• Title/Summary/Keyword: composite resins

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Thermo-rheological behaviors of Phenolic Resins Blended with Petroleum-based Pitches for High Temperature Carbon Composites (석유계 피치가 첨가된 고온 탄소복합재용 페놀수지의 열 유변학적 거동 연구)

  • Yang, Jae-Yeon;Kuk, Yun-Su;Seo, Min-Kang;Kim, Byoung-Suhk
    • Composites Research
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    • v.33 no.6
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    • pp.329-335
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    • 2020
  • In this study, the thermo-rheological behaivors of petroleum pitches with different softening points were studied, and a B-stage phenolic resins/petroleum pitches blends were prepared by adding petroleum pitches to the phenolic resins. As a result, the petroleum pitch with different softening points decreased the fluidity of the petroleum pitch as the Quinoline insoluble (QI) content increased and showed the viscous properties of the solid. In addition, the effect of adding petroleum pitches having different softening points on the thermo-rheological properties of phenolic resins was investigated. When petroleum pitch with a high softening point was added, the fluidity of the phenolic resin was reduced, and the hardening behavior was fast. It was possible to control the curing rate and curing behavior of the phenolic resin by adding petroleum pitches of different softening points. Among them, the phenolic resin mixture to which P-Pitch 2 was added has a higher fluidity than other blends under the same curing temperature condition.

THE STUDY ON THE COLOR STABILITY OF COMPOSITE RESIN (수종 복합레진의 색안정성에 관한 연구)

  • Kim Hye-Jin;Kim Kwang-Jun;Cho Hye-Won;Jin Tai-Ho
    • The Journal of Korean Academy of Prosthodontics
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    • v.40 no.1
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    • pp.79-87
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    • 2002
  • The purpose of this study was to investigate the color stability of composite resins used widely as esthetic restorative material. Surefil(Dentsply, U.S.A.), Esthet X(Dentsply, U.S.A.), Filtek P60(3M, U.S.A.) , Filtek Z250(3M, U.S.A.), Synergy Compact(Coltene, Switzerland), and Synergy Duo(Coltene, Switzerland) were chosen for this study. Thirty six specimens($7mm{\times}2mm$) of each composite resin were fabricated and polished after polymerization. Treatment conditions designed for this study were thermocycling, methylene blue staining, and filtered coffee staining. The color changes before and after treatment were measured by colorimeter(colorimeter, Model Tc-6Fx, Tokyo Denshoku Co.) and analyzed. The followings were drawn from this study: 1. The color changes of Filtek Z250, Surefil, Filtek P60 and Esthet X after thermocycling for 3 weeks were greater than those of the others. 2. The color changes of Surefil and Esthet X after methylene blue stainig and those of Surefil, Filtek Z250 and Filtek P60 after coffee staining were great. 3. The color changes or Synergy Duo and Synergy Compact after thermocycling and coffee staining were relatively lesser than those of other composite resins.

AN EXPERIMENTAL STUDY ON PENETRATION OF DYE IN COMPOSITE RESIN (수종(數種) Composite Resin의 색소침투(色素浸透)에 관(關)한 실험적(實驗的) 연구(硏究))

