• Title/Summary/Keyword: Resins

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Curing Behaviors and Mechanical Properties of Unsaturated Polyester Hosing with Different Glycol Molar Ratios (글리콜 몰비가 다른 UPE 수지의 경화거동과 물성에 관한 연구)

  • 이상효;이장우
    • Polymer(Korea)
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    • v.24 no.5
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    • pp.599-609
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    • 2000
  • In order to improve the mechanical properties of unsaturated polyester (UPE) resins, the UPE resins with different glycol molar ratios were prepared. The effects of molar ratios of the UPE resins on the curing behaviors and mechanical properties were investigated. The microgel reaction mechanism was employed to characterize the system. It was found that the final conversion increased with increasing NPG molar ratios, and the conversion at the peak of differential scanning calorimetry (DSC) thermogram appeared to decrease with increasing NPG molar ratios. The flexural strength, tensile modulus, water resistance, and infiltration increased with increasing NPG content, but the tensile strength, tensile elongation, and flexural modulus decreased. Among the UPE resins prepared from the glycols with the molar ratios (PG/NPG) of 0.5/0.5, 0.25/0.75, those of laminated composites plates showed better mechanical properties.

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Synthesis of Modified Silane Acrylic Resins and Their Physical Properties as Weather-Resistant Coatings

  • Yoo, Gyu-Yeol;Kim, Ji-Hyun;Park, Hong-Soo;Kim, Young-Geun;Kim, Seong-Kil
    • Journal of the Korean Applied Science and Technology
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    • v.25 no.1
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    • pp.1-14
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    • 2008
  • To prepare weather-resistant modified silane acrylic resin coatings for an architectural purpose, tetrapolymers were synthesized by radical polymerization. 3-Methacryloxypropyltrimethoxysilane (MPTS) as a silicone monomer and n-butyl acrylate, methyl methacrylate, and n-butyl methacrylate as acrylic monomers were used. The composition of monomers was adjusted to fix the glass transition temperature of acrylic polymer for $20^{\circ}C$. The composition of MPTS in the synthesized polymer were varied from 10 wt% to 30 wt%. On the basis of synthesized resin amber paints were prepared and their physical properties and effects on weatherability were examined. The presence of MPTS in modified silane acrylic resins generally resulted in low molecular weight and broad molecular weight distribution, and also lowered the viscosity of the copolymers. The coated films prepared from these resins showed good and balanced properties in general. Adhesion to the substrate was outstanding in particular. Weatherability tests were carried out in three different types such as outdoor exposure, QUV, and SWO. The test results showed that the modified silane acrylic resins containing 30 wt% of MPTS had superior weathering properties.

Synthesis of Porous 4-Vinylpyridine Divinylbenzene Resin and It's Properties (다공성 4-비닐피리딘디비닐벤젠 수지의 합성과 그의 성질)

  • Dong Won Kim;Hae Young Song;Suh Jung Muck;Jae Jick Oh;Beom Gyu Lee
    • Journal of the Korean Chemical Society
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    • v.29 no.3
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    • pp.283-286
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    • 1985
  • The non porous and porous 4-vinylpyridine-divinylbenzene ion exchange resins were synthesized by the suspension polymerization method. The functional groups of these resins were identified by means of infrared adsorption spectroscopy. The pore volume and pore spectra of these synthesized resins were determined with a mercury porosimeter. The influence of diluent and percentage of divinylbenzene on the pore size and volume of the porous 4-vinylpyridine-divinylbenzene copolymer, P-4VPDVB, 50-100 mesh was discussed. The ion exchange capacity of non-porous and porous 4-vinylpyridine divinylbenzene resins was 5.0meq/g, respectively.

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QUANTITATIVE ANALYSIS OF RESIDUAL MONOMERS IN VISIBLE LIGHT-CURED RESINS (치과용 가시광선중합형 복합레진의 잔류단량체 정량분석에 관한 연구)

  • Choi, Kyoung-Kyu;Min, Byung-Soon
    • Restorative Dentistry and Endodontics
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    • v.17 no.1
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    • pp.181-190
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    • 1992
  • The purpose of this study was to estimate the contents of the residual monomers, such as Bis-GMA and TEGDMA. In this study, materials used were six kinds of anterior and posterior visible light-cured resins. Resins were placed in disk-shaped Teflon mold (8.5mm in diameter, 2.0mm in thickness), and cured for 20 seconds with visible light source attached wide diameter lightguide. The specimens were immersed in 10ml ethanol and stored for 5 days at $37^{\circ}C$. The concentration of residual monomers in eluate solution was analysed by HPLC, and the following results are obtained. 1. The residual Bis-GMA and TEGDMA were detected in all materials used, and the ranges of quantity of the residual Bis-GMA was 0.101-1.236 wt% and that of TEGDMA was 0.230-5.794 wt%.2. The contents of residual TEGDMA was detected higher than that of residual Bis-GMA (P < 0.01). 3. The content of residual monomers was detected to be highest in Bis-Fil M as microfilled type. 4. In most of the materials used, there was no significant difference in the contents of residual monomers between anterior and posterior light-cured resins.

