• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.269-272
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• 2005

Epoxy resins are gradually becoming some of the most important and versatile polymers in modem civil engineering. Because epoxy resins have some unigue properties, such as toughness, versatility of viscosity and curing conditions, good handling characteristics, high adhesive strength, inertness, low shrinkage compared to most other thermo-setting resins and concrete, and resistance to chemicals, they have found many applications in construction castings, repair materials, road or bridge deck pavements, coatings, and as structural or non structural adhesives. In this applications, epoxy resins are widely used for polymer concretes, grouting materials, injection glues, and sealants. In this paper, characteristics of deformation of repair material after repaired have been investigated by viscosity of repair material and the width of crack. It is believed that flexural strength of epoxy resin with low viscosity is high because tensile strength is high and elongation at break is low, fracture energy is low.

• Advances in materials Research
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• v.3 no.3
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• pp.129-137
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• 2014

Biocomposites from polypropylene (PP) and corn cob (CC) were investigated. The effect of corn cob content and maleic anhydride polypropylene (MAPP) as compatibilizer were studied. Results showed that addition of corn cob (CC) in PP have decreased the tensile strength and elongation at break, whereas modulus of elasticity of biocomposites increased. The biocomposites with the MAPP as compatibilizer exhibited higher tensile strength and modulus of elasticity compared biocomposites without MAPP. The morphology study of biocomposites indicates that enhanced the interfacial interaction and adhesion between filler and matrix with the presence of MAPP.

• Journal of Aerospace System Engineering
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• v.7 no.4
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• pp.36-41
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• 2013

In order to improve incombustibility of EPDM(Ethylene propylene diene monomer)-based rubber, inorganic materials as $Al(OH)_3$ and $Sb_2O_3$ were added. The mechanical and thermal properties have been measured for vulcanized rubber loaded with different concentrations of $Al(OH)_3$ and $Sb_2O_3$. As inorganic material contents increases from 5phr to 30phr, the specific gravity and hardness increase while elongation at break decreases. This study performed incombustibility test and thermal analysis through TGA(Thermogravimetric Analyzer). As a results, incombustible and thermal properties of EPDM-based rubber were improved as $Al(OH)_3$ and $Sb_2O_3$ contents increase.

• Macromolecular Research
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• v.8 no.2
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• pp.73-79
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• 2000

The influence of mastication of natural rubber (NR) on properties of carbon black-filled NR compounds was studied. Variations of viscosities of the masticated NR and the carbon black-filled NR compound by heating were also investigated. The viscosities of the compounds decreased by increasing the mastication time of the raw rubber. The viscosities of the masticated NR and the compounds increased by increasing the heating time. This was explained by the combination reaction between functional groups in the rubber. The viscosity increment of the masticated rubber and the compounds by heating became larger with increased mastication time. Cure rate of the compound became faster by increasing the mastication time. Modulus of the vulcanizate made of the rubber masticated for a long time was higher than that of the vulcanizate made of the rubber masticated for a short time while elongation at break of the former was shorter than that of the latter. This was explained by the content of bound rubber and chain length of the rubber molecules.

• Journal of Radiation Industry
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• v.6 no.1
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• pp.49-54
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• 2012

Various anion exchange membranes were prepared by radiation graft copolymerization of vinylbenzyl chloride onto fluorinated films and subsequent quaternization with various tertiary amines such as trimethylamine, N,N-dimethylbuthylamine, N,N-dimethylaniline, and N-methylpiperidine. The quaternizations of the anion exchange membranes were confirmed by measuring of the ion exchange capacities of the membranes. The mechanical properties and the water uptakes were also measured. The elongation at break was found to be largely dependent on the fluorinated film, the quateranry ammonium, and the degree of grafting. The results indicate that the poly (ethylene-alt-tetrafluoroethylene) with quaternized trimethylamine moiety exhibits higher flexible property compared to the other prepared anion exchange membranes.