  • Lee, Myung-Chong
    • Restorative Dentistry and Endodontics
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    • v.12 no.1
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    • pp.155-163
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    • 1986
  • The purpose of this study was to measure penetration of dye stuff (2% Methylene blue, 2% Hematoxylin, 2% crystal violet and 2% safranin-O) on unfilled resin (Lang Dental MFG Co.) Hipol (Boopyung Dental Chemical Co. Macrocomposite resin) Durafill (Kulzer, Co. Microfilled Composite resin) and Heliosit (Vivadent Co. Microfilled Composite resin) The unfilled resin with dough stage was inserted into plastic tuble (5mm in diameter and 4mm in height) with condensation force of 1000 gr, 2000 gr and without condensation force. Hipol mixed on the mixed pad was inserted into the plastic tube by the same method as the unfilled resin. The microfilled resins which were Durafill and Heliosit were polymerized for 60 seconds with the visible light on each surface of the plastic tube which was upper and lower, under condensation force of 1000 gr, 2000 gr and without condensation force. All specimens were stored in the air for 24 hours, then specimens were immersed in the various kind of dye solution for different period of time (1 hour and 24 hours). These dye-treated specimens were polished horizontally until removing 0.5mm of each surface on the emery paper (#1000), and the dye penetration in the polished surface was measured under the digital microscope (Japan Fosuh). Following results were obtained 1. The penetration of dyes was the most excessive in Durafill and was not influenced on the condensation force and the period of immersion time. 2. All dyes were penetrated into Hipol, and Crystal violet was penetrated most excessively in all dyes. 3. The penetration of dye in all resins was not influenced by the period of immersion time and condensation force. 4. There was no evidence of dye penetration in unfilled resin.

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A STUDY ON THE ADAPTATION OF DENTIN BONDING AGENTS TO TOOTH STRUCTURE (치질에 대한 상아질 접착제의 접합도에 관한 연구)

  • Park, Sung-Taek;Cho, Young-Gon;Hwang, Ho-Keel
    • Restorative Dentistry and Endodontics
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    • v.20 no.2
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    • pp.732-743
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    • 1995
  • The purpose of this study was to evaluate the adaptation of light cured dentin bonding agents to tooth structure by measuring contraction gaps on interfaces between cavity wall and composite resin under SEM study. In this study, class V cavities with cementum margin were prepared on the buccal surfaces of 15 extracted human premolar teeth and teeth were randomly assigned 3 groups of 5 teeth each. The cavities were filled with three dentin bonding agents and two composite resins were investigated for this study: three dentin bonding agents; Scotchbond 2, Scotchbond Multi-Purpose. All-Bond 2, two composite resins; Silux Pius, Z-100. Group 1 : Scotchbond 2 + Silux Plus Group 2 : Scotchbond Multi~Purpose + Z-100 Group 3 : All-Bond 2 + Z-100 The restored teeth were stored in 100% relative humidity at $37^{\circ}C$ for 7 days. And then, the roots of the teeth were removed with the tapered fissure bur and the remaining crowns were sectioned occlusogingivally through the center of restorations. Adaptation at tooth-restoration interface was assesed occlusally, gingivally, and axially by scanning electron microscope. The results were as follows : 1. In Group 1, the adaptation to dentinal wall of Scotchbond 2 was poor, but the adaptation to enamel wall of Scotchbond 2 was excellent. 2. In Group 2, the adaptation to occlusal was axial wall and gingival wall of Scotchbond Multi-Purpose was excellent. Especially in axially wall, the dentin bonding agents infiltrated into dentinal tubules and there was excellent adaptation to dentinal wall. 3. In Group 3, the adaptation to occlusal wall and axial wall of All-Bond 2 was excellent. But in gingival wall, there was gap formation between composite resin and dentin bonding agent.

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RADIOPACITY OF DENTAL RESTORATIVE MATERIALS AND CEMENTS (수종의 치과용 수복재료 및 시멘트의 radiopacity)

  • Yang Hong-So;Chung Hyun-Ju;Kang Byung-Cheol;Oh Won-Mann
    • Journal of Korean Academy of Oral and Maxillofacial Radiology
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    • v.24 no.1
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    • pp.59-66
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    • 1994
  • The radiopacity of six composite resins, three resin luting cements and ten filling materials were studied. The purpose was to obtain an indication of radiopacity value of different brands within each of these groups of materials and to show differences in radiopacities of filling materials and natural tooth structures. On radiographs, the optimal densities of standardized samples were determined by computer imaging system and radiopacity values of the materials were expressed in millimeter equivalent aluminum. Within the groups of materials studied, there was considerable variation in radiopacity. The composite resins of P-50, Z100 and Prisma AP.H displayed much higher radiopacities than aluminum. Panavia resin cement was shown to be similarly radiopaque to aluminum. Generally, the radiopacity of base and filling materials appeared to be higher than that of the enamel and dentin. If materials with substantial difference in radiopacity are used in combined applications for restorative treatment of teeth, lower radiopacity can interfere with the diagnosis and detection of gaps near the restoration.

