• Title/Summary/Keyword: 가소성

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Pressure Sensitive Adhesion Performances of SIS/SBS based UV-curable Pressure Sensitive Adhesives using Thiol-ene Reaction (Thiol-ene 반응을 이용한 UV경화형 SIS/SBS계 점착제의 점착물성)

  • Lim, Dong-Hyuk;Do, Hyun-Sung;Kim, Hyun-Joong;Yoon, Goan-Hee;Bang, Jung-Suk
    • Journal of Adhesion and Interface
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    • v.6 no.3
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    • pp.19-25
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    • 2005
  • Synthetic rubber based pressure-sensitive adhesives (PSAs) usually containing SIS or SBS block copolymer, tackifier, plasticizer, and other additives are now widely used on various applications. As these PSAs are physically crosslinked and can be applied without the use of solvent, they are thermally processable and environmentally friendly. However these PSAs cannot be used in high temperature applications and in applications where solvent and chemical resistance properties are required. We developed the PSA adding UV curable system, such as thiol-ene system, to increase adhesion properties at elevated temperature. The adhesion properties such as probe tack, peel strength, shear adhesion failure temperature (SAFT) were evaluated. The probe tack test was conducted with varying probe materials and coating thickness of PSAs. Using the contact angle, the surface property of the cured PSAs was also observed.

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Shear Strength Property of Wood Treated by Steam Treatment at High Temperature (고온수증기처리 목재의 전단강도 특성)

  • Kim, Jung-Hwan;Lee, Weon-Hee;Kim, Jong-Man
    • Journal of the Korean Wood Science and Technology
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    • v.29 no.4
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    • pp.9-15
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    • 2001
  • This study deals with shear strength test for Pinus densiflora and Pinus radiata treated at above $100^{\circ}C$ by heat steam. Treatment conditions of this experiment were operated at regular intervals of $20^{\circ}C$ at temperatures up to $200^{\circ}C$ for 5, 10, 20 and 30 minutes by using the steam-explosion apparatus. It was examined, at high temperatures, degradation of some compounds from wood composition could lead to reduced the shear strength through heat steaming processes and play a large part in the plastic process of solid wood materials. It could be estimated that the shear strength of woods were gradually reduced by heat steaming time. Remarkable reduction of shear strength of woods was observed with increasing steaming temperatures above 10 minutes steaming time. Furthermore, this phenomenon shows a tendency to increase with higher temperatures. Therefore, it was considered that the softening by steaming treatment at high temperatures is necessary for the improvement on the wood processing ability.

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Properties of Polyamide Modified PVC-sol Sealants (II) (폴리아미드가 함유된 PVC졸 실란트의 물성 (II))

  • Lee, Seung-Jin;Kim, Hyun-Kyo;Park, Hwan-Man;Cho, Won-Jei;Ha, Chang-Sik
    • Elastomers and Composites
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    • v.34 no.1
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    • pp.53-64
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    • 1999
  • The mechanical, electrical, and thermal properties of polyamide-modified poly (vinyl chloride) (PVC)-sol was investigated. PVC-sol was plasticized with dioctyl phthalate (DOP). In this work, the effects of the addition of polyamide on the properties of PVC-sol seal-ants were investigated. Two kinds of polyamide resins having different amine value were used. It was found that the properties of the PVC-sol sealants were significantly affected by the contents and types of the added polyamide rosins. The PVC-sol sealants modified with polyamide A (low amino value) showed higher tensile properties than those modified with polyamide B(high amino value) did, and thermal stability of the sealants showed nearly the same trends. The tensile strength of sealants were decreased with increasing the $CaCO_3$ contents. The dielectric constant were not strongly dependent on the polyamide types and contents.

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Influence of Cutting Frequency on Yield and Growth Response of Grasses and Legumes in Germany (초지에서 예취회수의 경감이 수량 및 식생에 미치는 영향)

  • Ryoo, Jong Won
    • Korean Journal of Soil Science and Fertilizer
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    • v.31 no.1
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    • pp.33-38
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    • 1998
  • Field experiment was conducted from 1991 to 1993 at $Allg\ddot{a}u$ south western Germany to determine the effects of cutting frequencies on the yield and growth responses in intensively used grassland. Cutting frequency, 3 cutting(reduced) and 6 cutting(conventional) were tested. The yield, protein content, in vitro digestible dry matter and net energy value were markedly reduced with 3 cutting. Distribution ratio of grasses and legumes was not different between 3 and 6 cutting frequencies. However, the distribution of Dactylis glomerta at 3 cutting frequency was increased and that of Lolium perenne decreased. Nitrogen uptake by the plants at 6 cutting frequency was higher, 443kg/ha, than 308kg/ha of 3 cutting frequency.

