• Clean Technology
• /
• v.15 no.3
• /
• pp.180-185
• /
• 2009

The ethylene-propylene rubber (EPDM) scrap generated from automobile weatherstrip manufacturing process was used to make a thermoplastic elastomer through blending with polypropylene. The surface activated EPDM powder was obtained by the high temperature and shear pulverizer. The addition of surfactant resulted in more surface activated EPDM powder and the optimum loading amounts of surfactant was 1.5 phr. Maleic anhydride was grafted onto polypropylene by reactive blending to give functionalized polypropylene. The wetting property between EPDM scrap and polypropylene was improved by the addition of poly (ethylene-co-acrylic acid) as a compatibilizing agent. Poly(ethylene-co-acrylic acid) decreased the surface tension of polypropylene and thus would contribute to the wettability with EPDM powder.

• The Research Journal of the Costume Culture
• /
• v.30 no.6
• /
• pp.799-813
• /
• 2022

The environment has increasingly attracted attention and fashion brands need to use new growth models by developing eco-friendly products, along with the drastic climate change. This study drew design guidelines from the factors of clothing disposal and reuse to propose ways to extend the longevity of clothing. It sets the design goals for the longevity extension of clothing as flexibility, originality, durability, and adjustability and drew a specific design guideline. The design methods used to achieve such goals are as follows. First, the design that is flexible in terms of physical changes needs to increase its activity and to be changeable, by applying pleats, rubber bands and elastic materials to the parts with many physical changes and movements. Second, it is necessary to reinforce the brand identity, create design that is flexible in terms of fashion and design very rare and attractive products, for the goal of original design beyond fashion. Third, it is necessary to increase the quality of clothing and improve the durability which can be decreased by washing and wearing. Fourth, it is necessary to create the design that can produce various styles, preserve the state of clothing and maintain its hygienic conditions by using removable detailed designs, shape-transformation designs and the designs which can be adjusted to climate changes and states, for the goal of adjustable design with better functionality. The findings provide ideas for fashion experts to pay more attention to the extending the longevity of clothing products and to develop eco-friendly designs and strategies.

• Resources Recycling
• /
• v.10 no.3
• /
• pp.51-59
• /
• 2001

Impurities removal from waste carbon black was carried out to produce high-grade carbon black. A large amount of hydrophilic carbon black is produced as a byproduct of the hydrogen production process by flame decomposition of water. Due to its impurities content such as sulphur, iron, ash, etc., it can only be used as low-grade carbon or burnt out. High-grade hydrophilic carbon black is 3~5 times more expensive than oil-based carbon black because of high production cost associated with process complexly and pollutant treatment. Hydrophilic carbon is normally used for conductive materials for batteries, pigment for plastics, electric wire covering, additives for rubber, etc. In these applications, impurity content must be blow 1 fe. In this study, magnetic separation, froth flotation and ultrasonic treatment were employed to remove impurities from the low-grade hydrophilic carbon black. Results showed that the ash, iron and sulphur content of product decreased to less than 0.01 wt.%, 0.01 wt.% and 0.3 wt % respectively and the surface area of product was about 930 $m^2$/g for conductive materials.

• Elastomers and Composites
• /
• v.49 no.1
• /
• pp.31-36
• /
• 2014

Polyester polyols were synthesized by using each one mole of sebacic acid, isophthalic acid, ethylene glycol, and neopentyl glycol. The synthesized polyol had 56.6 mg KOH/g of hydroxy value and 1980 g/mole of molecular weight. From FT-IR structure analysis of polyester polyol, Hydroxy group(-OH) was observed around 3600 $cm^{-1}$, -CH shoulder of sebacic acid at 2950 $cm^{-1}$, carbony group of ester around 1730 $cm^{-1}$, and benzene ring of isophthalic ring was represented at 1600 $cm^{-1}$, 740 $cm^{-1}$. In case of polyurethane, hydroxy peak was showed at 3600 $cm^{-1}$, and -NH group around 3300 $cm^{-1}$, 1530 $cm^{-1}$. From $^1H$ NMR measurement of polyester polyol, it was found that sebacic acid was represented at 1.3, 1.5, 2.1 ppm, isophthalic acid at 7.3, 8.1, 8.7 ppm, ethylene glycol at 4.2 ppm, and neopentyl glycol at 0.8, 3.2, 3.9 ppm, respectively. In the polyurethane, it is almost the same as spectrum of polyester polyol, but showed very week peak at 7 ppm by benzene ring of toluene diisocyanate.

