• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.379-382
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• 2003

In this study, methyl methacrylate (MMA)- modified unsaturated polyester mortar, in which the MMA was added to the unsaturated polyester resin, was developed for improving the early-age strength and the workability of the conventional polymer concrete, binder of which was the unsaturated polyester resin. Then the strength properties of the MMA-modified unsaturated polyester mortar were surveyed. The experimental results showed that early-age strength was greater when the MMA contents were increased in the range of $20{\sim}40%$, but the strength rather showed a tendency of decrease when the MMA contents was 50%.

• Applied Chemistry for Engineering
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• v.16 no.1
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• pp.93-100
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• 2005

8 functionality photocurable polyester polyol modified hyperbranched methacrylates of two types were prepared from trimellitic anhydride, glycidyl methacrylate, and 4 functionality polyester polyol of two types. The physical properties of photocurable polyester polyol modified hyperbranched methacrylate were investigated. Thermal stability obtained by using TGA showed that HBMA-2 (hyperbranched methacrylate-2) was superior to the HBMA-1 (hyperbranched methacrylate-1). Hardness, abrasion resistance and tensile strength of HBMA-2 showed that were also superior to the HBMA-1. Value of yellow index of HBMA-2 showed the higher.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.292-295
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• 2004

Recently, polymer-clay hybrid materials have received considerable attention from both a fundamental research and application point of view. This organ-inorganic hybrid, which contains a nanoscale dispersion of the layered silicates, is a material with greatly improved thermal and mechanical characteristics. Two classes of nanocomposites were synthesized using an unsaturated polyester resin as the matrix and sodium montmorillonite as well as an organically modified montmorillonite as the reinforcing agents. X -ray diffraction pattern of the composites showed that the interlayer spacing of the modified montmorillonite were exfoliated in polymer matrix. The mechanical properties also supported these findings, since in general, tensile strength, modulus with modified montmorillonite were higher than the corresponding properties of the composites with unmodified montmorillonite. Adding organically modified clay improved the tensile strength of unsaturated polyester by $22\%$ and the tensile modulus of unsaturated polyester was also improved by $34\%$.

• Journal of The Korean Society of Agricultural Engineers
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• v.58 no.1
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• pp.19-26
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• 2016

This study was performed to evaluate the strength and durability properties of modified epoxy composites with waste tire chip, recycled coarse aggregate, filler and modified epoxy to improve elongation and elasticity of epoxy. Additionally, for comparing to modified epoxy and unsaturated polyester resin as a binder, unsaturated polyester resin composites were developed in the same condition. The mix proportions were determined to satisfy the requirement for the workability and slump according to aggregate size and binder content. Tests for the compressive and flexural strength, freezing and thawing and durability for 20 % sulfuric solution were performed. The compressive and flexural strength of modified epoxy composites were in the range of 34.9~61.6 MPa and 10.2~18.3 MPa at the curing 7 days, respectively. Also, the compressive and flexural strength of unsaturated polyester resin composites were in the range of 44.2~77.8 MPa and 11.3~20.8 MPa at the curing 7 days, respectively. After 300 cycles of freezing and thawing, weight decrease ratio and durability factor of modified epoxy composites were in the range of 0.8~1.9 % and 95~98, respectively. Accordingly, modified epoxy composites will greatly improve the durability of concrete.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.11a
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• pp.38-41
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• 2000

High temperature cure characteristics of polyester resin systems were investigated by isothermal and dynamic differential scanning calorimetries. During isothermal scanning, the experimental procedure was modified to reduce the initial Boss of heat. no kinetic equation from the isothermal experiment was compared with that from the dynamic experiment.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.769-774
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• 2002

In this study, methyl methacrylate (MMA)- modified polyester polymer concrete, in which the MMA was added to the unsaturated polyester resin, was developed for improving the early-age strength and the workability of the conventional polymer concrete, binder of which was the unsaturated polyester resin. Then the fundamental properties of the polymer concrete such as workability and strength were surveyed. The experimental results showed that the workability was remarkably improved as the MMA contents increased, and the filler-binder ratio was turned out to be important factor for the workability. Slump prediction equation was derived by the regression analysis based on MMA content and filler-binder ratio. Furthermore, early-age strength was greater when the MMA content were increased in the range of 20-40 % but the strength rather showed a tendency of decrease when the MMA content was 50 %.

