• International Journal of Automotive Technology
• /
• 제6권6호
• /
• pp.665-670
• /
• 2005

Nanocomposites of polypropylene with organically modified clays were compounded on a twin-screw extruder by two-step melt compounding of three components, i.e., polypropylene, maleic anhydride grafted polypropylene (PP-g-MA), and organically modified clay. The effect of PP-g-MA compatibilizers, including PH-200, Epolene-43, Polybond-3002, Polybond-3200, with a wide range of maleic anhydride (MA) content and molecular weight was examined. Morphologies of nanocomposites and their mechanical properties such as stiffness, strength, and impact resistance were investigated. X-ray diffraction patterns showed that the dispersion morphology of clay particles seemed to be determined in the first compounding step and the further dispersion of clays didn't occur in the second compounding step. As the ratio of PP-g-MA to clay increased, the clay particles were dispersed more uniformly in the matrix resin. As the dispersibility of clays was enhanced, the reinforcement effect of the clays increased, however impact resistance decreased.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2000년도 봄 학술발표회 논문집
• /
• pp.663-668
• /
• 2000

In this study, the Atterberg limit and grain-size analysis were carried for the purpose of investigating the influence on drying and organic matter of Ulsan marine deposited clay. The results revealed that Atterberg limit was decreased and grain-size distribution was variable on drying. The presence of organic matter also influenced on the physical properties of the soils. The physical properties of marine deposited clay were variable on drying, so that we recommended grain-size analysis and Atterberg limit test were performed under the wet condition of the soils after sampling.

• 한국전기전자재료학회논문지
• /
• 제26권2호
• /
• pp.126-133
• /
• 2013

This paper presents a study on the dispersion effect of the X-Ray diffraction, glass transition and DMA properties of organic modifier clay/epoxy nanocomposites produced in a homogenizer. Several experiments were conducted including different types of dispersion condition with varying processing conditions such as homogenizer rotor speed and applied time of homogenizer. The effects of these variables on the dispersion properties of nanocomposites were then studied. In order to fully understand the experimental results, a X-ray diffraction, DSC and DMA were used to investigate the effect of above mentioned variables on microstructure and intercalation/exfoliation of organic modifier clay/epoxy nanocomposites. The results from this work could be used to determine the best processing condition to obtain appropriate levels of d-spacing, glasss transition temperature and storage modulus in organic modifier clay/epoxy nanocomposites.

• Journal of Ginseng Research
• /
• 제9권1호
• /
• pp.36-41
• /
• 1985

The study was conducted to investigate the changes of soil physico-chemical properties between soils of preplanting fields and 2 years old ginseng fields, and compare the missing plant rate among the 2 years 016 ginseng fields. 1, The missing plant rate of 2 years old ginseng was high in sand loam while low in clay loam soil texture, soil porosity and NO3-N were remarkably increased in 2 years old ginseng field than preplanting soil, as the clay content was increased, soil porosity seemed to be increased but exchangeable nitrogen decreased. 2. The preplanting soil management methods did not significantly influenced on the missing plant rate and soil porosity in 2 years old ginseng fields, However NO3-N content and Fusarium density seemed to be decreased as the plow frequency was increased, exchangeable nitrogen content, whereas, seemed to be increased with more organic matter. 3. Differences of clay content (below 15% and above 20% of clay content) was significantly influenced on soil porosity, bulk density, total nitrogen, organic matter and P2O5 content. 4, Missing rate showed negative correlation with clay, soil moisture, and organic matter content but positive corelation with NO3-N in 2 years old ginseng fields.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제22권1호
• /
• pp.27-32
• /
• 2017

