• Journal of Dental Rehabilitation and Applied Science
• /
• v.27 no.1
• /
• pp.81-90
• /
• 2011

In this study, we observed the penetration of the resin infiltrant into natural initial caries by SEM and CLSM, evaluated the pH and viscosity of resin infiltrant and several adhesives(All-bond 2, Scotchbond Multi-purpose, Clearfil SE bond), and measured the surface roughness and the microhardness on permanent teeth before and after applied resin infiltrant into initial enamel caries. The viscosity(Pa.s) was observed for resin infiltrant($0.173{\pm}0.012$), All-bond 2($0.754{\pm}0.030$), Scotchbond Multi-purpose($1.46{\pm}0.137$), and Clearfil SE bond($1.28{\pm}0.125$). The pH was measured for resin infiltrant (4.7), All-bond 2(7.5), Scotchbond Multi-purpose(8.2), and Clearfil SE bond(4.67). An application procedure of resin infiltrant increased the surface roughness and the microhardness insignificantly(p>0.05), when compared to non-applied specimens.

• Journal of the Korean Ceramic Society
• /
• v.39 no.12
• /
• pp.1143-1148
• /
• 2002

Precipitated calcium carbonate is one of the most versatile mineral fillers and is consumed in an wide range of products including paper, paint, plastics, rubber, textiles, sealants, adhesives and printing ink and can be produced by several methods. Calcium carbonate has three isomorphism; vaterite, aragonite and calcite, with numerous variations of morphology in the natural mineral or organism. Formation process of vaterite in the reaction of system $Ca(OH)_2-CH_3OH-H_2O-CO_2$ were investigated by measuring the electrical conductivity, $Ca^{2+}$ ion concentration, pH in the slurries and by means of X-ray diffraction and electron microscopic observation. It was clearly established that the reaction temperature is important variable in the carbonation process; in general over 50${\circ}C$, the vaterite was precipitated with the calcite and aragonite. SEM and XRD observations revealed that the vaterite formation could be prepared the temperature range of 40 to 50${\circ}C$ and mean size of particles in this range is controlled from 0.5 to 0.8 ${\mu}m$.

• Journal of Conservation Science
• /
• v.33 no.1
• /
• pp.51-59
• /
• 2017

Lacquer has been used as a natural paint or adhesive in Korea since 2nd century B.C. It has been found to have been used as an adhesive as mentioned in old records and as seen in excavated relics, It was also mixed with flour, animal glue, or fish glue to produce lacquer adhesives. Qualitative analysis and evaluation of the applicability of lacquer and additives was performed in this study. The results of EGA analysis for lacquer additives confirmed that the pyrolysis temperature of lacquer, glucose glue, and animal glue. On the basis of this result, raw lacquer sample was checked that pyrolysis product that originated from urushiol side chain (R group). Components originating from glucose and amino acid were detected in glutinous rice paste and animal glue samples. In this study, the optimum pyrolysis temperature for each lacquer and additive mixture was determined from basic qualitative analysis data. By performing the qualitative analysis of each mixture, the applicability of this technique for analyzing real relics was evaluated.

• The korean journal of orthodontics
• /
• v.30 no.4 s.81
• /
• pp.483-490
• /
• 2000

The dental gold alloy shows a lower bond strength than the natural teeth in bracket bonding, and this can be a possible source of subsequent bond failure. This study aims to evaluate the effect of various gold alloy surface treatment techniques on shear bond strength between the orthodontic adhesives and the gold alloy and to find ways of increasing the bond strength. Two hundred and forty specimens made of the dental fold alloy were divided into twelve groups based on the combination of surface treatment methods(non-surface treatment, sandblasted, sandblasted plus tin-plated, and sandblasted plus intermediate adhesive) and adhesive systems (Ortho-one, Panavia 21, Superbond C&B). The specimens with bonded brackets were placed in distilled water at $37^{\circ}C$ for 24 hours and shear bond strength was measured by a universal testing machine. The results were as follows: 1. All surface-treated groups showed a significantly higher shear bond strength than non-surface-treated groups. 2. The sandblasted plus tin-plated group showed a significantly higher shear bond strength than the sandblasted group only when Panavia 21 was involved. 3. The sandblasted plus intermediate adhesive group showed a significantly higher shear bond strength than sandblasted group regardless of the type of adhesive used. 4. Of the three resin adhesive types, the Superbond C&B showed the highest bond strength, followed by Panavia 21 and Ortho-one. These findings suggest that a combination of sandblasting and intermediate resin treatment is desirable in order to enhance bracket bond strength regardless of adhesive types.

• Journal of Conservation Science
• /
• v.37 no.2
• /
• pp.135-143
• /
• 2021

Conservation treatment that involved filling the lifting parts of wooden cultural heritage is carried out by obtaining wood or wood powder of the same species and mixing it with synthetic resin or natural glue to charge the blank area. Various concentrations and mixing ratios of adhesives and additives are used, depending on the type and condition of the target. Accordingly, in this study, we determined the conditions of the filler suitable for conservation treatment of wooden sculptures with lifted or separated bark in the National Museum of Modern and Contemporary Art. The optimal filler conditions for each adhesive were selected based on drying speed, shrinkage and expansion rates, and physical deformation degree. Then, to verify their actual applicability, these fillers were applied to wood and exposed to high-humidity environment and their cross-sections were observed. The fillers showed stable application in the following order: animal glue, PVAc adhesive, acrylic adhesive. In conclusion, a 1:2 mixture of animal glue and wood powder is a suitable filler for conservation treatment of wooden sculpture with lifted bark. The results of this study suggest appropriate ways to stabilize the bark that was lifted or separated from a wooden sculpture, thus enabling the future conservation treatment of the artworks under similar conditions.

• Korean Chemical Engineering Research
• /
• v.59 no.4
• /
• pp.548-556
• /
• 2021

This study was conducted to investigate the applicability of lignocellulosic fiber and coconut shell activated carbon (CSA) for the production of a particulate matter (PM)-reducing air-filter as raw materials to solve the environmental problems of non-woven fabrics. CSA had a good potential to use as a raw material of air-filter for reducing volatile organic compounds as well as noxious metals, and reduction capability of the CSA was 5 times higher than that of wood fiber. Natural adhesives formulated with proteinaceous wastes mostly were applied successfully to fabricate air-filters with the shape of fiberboard. The air-filter fabricated with the minimum target density of 200 kg/m³ and the maximum CSA-content of 40 wt% in fiberboard had a good manageable strength. However, the fiberboard filters was required to make vent-holes for improving an air-permeability of the filters. Size of the CSA particles was adjusted to greater than 2 mesh with the consideration of strength and formability of the fiberboard. Three-layers fiberboard that only wood fiber and the mixture of wood fiber and CSA were formed in the surface and middle layers, respectively, was determined to the optimal condition for the production of air-filters. In addition, traditional Korean paper handmade from mulberry trees (TKP) showed a good PM-reducing property as an air-filter. It is concluded that air-filtering set composed of fiberboard with vent-holes and TKP instead of conventional air-filters made with non-woven fabrics can be used as a filter for reducing the concentrations of PM, VOC and noxious metals existed in indoor and outdoor spaces.