood cell walls. The combined volumes of mesopores and macropores (totally < ∼0.6 g g−1) in SBKP fibers after SCP drying were significantly lower than the entire WRV (∼1.6 g g−1) of the original never-dried SBKP. We hypothesize that external fibrils of SBKP fibers are formed during pulping, bleaching, washing, pressure-screening, and pressing processes at high and low solid contents in water under high shear forces. The WRV can be used as an indicator to evaluate such structural changes of external fibrils in pulp fibers and paper sheets during drying/wetting in papermaking process as well as in use under various conditions. In contrast, changes in mesopore and macropore volumes determined for SCP-dried sheets cannot properly detect such structural changes of external fibrils.

Comparison of KP Pulping Properties between Heartwood and Sapwood of Popla I-69

2011 ◽  
Vol 236-238 ◽  
pp. 1437-1441 ◽  
Author(s):  
Hui Gao ◽  
Li Ping Zhang ◽  
Sheng Quan Liu
Keyword(s):  
Chemical Composition ◽  
Fiber Length ◽  
Kappa Number ◽  
Pulp Yield ◽  
Width Ratio ◽  
Chemical Compositions ◽  
Factors Influencing ◽  
Tear Index ◽  
The Mean ◽  
Major Factors

The case was carried out to study the variance of fiber feature, chemical composition and pulping property between heartwood and sapwood of poplar I-69. As results showed, the mean fiber length in heartwood and sapwood of poplar I-69 were 770 and 1146µm separately, with the length-to-width ratio of 42.56 vs 51.76, and the wall-to-lumen ratio of 0.40 vs 0.59, respectively. The heartwood of poplar I-69 differed from sapwood in contents of chemical compositions, with holocellulose of 82.65% vs 81.35%, α- cellulose of 42.83% vs 42.82% and lignin of 18.01% vs 21.68%, respectively. Both the heartwood and sapwood of poplar I-69were suitable for pulping material. By investigating pulp yield and Kappa number, it was proven that the caustic soda dosage and the duration of reaction temperature were major factors influencing KP pulping properties of poplar I-69 sapwood. Under the same technical conditions of pulping, the pulp of the poplar I-69 sapwood was lower in Kappa number and higher in yield and in viscosity compared with those of heartwood. The tensile index, tear index and burst index of paper made by sapwood were higher than those made by heartwood. The sapwood of poplar I-69 showed overall better pulping aptitude in comparison with heartwood.

Comparison of KP Pulping Properties between Heartwood and Sapwood of Cedrus deodara (Roxb.) G. Don

2011 ◽  
Vol 55-57 ◽  
pp. 1778-1784 ◽  
Author(s):  
Hui Gao ◽  
Li Ping Zhang ◽  
Sheng Quan Liu
Keyword(s):  
Fiber Length ◽  
Kappa Number ◽  
Pulp Yield ◽  
Width Ratio ◽  
Chemical Compositions ◽  
Cedrus Deodara ◽  
Factors Influencing ◽  
Tear Index ◽  
The Mean ◽  
Major Factors

The case was carried out to study the variance of fiber feature, chemical composition and pulping property between heartwood and sapwood ofCedrus deodara (Roxb.)G. Don. As results showed, the mean fiber length in heartwood and sapwood of cedar were 1842 and 2552 µm separately, with the length-to- width ratio of 77.46 vs 79.41, and the wall-to-lumen ratio of 0.36 vs 0.38, respectively. The heartwood of cedar differed from sapwood in contents of chemical compositions, with holocellulose of 70.00% vs 75.87%, α- cellulose of 40.75% vs 42.75% and lignin of 26.64% vs 25.00%, respectively. Both the heartwood and sapwood of cedarwere excellent pulping material. By investigating pulp yield and Kappa number, it was proven that the caustic soda dosage and the duration of reaction temperature were major factors influencing KP pulping properties of cedar sapwood. Under the same technical conditions of pulping, the pulp of the cedar sapwood was lower in Kappa number and higher in yield and in viscosity compared with those of heartwood. The tensile index, tear index and burst index of paper made by sapwood were higher than those made by heartwood. The sapwood of cedar showed overall better pulping aptitude in comparison with heartwood.

Research on Preparation and Properities of Chemi-Mechanical Pulp from the Waste Poplar Wood

2013 ◽  
Vol 848 ◽  
pp. 325-329
Author(s):  
Xia Li ◽  
Chuan Shan Zhao ◽  
Jin Jin Yu ◽  
Wen Jia Han
Keyword(s):  
Optimal Time ◽  
Optimal Dosage ◽  
Poplar Wood ◽  
Fiber Morphology ◽  
Strength Index ◽  
Mechanical Pulp ◽  
Tear Index ◽  
Length Width ◽  
Normal Atmospheric Pressure ◽  
Crush Strength

In this study, we prepared unbleached chemi-mechanical pulp from waste poplar wood using alkaline processing under normal atmospheric pressure. The influnce of alkaline dosage and time to fiber morphology and properties of the paper were discussed. The parameters of fiber including the length ,width and curl index were measured by FQA. The optimal dosage of NaOH and the optimal time of soaking period in the preparation of pulp using waste poplar wood were studied. The results showed that the optimal dosage of NaOH was 6% and the time of soaking period was one day. The performance of the handsheet made from the poplar wood under the pulping conditions are as follows: tensile strength index of 27 N·m/g, tear index of 0.51 mN·m2/g, burst index of 1.7 KPa·m2/g, folding strength of 16 times, ring crush strength index of 5.7 N.m/g, whiteness of 55.5 ISO, white opacity of 97%, paper absorption liquid rate of 0.32 mm/s.

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