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A STUDY ON SURFACE HARDNESS OF COMPOSITE RESINS ACCORDING TO STORAGE CONDITON AND HEAT TREATMENT (보관조건과 열처리에 따른 복합레진의 표면경도에 관한 연구)

  • Kang, Seung-Hoon;Min, Byung-Soon
    • Restorative Dentistry and Endodontics
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    • v.19 no.1
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    • pp.194-204
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    • 1994
  • The purpose of this study was to evaluate the surface hardness of composite resins according to heat treatment. storage condition and storage time. In this study. two kinds of composite resin inlays and one kind of conventional posterior composite resin were used as experimental materials. One hundred eighty composite resin specimens were constructed from composite resin inlays and conventional posterior composite resin. The conditions of this study were heat treatment. storage condition and storage time. Hardness readings were taken from the top surface of each samples using the Vickers microhardness tester(MHT-l. Matsuzawa. Japan}. The following results from this study were obtained: 1. Regardless of storage condition. both composite resin inlay and conventional posterior composite resin have a higher surface hardness under heat treatment than not. 2. Composite resins with heat treatment have a higher surface hardness under dry storage than under water immersion. 3. In case of Clearfil Photo Posterior and Brilliant Enamel with heat treatment. there was no significant difference with time. but Clearfil CR Inlay with heat treatment. there was statistical difference after 24 hours. 4. Surface hardness of composite resins with coarse hybrid type was higher than that of composite resin with fine hybrid type.

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Effect of Electron Beam and ${\gamma}$-Ray Irradiation on the Curing of Epoxy Resin

  • Kang, Phil-Hyun;Park, Jong-Seok;Nho, Young-Chang
    • Macromolecular Research
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    • v.10 no.6
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    • pp.332-338
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    • 2002
  • The effect of an electron beam and ${\gamma}$-ray irradiation on the curing of epoxy resins was investigated. Diglycidyl ether of bisphenol A (DGEBA) and diglycidyl ether of bisphenol F (DGEBF) as epoxy resin were used. The epoxy resins containing 1.0-3.() wt% of triarylsulphonium hexafluoroantimonate(TASHFA) and triarylsulphonium hexafluorophosphate(TASHFP) as initiator were irradiated under nitrogen at room temperature with different dosage of EB and ${\gamma}$-rays from a Co$^{60}$ u source. The chemical and mechanical characteristics of irradiated epoxy resins were compared after curing of EB and ${\gamma}$-ray irradiation. The thermal properties of cured epoxy were investigated using dynamic mechanical thermal analysis. The chemical structures of cured epoxy were characterized using near infrared spectroscopy. Mechanical properties such as flexural strength, modulus were measured. The gel fraction of DGEBA with ${\gamma}$-ray was higher than that of the epoxy with EB at the same dose. Young's modulus of the sample irradiated by ${\gamma}$-ray is higher than that of sample cured by EB. From the result of strain at yield, it was found that the epoxy cured by ${\gamma}$-ray had a higher stiff property compared with the irradiated by EB.

Investigation of the Part Shrinkage in Injection Molding for Class Fiber Reinforced Thermoplastics (유리섬유가 첨가된 수지에서 사출성형품의 성형수축에 관한 연구)

  • Mo J.-H.;Lyu M.-Y.
    • Transactions of Materials Processing
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    • v.13 no.6 s.70
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    • pp.515-521
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    • 2004
  • The shrinkages of injection molded parts are different in molding operational conditions and mold design. It also differs from resins. The shrinkages of injection molded parts fur PBT (polybutylene terephthalate), PC (polycarbonate), and glass reinforced PBT and PC have been studied for various operational conditions of injection molding. The part shrinkage of crystalline polymer, PBT was higher than that of amorphous polymer, PC by about two times. The part shrinkages of both polymers decreased as glass fiber content increases. Higher injection temperature and lower injection pressure resulted in a higher shrinkage in both PBT and PC resins. As mold temperature increases the part shrinkage of PC decreased. However, the part shrinkage of PBT increased as mold temperature increases. The part shrinkages of PBT and PC resins decreased as gate size increases since the pressure delivery is mush easier for a larger gate size. The part shrinkage of flow direction was less than that of the perpendicular direction to the flow for both pure and glass fiber reinforced resins. The part shrinkage at the position close to the gate was less than that of the position far from the gate.

