• The Journal of Advanced Prosthodontics
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• v.16 no.2
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• pp.105-114
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• 2024

PURPOSE. This study aimed to evaluate the effect of pretreatment of three different universal adhesives (Single Bond Universal [SBU], All-Bond Universal [ABU], and Prime&Bond universal [PBU]) on the bonding durability of an adhesive (Panavia F 2.0, PF) and a conventional (Duo-Link, DL) resin cements to air-abraded zirconia. MATERIALS AND METHODS. Rectangular-shaped zirconia specimens were prepared. The chemical composition and surface energy parameters of the materials were studied by Fourier transform infrared spectroscopy and contact angle measurement, respectively. To evaluate resin bonding to the zirconia, all the bonding specimens were immersed in water for 24 h and the specimens to be aged were additionally thermocycled 10000 times before the shear bond strength (SBS) test. RESULTS. The materials showed different surface energy parameters, including the degree of hydrophilicity/hydrophobicity. While the DL/CON (no pretreatment) showed the lowest SBS and a significant decrease in the value after thermocycling (P < .001), the PF/CON obtained a higher SBS value than the DL/CON (P < .001) and no decrease even after thermocycling (P = .839). When the universal adhesives were used with DL, their SBS values were higher than the CON (P < .05), but the trend was adhesive-specific. In conjunction with PF, the PF/SBU produced the highest SBS followed by the PF/ABU (P = .002), showing no significant decrease after thermocycling (P > .05). The initial SBS of the PF/PBU was similar to the PF/CON (P = .999), but the value decreased after thermocycling (P < .001). CONCLUSION. The universal adhesive pretreatment did not necessarily show a synergistic effect on the bonding performance of an adhesive resin cement, whereas the pretreatment was beneficial to bond strength and durability of a conventional resin cement.

• KSBB Journal
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• v.24 no.5
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• pp.415-419
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• 2009

In this study, the detoxification methods were evaluated for the removal of fermentation inhibitors from synthetic solution containing the composition similar to the lignocellulosic hydrolysate. The enzyme peroxidase and laccase were used as a biological treatment method. The physico-chemical methods such as adsorption and ion exchange were applied by using activated charcoal and ion exchange resins. The enzyme peroxidase showed a excellent removal of phenolic compounds. The 5-HMF and furfural were completely removed by activated charcoal. The anion exchange resin showed a good result for detoxification of acetic acid. The activated charcoal and ion exchange resins lead to a loss of sugars more or less. The choice of detoxification method must be made after considering the composition and inhibitors in hydrolysates.

• Journal of Adhesion and Interface
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• v.11 no.4
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• pp.155-161
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• 2010

A series of ethylene vinyl acetate (EVA) based hot melt adhesives containing different types and compositions of tackifier resins were prepared to investigate their rheological behavior and T-peel adhesion strength on polyurethane (PU) elastomeric sheets. C5 aliphatic hydrocarbon resin (C5 resin), C9 aromatic hydrocarbon resin (C9 resin), hydrogenated dicyclopentadiene resin ($H_2$-DCPD resin), and dicyclopentadiene and acrylic monomer copolymer resin (DCPD-acrylic resin) were used as the tackifiers for the hot melt adhesives. To determine the polarity of the tackifiers, their oxygen contents were analyzed, and the DCPDacrylic resin was found to contain an oxygen content higher than the other tackifiers. Only the DCPD-acrylic resin showed complete miscibility with EVA and the homogeneous phase of the hot melt adhesive blends at all compositions. The T-peel adhesion strength between the hot melt adhesives and polyurethane elastomeric sheets was mainly affected by the polarity of the tackifier resins in the hot melt adhesives, rather than by the storage moduli, G', of the hot melt adhesives themselves.

• Restorative Dentistry and Endodontics
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• v.27 no.1
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• pp.77-86
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• 2002

