• Title/Summary/Keyword: 중합 효과

Search Result 346, Processing Time 0.023 seconds

EFFECT OF THE EXPONENTIAL CURING OF COMPOSITE RESIN ON THE MICROTENSILE DENTIN BOND STRENGTH OF ADHESIVES (복합레진의 exponential 중합법이 상아질접착제의 미세인장접착강도에 미치는 영향)

  • Seong, So-Rae;Seo, Duck-kyu;Lee, In-Bog;Son, Ho-Hyun;Cho, Byeong-Hoon
    • Restorative Dentistry and Endodontics
    • /
    • v.35 no.2
    • /
    • pp.125-133
    • /
    • 2010
  • Objectives: Rapid polymerization of overlying composite resin causes high polymerization shrinkage stress at the adhesive layer. In order to alleviate the shrinkage stress, increasing the light intensity over the first 5 seconds was suggested as an exponential curing mode by an LED light curing unit (Elipar FreeLight2, 3M ESPE). In this study, the effectiveness of the exponential curing mode on reducing stress was evaluated with measuring microtensile bond strength of three adhesives after the overlying composite resin was polymerized with either continuous or exponential curing mode. Methods: Scotchbond Multipurpose Plus (MP, 3M ESPE), Single Bond 2 (SB, 3M ESPE), and Adper Prompt (AP, 3M ESPE) were applied onto the flat occlusal dentin of extracted human molar. The overlying hybrid composite (Denfil, Vericom, Korea) was cured under one of two exposing modes of the curing unit. At 48h from bonding, microtensile bond strength was measured at a crosshead speed of 1.0 mm/min. The fractured surfaces were observed under FE-SEM. Results: There was no statistically significant difference in the microtensile bond strengths of each adhesive between curing methods (Two-way ANOVA, p > 0.05). The microtensile bond strengths of MP and SB were significantly higher than that of AP (p < 0.05). Mixed failures were observed in most of the fractured surfaces, and differences in the failure mode were not observed among groups. Conclusion: The exponential curing method had no beneficial effect on the microtensile dentin bond strengths of three adhesives compared to continuous curing method.

EFFECT OF CURING CONDITIONS ON THE MONOMER ELUTION OF ORTHODONTIC ACRYLIC RESIN (교정용 아크릴릭 레진의 중합조건에 따른 모노머 용리)

  • Noh, Hong-Seok;Kim, Jae-Moon;Kim, Shin;Jeong, Tae-Sung
    • Journal of the korean academy of Pediatric Dentistry
    • /
    • v.35 no.3
    • /
    • pp.477-486
    • /
    • 2008
  • Acrylic resin is widely used in dental practice. However, the residual monomer in acrylic resin could act as a negative biocompatability on human body. The aim of this study was to evaluate the amount of the monomer elution from polymerized orthodontic acrylic resin. Orthodontic acrylic resin was used in the study. The curing condition of the resin was controlled by temperature, pressure, aquatic and atmospheric environment. The duration and amount of monomer elution and timedependent plot was recorded by high performance liquid chromatography. The result showed that the only monomer eluted from the resin was methyl methacrylic acid. And the amount of the monomer elution has diminished considerably by time progress especially within 24 hours. Furthermore, elution of the residual monomer was significantly lower in group of pressure, moisture and elevated temperature than control (p<.05). According to this study, it was thought that the elution of residual monomer might be influenced by curing environment.

  • PDF

Basic Studies on Propellant Casting (II). Effects of Solid Additives on Urethane Polymerization (추진제 성형에 관한 기초연구 (제2보). 우레탄 중합에 미치는 첨가제 효과)

  • Young Gu Cheun;Ik Choon Lee;Shi Choon Kim
    • Journal of the Korean Chemical Society
    • /
    • v.25 no.4
    • /
    • pp.214-218
    • /
    • 1981
  • Kinetic studies were carried out on urethane polymerization reaction of hydroxyl-terminated polybutadiene with isophorone diisocyanate under presence of Hexogen as solid additive. The rate was found to increase with the amount of Hexogen added. However the rate acceleration was not a catalytic effect but solely due to an increase of activation entropy. The reaction was a good 2nd order process with nearly constant activation energy of 8.4 kcal/mole.

