• Title/Summary/Keyword: thickness swelling

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Microscopic Interpretation on Thickness Swelling Mechanism of Nonwoven Web Composites from Wood Particles and Polypropylene Fibers

  • Chae, Shoo-Geun;Eom, Young-Geun
    • Journal of the Korea Furniture Society
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    • v.17 no.2
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    • pp.9-23
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    • 2006
  • Control particleboards were significantly higher in thickness swelling than wood particle-polypropylene fiber composites and their thickness swelling increased with the increase of target density. In the composites, thickness swelling did not vary significantly with the increase of target density but increased with the increase of wood particle content. And the composites with fine wood particles were significantly lower in thickness swelling than those with coarse wood particles irrespective of target density and formulation. In the scanning electron microscopy, significantly higher thickness swelling in the composites with coarse wood particles was thought to be the result of more interfacial separations by higher swelling stresses.

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Studies on Thickness Swelling Mechanism of Wood Particle-Polypropylene Fiber Composite by Scanning Electron Microscopy

  • Lee, Chan Ho;Cha, Jae Kyung;Eom, Young Geun
    • Journal of the Korean Wood Science and Technology
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    • v.30 no.3
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    • pp.48-58
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    • 2002
  • This study was carried out through scanning electron microscopy to elucidate the mechanism of thickness swelling in wood particle-polypropylene composite which is a typical way of using wood and plastic materials. For this purpose, control particleboards and nonwoven web composites from wood particle and polypropylene fiber formulations of 100:0, 70:30, 60:40, and 50:50 were manufactured at target density levels of 0.5, 0.6, 0.7, and 0.8 g/cm3. Their water absorption and thickness swelling were tested according to ASTMD 1037-93 (1995). To elucidate thickness swelling mechanism of composite through the observation of morphological change of internal structures, the specimens before and after thickness swelling test by 24-hour immersion in water were used in scanning electron microscopy. From the scanning electron microscopy, thickness swelling of composite was thought to be caused by the complicated factors of degree of built-up internal stresses by mat compression and/or amount of wood particles encapsulated with molten polypropylene fibers during hot pressing. In the composites with wood particle contents of 50 to 60% at target densities of 0.5 to 0.8 g/cm3 and with wood particle content of 70% at target densities of 0.5 to 0.7 g/cm3, thickness swellings seemed to be largely dependent upon the restricted water uptake by encapsulated wood particles with molten polypropylene fibers. Thickness swelling in the composite with wood particle content of 70% at target density of 0.8 g/cm3, however, was thought to be principally dependent upon the increased springback phenomenon by built-up internal stresses of compressed mat.

Physical Properties of Agro-Flour Filled Aliphatic Thermoplastic Polyester Bio-Composites

  • Eom, Young Geun;Kim, Hee Soo;Yang, Han Seung;Kim, Hyun Joong
    • Journal of the Korean Wood Science and Technology
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    • v.32 no.3
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    • pp.71-78
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    • 2004
  • The purpose of this study was to investigate the water absorption and thickness swelling of biocomposites at room temperature. These properties of bio-composites mainly depend on the ability of the agro-flour to absorb water through hydrogen bonding between water and the hydroxyl groups of the holocellulose and lignin in the cell wall. As the content of agro-flour increased, the water absorption and thickness swelling of the bio-composites increased. The effects of agro-flour content and rice husk flour (RHF) particle size on the water absorption and thickness swelling of the bio-composites were evaluated. In general, wood-based materials showed significantly higher water absorption and thickness swelling than the bio-composites. This might be attributed to the ability of the polybutylene succinate (PBS) hydrophobic polymer to prohibit the water absorption and thickness swelling of the bio-composites, Therefore, the use of agro-flour filled PBS bio-composites, which exhibit improved dimensional stability in comparison with wood-based materials, is recommended.

Textural Characterization of Gel Layer Thickness and Swelling Boundary in a Hydrophilic Compact (친수성 정제의 겔층두께와 겔팽창 영역의 조직 특성화)

  • Kim, Hyun-Jo;Fassihi, Reza
    • Journal of Pharmaceutical Investigation
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    • v.31 no.1
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    • pp.13-18
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    • 2001
  • This study was to investigate the relationship between the gel layer thickness and swelling boundary via strength measurements using texture analysis. The novel texture analysis approach was used to examine the dynamics of swelling behavior in a ternary polymeric matrix tablet. The method permitted the characterization of the changes occurring at the peripheral as well as within interior boundary of the swelling during water ingress. The increase in gel strength for pectin, HPMC, and a ternary mixture with gelatin was found to depend on polymer concentration. Therefore, this method is further applicable to characterize the swelling behavior and provide opportunity to differentiate the gel-layer from that of swelling boundary.

