Characterisation of fines from unbleached kraft pulps and their impact on sheet properties

Holzforschung ◽  
2008 ◽  
Vol 62 (5) ◽  
Author(s):  
Marie Bäckström ◽  
Marie-Claude Kolar ◽  
Myat Htun
Keyword(s):  
Mechanical Properties ◽  
Capillary Forces ◽  
Strength Properties ◽  
Kraft Pulps ◽  
Paper Strength ◽  
Essential Component ◽  
Profound Influence ◽  
The Creation ◽  
Strength Improvement

Abstract Fines are an essential component in the papermaking process because they have a profound influence on the behaviour of the wet web and on the mechanical properties of the final sheet. Primary fines are present in the pulp prior to refining, and secondary fines are produced during refining. In the present investigation, two commercially manufactured unbleached pulps with kappa numbers of 45 and 90 were studied in terms of how they responded to refining with respect to the quality of fibre and fines. Primary and secondary fines were collected and characterised and their impact on sheet strength was evaluated by addition of known amounts to a refined and decrilled pulp. All the measured paper strength properties improved when primary and secondary fines were added. The strength improvement was generally somewhat higher in the second case. The effect was more pronounced at a higher level of addition. We attribute the main strength improvements associated with fines to improved consolidation by the creation of capillary forces between the surfaces.

Thermal and natural aging of bagasse paper sheets coated with gelatin

2018 ◽  
Vol 33 (2) ◽  
pp. 327-335 ◽  
Author(s):  
Mohamed El-Sakhawy ◽  
EL-Shahat H. A. Nashy ◽  
Ahmed El-Gendy ◽  
Samir Kamel
Keyword(s):  
Mechanical Properties ◽  
Natural Aging ◽  
Strength Properties ◽  
Paper Strength ◽  
Paper Sheet ◽  
Direct Proportion ◽  
Time Intervals ◽  
Coating Solution ◽  
Tannery Wastes ◽  
Gelatin Coating

Abstract The utilization of the solid tannery wastes as a promoting agent to improve paper sheet properties was investigated. Solid tannery wastes from pickled hide shavings are treated to remove acid and salts, and hydrolyzed at pH 10 by using potassium carbonate. The produced hydrolysable collagen (gelatin) was used as coating for paper sheets. The gelatin concentrations from 0.5–2.5 % were used as coating solution and its effect on thermal aging and mechanical properties was studied. A direct proportion between gelatin concentration and improvements of paper mechanical properties was observed. A kinetic study based on paper strength properties confirmed the stabilizating effect of gelatin on paper sheets. Paper sheets coated with 2.5 % gelatin solution were thermally aged at temperatures range between 100–200 °C for different time intervals from 1–6 h, and after that it was subjected to natural aging for two years. Gelatin coating improves the paper sheets mechanical properties and thermal stability.

scholarly journals PENINGKATAN MUTU KERTAS DAUR ULANG MENGGUNAKAN XYLAN ( IMPROVEMENT QUALITY OF RECYCLED FIBER USING XYLAN )

2017 ◽  
Vol 7 (01) ◽  
pp. 33
Author(s):  
Sonny Kurnia Wirawan ◽  
Chandra Apriana Purwita ◽  
Nina Elyani
Keyword(s):  
Agricultural Waste ◽  
Strength Properties ◽  
Paper Strength ◽  
Tensile Index ◽  
Potential Source ◽  
Recycled Fiber ◽  
Corrugated Cardboard

