• Analytical Science and Technology
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• v.24 no.5
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• pp.336-344
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• 2011

The study attempted to find out any effect to prevent photo aging of epoxy resin used for conservation by way of adding UV stabilizer, one of plastic additives. Specimens were made by adding HALS and UVA UV stabilizer as each concentration to 3 kinds of epoxy resin, which are most frequently used for artifacts joining and restoration process, and aging effects were investigated through Color change, SEM, contact angle, FTIR analysis during UV aging experiments. Last, usage suitability was checked when UV stabilizer was added through Universal Tensile strength tester. In result, it is impossible to prevent decomposition of chemical structure in spite of adding UV stabilizer but in the case of epoxy A and R, it is believed that photo aging such as yellowing or crack can be minimized without giving a big influence to adhesive strength of epoxy resin through adding less than 0.1% of UVA. It is expected that above will solve photo aging problem of epoxy resin used for joining and restoration of artifacts and will extend its life as joining and restoration materials.

• Polymer(Korea)
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• v.25 no.5
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• pp.625-634
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• 2001

New polymeric photostabilizers containing hindered amine light stabilizer (HALS) were prepared by the reaction of liquid polyisoprene rubber grafted maleic anhydride (MAH) and 2,2,5,6-tetramethyl-4-piperidinol (TMPO). Their chemical composition and physical properties were characterized by titration, GPC and TGA analysis. The effects of polymeric HALS on the photooxidation of the styrene-butadiene rubber were studied from the UV, IR spectral changes, and photo-crosslinking was examined by the measurement of the insoluble fraction. The photooxidation of SBR upon irradiation was inhibited by addition of the new polymeric HALS. The extraction resistance of new polymeric photostabilizer was much better than that of the low molecular weight compound which is prepared by the reaction of MAH and TMPO. The new polymeric HALS ate fairly compatible with the SBR.

• Polymer(Korea)
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• v.33 no.5
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• pp.413-419
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• 2009

As the refractive index of the prism layer becomes higher, the optical performance of the prism sheet gets better and the efficiency of the LCD backlight unit is improved. In order to increase the refractive index of the prism layer, the ultraviolet curing type resins were prepared by mixing high refractive index materials containing aromatic groups and the multi-functional reactive diluents. By using 9,9-bis [4-(2-acryloyloxyethoxy)phenyl] fluorene, the refractive index of the prism layer was increased up to 1.58 and the brightness of the backlight unit was improved. Since the light source used in the backlight unit caused the yellowing in the prism sheet and deteriorated the brightness accordingly, the hindered amine light stabilizer was used to improve the yellowing resistance successfully.

• Journal of Conservation Science
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• v.33 no.3
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• pp.203-214
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• 2017

This study evaluated the degradation characteristics of FRP by ultraviolet (UV) rays and applied a UV-resistant coating to prevent the degradation of the surface of these sculptures. As a result of the degradation caused by UV rays, there were slight changes in the FRP surface and contact angle. The chromaticity sharply increased in the early phase of degradation. After applying the coating to the FRP, no significant surface changes were observed. However, it had lower changes in color as compared to the uncoated specimen, so it was verified that the control of discoloration could be possible. Some changes in the gloss and contact angle were observed depending on the extent of degradation, but the UV coating agent remained relatively stable. Analysis of the infrared light spectrum showed that there were almost no chemical changes, and it could be concluded that the coating treatment prevented degradation for a certain period. This study investigated the degradation of FRP used as materials in artwork exposed to UV rays, and it was found that there was a delay in the onset of degradation in the FRP with the UV-resistant coating when compared to the uncoated FRP.

• Journal of the Korean Geosynthetics Society
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• v.2 no.3
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• pp.25-38
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• 2003

Geotextile composites to improve the resistance to the application environment were manufactured of recycled polyester geotextile with carbon black as ultraviolet stabilizer and polypropylene geotextile by needle-punching method. Mechanical properties, ultraviolet resistance and chemical stability were evaluated. Retention ratio of tensile properties of polypropylene geotextiles were decreased about 50% with the exposed condition by ultraviolet but those of geotextile composites showed the slightly decrease. Geotextile composites which have larger weights of recycled polyester geotextile were more stable against ultraviolet. For chemical stability, the changes of tensile strength values of geotextile composites were in the range of -20~+10% at the various chemical conditions.