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Adsorption and Release Characteristics of Sulindac on Chitosan-based Molecularly Imprinted Functional Polymer Films (키토산 기반 분자 각인 고분자 필름의 슐린닥 흡착 및 방출 특성)

  • Yoon, Yeon-Hum;Yoon, Soon-Do;Nah, Jae Woon;Shim, Wang Geun
    • Applied Chemistry for Engineering
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    • v.30 no.2
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    • pp.233-240
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    • 2019
  • Molecular recognition technology has attracted considerable attention for improving the selectivity of a specific molecule by imprinting it on a polymer matrix. In this study, adsorption and release characteristics of chitosan based drug delivery films imprinted with sulindac (SLD) were investigated in terms of the plasticizer, temperature and pH and the results were also interpreted by the related mathematical models. The adsorption characteristics of target molecules on SLD-imprinted polymer films were better explained by the Freundlich and Sips equation than that of the Langmuir equation. The binding site energy distribution function was also useful for understanding the adsorption relationship between target molecules and polymer films. The drug release of SLD-imprinted polymer films followed the Fickian diffusion mechanism, whereas the drug release using artificial skin followed the non-Fickian diffusion behavior.

Chewable pet treats made from mushroom mycelia (버섯 균사체로 제조된 반려동물용 개 껌)

  • Yong-Hyeon Jeong;Ho-Seong Im;Jin-Hee Song;Hui-Won Heo;Hyun-Jae Shin
    • Journal of Mushroom
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    • v.22 no.1
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    • pp.17-21
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    • 2024
  • Mushroom-based vegan meat has thus far been used as a food for humans instead of pets. However, based on its texture and nutritional content, it is considered suitable for processing into pet treats. In the present study, we developed a prototype dog chew with a sweetening coating added to a fungal mycelium mat obtained by culturing the Basidiomycetous fungus Trametes orientalis. The palatable coating applied to the mycelium mat by plasticizing the mat with glycerol improved the taste and aroma of the existing mat, and the dog consumed it without difficulty. Future improvements may include a softening process to reduce the chewiness level and a procedure to reduce the crude fiber content. Mycelium-mat-based dog chews, manufactured using eco-friendly materials and processes that are not harmful to the environment are expected to enter the market as eco-friendly alternatives to conventional pet treats. Controlling their physical properties require further study.

Study of Polysulfone Membrane for Membrane-covered Oxygen Probe System (산소 전극 시스템에 사용되는 polysulfone막에 대한 연구)

  • Hong, Suk In;Kim, Hyun Joon;Park, Hee Young;Kim, Tae Jin;Jeong, Yong Seob
    • Applied Chemistry for Engineering
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    • v.7 no.5
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    • pp.877-887
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    • 1996
  • The ideal membranes for membrane-covered oxygen probes system should be selectively permeable for oxygen and chemically inert, and have good mechanical strength. Polysulfone(PSf) was selected to develop the membrane for membrane-covered oxygen electrodes system. PSf membranes have properties such as good reproducibility, good mechanical strength, chemical inertness, and high heat resistance. PSf membranes were cast from polymer solution on the glass plate at constant temperature, and casting solvents used were tetrahydrofuran(THF), methylene chloride, and N-methyl-2-pyrrolidone(NMP). Tricresyl phosphate(TCP) as plasicizer was added to PSf to increase the softness of membrane. The permeation characteristics were observed for pure oxygen and nitrogen through pure PSf membranes by variable volume method and membrane-covered electrode system. The permeability coefficients of oxygen and nitrogen measured by variable volume method were slightly decreased with increasing of upstream pressure. The permeation properties of PSf membrane using methylene choride as casting solvent were not affected by the PSf amount of polymer solution. The permeability coefficients of oxygen and nitrogen for PSf membrane containing TCP were very slightly lower than those for pure PSf membrane, but ideal separation factors were slightly higher. The flexibility of PSf membrane containing 2wt% TCP was better than that of pure PSf membrane. It was expected that this increase in flexibility would solve the difficulty of fixing the membrane to the cathode. The membrane-covered oxygen probes system was composed of anode, cathode and electrolyte. The type of the anode was Ag/AgCl half-cell, that of cathode was Ag, and the electrolyte was 4N KCl solution. The result of sampled current voltametry for PSf membrane showed the plateu region at -0.3V~-1.0V. The correlation coefficient of oxygen partial pressure versus current for PSf membrane was relatively high, 0.99949. It was concluded that PSf membrane was the good candidate for the membrane-covered oxygen probes system.

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Comparison of Forage Productivity and Quality of Italian Ryegrass and Barley Mono, and Mixtures Sown in Early Spring (이탈리안 라이그라스와 청보리의 이른 봄 단파 및 혼파 재배 시 생산성과 사료가치 비교)