Cesium (Cs) generated by nuclear accidents is one of the most hazardous radionuclides because of its gamma radiation and long half-life. Especially, when Cs is exposed on the soil environments, Cs is mainly adsorbed on the topsoil and is strongly combined with tiny soil particle including clay minerals. The adsorption of Cs onto soil can vary depending on various physicochemical properties of soil. In this study, the adsorption characteristics between soil and Cs were investigated according to various physicochemical properties of soil including organic matter contents, cation exchange capacity (CEC), soil particle size, and the types of clay minerals. Soil organic matter inhibited the adsorption of Cs onto the soil because organic matter was blocking the soil surface. In addition, it was estimated that the CEC of the soil influenced the adsorption of Cs onto the soil. Moreover, more Cs was adsorbed as the soil particles size decreased. It was estimated that Cs was mostly adsorbed onto the topsoil, this is related to the clay mineral. Therefore, soil organic matter, CEC, soil particle size, and clay minerals are considered the key factors that can influence the adsorption characteristics between soil and Cs.

• 청정기술
• /
• 제19권4호
• /
• pp.401-409
• /
• 2013

폐플라스틱에 의한 환경오염 증가로 생분해성 고분자에 대한 관심이 커지고 있다. 본 연구에서는 생분해성 고분자인 폴리 L-락타이드(polylactic acid, PLA)와 폴리 L-락타이드(polylactic acid, PLA)/폴리 부틸렌 숙신산(polybutylene succinate, PBS)(90/10)수지를 기지재료로 하고 유기 크로사이트(cloisite ) 20을 나노 클레이(clay) 20으로 사용하여 이축압출기에서 Clay-20 함량별 로 압출시켜 나노복합체를 제조하였다. 사출성형기로 사출성형시편을 제조하여 나노복합체의 열적, 기계적, 형태학적 및 라만 분광학 특성을 시차열량분석기(differential scanning calorimeter, DSC), 인장시험기, 주사전자현미경(scanning electron microcopy, SEM), 라만-현미경 분광광도계로 조사하였고, 또한 가수분해특성을 조사하였다. 시차열량분석기와 주사전자현미경 시험 결과에서 PLA/Clay-20과 PLA/PBS/Clay-20 나노복합체의 결정화도가 Clay-20 함량이 증가함에 따라 증가하였고, Clay-20과 PLA 및 PLA/PBS 수지가 서로 상용성이 있는 것으로 확인되었다. 또한 Clay-20 함량이 증가함에 따라 두 나노복합체의 인장강도는 감소하지만 신도, 충격강도, 인장탄성률 및 굴곡탄성률이 증가하였다. 특히 Clay-20이 5 wt% 첨가된 PLA/Clay-20과 PLA/PBS/Clay-20 나노복합체의 충격강도는 순수 PLA와 PLA/PBS (90/10) 보다 2배 이상으로 증가하였다. Clay-20 3 wt% 첨가된 PLA/Clay-20 나노복합체의 가수분해속도는 순수 PLA 가수분해속도보다 두 배 정도 빨랐다. 이는 유기화 처리된 Clay-20 나노입자 표면의 친수성으로 계면에서 가수분해가 쉽게 일어나기 때문인 것으로 판단된다. 본 연구에서 적당량의 Clay-20 첨가로 PLA의 기계적특성 개선과 생분해 특성 조절 가능성을 확인하였다.

• Current Research on Agriculture and Life Sciences
• /
• 제31권1호
• /
• pp.18-24
• /
• 2013