• Journal of the Korean Applied Science and Technology
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• v.15 no.2
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• pp.59-66
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• 1998

Two-packaged polyurethane coatings were prepared by blending benzoic acid lactone modified polyester polyol(BLMPs) and HDI-biuret. BLMPs were synthesized by polycondensation of benzoic acid, viscosity depression component, with 1,4-butanediol, adipic acid, and polycaprolactone polyol. Kinematic viscosity of BLMP was gradually decreased with increasing benzoic acid content in BLMP. The low viscosity of modified polyester has an advantage of making a high-solid content coatings. After the film was coated with the prepared polyurethane coatings and cured at room temperature, the various physical properties were measured. They showed good physical properties such as flexibility, impact resistance, cross hatch adhesion, yellowness index, and rust resistance. These advantages are the results of introducing polycaprolactone polyol.

• Journal of the Korean Applied Science and Technology
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• v.22 no.1
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• pp.1-8
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• 2005

Chlorine-containing modified polyester polyols were synthesized by two-step condensation reactions. Intermediate was synthesized by the esterification of monochloroacetic acid with trimethylolpropane in the first step. Polycondensation of the intermediate (MCAOs), 1,4-butanediol, and trimethylolpropane with adipic acid was carried out. Two-component polyurethane (PU) coatings were prepared by blending MCAOs and IPDI-isocyanurate. There new flame-retardant coatings showed various properties comparable to other non-flame-retardant coatings. They were superior to flammable coatings from the experimental results showing rapid and 10 to 13 hours of pot-life. Coatings with 30wt% monochloroacetic acid was not flammable by the vertical flame retardancy test.

• The International Journal of Costume Culture
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• v.5 no.2
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• pp.53-65
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• 2002

Morphology of polyester fiber was physically modified by solvent treatment. PET fiber was treated with N,N-dimethylformamide (DMF) at 100, 120, $140^{circ}C$ for 10 minutes without tension. The structural changes in the morphology of DMF-induced modified PET fiber were FTIR and SEM analysis. Also dyeing behavior of DMF-treated polyester fibers with various disperse dyes was studied to detect changes of amorphous area in fine structure. DMF treatment resulted in increases in total void content, degree of crystallinity, trans isomer content, chain folding, segmental mobility and molecular packing, but it resulted in decreases in amorphous orientation, intermolecular forces and individual void size through longitudinal shrinkage, lateral welling and removal of oligomers. Void-size distribution could be estimated from the dye uptake with various sizes of disperse dyes. In contrast to the large increases in dye uptake with small dye molecules, there is no and little dye uptake with the bulkiest dye, which means that void size is bigger or smaller than the volume of each dye. Diffusion rates of dye molecules showed increases. This dyeing study revealed that the disperse dyeing is very effective method for characterizing the internal morphology of polyester fiber.

• Korean Chemical Engineering Research
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• v.50 no.1
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• pp.30-34
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• 2012

For the purpose of development of polymeric material for marine applications, the effects of silica and chopped glass fiber on tensile strength of polyester resin were studied. A series of experiments were performed with different contents of silica and chopped glass fiber. Tensile strength of polyester resin was increased with the contents of unmodified glass fiber, and decreased with that of silica. The surfaces of silica and chopped glass fiber were modified with coupling agent at different concentrations, and the modification showed positive effect on the increase of tensile strength of polyester resin. Synergistic effect on the tensile strength of polyester resin was observed by modified silica and chopped glass fiber.