FRACTURE BEHAVIOUR OF POSTERIOR COMPOSITE RESINS (구치부(臼齒部) 수복용(修復用) Composite Resin의 파괴거동(破壞擧動)에 관(關)한 연구(硏究))

  • Park, Young-Ho;Min, Byung-Soon;Park, Sang-Jin;Choi, Ho-Young
    • Restorative Dentistry and Endodontics
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    • v.12 no.2
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    • pp.33-44
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    • 1987
  • The use of composite resin for the posterior teeth gives rise to clinical problem due to the lack of mechanical properties. The purpose of this study was to observe the fractured surfaces of light posterior composite resins which are P-10, Clearfil posterior, Adaptic anterior & posterior, P-30, Lite-fil posterior, Estilux posterior, Helio-molar, and Ful-fil com pules (Table 1). The failure of composite resin specimens of I, T and Y-Type (Fig. 1,2) occured under compression. Fractographical observations by SEM (JSM-T20, JEOL) were carried out in order to examine the fracture behaviour of eight composite resins in different types of specimens. The results obtained from this study were as follows: 1. Similar features were found in fractured surfaces of eight composite resins. 2. The crack growth was initiated at the regions of porosities. 3. The crack propagated on the filler-matrix interface. 4. As the crack increased in size, it accelerated to form secondary crack. 5. The fracture behaviour was dependent on the content, size, shape, and distribution of fillers.

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Mechanical Properties of Radiation-Curing Vinyl Ester Resin (방사선 경화 비닐에스터 수지의 기계적 특성 연구)

  • Shin, Bum-Sik;Jeun, Joon-Pyo;Kim, Hyun Bin;Kang, Phil-Hyun
    • Journal of Radiation Industry
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    • v.4 no.1
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    • pp.19-23
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    • 2010
  • Vinyl ester (VE) resins, introduced in the late 1960s, have made large strides in reinforced plastics applications as adhesive and matrix materials on their appropriate mechanical performance characteristics in the glassy state. Generally, VE resins are a group of dimethacrylate resins based on bisphenol A type epoxy resin. They exhibit easy handling properties as well as good resistance to most chemical agents due to their mechanical and thermal properties. In this study, the effects of curing methods of vinyl ester resins on gel contents, flexural strength and dynamic mechanical properties were investigated. Thermal curing (room temperature, $80^{\circ}C$) and electron beam curing were used to crosslink a VE resin/styrene complex (65/35 wt%) with methyl ethyl ketone peroxide (MEKPO) as a catalyst and an 8 wt% cobalt naphthenate in styrene solution as a accelerator. For the samples, gel contents as well as flexural strength and dynamic mechanical properties were characterized and compared by soxhlet apparatus, universal testing machine (UTM) and dynamic mechanical analysis (DMA). As a result, the electron-cured VE resin was confirmed as a better condition than those for gel contents, flexural strength and dynamic mechanical properties, respectively.

Effect of Substituted Trifluoromethyl Groups on Thermal and Mechanical Properties of Fluorine-containing Epoxy Resin

  • Heo, Gun-Young;Park, Soo-Jin
    • Macromolecular Research
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    • v.17 no.11
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    • pp.870-873
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    • 2009
  • In this study, 2-diglycidylether of benzotrifluoride (2-DGEBTF) and 4-diglycidylether of benzotrifluoride (4-DGEBTF) epoxy resins, which contained fluorine groups in the main chain, were synthesized. The resins were characterized by FTIR, $^1H$ NMR, $^{13}C$ NMR and $^{19}F$ NMR spectroscopy. The 2-DGEBTF and 4-DGEBTF epoxy resins were cured with triethylene tetramine (TETA), and the effect of the fluorine group on the synthesized epoxy resin on the cure behavior, thermal, and mechanical properties was investigated. The 2-DGEBTF/TETA system was more reactive than the 4-DGEBTF/TETA system, whereas the thermal stability factor i.e., the decomposition activation energy ($E_d$), of 4-DGEBTF/TETA was higher than that of 2-DGEBTF/TETA. These results can be explained by the decrease in cross-linking density and decomposition of the short side chains, resulting in the $CF_3$ group at the para position. However, the $K_{IC}$ value of 4-DGEBTF/TETA was higher than that of 2-DGEBTF/TETA. This was attributed to the increase in flexibility in the epoxy backbone, resulting in a difference in steric hindrance and polarlizability.