• Title, Summary, Keyword: pore structure

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Comparison of pore analysis techniques of the paper (종이의 Pore 특성 측정 기법의 비교)

  • Nam, Ki-Young;Chung, Sun-Ki;Won, Jong-Myoung
    • Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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    • pp.179-186
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    • 2007
  • The best way to understand paper properties is to study paper structure. Paper is composed solid materials (pulp and other additives) and air three-dimensionally, it's important to understand pore structure of the paper. There are several method to analysis pore structure of the paper. Mercury intrusion technique is frequently used for the characterization of the porous paper, giving access to parameters such as pore size and pore distribution. But some researchers indicated mercury intrusion distorts the structure due to application of high pressure. So this paper suggest new analysis technique to pore structure of the paper. New pore analysis technique with SEM does not require high pressure, gives good resolution and measures pore structure.

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Studies on the Pore of Coating Layer and Printability(III) -Effects of Properties of Latices on Pore of Coating Layer- (도공층의 공극과 인쇄적성에 관한 연구(제3보) -라텍스의 특성이 미치는 영향-)

  • 이용규;김창근
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.33 no.2
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    • pp.41-48
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    • 2001
  • This paper was made to evaluate the effect of the type of latex for coating on the printability by investigating the structure of pore such as the pore fraction, the number of pores, pore size and distribution of coated paper. The coated structure is mainly depend on the results of interaction between pigment and binder. It means that the structure of pore formed is chiefly affected by the type of latex. This physical properties of pore have a close relation with ink set-off associated with the drying rate, the speed of penetration of ink into base paper and printing gloss. Therefore it was necessary to find out the relationship between pore structure and the performance of printability by modifying the type of latex to vary the pore structure of coated paper. Acrylic latex was superior to S/B latex in the sedimentation volume, compressibility, smoothness, pore fraction and its number, the weight of transferred ink onto the coated paper and ink repellance. In contrast, water retention and ink setting were not good. in the comparison of anionic and amphoteric latex, amphoteric latex showed better performance in the thickness, smoothness, pore fraction and its number, pore size, the weight of ink transmitted and K&N ink receptivity, etc.

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Indentation Damage of Porous Alumina Ceramice

  • Ha, Jang-Hoon;Lee, Chul-Seung;Kim, Jong-Ho;Kim, Do-Kyung
    • Journal of the Korean Ceramic Society
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    • v.41 no.1
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    • pp.19-23
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    • 2004
  • The Hertzian indentation contact damage behavior of porous alumina with controlled pore shape was investigated by experiments. Porous alumina ceramics containing well-defined pore shape, size and distribution were prepared by incorporation of fugitive spherical starch. Porous alumina with isolated pore structure was prepared with porosity range up to 30%. The indentation stress-strain curves of porous alumina were constructed. Elastic modulus and yield stress can be obtained from the stress-strain relationship. Impulse excitation method for the measurement of elastic modulus was also conducted as well as Hertzian indentation and was confirmed as a useful tool to evaluate the elasticity of highly porous ceramics. Elastic modulus of the inter-connected pore structure is more sensitive to porosity than that of the isolated pore structure. When the specimen had isolated pore structure, higher yield point was obtained than it had inter-connected pore structure. This study proposed that the elastic modiulus of porous ceramics is strongly related to not only porosity, but also the structure of pore.

Pore Structure of Non-Sintered Cement Matrix (비소성 시멘트 경화체의 공극구조)

  • Mun Kyoung-Ju;Park Won-Chun;Soh Yang-Seob
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.329-332
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    • 2004
  • This study aims to manufacture non-sintering cement(NSC) by adding phosphogypsum(PG) and waste lime(WL) to granulated blast furnace slag(GBFS) as sulfate and alkali activators. This study also investigates the pore structure of NSC Matrix. The result of experiment of pore structure properties, showed no considerable difference for total pore volume by cement mixing ratio but shows a large distinction in distribution of pore diameter. On the whole, pore-diameter of paste of NSC show that occupation ratio of pore diameter below 10mm is larger and is smaller than OPC and BFSC at pore diameter of over 10nm. Such a reason is that the hydrate like CSH gel and ettringite formed dense pore structure of NSC matrix.

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Studies on the Pore of Coating Layer and Printability (IV) -Effects of Blending Ratio of Pigments- (도공층의 공극과 인쇄적성에 관한 연구(제4보) -안료 배합 비율이 미치는 영향-)

  • 김창근;이용규
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.33 no.3
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    • pp.29-36
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    • 2001
  • This paper was made to evaluate the effect of the blending ration of GCC and No. 1 clay on the printability by investigating the structure of pore such as the pore rate, the number of pores, pore size and distribution of coated paper. The coated structure is mainly depended on the results of correlation between pigment and binder. It means that the structure of the pore occurred is chiefly affected by the blending ratio of GCC and No. 1 clay. This physical properties of the pore have a close relation with ink set-off associated with the drying rate and the penetration in ink into base paper and with printing gloss. Therefore it was needed to find out how the pore structure and the printability will be changed by modifying the blending ratio of GCC and No. 1 clay to vary the pore structure of coated paper. Below are the results of measurement: As the blending ratio of clay going up, water retention, sedimentation volume. smoothness, and paper gloss were increased, but relatively brightness and opacity were decreased. Pore rate was the highest at the blending ratio of No. 1 clay to GCC, 70:30. In this case, average pore radius was also increased. Ink receptivity and K&N ink receptivity were improved with the increase of the blending ratio of GCC, where was, ink setting was vice versa. No difference was observed in the weight of ink, but ink repellance decrease with the decrease of blending ratio of GCC.