• Elastomers and Composites
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• v.26 no.1
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• pp.15-22
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• 1991

Blends of ethylene-propylene-diene terpolymer(EPDM) and high density polyethylene(HDPE) have been prepared in a roll mill by the process "dynamic curing" where both blending and a crosslinking reaction was carried out simultaneously. As a crosslinking agent, dicumyl peroxide(DCP) was used. Throughout the experimental ranges, the dynamically cured polyblends were shown to be thermoplastic elastomers except highly crosslinked blends of high compositions of EPDM. The increase of melt viscosity was observed as EPDM composition and DCP contents increased. From DSC determinations, the crystallinity decreased with increasing contents of DCP. The tensile strength and elongation at break generally increased with increasing DCP content and increasing HDPE compositions, but highly depended on the combined effects of decreasing crystallinity and increasing crosslinking density.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.2_1
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• pp.79-89
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• 2021

Poly(lactic acid) (PLA) is considered as one of the most promising bio-based polymers due to its high strength, high modulus, good processability, transparency after processing, and commercial availability. This study aimed to investigate the mechanical, thermal, and migration properties of poly(lactic acid)/zeolite (10 phr) composites prepared with various biocompatible plasticizers, such as triethyl citrate(TEC), tributyl citrate(TBC), and poly(ethylene glycol)(PEG400), through differential scanning calorimetry(DSC), thermo-gravimetric analysis(TGA) and standard tensile testing. The incorporation of PEG400 significantly increased the elongation at break, and DSC results showed that the addition of plasticizers drastically decreased the T_g of PLA/zeolite composites and improved the melt flow and processability. Besides, it was found from TGA results that PLA/zeolites composites plasticized by TEC and TBC were more easily to be thermally degraded than the composites plasticized by PEG400.

• Korean Journal of Chemical Engineering
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• v.35 no.11
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• pp.2296-2302
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• 2018

Internally plasticized PVC was prepared via chemical reaction of azide PVC and alkynyl group containing castor oil methyl ester. The chemical structure of alkynyl group containing castor oil methyl ester and internally plasticized PVC was characterized with FT-IR and $^1H$ NMR. Properties of internally plasticized PVC, including thermal stability, tensile tests and resistance to extraction in different solvents, was investigated. The results showed that alkynyl group containing castor oil methyl ester, as internal plasticizer of PVC, not only decreased the $T_g$ of PVC from $84.6^{\circ}C$ to $41.6^{\circ}C$ efficiently, but also presented no plasticizer loss in five different solvents. The tensile tests showed that elongation at break and tensile strength of internally plasticized PVC was 353.8% and 18.1 MPa. The internally plasticized PVC has potential application in replacing the traditional PVC material in PVC products with high durability.

• Carbon letters
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• v.9 no.2
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• pp.115-120
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• 2008

Rubber reinforcing carbon black N330 was treated by physical activation under $CO_2$ to different degrees of burn-off. The mechanical properties indicating the reinforcement of SBR (Styrene-Butadiene Rubber) vulcanizates filled by activated carbon blacks, such as tensile strength, modulus at 300% strain and elongation at break were determined. During $CO_2$ activation of fresh carbon blacks, the development of microporous structure caused an increase of extremely large specific surface area and the porosity turned out to be an increasing function of the degree of burn-off. The tensile strength and modulus at 300% of activated carbon blacks filled rubber composites were improved at lower loading ratios of 20 and 30 phr, but decreased drastically after 30 phr, which is considered that it might be difficult to get a fully dispersed rubber mixture at higher loading ratios for fillers having very large specific surface areas. However, the Electromagnetic Interference (EMI) shielding effectiveness of SBR rubber composites having activated carbon black at 74% yield were improved at a large extent when compared to those having raw carbon black and increased significantly as a function of increasing loading ratio.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.1
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• pp.33-40
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• 1994

Effects of blanching on protein composition and texture in geoduck muscle during frozen storage at $-20^{\circ}C$ were investigated. In frozen muscle, sarcoplasmic protein and myofibrillar protein were decreased, while alkali-soluble protein increased rapidly. During the storage of the blanched muscle(at $95^{\circ}C$ for 2 min.), sarcoplasmic and myofibrilla protein showed slow decreases. The muscle blanched for 2 min(BM) showed the best texture among the samples treated with various blanching times(at $95^{\circ}C$ for 1, 2, 3, and mins). In comparing the textures of BM with raw muscle, hardness of BM was similar raw muscle, and elasticity and stress relaxation of BM revealed lower levels than those of raw muscle, but break elongation and toughness were higher. In the changes of texture of raw muscle and BM during the frozen storage, as the storage time lengthened, hardness and toughness of both muscles were stronger, and both stress relaxations showed greatly decreases during initial storage(7 days), and break elongation level of raw muscle showed rapid increases in 100 days but there were no changes in that of BM, Elasticity of raw muscle gradually reduced during storage while that of BM increased.