ABSTRACTCorncob as agricultural waste is a potential source of xylan to be used as an additive to increase the paper strength sheets originating from old corrugated cardboard (OCC). The aim of this research is to know increasing of strength properties from recycled fiber after addition of corncob xylan, compared to the commercial xylan. The xylan extraction was carried out by acid and the addition of xylan to the fiber was carried out at 80 ºC for 30 minutes. The results showed that the use of corncob xylan 5% (w/w) can increase the tensile index by 13.08%, burst index by 9.24%, ring crush test (RCT) index by 39.13% and corrugated medium test (CMT) index by 17.44%.ABSTRAKTongkol jagung sebagai limbah pertanian merupakan sumber xylan yang potensial yang dapat digunakan sebagai aditif untuk meningkatkan kekuatan lembaran kertas daur ulang yang berasal dari Kertas Karton Gelombang (KKG) bekas. Tujuan penelitian ini adalah untuk mengetahui peningkatan kekuatan lembaran kertas daur ulang setelah penambahan xylan dari tongkol jagung, dibandingkan dengan xylan komersial. Ekstraksi xylan dilakukan dengan metode asam dan penambahan xylan terhadap serat dilakukan pada temperatur 80ºC selama 30 menit. Hasil penelitian menunjukkan bahwa penggunaan xylan tongkol jagung sebanyak 5% (berat xylan/berat kering pulp) dapat meningkatkan indeks tarik 13,08%, indeks retak 9,24%, indeks RCT 39,13% dan indeks CMT 17,44%.

The effects of TMP and filler stratifying on wet web runnability and end product quality of fine paper

2012 ◽  
Vol 27 (1) ◽  
pp. 130-136
Author(s):  
Antti Oksanen ◽  
Kristian Salminen ◽  
Jarmo Kouko ◽  
Elias Retulainen
Keyword(s):  
Mechanical Properties ◽  
Filler Content ◽  
Length Distribution ◽  
Fibre Length ◽  
Strength Properties ◽  
Raw Material ◽  
Paper Machine ◽  
Precipitated Calcium Carbonate ◽  
Purity Analysis

Abstract Increase of filler content in paper improves quality of the final product and reduces raw material costs. However, this is often accompanied by deterioration of paper machine runnability. In this paper the effects of stratifying PCC (precipitated calcium carbonate) and TMP on fine paper quality and the mechanical properties of dry and wet paper were studied. In addition, a new method was introduced for evaluating the layer purity of pulp and filler stratifying by measuring the fibre length distribution in the thickness direction of the paper. The filler addition reduced the mechanical properties of paper more with chemical than mechanical pulps, with similar dry tensile indices. Stratifying filler onto paper surfaces gave higher dry tensile strength properties than samples with mixed structures, whereas only a small positive effect was detected for wet tensile and relaxation properties as a result of stratifying. Stratifying fillers only had a small negative effect on the internal bond strength. Stratifying or mixing TMP with a chemical pulp blend was shown to enable an increase in the filler content of 10% without significant changes in the residual tension (tension after 0.475 s of relaxation) or tensile index of wet samples. Based on layer purity analysis, stratifying TMP and filler was found to be successful in these trials.

STUDY ON THE INFLUENCE OF CURING TEMPERATURE ON MECHANICAL PROPERTIES OF MODIFIED FLY ASH MORTAR

2018 ◽  
Vol 5 (2) ◽  
Author(s):  
Hirotaka Matsuo ◽  
Koji Takasu ◽  
Hidehiro Koyamada ◽  
Hiroki Suyama
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Strength Properties ◽  
Curing Temperature ◽  
Static Elasticity ◽  
Flotation Technique ◽  
Accumulated Temperature ◽  
Modified Fly Ash

Using fly ash as an admixture for concrete can contribute to environmental load reduction and concrete quality improvement. However, as the quality of fly ash fluctuates depending on the ash source, quality stabilization is required. It was proved that concrete with fly ash of Japanese Industrial Standardized class II has different strength properties depending on curing temperature, but it is not obvious whether concrete with modified fly ash by flotation method has similar properties. In this study, the influence was examined on the mechanical properties when changing the curing temperature of mortar using fly ash modified by the flotation technique. The sealing curing was set to 5°C, 20°C, 40°C and 60°C. Also, after 7 days, 5°C, 40°C and 60°C, is changed to 20°C and compression strength and static elasticity coefficient were measured. The value of compressive strength and static elastic modulus showed that mortar using modified fly ash had the same characteristics as mortar with ordinary fly ash. Because it was represented by one strength compressive estimation curve regardless of the curing temperature, it became clear that compressive strength can be evaluated by roughly using accumulated temperature as an indicator.