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Alkali-Swollen Morphology of Native Cellulose Fibers

  • Kim, Nam-Hun
    • Journal of the Korean Wood Science and Technology
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    • v.35 no.2
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    • pp.16-22
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    • 2007
  • The behavior of ramie fibers and some wood elements in the early stage of alkali swelling was examined. When the fibers were treated with alkali solution, they significantly shrank in length and swelled in wall thickness. Ramie fibers showed a shrinkage averaging 23% in length and a swelling averaging 92% in width in 100 seconds treating time. Dimensional changes showed different fashion in each element of woods. The tracheids of latewood especially in Pinus densiflora and Larix kaempferi woods swelled intensively and showed balloon swelling, but in the case of Cryptomeria japonica, it was hardly observed. The swelling morphology of libriform fibers was similar to that of tracheids. The walls of vessel elements and parenchyma cells also swelled considerably in thickness but, no balloon swelling was found in both elements. The differences of swelling in different elements can be interpreted in terms of the differences of organization and/or chemical components of the cell walls.

Alkali swelling characteristics of wood elements (목재 구성세포의 알칼리 팽윤 특성)

  • 황원중;김남훈
    • Journal of Korea Foresty Energy
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    • v.20 no.1
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    • pp.62-72
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    • 2001
  • To elucidate the behaviors of alkali swelllng of woods. the dimensional change in cross section of cell elements of four major Korean woods during alkali swelling were examined by an optical microscory, an imaging analysis method and an X-ray diffrartion During alkali swelling, tracheid diameter of Larix kaempferi wood showed greater swelling property than that of Pinus koraiensis wood, and the cell wall swelled highly over 10% sodium hydroxide solution treatment. The radial diameter of vessel elements in earlywood shrunk, but it swelled slightly in tangential direction. When treated with 5% NaOH, the wall thickness of wood fiber increased about three times over the original one. The thickness of cell wall in all elements and the diameter of wood fiber and tracheid showed almost isotropic shrinkage. The diameter of cell elements during the mercerization process decreased, but cell wall thickness Increased. Crystal transformation of cellulose in wood was not occurred by alkali treatments. but relative crystallinity and crystallite width of the woods increased slightly. Consequently, it was demonstrated that the swelling properties of woods were dependant on wood species, cell elements and alkali concentration.

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Influence of Adding Silicon Dioxide in Particleboard from Teak Sawdust to Reduce Water Absorption and Thickness Swelling

  • Thiti WANISHDILOKRATN;Jirapa WANISHDILOKRATN
    • Journal of the Korean Wood Science and Technology
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    • v.52 no.5
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    • pp.438-449
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    • 2024
  • This study investigated the influence of silicon dioxide (SiO2) addition to particleboard from teak sawdust to reduce water absorption and thickness swelling using standard tests of physical and mechanical properties. The experiment had a completely randomized design with four treatments (SiO2 concentrations of 5%, 3%, 1%, and 0%), each with three replicates, for a total of 12 conditions. The results showed that 1% concentration was the optimal concentration to reduce both water absorption (32.42% ± 1.78%) and thickness swelling (8.65% ± 1.16%). The product passed the standard tests for physical and mechanical properties, which reduced the cost of the SiO2 content for particleboard processing. These results suggest that SiO2 can resist moisture content but may slightly reduce strength.

