• Title/Summary/Keyword: tear properties

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Manufacture of Specialty Paper with Hemp Bast Fiber Cultivated in Korea (Part 1) - Characteristics of Hemp-Wood Paper by Soda Pulping - (삼섬유를 이용한 특수기능지 개발 (제 1보) - 소다펄프화 삼 섬유의 수초지 특성 -)

  • Lee, Dah-Hee;Lee, Myoung-Ku
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.45 no.6
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    • pp.30-35
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    • 2013
  • To conserve wood resources for papermaking, chemical compositions of the hemp (Cannabis sativa L.) bast fiber cultivated in Korea such as holocellulose, ${\alpha}$-cellulose, lignin, alcohol-benzene extractives, hot and cold water extractives, and ash contents were investigated to manufacture the specialty packaging paper effectively. Significantly very low klason lignin content of 3.3% was accomplished by removing of the outer shell of bark. Laboratory soda pulping method which is very useful for the nonwood fiber was adapted, and it was found that there was no significant difference in both kappa number and H-factor between 25% and 30% NaOH charge. Hemp pulp cooked with the laboratory digester in 25% NaOH at $170^{\circ}C$ were mixed together with the wood pulp(NBKP:LBKP=1:1) in order to find the optimum mixture ratio which exhibited acceptable paper strength properties such as tensile index, burst index, and tear strength. When 10% of hemp soda pulps was mixed with 90% of wood pulps comprised of SwBKP and HwBKP (1:1), all physical strength increased significantly. The physical strength decreased as the amount of hemp pulp increased because the cell wall of bast fiber is very thick which causes low conformability and low fiber-fiber bonding. These results showed that paper made of hemp-wood pulp can be used for the specialty packaging paper which requires both the characteristic surface properties and the high physical strength of hemp fiber.

Study on the Characteristics of the Hybrid Parylene Thin Films (하이브리드 타입 패럴린의 박막 특성 연구)

  • Cha, Gook-Chan;Lee, Ji-Yeon;Jung, Seong-Hee;Song, Jeom-Sik;Lee, Suk-Min
    • Elastomers and Composites
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    • v.45 no.4
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    • pp.298-308
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    • 2010
  • The mechanical properties and surface characteristics of parylene thin film were improved using Xylydene-based dimers (DPX-C, DPX-D, and DPX-N). A single-parylene-C, D, N film and a hybrid chemical and physical parylene thin films in which two types are mixed were manufactured for each dimer by adjusting the deposition conditions and the thickness of the thin film by input. Parylene was deposited by chemical vapor deposition (CVD) and the thermal characteristics of the single thin film and the hybrid thin film were compared by thermal analysis. The mechanical properties of the thin films were characterized by tensile strength, elongation, and tear force tests, and the surface characteristics of the thin films were evaluated by contact angle and surface energy measurements. The hybrid chemical parylene thin film in which two types are mixed can complement the strengths and weaknesses of the different dimers, while the physical parylene thin film can freely adjust the thin film characteristics of the coated surface and the opposite surface.

Properties of Rubbers and Coated Fabrics according to Different Cross-linking Density of Coating Agent (코팅제의 가교 밀도에 따른 고무와 코팅원단의 물성 변화)

