• Title/Summary/Keyword: 표면젖음성

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The Effect of Acid Treatment on the Adhesion Property of Polyketone with Rubber (폴리케톤과 고무의 접착성에 미치는 산처리의 영향)

  • Choi, Hae Young;Lee, Tae Sang;Lee, Jong;Lee, Seung Goo
    • Journal of Adhesion and Interface
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    • v.12 no.1
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    • pp.26-33
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    • 2011
  • Phosphoric acid treatments were conducted to improve the adhesion property of polyketone film to rubber. The effects of phosphoric acid treatments were characterized by using a contact angle analyzer and a XPS (X-ray photoelectron spectroscopy). Morphological changes were observed by using a scanning electron microscope (SEM) and an atomic force microscope (AFM) as the acid treatment condition varied in concentration and time. The contact angle was found to significantly decrease with the acid treatment. According to the XPS, increased wettability was attributed to the inclusion of oxygen containing groups such as hydroxyl, carbonyl and carboxyl by acid treatments. Cracks and pores were produced on the polyketone film surface and thus, roughness increased with the acid treatment. Interfacial adhesion strength between polyketone and natural rubber was largely improved by acid treatment due to the increased wettability and roughness of the polyketone surface. However, the higher level of acid treatment caused the degradation of the polyketone surface, and thus, its interfacial adhesion consequently decreased.

Improvement of Interfacial Adhesion of Plasma Treated Single Carbon Fiber Reinforced CNT-Phenolic Nanocomposites by Electrical Resistance Measurement and Wettability (젖음성 및 전기저항 측정을 이용한 플라즈마 처리된 단일 탄소섬유 강화 탄소나노튜브-페놀수지 나노복합재료의 계면접착력 향상)

  • Wang, Zuo-Jia;Kwon, Dong-Jun;Gu, Ga-Young;Park, Jong-Kyoo;Lee, Woo-Il;Park, Joung-Man
    • Journal of Adhesion and Interface
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    • v.12 no.3
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    • pp.88-93
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    • 2011
  • Optimal dispersion and fabrication conditions of carbon nanotube (CNT) embedded in phenolic resin were determined by electrical resistance measurement; and interfacial property was investigated between plasma treated carbon fiber and CNT-phenolic composites by electro-micromechanical techniques. Wettability of carbon fiber was improved significantly after plasma treatment. Surface energies of carbon fiber and CNT-phenolic nanocomposites were measured using Wilhelmy plate technique. Since surface activation of carbon fiber, the advancing contact angle decreased from $65^{\circ}$ to $28^{\circ}$ after plasma treatment. It was consistent with static contact angle results of carbon fiber. Work of adhesion between plasma treated carbon fiber and CNT-phenolic nanocomposites was higher than that without modification. The interfacial shear strength (IFSS) and apparent modulus also increased with plasma treatment of carbon fiber.

Microdroplet Impact Dynamics at Very High Velocity on Face Masks for COVID-19 Protection (코로나-19 보호용 페이스 마스크에서의 액적 고속 충돌 거동)

  • Choi, Jaewon;Lee, Dongho;Eo, Jisu;Lee, Dong-Geun;Kang, Jeon-Woong;Ji, Inseo;Kim, Taeyung;Hong, Jiwoo
    • Korean Chemical Engineering Research
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    • v.60 no.2
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    • pp.282-288
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    • 2022
  • Facial masks have become indispensable in daily life to prevent infection and spread through respiratory droplets in the era of the corona pandemic. To understand how effective two different types of masks (i.e., KF-94 mask and dental mask) are in blocking respiratory droplets, i) we preferentially analyze wettability characteristics (e.g., contact angle and contact angle hysteresis) of filters consisting of each mask, and ii) subsequently observe the dynamic behaviors of microdroplets impacting at high velocities on the filter surfaces. Different wetting properties (i.e., hydrophobicity and hydrophilicity) are found to exhibit depending on the constituent materials and pore sizes of each filter. In addition, the pneumatic conditions for stably and uniformly dispensing microdroplets with a certain volume and impacting behaviors associated with the impacting velocity and filter type change are systematically explored. Three distinctive dynamics (i.e., no penetration, capture, and penetration) after droplet impacting are observed depending on the type of filter constituting the masks and droplet impact velocity. The present experimental results not only provide very useful information in designing of face masks for prevention of transmission of infectious respiratory diseases, but also are helpful for academic researches on droplet impacts on various porous surfaces.