Mechanical Properties of Bamboo-reinforced Boards Manufactured with Phyllostachys bambusoides Growing in Damyang District (I) -- Physical Properties of Bamboo Strand Board -- (담양산 왕대를 이용한 대나무 강화 복합보드의 제조 및 역학적 특성 평가 (I) - 대나무 스트랜드 보드의 물리적 특성 -)

  • 소원택;박병대
    • Journal of Korea Foresty Energy
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    • v.22 no.2
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    • pp.26-35
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    • 2003
  • Bamboo strand board (BSB) was made with Phyllostachys banbusoides growing in Damyang district. Physical and mechanical properties of this BSB were summarized as follows; The specific gravity of BSB was 0.63∼0.79. Specific gravity decreased slightly with the thickness and length of BSB. Moisture content of BSB manufactured was 5.8∼6.9%. The absorption ate of BSB (42∼48%) did not show any relationship with the thickness and length of BSB. The thickness swelling rate of BSB was 13.9∼17.0%, relatively higher than any other panel products. Thickness swelling rate increased with the thickness of BSB, showing the strand thickness influenced much more on the rate of thickness swelling of BSB than the length of strand. The 3-point bending strength of BSB was 98∼126kgf/$\textrm{cm}^2$. Bending strength of showed the tendency of increase with the increased length of BSB, but with the decreased thickness. In particular, the length of BSB showed more effect on the increase of bending strength of BSB than the thickness of BSB. The compression strength perpendicular to BSB surface was 411 ∼ 465 kgf/$\textrm{cm}^2$, and the optimal length of strand for the 1mm- and 2mm-thickness of strand was 40mm and 60mm, respectively. Compression strength paralleled to BSD was 160∼221kgf/$\textrm{cm}^2$ and the optimal length of strand for the 2mm-thickness of strand appeared to be 60mm. The present work showed that appearance, physical and mechanical strength of BSB appeared quite positive in terms of board qualities, suggesting that bamboo would be appropriate for the production of board materials. In addition, our work showed that the crucial factor for determining the mechanical characteristics of BSB was the dimension of strand.

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Fabrication and Characterization of 3-D Porous Collagen Scaffold (3차원 다공성 콜라겐지지체의 제조 및 특성 분석)

  • Kim, Jin-Tae;Lim, Sumin;Kim, Byoung Soo;Lee, Deuk Yong;Choi, Jae Ha
    • Journal of Biomedical Engineering Research
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    • v.35 no.6
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    • pp.192-196
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    • 2014
  • Collagen scaffolds were synthesized by cross linking into a solution mixture of 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochlorid(EDC) in ethanol, followed by pressing, cleaning and lyophilization process after the type I atelo-collagen solutions in D.I water(pH3). The experimental conditions are collagen concentration of 1.0 wt%, 3.0 wt%, 5.0 wt% and differential concentration of cross-linker. Then, parametric studies were performed by varying the parameters to investigate the morphology, the porosity, the swelling ratio and the thickness and genotoxicity of the scaffolds. The scaffolds thickness pattern was regular to concentration of the degree of cross-linker and collagen. It was observed that the swelling ratio, the degree of crosslink, and the pore size(thickness of scaffold) can be controlled by adjusting the collagen, crosslinker. Among the parameters investigated, the smallest thickness can be achieved by collagen, crosslinker concentrate condition. The collagen scaffold is induced no genotoxicity. The lowest swelling ratio, as an indication of the highest degree of crosslink, can be obtained by adding crosslink agent.

Development and Characterization of Asymmetric Swelling-Induced Wrinkles on Natural Rubber Surface

  • Lee, Gi-Bbeum;Sathi, Shibulal Gopi;Kim, Min Jung;Park, Changsin;Huh, Yang Il;Nah, Changwoon
    • Elastomers and Composites
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    • v.51 no.4
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    • pp.342-349
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    • 2016
  • Characteristics of the swelling-induced wrinkles on the surfaces of natural rubber (NR) film were investigated. The wrinkle structure was generated by swelling of NR film pre-stretched and firmly bonded onto an aluminum substrate in hexane. A novel experimental method was adopted to replicate the swelling-induced wrinkles on the NR film using an epoxy-hardener system. To get insight into the wrinkle parameters; the wrinkle length (L), wrinkle distance (D), wrinkle height (H) and the angle between two consecutive wrinkles (${\theta}$), the cross-sections of the replicas obtained from saturated swollen NR film were examined using an optical microscopy (OM). From the OM images, the wrinkling parameters were measured as a function of the thickness of NR film from 0.42 to 1.76 mm. Also, it was evaluated that the effects of swelling time on the wrinkling parameters. The length (L), distance (D) and height (H) of wrinkles increased as the thickness of the NR film and the swelling time increased. However, the angle between the wrinkles (${\theta}$) showed a sharp decrease up to a swelling time of 200 minutes and slightly decreased afterwards.