  • PDF

Radiation-Induced Graft Copolymerization of Acrylic Acid onto Polyester

  • Chang, Hoon-Sean;Kong, Young-Kun;Lee, Chong-Kwang;Park, Jae-Ho
    • Nuclear Engineering and Technology
    • /
    • v.9 no.2
    • /
    • pp.65-74
    • /
    • 1977
  • The radiation-induced graft polymerization of acrylic acid onto polyester fabric was investigated with accelerated electron beams as ratiation source at high dose rates. Homopolymerization was suppressed by addition of cations which is known as homopolymerization inhibitor, but this practical advantage was obtained at the expense of grafting efficiency. The rate of grafting (%/sec) was proportional to the 0.82th power of dose rates over the range from 1.6$\times$10$^{6}$ to 10$\times$10$^{6}$ rad/sec. The grafted polyester fabric showed considerable improvement in moisture regain and antistatic properties.

  • PDF

Holographic recordings in acrylamide photopolymer (Acrylamide Photopolymer의 제작 및 홀로그램 기록 특성)

  • 경천수;성기영;곽종훈;최옥식;이윤우;이인원;서호형;이일항
    • Korean Journal of Optics and Photonics
    • /
    • v.9 no.1
    • /
    • pp.31-37
    • /
    • 1998
  • We fabricated acrylamie photopolymer holographic recording materials by photopolymerization of acrylamide, and described hologram formation process. Light absorption and phtobleaching process by MB(methylene blue) dye and radical polymerization process due to TEA(triethanolamind) are explained in detail. We adopted the Beer-lambert law in order to explain the photobleaching kinetics. Dependencies of diffraction efficiency of the hologram on monomer amout and the exposure are investigated. The scattering effect caused by grain of polymer crystal, and fixing method are also illustrated.

  • PDF

Effects of Comonomer and Various Polymerization Conditions on Terpolymerization (삼원공중합에 있어서 공단량체 및 여러 가지 중합조건이 미치는 영향)

  • Kim, Jung Soo;Jeon, Dong-Gyu;Kim, Tae-Wan;Kim, Hyun Ki;Kim, Dong Hyun
    • Elastomers and Composites
    • /
    • v.48 no.4
    • /
    • pp.263-268
    • /
    • 2013
  • In this study, we prepared poly(ethylene-ter-1-hexene-ter-divinylbenzene) using bridged rac-$Et[Ind]_2ZrCl_2$ metallocene catalysts. The effect of 1-hexene on the terpolymerization rate was evaluated. When cocatalyst/catalyst molar ratio was 3,000, catalytic activity indicated more than 8,000 which was very remarkable value. As polymerization time increased, the weight-average molecular weight of the terpolymer gradually increased to some degree. In case of a polymerization time of 50 minutes, the terpolymer became amorphous state. The molecular weight distribution and densities of the terpolymer were 110,000-200,000 and $0.85-0.89g/cm^3$, respectively. Thermal properties and structure of the terpolymer were also identified.

Effects of Treatment of Silane Coupling Agent in MPS Concentration on the Shear Bond Strength between Self Curing Resins and Heat Curing Resin (Silane coupling agent인 MPS 농도별처리에 따른 열중합 레진과 자가중합 레진 간의 전단결합강도)

  • Choi, Esther;Kwon, Eun-Ja
    • The Journal of the Korea Contents Association
    • /
    • v.15 no.2
    • /
    • pp.344-351
    • /
    • 2015
  • The purpose of this study was to evaluate the effect of the surface treatment of widely used in dental of silane coupling agent concentration on the shear bond strength of denture base resin and self curing resins. Denture base resin surface was treated with silane coupling agent concentration, after self curing resins were injected shear bond strength was measured. The results of silane coupling agent(MPS) concentration on the shear bond strength of Vertex self curing resin showed that the value of 5%, 7% groups were higher than that of other group(P<0.05). Silane coupling agent concentration on the shear bond strength of Kooliner resin showed that the value of 5% was highest(P<0.05). Therefore, we could conclude 5% MPS to strengthen effectively the shear bonding property of denture base resin and self curing resins of this study.