• Journal of the Korean Magnetics Society
• /
• v.15 no.2
• /
• pp.67-75
• /
• 2005

For th aim of lightweight microwave absorbers, conductive and magnetic microspheres are fabricated by plating of Co films on hollow ceramic microspheres of low density. Metal plating was carried out in a two-step electroless plating process (pre-treatment of activation and plating). Uniform coating of the film with about $2{\~}3{\cal}um$ thickness was identified by SEM. High-frequency magnetic and microwave absorbing properties were determined in the rubber composites containing the Co-coated microspheres. Due to conductive and ferromagnetic behavior of the Co thin films, high dielectric constant and magnetic loss can be obtained in the microwave frequencies. Due to those electromagnetic properties, high absorption rate (25 dB) and thin matching thickness ($2.0{\~}2.5{\cal}mm$) are predicted in the composite layers containing the metal-coated microspheres of low density (about 0.84 g/cc) for the electromagnetic radiation in microwave frequencies.

• Journal of the Korean Magnetics Society
• /
• v.19 no.6
• /
• pp.203-208
• /
• 2009

Magnetic and Ka-band absorbing properties have been investigated in Ti-Co substituted M-type barium hexaferrites with $BaTi_{0.5}Co_{0.5}Fe_{11}O_{19}$ composition. The ferrite powders were prepared by conventional ceramic processing technique and used as absorbent fillers in ferrite-rubber composites. The magnetic properties were measured by vibrating sample magnetometer. The complex permeability and dielectric constant were measured by using the WR-28 rectangular waveguide and network analyzer in the frequency range 26.5~40 GHz. For the Ti-Co substituted M-hexaferrites, the ferromagnetic resonance is observed at Ka-band (29.4 GHz). The matching frequency and matching thickness are determined by using the solution map of impedance matching. A wide band microwave absorbance is predicted with controlled ferrite volume fraction and absorber thickness.

• Journal of Adhesion and Interface
• /
• v.16 no.1
• /
• pp.29-34
• /
• 2015

Hydrocarbon resins, which are defined as low molecular weight, amorphous, and thermoplastic polymers, are widely used as tackifier for various types of adhesives, as processing aids in rubber compounds, and as modifiers for plastics polymers such as isotactic polypropylene. Typically, hydrocarbon resins are non-polar, and thus highly compatible with non-polar rubbers and polymer. However, they are poorly compatible with polar system, such as acrylic copolymer, polyurethanes, and polyamides. Moreover, recently the raw materials of hydrocarbon resin from naphtha cracking had been decreased because of light feed cracking such as gas cracking. To overcome this problem, in this study, novel hydrocarbon resins were designed to have a highly polar chemical structure which material is sustainable. And, it was successfully synthesized by Diels-Alder reaction of dicyclopentadiene monomer and sorbic acid from blueberry as renewable resources. Acrylic resins were formulated with various tackifiers solution including sorbic acid grafted hydrogenated dicyclopentadiene hydrocarbon resins in acrylic adhesive and rolling ball tack, loop tack, $180^{\circ}$ peel adhesion strength, and shear adhesion strength were measured. The properties depend on the softening point and polar content of tackifiers.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.30 no.2
• /
• pp.173-180
• /
• 2004