This work attempted to fabricate organic/inorganic nanocomposite by combining organic cellulose nanofibrils (CNFs), isolated by 2,2,6,6-tetramethylpiperidine-1-oxy radical (TEMPO)-mediated oxidation of native cellulose with inorganic nanoclay. The morphology and dimension of CNFs, and tensile properties and thermal stability of CNF/clay nanocomposites were characterized by transmission electron microscope (TEM), tensile test, and thermogravimetry (TG), respectively. TEM observation showed that CNFs were fibrillated structure with a diameter of about $4.86{\pm}1.341nm$. Tensile strength and modulus of the hybrid nanocomposite decreased as the clay content of the nanocomposite increased, indicating a poor dispersion of CNFs or inefficient stress transfer between the CNFs and clay. The elongation at break increased at 1% clay level and then continuously decreased as the clay content increased, suggesting increased brittleness. Analysis of TG and derivative thermogravimetry (DTG) curves of the nanocomposites identified two thermal degradation peak temperatures ($T_{p1}$ and $T_{p2}$), which suggested thermal decomposition of the nanocomposites to be a two steps-process. We think that $T_{p1}$ values from $219.6^{\circ}C$ to $235^{\circ}C$ resulted from the sodium carboxylate groups in the CNFs, and that $T_{p2}$ values from $267^{\circ}C$ to $273.5^{\circ}C$ were mainly responsible for the thermal decomposition of crystalline cellulose in the nanocomposite. An increase in the clay level of the CNF/clay nanocomposite predominately affected $T_{p2}$ values, which continuously increased as the clay content increased. These results indicate that the addition of clay improved thermal stability of the CNF/clay nanocomposite but at the expense of nanocomposite's tensile properties.

• 공업화학
• /
• 제33권5호
• /
• pp.502-522
• /
• 2022

Clay minerals are natural materials that show widespread applications in various branches of science, including environmental sciences, in particular the remediation of water contaminated with various water pollutants. Modified clays and minerals have attracted the attention of researchers in the recent past since the modified materials are seemingly more useful and efficient for removing emerging water contaminants. Therefore, modified engineered materials having multi-functionalities have received greater interest from researchers. The advanced clay-based materials are highly effective in the remediation of water contaminated with organic and inorganic contaminants, and these materials show enhanced selectivity towards the specific pollutants. The review inherently discusses various methods employed in the modification of clays and addresses the challenges in synthesizing the advanced engineered materials precursor to natural clay minerals. The changes in physical and chemical properties, as investigated by various characterization techniques before and after the modifications, are broadly explained. Further, the implications of these materials for the decontamination of waterbodies as contaminated with potential water pollutants are extensively discussed. Additionally, the insights involved in the removal of organic and inorganic pollutants are discussed in the review. Furthermore, the future perspectives and specific challenges in the scaling up of the treatment methods in technology development are included in this communication.

• 자원환경지질
• /
• 제32권2호
• /
• pp.151-159
• /
• 1999

This research was carried out to evaluate the possible usage of natural clay materials collected from the Kimpo landfill site and nearby clay mines as a clay liner material. In order to evaluate the possible usage as a clay liner material, specific gravity, pH, loss-on-ignition, organic carbon content and mineralogical composition of clay materials were measured. The Atterberg limit test and the size analysis were performed for the engineering classification and the prediction of hydraulic conductivity of clay materials. Caution exchange capacity and batch tests were also carried out for the assessment of attenuation capacity. Clay specimens of KPNCL, KP-1, KP-2 and SH were recommended as suitable clay linder materials from viewpoint of their basic quality and attenuation capacity.

• 한국농공학회지
• /
• 제39권6호
• /
• pp.80-87
• /
• 1997

A series of tests was performed to determine a threshold concentration of water-soluble organic permeant(ethanol) for permeability to be increased in clay and to estimate long-term permeability behaviors, effects of overburden pressure and compaction conditions on permeability in clay. Results of study are as follows ; 1. A threshold concentration of water-soluble organic permeant(ethanol) in clay was about 7O~8O% and its dielectric constant was 40, and dielectric constant seems to be closely related with absolute permeability. 2. Permeability of long-term tests was more or less larger than that of short-term tests. 3. Overburden pressures applied for a long time elapsed have little effects on the restriction of permeability increase. 4. Since water content has no effects of compaction capability when it is compacted with OMC or wet side of OMC, its permeability is to be estimated as same level of dry side of OMC. 5. Clays matured in the humid chamber are increased in permeability 2 times larger than unmatured ones. Thixotropy, therefore, should be considered in the design procedures because field conditions of construction would be quite similar to this..