scholarly journals Assessment of the Mechanical Properties of Some Selected Sandcrete Hollow Blocks in Kogi State

2017 ◽  
Vol 2 (11) ◽  
pp. 43
Author(s):  
Ajibola Ibrahim Quadri ◽  
Lawrence Irobekhian Ijesoh
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Water Absorption ◽  
Strength Properties ◽  
Poor Quality ◽  
Regulatory Body ◽  
Sieve Analysis ◽  
Minimum Requirement ◽  
Analysis Of Results

The current wave of the collapse of building structure all over Nigeria necessitates the need to carry out research on the mechanical properties of sandcrete hollow blocks. This study looks into the quality of blocks produced by block industries in Kogi state, Nigeria to ascertain its water absorption ratio, compressive strength and sieve analysis. In order to clarify these problems, the study is directed towards testing the strength properties of commercially produced sandcrete blocks; to verify whether the sandcrete block can be improved to achieve good quality in the building industries.  A Total of five block industries were visited and twenty samples were picked at random from each of the selected block industry and also, soil samples obtained for soil tests in the laboratory. The analysis of results obtained was compared with the Nigerian Industrial Standard (NIS). The average water absorption rate of the sandcrete blocks for block industry D was found to be 12.5% higher than the 12% maximum requirement of the [9]. The average compressive strength values of the sandcrete blocks range between 0.64N/mm2 and 0.87N/mm2 which when compared with standard, was found to be below the minimum requirement of the [9]. Inadequate mix ratio was observed to be one of the factors of poor quality sandcrete block production in this area. The study recommends compliance monitoring by the various regulatory body to ensure good quality of sandcrete block production.

scholarly journals Effect of Different Hardwood Species and Lay-Up Schemes on the Mechanical Properties of Plywood

Forests ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 649 ◽  
Author(s):  
Heikko Kallakas ◽  
Anti Rohumaa ◽  
Harti Vahermets ◽  
Jaan Kers
Keyword(s):  
Mechanical Properties ◽  
Wood Species ◽  
Bending Strength ◽  
Processing Parameters ◽  
Strength Properties ◽  
Product Density ◽  
Black Alder ◽  
Hardwood Species ◽  
Birch Veneer

In Estonia, hardwoods form approximately 50% of all forest area, where the main species are birch (30%), gray alder (9%), aspen (6%) and black alder (4%). Birch has been extensively used by the veneer-based industry, but species like black alder, gray alder and aspen have not been commonly used by the veneer-based products industry due to the lower quality of this resource. The aim of this research is to determine the effect of different lay-up schemes and usages of gray alder, black alder and aspen on the mechanical properties of plywood, by replacing birch veneer in the plywood core with alternative wood species. The main veneer and plywood characteristics will be evaluated according to the current standards, e.g., veneer strength perpendicular to grain, plywood bonding and bending strength, and modulus of elasticity. All processing parameters will be kept similar to those used generally by birch plywood manufacturers. The results showed that birch and black alder plywood panels had generally the highest bending strength properties, followed by grey alder and aspen. It was also found that, for proper gluing, birch veneers had the lowest glue consumption, 152 g/m2, and aspen had the highest glue consumption, 179 g/m2. It was found that when lower density wood was used in the plywood, the product density increased. Low density wood veneers had higher glue consumption, and also higher compaction in thickness than birch veneers under the same pressure. Overall, it was shown that the wood species used in this study have slightly lower strength properties, but with proper lay-up schemes, these wood species could be successfully used by the veneer-based products industry.