  • Suhong Kim;Kisuk Sung;Doohyun Baik
    • Textile Coloration and Finishing
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    • v.35 no.1
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    • pp.8-19
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    • 2023
  • Silicone rubber is widely used in most industries due to diverse advantages like heat stability, UV stability, durability, chemical resistance, environment friendliness, inertness and so on. But there is limitation to expand applications due to relatively weak rubber strengths such as tensile strength and tear strength, especially in fabric coating applications. The purpose of this study is to find influence of coating agent on performances of rubber and coated fabrics and their correlation according to different crosslinking densities of silicone rubbers. Addition cure type of silicones were formulated using crosslinked MQ-type silicone resin consisting of M (R3SiO1/2) and Q (SiO4/2) and linear polymers. Raw materials used were; 1) linear vinyl endblocked polymers and vinyl functional MQ resin as main polymers, 2) linear silicone hydride polymers as crosslinkers, 3) platinum catalyst and 4) inhibitor to control curing speed. Rubber specimens were prepared to check mechanical strength using universal testing machine (UTM). Crosslinking density was calculated using Flory-Rhener equation using solvent swelling method. Differential scanning calorimetry (DSC) and scanning electron microscope (SEM-EDS) were used to characterize rubbers. Consequently, it was found that physical properties of silicone rubbers and coated fabrics can be expected by crosslinking density of rubbers. Silicone rubber formulations that contain 20 ~ 30 wt% of vinyl MQ resin showed strongest balanced performances.

Soil Media and Seeding Rates for the Establishment of Kentucky bluegrass Carpet-type Sod over a Plastic Sheet (플라스틱 시트 위에 재배한 켄터키 블루그래스(Poa pratensis) 카펫형 뗏장의 배양토 및 파종량)

  • Shim, Sang-Ryul;Jeong, Dae-Young
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.2 no.1
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    • pp.20-28
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    • 1999
  • Nine soil media when placed over a plastic sheet with three seeding rates were evaluated for influence on covering rate, height, growth, surface hardness, tear strength and sod establishment of Kentucky bluegrass. 1. Bark, peat and vermiculite over a plastic sheet had good effect in terms of the establishment of Kentucky bluegrass sod. 2. The good establishment of Kentucky bluegrass sod grown on bark, peat and vermiculite over a plastic sheet seemed to be caused by physical and chemical properties of each soil medium. 3. Sand, sandy loam, perlite and peatmoss caused poor effects on the covering rate, the growth, and the tear strength of Kentucky bluegrass. 4. Optimum seeding rate was $10g/m^2$ in terms of density and competition. 5. Good quality sod more depended on soil media than on seeding rates in this study.

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Cell Opening of High Resilience Polyurethane foam II. Structure Effect of Polyether Type Cell Opener (고탄성 폴리우레탄 발포체의 기포개방 II. 폴리에테르형 기포개방제의 구조 영향)

  • 송기천;이상목;이동호
    • Polymer(Korea)
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    • v.26 no.2
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    • pp.218-226
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    • 2002
  • For the preparation of high resilience polyurethane (PU) foams with polyether type cell openers which have different ethylene oxide (EO) content, molecular weight and chain structure, the influences of tell opener structure on the kinetics, rheology, structural stability, open cell content and mechanical properties of the obtained foam were investigated. It was observed that urea formation reaction was delayed with the increase of EO content and incorporation of ester linkage in cell opener molecule and was relatively independent on the molecular weight. With the rheological studies, the decreases of viscosity and storage modulus were confirmed for the increase of EO content and molecular weight, so that the resulted foam had low structural stability and high open cell content. The cell opener having ester linkage in molecule exhibited the lowest values of viscosity and storage modulus and the obtained foam has high open cell content. However, the structural stability increased due to the larger intermolecular interaction of ester linkage. The hardness, tensile strength, tear strength and elongation of foam were deteriorated with increase of EO content and molecular weight of tell opener. On the other hand, the cell opener having ester linkage in molecule improved the values of tensile strength, tear strength and elongation.

Exploration of Optimum Retention of Antibacterial Agents in Functional Packaging Paper (항균 포장원지내 항균소재의 최적 정착법 탐색)

  • Kim, Chul-Hwan;Kim, Jae-Ok;Jung, Jun-Ho;Cho, Sung-Hwan
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.34 no.2
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    • pp.298-305
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    • 2005
  • Antimicrobial packaging paper was prepared with a powder-type botanical antimicrobial agent from grapefruit seed extract (BAAG) and zeolite according to TAPPI standard method. The functional fillers containing BAAG fixed to CaCO$_3$ and zeolite were well retained in the fiber network by a retention aid such as cationic polyacrylamide, which was ascertained by the ash contents of paper and the SEM microphotographs. With addition of the functional fillers to paper, tensile strength and burst strength of the paper decreased by interference of the functional fillers with interfiber bonding but bending stiffness and tear strength increased by improved elastic modulus of paper and delayed transfer of tearing energy. Finally, it was confirmed that the antimicrobial packaging paper might be able to be used to make packaging bags and corrugated containers due to the minor deterioration of strength properties.