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AN EXPERIMENTAL STUDY ON SOME PHYSICAL CHARACTERISTICS OF COMPOSITE RESINS - A study of the hardness, water sorption and solubility (시판 복합레진의 물성에 관한 실험적 연구)

  • Park, Sang-Duk;Park, Dong-Soo;Lee, Chan-Young;Lee, Chung-Suck
    • Restorative Dentistry and Endodontics
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    • v.10 no.1
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    • pp.17-30
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    • 1984
  • This study was done to evaluate the hardness, water sorption and solubility values of twelve well known composite resins, and to compare each other. For the hardness test, the specimens were made in cylinder form with 4mm in diameter and 2mm in thickness as a modification of the American Society for Testing and New Materials, 1966, and for water sorption and solubility tests, the specimens were prepared in same shape of 20mm in diameter and 0.5mm in thickness as a modification of the ADA Specification No. 12. The results were obtained as follow: 1. The hardness range were from 17.9 to 87.5 respectively. As time passed by, the noticable change was evident in early 12 hours. 2. Of the water sorption. the range was from 0.38 to 0.93. The significant change was appeared within 12 hours and on 3 day by 1 week except four brands. 3. Of the water solubility, the range was 0.06 to 0.16. The highest value was found within early 24 hours. 4. Generally, four brands could be chosen as preferable products of hardness. water sorption and solubility tests according to the ADA Specification No. 12.

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A STUDY ON THE MATERIAL PROPERTIES OF VARIOUS COMPOSITE RESINS FOR CORE BUILD-UP (수종 코어용 복합레진 수복재의 물성에 관한 연구)

  • Shin, Soo-Il;Shin, Dong-Hoon
    • Restorative Dentistry and Endodontics
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    • v.29 no.2
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    • pp.191-199
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    • 2004
  • The purposes of this study were to estimate the material properties of the recently developed domestic composite resins for core filling material (Chemical, Dual A, Dual B;Vericom, Korea) and to compare them with other marketed foreign products (CorePaste, Den-Mat, USA;Ti-Core, Essential Dental Systems, USA;Support. SCI-Pharm. USA). Six assessments were made:working time. setting time. depth of polymerization. flexural strength. bonding strength. and marginal leakage. All items were compared to ISO standards. All domestic products satisfied the minimum requirements from ISO standards (working time:above 90 seconds. setting time:within 5 minutes). and showed significantly higher flexural strength than Core Paste. Dual A and B could. especially. reduce the setting time to 60 seconds when cured with $600mW/cm^2$ light intensity. All experimental materials showed 6 mm depth of polymerization. Bond strengths of Ti-Core and Dual B materials were significantly higher than the other materials. Furthermore. three domestic products and Ti-Core could reduce the microleakage effectively.

Characteristics of Epoxy-Granite Composite Material For Ultra-Precision Machine Bed Structures (초정밀 가공기계 베드 구조물용 에폭시-그래나이트재의 특성에 관한 연구)

  • Kim, Jong-Ho;Won, Si-Tae;Maeng, Huee-Young;Park, Yeong-Il
    • Journal of the Korean Society for Precision Engineering
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    • v.7 no.2
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    • pp.74-84
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    • 1990
  • The machine tool structures for ultra-precision machining muxt be manufactured with materials which have high static and dynamic stiffness, high damping, a long term dimensional and thermal stability. This study aims at the development of new composite material Epoxy-Granite which exhibits the satisfactory characteristics as a material of ultra-precision mchine tool bed. The Epoxy-Granite testpieces that use epoxy resins as a binder and granite particles as a aggregate have been manufactured so as to examine the material properties about mechanical, thermal and damping characteristics. Experiments were carried out to obtain the proper manufacturing conditions of Expoxy-Granite specimens by varying the several testing conditions such as types of epoxy resins, particle sizes of granite and mixture ratio of epoxy resin and aggregate. Also, when Epoxy-Granite was compared with cast iron, GRANITAN which was imported from CMS of U.K. and granite materials, it has exhibited the superior or almost the same mechanical and damping properties and thermal conductivity, except for the thermal expansion.