A Study on the Electrical and Optical Properties of Micro-Pattern of Polypyrrole(PPy) by Using Vapor Phase Polymerization (기상중합법을 이용한 Polypyrrole(PPy) 필름의 전기적/광학적 특성 및 미세패턴 형성에 관한 연구)

  • Han, Yong-Hyeon;Yim, Jin-Heong
    • Polymer(Korea)
    • /
    • v.34 no.5
    • /
    • pp.450-453
    • /
    • 2010
  • The electrical/optical properties and surface structures of polypyrrole (PPy) thin films, which were prepared by liquid phase polymerization (LPP) and vapor phase polymerization (VPP) of pyrrole using FTS as an initiatior are compared. The PPy thin film prepared by VPP showed superior surface resistance characteristics as compared with that prepared by LPP. We investigated the relation between surface morphology of PPy film and surface resistance by surface characteristic analysis. The surface of PPy thin film prepared by VPP was smoother than that prepared by LPP. Micro-patterned PPy thin film could be prepared effectively using VPP-combined ink-jet printing and soft lithography.

하이드록시 아파타이트와 폴리유산 블렌드에서 하이드록시 아파타이트의 화학적 개질의 영향

  • Lee, Won-Gi
    • Proceedings of the Korean Environmental Sciences Society Conference
    • /
    • 2007.05a
    • /
    • pp.545-547
    • /
    • 2007
  • 본 연구에서는 생체 적합성이 뛰어난 HA가 고분자와의 낮은 친화성을 개선하기 위하여 HA를 화학적으로 개질하여 고분자와의 친화성을 높이는 연구를 수행하였다. 결과에서 나타나 바와 같이 효과적으로 개환중합을 이용하여 HA를 효과적으로 개질하였고 고분자와의 복합재료에 대한 특성을 고찰 하였다.

  • PDF

EFFECT OF SOFT-START CURING ON THE CONTRACTION STRESS OF COMPOSITE RESIN RESTORATION POLYMERIZED WITH LED AND PLASMA CURING UNIT (LED와 플라즈마 광원의 완속기시 광중합 방식이 복합레진의 수축응력에 미치는 영향)

  • Chung, Yang-Seok;Lee, Nan-Young;Lee, Sang-Ho
    • Journal of the korean academy of Pediatric Dentistry
    • /
    • v.34 no.4
    • /
    • pp.623-631
    • /
    • 2007
  • Effect of Soft-start curing on the contraction stress of composite resin restoration polymerized with LED and plasma curing unit The purpose of this study was to evaluate the influence of soft-start light curing on contraction stress and hardness of composite resin. Composite resin (Filtek $Z-250^{TM}$, 3M ESPE, USA) was cured using the one-step continuous curing method with three difference light sources ; conventional halogen light ($XL3000^{TM}$, 3M ESPE, USA) cure for 40 seconds at $400 mw/cm^2$, LED light (Elipar Freelight $2^{TM}$, 3M-ESPE, USA) cure for 20 seconds at $800\;mW/cm^2$ a and plasma arc light ($Flipo^{TM}$, LOKKI, France) cure for 12 seconds at $1300 mW/cm^2$. For the soft-start curing method ; LED light (Elipar Freelight $2^{TM}$, 3M-ESPE, USA) cure exponential increase with 5 seconds followed by 17 seconds at $800\;mW/cm^2$ and plasma arc light ($Flipo^{TM}$, LOKKI, France) cure 2 seconds light exposure at $650\;mW/cm^2$ followed by 11 seconds at $1300\;mW/cm^2$. The strain guage method was used for determination of polymerization contraction. Measurements were recorded at each 2 second for the total of 800 seconds including the periods of light application. Obtained data were analyzed statically using Repeated measures ANOVA, One way ANOVA, and Tukey test. The results of present study can be summarized as follows: 1. Composite resin restoration showed transient expansion just after irradiation of curing light. Contraction stress was increased rapidly at the early phase of polymerization and reduced slowly as time elapsed (P<0.05). 2. Contraction stress was not revealed significant difference between Halogen curing light groups and LED and Plasma Light curing with soft-start group (P>0.05). 3. LED and Plasma Light curing with soft-start showed lower contraction stress than the one-step continuous light curing (P<0.05).

  • PDF