The Properties and Production of Hand-Made Paper Made from Various Plant Fibers (식물섬유 수초지의 제조와 물성에 대한 연구)

  • Lee, Hye-Ja;Lim, Hee-Jung;Bae, Hyun-Young;Mo, Tae-Wha;Yoo, Hye-Ja;Han, Young-Sook
    • Journal of the Korean Society of Clothing and Textiles
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    • v.32 no.9
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    • pp.1366-1375
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    • 2008
  • This studies were carried out in order to develope environmentally-friendly fiber materials and substitute resources of Paper mulberry. Various plant fibers such as New Zealand flax, Indian mallow, Kuzu vine and Yucca were used as raw materials of hand-made papers. We rotted these 4 kinds of plant fibers and removed non-cellulose. After rotting, the pulping rate(%) and the length of fibers in pulps were measured. The physical characteristics of papers made of various plants fiber were investigated and the probabilities of practical use were considered. The results were as follow: The non-cellulose contents of plant fibers were $30{\sim}40%$ and those contents must be lower down to 8% to be able to manufacture the hand made papers. The lignin in pulps were removed almost and the hemicellulose were partially removed to reach up to appropriate level of the pulp rates and fiber lengths. The more hemicellulose removed, the finer fiber thickness were and rapidly the lower Hanji tensile strength were. But the tear strength of these plants of hand-made papers do not decreased so much as tensile strength. So the property of 4 types of plant fibers might be of great advantages to make hand-made papers. Both tensile and tear strengths of Hanji of New Zealand flax, Indian mallow, Kuzu vine and Yucca were higher than Paper mulberry hand-made paper. When 30% of mulberry paper were mixed, the mixing effect showed maximum. Because of the functions of all plant fiber hand-made papers showed better than those of Paper mulberry hand-made paper, 4 types of plant fibers could be substitute Paper mulberry.

Adsorption Properties of the Lysozyme and Albumin with Physicochemical Properties of the Contact Lens (콘택트렌즈의 물리화학적 특성에 따른 라이소자임과 알부민의 흡착 특성)

  • Sung, Yu-Jin;Ryu, Geun-Chang;Jun, Jin
    • Journal of Korean Ophthalmic Optics Society
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    • v.18 no.3
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    • pp.261-270
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    • 2013
  • Purpose: Adsorption properties of lysozyme and albumin according to physiochemical properties of commercial contact lens classified with the FDA categories and a contact lens fabricated in the laboratory were investigated. Methods: The contact lens were prepared using HEMA(2-hydroxyethyl methacrylate) and TRIM(3-(trimethoxysilyl) propyl methacrylate) in a cast mold. Artificial tears containing lysozyme and albumin were prepared. We measured the amounts of protein adsorbed on the each lenses with varying adsorbed time (48 hour) and the pH range (6, 6.8, 7.4, 8.2, 9) of artificial tear. Amount of the proteins absorbed on the contact lenses were measured by using HPLC. Results: Time to reach the equilibrium of protein adsorption for silicone hydrogel lens was taken longer than hydrogel lens. The amount of adsorbed both lysozyme and albumin at equilibrium were greater for the hydrogel lens than the silicone hydrogel lens, and larger for the ionic lens than the non-ionic lens. Lysozyme was more adsorbed on the higher water content of contact lens, whereas albumin was more adsorbed on the lower water content of contact lens. Only lysozyme was adsorbed on the Group IV hydrogel lens of ionic higher water content. The adsorption of protein on contact lens increased with pH of artificial tears as close to the isoelectric point of each protein. Conclusions: The adsorption amount of lysozyme is more affected by the ionic strength of the contact lens surface than the water content of contact lens. Albumin adsorption is more affected by water content than the ionic strength of the contact lens surface. For the adsorption of proteins on the silicone hydrogel lens, the pore size, determined both by the number of Si atoms and the chemical structure of the silicone-containing monomers, as well as the polarity of contact lens should be also considered.