• The Korean Journal of Rheology
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• v.10 no.4
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• pp.256-258
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• 1998

An experimental study was done to improve the processability and optical property of linear low density polyethylene(LLDPE) film. By modifying the molecular structure of LLDPE with electron beam we could get the improved processability and optical property of film. By appropriate dosing of electron beam and a small addition of UV-stabilizer it was possible to produce gel-free film with low haze. The proceassability was also improved.

• Elastomers and Composites
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• v.42 no.2
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• pp.93-101
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• 2007

In this study, for enhancing the durability of permeable pavement material polyurethane(PU) adhesives were developed, and the physical properties upon polymerization and additives were studied. PU polymerization followed the bulk polymerization of free solvent type considering ecological aspect. Additives used in this study were carbon black, calcium carbonate and ultra violet stabilizer. The property changes upon different environment were evaluated with the compressive strength which is the principal measurement of the property of pavement materials. Among polymerized PU, one formulated with esterpolyol and crosslinkable chain extender gave the highest compressive strength of $74.9kgf/cm^2$, better than commercial $60kgf/cm^2$. The strength was the highest when the material specimen contained carbon black and calcium carbonate 20 wt%, respectively. However, UV stabilizer did not show good weathering properties.

• Elastomers and Composites
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• v.41 no.3
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• pp.182-193
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• 2006

The retardation effects of a new polymeric UV stabilizer, DGEBA-HALS, on the UV degradation of SBR and NR were investigated in this study. The UV degradation behaviors of three different rubber compounds, without any photostabilizer and with commercial Cyabsorb UV-3529 and DGEBA-HALS, were compared. Also, the physical characteristics such as Young's modulus, tensile strength, blow-off deformation and crosslink density were examined. The Young's modulus was increased by UV irradiation for all samples, and the tensile strength, after UV irradiation, of the compound with UV stabilizer was better than that of the compound without stabilizer. Especially, the tensile strength of UV irradiated NR was improved by adding DGEBA-HALS. The results of blow-off deformation were in accord with those of Young's modulus. The degree of transmission of SBR compounds obtained from UV-vis transmission spectra was improved about 4% by adding the UV stabilizer. Commercial Cyabsorb UJV-3529 and DGEBA-HALS showed similar trends of transmission. The SEM photographs of SBR surface showed that the size of cracks created by UV irradiation became smaller by adding UV stabilizer. In particular, it is observed that the stabilization effect of DGEBA-HALS was better than that of commercial Cyabsorb UV-3529.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.4
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• pp.30-37
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• 2002

This paper reports on the results of weathering test, tracking test and salt-fog test of various kinds of cycloaliphatic epoxy systems. UV irradiation dramatically induced the loss of surface hydrophobicity due to the chain scission attack at the surface under UV irradiation. It could be seen that samples containing an UV absorbent/antioxidant and a silicone oil additive have a good performance in weathering test, while ATH(alumina tri-hydrate) filled ones have high resistance against tracking failure than others. Under salt fog chamber test, specimens mixed with silicone oil are able to suppress leakage current development. It was thought that silicone oil mixed into cycloaliphatic epoxy system could lead to lower the surface energy and to retain hydrophobic properties for a long time, which are desirable for outdoor use.

• Journal of Radiation Industry
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• v.7 no.1
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• pp.23-28
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• 2013

In this study, we fabricated high density polyethylene (HDPE) composites filled with antioxidants and UV stabilizers. The electron beam irradiation on the fabricated composites was carried out over a range of absorbed doses from 50 to 200 kGy to confirm the changes of discoloration. The changes of discoloration were characterized using a color difference meter and FT-IR for confirming the changes of the color difference and structural change. It was observed that the color difference of IRGANOX 1010-, IRGAFOS 168-, and TINUVIN 328- added HDPE was higher than that of the control HDPE by electron beam irradiation. The melting temperature of UV stabilizer-added HDPE was not significantly changed by electron beam irradiation. However, the melting temperature of phenol-containing antioxidant-added HDPE was increased with increasing the absorbed dose. And the melting temperature of phosphorus-containing antioxidant-added composite was decreased with increasing the absorbed dose.