Current composites are made with dimethacrylate monomers and silane-treated silica microfillers, either alone or with silane treated glass fillers The main reasons for clinical failure of dental composites are secondary caries, wear and fracture. Most of practitioner want to get a composite which is more tougher under occlusal stress, less polymerization contraction, and better handling properties in application clinically. The aim of this study was to investigate the influence of resin matrix with various flows on the physical proper-ties such as fracture toughness and degree of conversion of the experimental resins. It was hypothesized that flexible or tough resin composites can be designed by judicious choice of monomer composition Various flow resin matrices containing Bis-GMA, UDMA, and TEG-DMA were made by altering the pro-portion of the monomers. After the unfilled resins were light-cured for different light intensity, the fracture toughness(K$_{1c}$) was measured according to ASTM standard using the single edge notched geometry, and degree of conversion(DC) was measured by FTIR. And experimental composites were formulated with variations in the proportion of silanated quartz and strontium glass fillers as 60, 75, and 77wt%. Also, the physical properties of composites with various filer contents were evaluated as same manner. All resulting data were compared by ANOVA/Tukeys test at 0.05 level. The results were as follows; 1. The degree of conversion of high flow resin containing less Bis-GMA was higher than that of low flow unfilled resin 2. While the degree of conversion of unfilled resin was increased according to light intensity for polymerization, there was no significant increase with moderate and high light intensity. Also, the fracture toughness was not increased by high light intensity. 3. The fracture toughness was high in the low flow unfilled resin containing higher contents of Bis-GMA. 4. There was a significant increase for fracture toughness and a tendency for degree of conversion to be reduced when the content of fillers was increased. 5. In the experimental composites, the flow of resin matrix did not affected on the fracture toughness, even, which was decreased as increase of viscosity. These results showed that the physical properties of a dental composite could be attributed to the flow of resin matrix with relative content of monomers. Specific combination of resin monomers should be designed to fulfil the needs of specific indication for use.

• Polymer(Korea)
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• v.27 no.2
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• pp.120-128
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• 2003

The effects of catalyst, accelerator and blend composition on the cure behavior of unsaturated polyester resin (UPE), vinyl ester resin (VE) and their blends were studied using differential scanning calorimetry(DSC). The DSC thermograms strongly depend on each variable. The result shows that the small exothermic peak at 115$^{\circ}C$ is due mainly to the UPE component in the UPE/VE blends and the large one at 134~138 $^{\circ}C$ is due mainly to the VE component. The results also indicate that the change of the DSC thermogram measured after each blend was exposed to high temperature 18$0^{\circ}C$ and the fast curing conditions of a few tens seconds provide useful information on understanding the thermal processing of a blend at high speed. The measurements of resin flow time represent that there are three distinct stages of cure in the UPE/VE blends: induction, transition and macro-gelation stages, as similarly reported for UPE by others earlier. The thermal stability and flexural properties of the cured UPE are significantly improved by blending it with the VE, depending on the composition.

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.5
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• pp.698-713
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• 1999

Adherence of Candida albicans(C. albicans) to the surface of a denture is believed to be an initial and essential step in the formation of denture-induced stematitis. Previous studies have provided enormous infomation on the relationship between composition of palatine gland/parotid saliva and upper denture stomatitis. Relatively little information is available on the correlation between lower denture stomatitis and sublingual-submandibular ( SLSM ) saliva. The plaque samples were collected from the two sites($100mm^2$) on the inner surface of lower partial denture corresponding to the stematitis and healthy region of the lower partial dentures of 12 denture stomatitis patients and 6 nor-mal persons who wore lower partial dentures. The samples were plated to isolate C. albicans on a selective Saboraud's dextrose agar plate and the isolates were identified by germ tube test and gram staining. The subjects were divided into group I (stomatitis with C. albican), group II (lesion without C. albicans), group III (no lesion but C. albicans), and group IV (normal and healthy denture wearer). Individual SLSM saliva($20{\mu}g$ of protein) was analyzed by SDS-PAGE (SDS -poly-acrylamide gel electrophoresis) with Coomassie brilliant blue and PAS(Periodic Acid Schinff) stain-ing. The salivary proteins separated in the polyacryamide gels were subjected to immunoblot anaysis using anti-lactoferrin, anti-sIgA, and anti-secretory component of sIgA. In this study using custom made acrylic denture resin beads(5mm in diameter) coated with stimulated individual SLSM saliva, the binding ability of individual C. albicans strains to the beads was observed. Levels of C, albicans adhered to the acrylic resin beads were determined by measuring the optical density of the bound C. albicans to the beads at 580nm. The results showed that a higher number of C. albicans was observed in the lesion site than healthy site. The saliva of group I contained more high molecular weight glycoprotein(mucin, MGI) as compared to group II, III and IV. And lactoferrin and sIgA affected to the binding ability of C. albicans to acylic resin beads. Binding ability of individual C. albicans to the acrylic resin coated with respective individual saliva was found to be greater in group I than the other 3 groups. And when bound cells of C. albicans isolated from individual subject #2 to the saliva coated beads were used binding ability of subject #2 saliva coated beads was founed to be greater than the other sutjects. These results suggested that denture induced stomatitis is related to individual patient's salivary protein composition, especially MG-1. Future studies will be directed toward saliva exam-ination of patients who have general disease and analysis of pellicles formed on prosthesis with respect to oral disease.