  • Seo, Sung;Chung, Eui-Soo;Kim, Ki-Yong;Choi, Gi-Jun;Ahn, Jong-Nam;Han, Jong-Seok;Park, Hyun-Kyung;Kim, Yong-Su
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.30 no.2
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    • pp.115-120
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    • 2010
  • This study was carried out to determine the forage production and quality of Italian ryegrass (IRG) and forage barley sown in early spring in Suwon, 2009. The five treatments used in this experiment were IRG Kowinearly (early maturity), IRG Kowinmaster (medium maturity), Yuyeon barley, Kowinearly + Yuyeon mixture, and Kowinmaster + Yuyeon mixture. The lodging was observed in IRG, but no lodging was found IRG + barley mixtures. The heading date of Kowinearly and Kowinmaster were 16 May and 22 May, respectively, and that of barley was 13 May. The dry matter (DM) percentage at harvest was 22.2~27.6%. The forage quality among treatments were similar, but the crude protein (CP) content of IRG was higher than that of barley, and in vitro DM digestibility was a little low in Kowinmaster. The yields of DM, CP and digestible DM were high in Kowinearly + Yuyeon barley mixtures as a 13,816 kg, 1,384 kg and 10,387 kg per ha, respectively (p<0.05). In conclusion, the mixture cultivation of IRG and forage barley was very effective, because of preventing of IRG lodging, increasing of forage yield, and stable production of forages. The optimum harvest date for silage manufacture of IRG and barley sown in early spring was recommended early June instead of May.

THE EFFECT OF REPEATED MATERNAL SEPARATION ON GLUCOCORTICOID RECEPTOR AND CYCLOOXYGENASE-2 IN PREWEANLING RAT BRAIN (반복 모성 분리가 이유 전기 백서 뇌의 Glucocorticoid Receptor와 Cyclooxygenase-2에 미치는 영향)

  • Yoon, Doh-Joon;Chang, Hwan-Il;Song, Ji-Young;Bahn, Geon-Ho;Chung, Joo-Ho;Kim, Jong-Woo;Yoo, Hee-Jeong
    • Journal of the Korean Academy of Child and Adolescent Psychiatry
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    • v.15 no.1
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    • pp.91-100
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    • 2004
  • Objectives:The effects of repeated maternal separation on the expression of glucocorticoid receptor (GR) and cyclooxygenase-2(COX-2) in the hippocampus of rat pups at preweanling stage were evaluated. Methods:The experimental, Repeated Maternal Separation group(N=4) was separated from the mother for four hours a day over a period of ten days beginning with postnatal day 4. The Control group(N=4), on the other hand, did not separated from the mother at all. GR and COX-2 expression in the hippocampus was examined by immunohistochemistry on postnatal day 14. Results:It was determined that the number of GR-immunopositive cells in the dentate gyrus of the hippocampus was significantly increased in the Repeated Maternal Separation group. The numbers of COX-2-immunopositive cells in the CA1 and CA3 were also significantly higher in the Repeated Maternal Separation group. Conclusion:These results suggest that maternal separation may be a significant developmental stress that induces GR and COX-2 expression in the hippocampus of developing pups.

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Preparation of Polymer Gel Electrolyte for EDLCs using P(VdF-co-HFP)/PVP (P(VdF-co-HFP)/PVP를 이용한 EDLC용 고분자 겔 전해질의 제조)

  • Jung, Hyun-Chul;Jang, In-Young;Kang, An-Soo
    • Applied Chemistry for Engineering
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    • v.17 no.3
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    • pp.243-249
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    • 2006
  • Porous polymer gel electrolytes (PGEs) based on poly(vinylidenefluoride-co-hexafluoropropylene) (P(VdF-co-HFP)) as a polymer matrix and polyvinylpyrolidone (PVP) as a pore-forming agent were prepared and electrochemical properties were investigated for an electric double layer capacitor (EDLC) in order to increase a permeability of an electrolyte into the PGE. Propylene carbonate (PC) and ethylene carbonate (EC) as plasticizers, and tetraethylammonium tetrafluoroborate ($TEABF_4$) as a supporting salt for the PGE were used. EDLC unit cells were assembled with the PGE and electrode comprising BP-20 and MSP-20 as activated carbon powders, Super P as a conducting agent, and P(VdF-co-HFP)/PVP as a mixed binder. Ion conductivity of PGEs increased with an increased PVP content and was the best at 7 wt% PVP, whereas electrochemical characteristics such as AC-ESR of unit cell were better in 3 wt%. And electrochemical characteristics of the unit cell with PGE were the best at a 33 : 33 weight ratio of PC to EC. Specific capacitance of a mixed plasticizer system of PE and EC was higher than that of pure PC. Ion conductivity of PGEs with a film thickness of $20{\mu}m$ was higher, but electrochemical characteristics of unit cells were higher for a $50{\mu}m$ membrane thickness. Also, the unit cell has shown the highest capacitance of 31.41 F/g and more stable electrochemical performance when PGE and electrode were hot pressed. Consequently, the optimum composition ratio of PGE for EDLCs was 23 : 66 : 11 wt% such as P(VdF-co-HFP) : PVP = 20 : 3 wt% and PC : EC = 44 : 22 wt%. In this case, $3.17{\times}10^{-3}S/cm$ of ion conductivity was achieved at the $50{\mu}m$ thickness of PGE for EDLCs. And the electrochemical characteristics of unit cells were $2.69{\Omega}$ of DC-ESR, 28 F/g of specific capacitance, and 100% of coulombic efficiency.