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Adsorption of Carbon Dioxide onto Tetraethylenepentamine Impregnated PMMA Sorbents with Different Pore Structure

  • Jo, Dong Hyun;Park, Cheonggi;Jung, Hyunchul;Kim, Sung Hyun
    • Korean Chemical Engineering Research
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    • v.53 no.3
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    • pp.382-390
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    • 2015
  • Poly(methyl methacrylate) (PMMA) supports and amine additives were investigated to adsorb $CO_2$. PMMA supports were fabricated by using different ratio of pore forming agents (porogen) to control the BET specific surface area, pore volume and distribution. Toluene and xylene are used for porogens. Supported amine sorbents were prepared by wet impregnation of tetraethylenepentamine (TEPA) on PMMA supports. So we could identify the effect of the pore structure of supports and the quantity of impregnated TEPA on the adsorption capacity. The increased amount of toluene as pore foaming agent resulted in the decreased average pore diameter and the increased BET surface area. Polymer supports with huge different pore distribution could be fabricated by controlling the ratio of porogen. After impregnation, the support with micropore structure is supposed the pore blocking and filling effect so that it has low $CO_2$ capacity and kinetics due to the difficulty of diffusing. Macropore structure indicates fast adsorption capacity and low influence of amine loading. In case of support with mesopore, it has high performance of adsorption capacity and kinetics. So high surface area and meso-/macro- pore structure is suitable for $CO_2$ capture.

Strength and Reliability of Porous Ceramics Measured by Sphere Indentation on Bilayer Structure

  • Ha, Jang-Hoon;Kim, Jong-Ho;Kim, Do-Kyung
    • Journal of the Korean Ceramic Society
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    • v.41 no.7
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    • pp.503-507
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    • 2004
  • The importance of porous ceramics has been increasingly recognized and adequate strength of porous ceramics is now required for structural applications. Porosities of porous ceramics act as flaws in inner volume and outer surface which result in severe strength degradation. The effect of pore structure, however, on strength and reliability of porous ceramics has not been clearly understood. We investigate the relationship between pore structure and mechanical properties using a sphere indentation on bilayer structure, porous ceramic top layer with soft polymer substrate. Porous alumina and silica were prepared to characterize the isolated pore structure and interconnected pore structure, respectively. The porous ceramic with 1mm thickness were bonded to soft polycarbonate substrate and then fracture strengths were estimated from critical loads for radial cracking of porous ceramics during sphere indentation from top surface. This simple and reproducible technique provides Weibull modulus of strength of porous ceramics with different pore structure. It shows that the porous ceramics with isolated pore structure have higher strength and higher Weibull modulus as well, than those with interconnected pore structure even with the same porosity.

Studies on the Pore of Coating Layer and Printability(II) -Effects of Pigment Shape on Pore of Coating Layer- (도공층의 공극과 인쇄적성에 관한 연구(제2보) -안료의 입자형태가 미치는 영향-)

  • 김창근;이용규
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.33 no.1
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    • pp.53-61
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    • 2001
  • This study was carried out to evaluate the effect of coating pigments on the printability by investigating the pore structure of casting layer such as the number, size and distribution of pores and the pore rate. The coating structure was mainly determined by the interaction between pigment and binder. It means that the structure of pores was chiefly affected by the shape and size distribution of pigments and their packing rate. The physical properties of pore have close relationships with ink set-off, the speed of ink penetration and printing gloss. The results suggested that the rate and number of pores were greatly affected by the particle size distribution and shape of pigments. The rate of pore increased with the reduction of particle size distribution of pigments. Calcite was effective to improve greatly the printability of coated paper.

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Pore Structure and Reflectivity of Light of Paper

  • Won, Jong-Myoung
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.38 no.3
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    • pp.7-12
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    • 2006
  • The pore structure of paper was modified by the application of the blending of pulp, refining, and filler particle size and ash content. It was conformed that the reflectivity of paper can be modified by the combination of the above parameters. It was also found that the change of reflectivity of paper was greatly dependent on the pore structure, such as average pore size, pore size distribution and porosity. The average pore size was decreased with addition of HwBKP, but the smallest average pore size was obtained from the addition of 80% HwBKP Refining of pulp decreased both average pore size and the reflectivity of paper. The pore size distribution of filled paper can be varied by the combination of filler particle size and ash content

Realistic pore structure of Portland cement paste: experimental study and numerical simulation

  • Ma, Hongyan;Li, Zongjin
    • Computers and Concrete
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    • v.11 no.4
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    • pp.317-336
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    • 2013
  • In this study, the pore structure of Portland cement paste is experimentally characterized by MIP (mercury intrusion porosimetry) and nitrogen adsorption, and simulated by a newly developed status-oriented computer model. Cement pastes with w/c=0.3, 0.4 and 0.5 at ages from 1 day to 120 days are comprehensively investigated. It is found that MIP cannot generate valid pore size distribution curves for cement paste. Nevertheless, nitrogen adsorption can give much more realistic pore size distribution curves of small capillary pores, and these curves follow the same distribution mode. While, large capillary pores can be effectively characterized by the newly developed computer model, and the validity of this model has been proved by BSE imaging plus image analysis. Based on the experimental findings and numerical simulation, a hypothesis is proposed to explain the formation mechanism of the capillary pore system, and the realistic representation of the pore structure of hydrated cement paste is established.