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Study on the Composites of Soluble Aromatic Liquid Crystalline Polyesters and Acetylene-terminated Thermoset Resins (가용성 방향족 액정 폴리에스테르와 아세틸렌 말단기 함유 열경화성 수지의 복합화 연구)

  • Cho, Young-Gon;Sinh, Le-Hoang;Park, Min-A;Bae, Jin-Young
    • Polymer(Korea)
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    • v.35 no.2
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    • pp.176-182
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    • 2011
  • Liquid crystalline aromatic polyesters (LCPs) are representative examples of thermotropic liquid crystalline polymers, whose structure-property relationships have been the subject of many researches. In this study, we synthesized organo-soluble liquid crystalline aromatic polyesters, and their composites with acetylene-terminated thermoset resins were prepared and characterized. Soluble LCPs were synthesized by employing 6-hydroxy-2-naphthoic acid, terephthalic acid, isophthalic acid, and 4-aminophenol as monomers via condensation polymerization based on transesterfication and transamidation. Acetylene-terminated thermoset resins were synthesized by the reaction of 4-ethynylaniline with terephthaloyl dichloride, isophthaloyl dichloride or 4,4'-biphenyldicarbonyl dichloride. We prepared the soluble LCP/thermoset composites by solution blending followed by thermal treatment. The thermal stability, thermal expansion coefficient, and dielectric properties of the composite were studied.

A STUDY ON THE VOND STRENGTH OF PORCELAIN LAMINATE AND COMPOSITE RESIN CEMENTS (라미네이트 도재와 복합레진 시멘트의 결합강도에 관한 연구)

  • Kim, Sung-Il;Lim, Ho-Nam;Park, Nam-Soo
    • The Journal of Korean Academy of Prosthodontics
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    • v.29 no.1
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    • pp.91-109
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    • 1991
  • The purpose of this study were to comfirm the effects of the thickness and kinds of porcelain, etchants, illumination time, elapsed time for the measurement, and chemical cure component to the bond strength of porcelain laminate and composite resin cement, and to compare the effects between the light cured resin and the dual cured resins. The etched porcelain surface, the sectioned surface crossing porcelain and resin after bonding, and the debonded surfaces were observed by the SEM. One product of laminate porcelain powder, one light cured resin and two dual cured resins were selected. Each resin cements are lightened through the thin porcelain disc which was cut from cylindrical porcelain specimen by the diamond saw, and by the light through the porcelain disc they were bonded. Changes of thickness and kinds of porcelain, etchants, illumination time, and the elapsed time for the measurement were considered as variables for the bond strength. And the bond strength of porcelain and dual cured resins under the conditions of autopolymerization or the removal of chemical cure component were measured and compared. Bond strength were measured by shear stress. The etched surface, the cross-sectioned surface, and the debonded surface of porcelain or resin were observed by SEM. On the summary of this study, the following conclusions can be stated; 1. Bond strength of light cured resin was decreased inversely by the thickened porcelain laminate and showed the lowest value to the masking dentin porcelain among 4 kinds of porcelain powder. 2. Bond strength of autopolymerization of dual cured resin without illumination in dark chamber were from 75% to 98% to the data of dual cured resin with illumination. 3. Bond strength of dual cured resin used without chemical cured components were same to them of light cured resin. 4. Cross-sectioned surface treated by silane did not show the gap between the porcelain and resin. 5. Illumination over 80 seconds did not make the significant increase of bond strength on all kinds of resin.

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