Nano sized ZnO particle as 20-30nm applies for material, pigments, rubber additives, gas sensors, varistors, fluorescent substance as well as new material such as photo-catalyst, sensitizer, fluorescent material. ZnO with a particle size in the range 20-30nm has provided to be an excellent UV blocking material in the cosmetics industry, which can be used in sunscreen product to enhance the sun protection factor and natural makeup effect. But pure ZnO particles application limits for getting worse wearing feeling. We make high-functional inorganic-composite that coated with nano-ZnO on the plate-type particle such as sericite, boron nitride and bismuthoxychloride. In this experiment, we synthesized composite powder using hydrothermal precipitation method. The starting material was ZnCl$_2$ Precipitation materials were used hexamethylenetetramine(HMT) and urea. We make an experiment with changing as synthesis factors that are concentrations of starting material, precipitation materials, nuclear formation material, reaction time, and reaction temperature. We analyzed composite powder's shape, crystallization and UV-blocking ability with FE-SEM, XRD, FT-IR, TGA-DTA, In vitro SPF test. The user test was conducted by product's formulator. In the results of this study, nanometer sized ZnD was coated regardless of the type of plate-powder at fixed condition range. When the coated plate-powders were applied in pressed powder product, the glaze of powder itself decreased, but natural make-up effect, spreadability, and adhesionability were increased.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.32 no.6
• /
• pp.349-357
• /
• 2019

Finite element method (FEM) is utilized in the development of products to realistically analyze and predict the mechanical behavior of materials in various fields. However, the approach based on the numerical analysis of glass fiber reinforced plastic (GFRP) composites, for which the fiber orientation and strain rate affect the mechanical properties, has proven to be challenging. The purpose of this study is to define and evaluate the mechanical properties of glass fiber reinforced plastic composites using the numerical analysis models of Digimat, a linear, nonlinear multi-scale modeling program for various composite materials such as polymers, rubber, metal, etc. In addition, the aim is to predict the behavior of realistic polymeric composites. In this regard, the tensile properties according to the fiber orientation and strain rate of polybutylene terephthalate (PBT) with short fiber weight fractions of 30wt% among various polymers were investigated using references. Information on the fiber orientation was calculated based on injection analysis using Moldflow software, and was utilized in the finite element model for tensile specimens via a mapping process. LS-Dyna, an explicit commercial finite element code, was used for coupled analysis using Digimat to study the tensile properties of composites according to the fiber orientation and strain rate of glass fibers. In addition, the drawbacks and advantages of LS-DYNA's various anisotropic material models were compared and evaluated for the analysis of glass fiber reinforced plastic composites.

• Journal of Adhesion and Interface
• /
• v.4 no.1
• /
• pp.28-34
• /
• 2003

Steel tire cords were subjected to plasma polymerization coating of acetylene in order to enhance the adhesion to rubber compounds. Plasma polymerization coating was varied to plasma polymerization coating of acetylene, argon plasma etching+plasma polymerization, or argon plasma. etching+plasma polymerization with Ar carrier gas. Adhesion was evaluated via TCAT samples and compared to those with brass coated tire cord. For durability study, plasma polymer cooled tire cords were aged in lab atmosphere for 1, 3, 5, 10 or 15 days, while TCAT specimens prepared with plasma polymer coated tire cords were aged in distilled water, 10% NaCl solution or $100^{\circ}C$ oven for 1, 2, 3 or 4 weeks. After testing, failure surfaces were analyzed with SEM/EDX. Among the treatments, the highest adhesion was obtained by Ar etching+acetylene plasma. polymerization coating with Ar carrier gas, providing almost same pull-out force as the brass coated tire cords. Upon the aging of the tire cords in the lab atmosphere, brass coated tire cords provided better adhesion than plasma polymer coated tire cords, while the TCAT samples with plasma polymer coated tire cords exhibited similar or slightly superior durability to those with brass coated tire cords.