Cure Characteristics and Mechanical Properties of Ternary Accelerator System in NR/BR Compounds (NR/BR Compounds의 가황촉진제 병용에 의한 가황 특성 및 기계적 물성 연구)

  • Kim, Il-Jin;Kim, Wook-Soo;Lee, Dong-Hyun;Bae, Jong-Woo;Byon, Young-Hoo;Kim, Wonho
    • Korean Chemical Engineering Research
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    • v.47 no.4
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    • pp.403-409
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    • 2009
  • In the 1840s, Goodyear found out sulfur cure system, but cure time was too slow. So producing of rubber product takes a long time. In 1904, Oenslager et al. found that aniline is accelerated sulfur cure system. Recently, many rubber industries needed high yield and good quality. So, many researchers have studied a rubber system with fast vulcanization time and good mechanical properties. In this study, cure characteristics and mechanical properties of NR/BR compounds by accelerator with MBTS(2,2' Dithiobisbenzothiazole), TMTM(Tetramethylthiuram Monosulfide), ZDMC (Zinc dimethyldithiocarbamate), CBS(N-Cyclohexyl benzothiazolyl-2-sulfenamide), DPG(Diphenylguanidine) were evaluated. The results of the study indicate that cure charateristics($t_{90}$: 235 sec, $T_{max}$: 5.77 Nm) and mechanical properties (100, 300% modulus : 2,180, 5.656 Mpa and tear strength: 59.58 kgf/cm) of NR/BR compounds shows efficient acceleration with MBTS 1.5 phr, TMTM 0.5 phr, DPG 0.15phr. This is due to the synergistic activity of ternary accelerator system in rubber vulcanization.

A Study on the Flame Retardant Properties of EPDM Rubber Mixed with Phosphorus and Halogen Compound (인 및 할로겐 함유 EPDM 고무 혼합물의 난연 특성에 관한 연구)

  • Choi, Seong Su;Im, Wan-Bin;Kim, Jin Hong;Park, Young-ae W.;Woo, Je-Wan
    • Elastomers and Composites
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    • v.37 no.4
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    • pp.224-233
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    • 2002
  • This study has investigated the flame retardant properties of EPDM rubber with the addition of various flame retardants. Carbon black, stearic acid, zinc oxide cross-linking agent were mixed with EPDM rubber to produce the base rubber E0 without the addition of flame retardants. Phosphorus flame retardant Tricrecyl phosphate(TCP) was added to E0 in 0.5, 1, 1.5, 2 phr to make E1~E4 samples and red phosphorus was added in 3, 6, 9, 12 phr to make E5~E8 samples. A flame retardant of the bromine family Decabromodiphenyloxide(DBDPO), and a chlorinated paraffin retardant of the chlorine family was added to E0 in 3, 6, 9, 12 phr to make E9~E12 and E13~E16 samples, repectively. Basic physical properties such as tensile strength, tear strength and hardness were measured for all the rubber samples with various flame retardant additions. There was no substantial differences. On the other hand, Oxygen index and UL94 were measured to study flame retardant properties. From oxygen index measurements E0 sample showed a value of 23.5%, indicating the improvement of flame retardant properties. Also from UL94 measurements, it was found that addition of red phosphorus resulted in maximum flame retardant effect. It was found that increasing the amount of addition resulted in decreasing combustion rate and improving flame retardant effect regardless of the kind of flame retardant.