The Use of Oil Palm Empty Fruit Bunches (OPEFB) Fibers as Partial Replacement for Imported Recycled Fibers

2017 ◽  
Vol 737 ◽  
pp. 335-340 ◽  
Author(s):  
A.B. Khairul Hafizuddin ◽  
Roslan Rohaizu ◽  
W.D. Wan Rosli
Keyword(s):  
Oil Palm ◽  
Paper Industry ◽  
Strength Properties ◽  
Partial Replacement ◽  
Paper Strength ◽  
Empty Fruit Bunches ◽  
Recycled Pulp ◽  
Recycled Fibers ◽  
The Cost

Papermaking in Malaysia is basically based on recycled (secondary) fibers which are sourced from various parts of the world with prices depending on the quality of the fibers procured. The costs of paper production could possibly be reduced by using local fibers as partial replacement provided that the strength requirements are not compromised; and one such type is the oil palm fibers which are obtained as the by-product of the palm oil industry. This paper reports the use of the oil palm empty fruit bunch (OPEFB) fiber as a partial substitute in the production of corrugating medium. Both unbleached and totally chlorine free (TCF) bleached OPEFB pulps were mixed in different ratios with high quality recycled pulps which had been mechanically and chemically treated. Burst strength results indicate as high as 70% recycled pulp can be replaced by OPEFB pulps yet still having strength properties that are comparable with the industrial produced corrugating medium. Although the effect of bleached pulp is significant at high addition levels of more than 70%, the cost-energy balance will not be effective to use these bleached fibers, and furthermore the utilization of unbleached pulps also gave the same desired results. The use of the underutilized OPEFB fibers for replacement of imported recycled fibers without compromising the paper strength qualities could help the Malaysian paper industry in their quest for finding fiber alternatives.

Bond quality of timber in technology of the laminated board for dwelling houses

2016 ◽  
Vol 6 (3) ◽  
pp. 127-134
Author(s):  
Разиньков ◽  
Egor Razinkov
Keyword(s):  
Mechanical Properties ◽  
Strength Properties ◽  
Bond Quality ◽  
Environmental Friendliness ◽  
Timber Quality ◽  
Home Building ◽  
Harmful Substances

The article deals with laminated board production. In recent years laminated board produc-tion is widely developed for home building. Despite rather high cost of houses from such bar demand for the products grows constantly. It is because of its environmental friendliness, first, and its harmful substances within admissible level, second. Besides, the received bar as for phys-ical and mechanical properties is similar to the properties of bar from genuine wood. The tech-nology of the bar is not really difficult, but the requirements to strength properties are quite high. And first of all these requirements concern timber quality and their bond quality.

A novel predictive method for filler coflocculation with cellulose microfibrils

TAPPI Journal ◽  
2019 ◽  
Vol 18 (11) ◽  
pp. 653-664
Author(s):  
IGNACIO DE SAN PIO ◽  
KLAS G. JOHANSSON ◽  
PAUL KROCHAK
Keyword(s):  
Negative Impact ◽  
High Strength ◽  
Strength Properties ◽  
Cellulose Microfibrils ◽  
Paper Strength ◽  
Flow Loop ◽  
Cationic Starch ◽  
Reflectance Measurement ◽  
Drainage Rate ◽  
Complete Study

Different strategies aimed at reducing the negative impact of fillers on paper strength have been the objective of many studies during the past few decades. Some new strategies have even been patented or commercialized, yet a complete study on the behavior of the filler flocs and their effect on retention, drainage, and formation has not been found in literature. This type of research on fillers is often limited by difficulties in simulating high levels of shear at laboratory scale similar to those at mill scale. To address this challenge, a combination of techniques was used to compare preflocculation (i.e., filler is flocculated before addition to the pulp) with coflocculation strategies (i.e., filler is mixed with a binder and flocculated before addition to the pulp). The effect on filler and fiber flocs size was studied in a pilot flow loop using focal beam reflectance measurement (FBRM) and image analysis. Flocs obtained with cationic polyacrylamide (CPAM) and bentonite were shown to have similar shear resistance with both strategies, whereas cationic starch (CS) was clearly more advantageous when coflocculation strategy was used. The effect of flocculation strategy on drainage rate, STFI formation, ash retention, and standard strength properties was measured. Coflocculation of filler with CPAM plus bentonite or CS showed promising results and produced sheets with high strength but had a negative impact on wire dewatering, opening a door for further optimization.

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