Assessment of Maximum Spreading Models for a Newtonian Droplet Impacting on a Solid Surface (고체 표면에 충돌하는 뉴턴 액적에 대한 최대 액막 직경 모델 검토)

  • An, Sang-Mo;Lee, Sang-Yong
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.36 no.6
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    • pp.633-638
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    • 2012
  • The maximum spreading is the maximum extent to which a drop can spread after impacting on a surface. It is one of the crucial factors determining the spraying performance in many applications. In this study, the existing maximum spreading models for a Newtonian liquid droplet impacting on a dry solid surface were reviewed and compared with the experimental results over the ranges of $4{\leq}Re{\leq}11700$, $23{\leq}We{\leq}786$, and $37.9^{\circ}{\leq}{\theta}_s{\leq}107.1^{\circ}$. The surface wettability was found to have only a minor influence on the maximum spreading, compared to the liquid viscosity and impact velocity. Among the models tested, the Roisman (2009) model showed the best agreement with the experimental results, matching 80% of the measured data within ${\pm}5%$.

Nondestructive Microfailure and Interfacial Evaluation of Plasma-Treated PBO and Kevlar Fibers/Epoxy Composites using Micromechanical Test and Acoustic Emission (Micromechanical 시험법과 음향방출을 이용한 플라즈마 처리된 PBO와 Kevlar 섬유강화 Epoxy 복합재료의 비파괴적 파단특성 및 계면물성 평가)

  • 박종만;김대식;김성룡
    • Composites Research
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    • v.16 no.4
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    • pp.74-79
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    • 2003
  • Comparison of interfacial properties and microfailure mechanisms of oxygen-plasma treated poly(p-phenylene-2,6-benzobisoxazole(PBO. Zylon) and poly(p-phenylene terephthalamide)(PPTA, Kevlar) fibers/ epoxy composites were investigated using micromechanical technique and nondestructive acoustic emission(AE). Interfacial shear strength(IFSS) and work of adhesion, Wa of PBO or Kevlar fibers/epoxy composites increased by oxygen-plasma treatment. Plasma-treated Kevlar fiber shooed the maximum critical surface tension and polar term, whereas the untreated PBO fiber showed the minimum value. Microfibril fracture pattern of plasma-treated Kevlar fiber appeared obviously. Based on the propagation of microfibril failure toward core region. the number of AE events for plasma-treated PBO and Kevlar fibers increased significantly. The results oi nondestructive AE were consistent well with microfailure modes by optical observation in microdroplet and two-fiber composites tests.

Study on the Flow Characteristics of the Epoxy Resin w.r.t. Sizing Materials of Carbon Fibers (탄소섬유 사이징에 따른 에폭시 수지 유동 특성에 관한 연구)

  • Lim, Su-Hyun;On, Seung Yoon;Kim, Seong-Su
    • Composites Research
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    • v.31 no.6
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    • pp.379-384
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    • 2018
  • This paper aims to study flow characteristics of epoxy resin w.r.t. the sizing agents treated on the carbon fibers which have the same surface morphologies before sizing treatment. Dynamic contact angle (DCA) was measured to evaluate wettability of a single carbon fiber. Wicking test and Vacuum Assisted Resin Transfer Molding (VARTM) were performed to find relation between DCA measurement results and impregnation characteristics. In addition, surface properties of the carbon fibers such as surface free energy and chemical compositions were measured and interfacial shear strength (IFSS) between the carbon fiber and the resin were experimentally characterized by using micro-droplet tests. According to these experimental results, the sizing agent for carbon fibers should have appropriate level of surface free energy and good chemical compatibility with the resin to reconcile resin flow characteristics and interfacial strength.

Surface Treatment of Multi-walled Carbon Nanotubes for Increasing Electric Double-layer Capacitance (다중벽 탄소나노튜브의 표면처리에 따른 전기이중층 커패시터의 특성)

  • Kim, Ji-Il;Kim, Ick-Jun;Park, Soo-Jin
    • Journal of the Korean Chemical Society
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    • v.54 no.1
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    • pp.93-98
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    • 2010
  • In this work, the electrochemical properties of surface treated multi-walled carbon nanotubes (MWNTs) were studied. Nitrogen and oxygen functional groups of the MWNTs were introduced by urea and acidic treatment, respectively. The surface functional groups of the MWNTs were confirmed by X-ray photoelectron spectroscopy (XPS) measurements and zeta-potential method. The characteristics of $N_2$ adsorption isotherm at 77 K, specific surface area, and total pore volumes were investigated by BET eqaution, BJH method and t-plot method. Electrochemical properties of the functionalized MWNTs were accumulated by cyclic voltammetry at the scan rates of 50 $mVs^{-1}$ and 100 $mVs^{-1}$ in 1M $H_2SO_4$ as electrolytes. As a result, the functionalized MWNTs led to an increase of capacitance as compared with pristine MWNTs. It was found that the increase of capacitance for urea treated MWNTs was attributed to the increase in density of surface functional groups, resulting in improving the wettability between electrode materials and charge species.