• Polymer(Korea)
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• v.30 no.4
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• pp.350-356
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• 2006

In order to investigate the effect of the composition of weather-resistant coatings on physical properties, three different weather-resistant coatings were prepared by varying the ratio of a mill-base silicone/acrylic resin and let-down silicone/acrylic resin in weight ratios of 2 : 8, 3 : 7, and 4 : 6. The physical properties and weather-resistance of the prepared coatings were tested. It was found that the thermal stability, salt spray exposure, and weather-resistance were improved with increasing the amount of silicone. The optimum mixing ratio of mill-base silicone/acrylic resin to the let-down silicone/acrylic resin was 2 : 8. The coating containing silicone component of 30 wt% was found to be suitable as high weather-resistant coatings.

• The Korean Journal of Ceramics
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• v.3 no.2
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• pp.116-123
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• 1997

A chemically stabilized $\beta$-cristobalite, which is stabilized by stuffing cations of $Ca^{2+}$ and $Al^{3+}$, was prepared by a solution-polymerization route employing Pechini resin or PVA solution as a polymeric carrier. The polymeric carrier affected the crystallization temperature, morphology of calicined powder, and particle size distribution. In case of the polyvinyl alcohol (PVA) solution process, a fine $\beta$-cristobalite powder with a narrow particle size distribution (average particle size : 0.3$\mu\textrm{m}$) and a BET specific surface area of 72 $\m^2$/g was prepared by an attrition-milling for 1 h after calcination at 110$0^{\circ}C$ for 1h. Wider particle size distribution and higher specific surface area were observed for the $\beta$-cristobalite powder derived from Pechini resin. The cubie(P1-to-tetraganalb) phase transformation in polynystalline $\beta$-cristobalite was induced at approximately 18$0^{\circ}C$. Like other materials showing transformation toughening, a critical size effect controlled the $\beta$-to-$\alpha$ transformation. Densifed cristobalite sample had some cracks in its internal texture after annealing. The cracks, occurred spontaneoulsy on cooling, were observed in the sample with an average grain sizes of 4.0 $\mu\textrm{m}$ or above. In case of the sintered cristobalite having a composition of CaO.$2Al_2O_3$.40SiO$_2$, small amount of amorphous phase and slow grain growth during annealing were observed. Shear stress-induced transformation was also observed in ground specimen. Cristobalite having a composition of CaO.2Al2O3.80SiO2 showed a more sensitive response to shear stress than the CaO.$2Al_2O_3$.40SiO$_2$ type cristobalite. Shear-induced transformation resulted in an increase of volume about 13% in $\alpha$-cristobalite phase on annealing for above 10 h in the case of the former composition.

• Journal of Adhesion and Interface
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• v.15 no.3
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• pp.109-115
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• 2014

In this study, we synthesized and identified microcapsule containing isocyanate, and investigated the mechanical and adhesion properties of polyurethane resin by adding microcapsule. We found out that the core material of microcapsule and the component weight fraction of microcapsule from the FT-IR and TGA analysis. From the results of adhesion and mechanical property tests, we confirmed that in case of using microcapsule for adhesive resin composition, adhesion strength, tensile strength and abrasion were improved by cross-linking reaction between urethane and IPDI in microcapsule.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.228-229
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• 2006

본 연구에서는 PCB에 적용하기 위한 폴리머 타입 후막저항의 하나로서, 포토공정으로 저항 패턴의 형성이 가능한 페이스트를 제조하였다. 기존의 폴리머 후막저항은 스크린 인쇄를 패터닝의 주요 방법으로 하고 있어 패턴의 정밀성이 떨어지는 단점이 있었다. 이를 개선하여 고정밀 저항 패턴의 형성이 가능하도록 Photoimageable Resin을 저항 페이스트의 개발에 도입하였다. Acrylated oligomer 및 monomer, 그리고 Novolac Epoxy를 주 기지상 재료로서 사용하였으며, acrylate와 epoxy의 함량비에 따른 저항 페이스트의 현상성 및 시트저항을 평가하였다. 전도성 Filler 재료로 카본블랙을 이용하였는데, 그 물리적 특성차와 함량이 저항 페이스트의 현상성과 저항값에 미치는 영향을 평가하였다. 실험결과 Acrylate와 epoxy의 비가 2.5:1일 때 현상성이 가장 양호하였으며, 이 조성에 XC72R 카본블랙을 2g 첨가하였을 때 시트저항의 평균값은 약 $6\;k{\Omega}\{\square}$였다.