Preparation and properties of glass fiber-reinforced endodontic (root canal therapy) posts (유리섬유 강화 근관치료 포스트의 제조 및 특성에 대한 연구)

  • Son, Jae-Yong;Kim, Kyoung-Ja;Kim, Kyoung-Hun;Park, Joo-Seok;Shim, Kwang-Bo
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.25 no.3
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    • pp.105-110
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    • 2015
  • The fiber-reinforced endodontic posts were prepared using a photocurable resin and a glass fiber. The mechanical property of the posts increased with increasing density of glass fiber and the micro-pores in the post were removed by a vacuum impregnation process. To improve the interfacial adhesion between glass fiber and polymer, silane coupling agent was used. The surface treatment of glass fiber increased the surface wettability of resing on glass fiber and increased the adhesion property with resin, consequently improved the mechanical property of posts.

Effect of Anodized Carbon Fiber Surfaces on Mechanical Interfacial Properties of Carbon Fibers-reinforced Composites (탄소섬유의 양극산화가 탄소섬유 강화 복합재료의 기계적 계면 특성에 미치는 영향)

  • 박수진;오진석;이재락
    • Composites Research
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    • v.15 no.6
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    • pp.16-23
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    • 2002
  • In this work, the effect of anodic oxidation on surface characteristics of high strength PAN-based carbon fibers was investigated in mechanical interfacial properties of composites. The surface properties of the carbon fibers were determined by acid-base values, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and contact angles. And their mechanical interfacial properties of the composites were studied in interlaminar shear strength (ILSS) and critical stress intensity factor ($K_{IC}$). As a result, the acidity or the $O_{ls}/C_{ls}$ ratio of carbon fiber surfaces was increased, due to the development of the oxygen functional groups. Consequently, the anodic oxidation led to an increase in surface free energy of the carbon fibers, mainly due to the increase of its specific (or polar) component. The mechanical interfacial properties of the composites, including ILSS and $K_{IC}$, had been improved in the anodic oxidation on fibers. These results were explained that good wetting played an important role in improving the degree of adhesion at interfaces between fibers and epoxy resin matrix.

EFFECTS OF VARIOUS SURFACE TREATMENTS FOR TITANIUM ON SURFACE MICRO ROUGHNESS, STATIC WETTABILITY, FIBRONECTIN ADSORPTION (표면 처리 방법에 따른 타이타늄의 미세 표면 거칠기, 표면 젖음성, fibronectin 흡착량에 미치는 영향)

  • Shin Hwa-Sub;Kim Young-Su;Shin Sang-Wan
    • The Journal of Korean Academy of Prosthodontics
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    • v.44 no.4
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    • pp.443-454
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    • 2006
  • Purpose: This study aims to get the fundamental data which is necessary to the development direction of implant surface treatment hereafter, based on the understanding the surface structure and properties of titanium which is suitable for the absorption of initial tissue fluid by researching effects of additional surface treatments fir sandblasted with large git and acid-etched(SLA) titanium on surface micro-roughness, static wettability, fibronectin adsorption Materials and Method: In the Control groups, the commercial pure titanium disks which is 10mm in diameter and 2mm in thickness were treated with HCI after sandblasting with 50$\mu$m $Al_2O_3$. The experiment groups were made an experiment each by being treated with 1) 22.5% nitric acid according to SLA+ASTM F86 protocol, 2) SLA+30% peroxide, 3) SLA+NaOH, 4) SLA+ Oxalic acid, and 5) SLA+600$^{\circ}C$ heating. In each group, the value of Ra and RMS which are the gauges of surface roughness was measured, surface wettability was measured by analyzing with Sessile drop method, and fibronectin adsorption was measured with immunological assay. The significance of each group was verified by (SPSS, ver.10.0 SPSS Inc.) Kruskal-Wallis Test. (α=0.05) And the correlation significance between Surface micro-roughness and surface wettability. surface roughness and fibronectin adsorption, and surface wettability and fibronectin adsorption was tested by Spearman's correlation analysis. Result: All measure groups showed the significant differences in surface micro-roughness, surface wettability, and fibronectin adsorption. (p<0.05) There was no significance in correlation among the surface micro-roughness, surface wettability, and fibronectin adsorption. (p>0.05) Conclusion: Surface micro-roughness and surface wettability rarely affected the absorption of initial tissue fluid on the surface of titanium.