Physicochemical characteristics of a nanocomposite film based on purified sodium carboxymethylcellulose and selenium nanoparticles

Yunusov Khaydar Ergashovich,Turakulov Fozil Mamaraim Ugli,Sarymsakov Abdushkur Abdukhalilovich,Yuldoshov Sherzod Abdullaevich,Rashidova Sayyora Sharafovna,Guohua Jiang 대한화학회 2024 Bulletin of the Korean Chemical Society Vol.45 No.3

In this study, selenium nanoparticles (SeNPs) were synthesized and stabilized by reducing sodium selenite using ascorbic acid in an aqueous solution of sodium carboxymethylcellulose (Na‐CMC) with a degree of substitution of 0.97 and a degree of polymerization of 810. IR‐Fourier spectroscopy revealed that coordination bonds between functional groups in Na‐CMC and SeNPs resulted in the development of polymer‐metal complexes. UV–Vis spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), and dynamic light scattering (DLS) methods were used to determine the SeNP sizes in the structure of the nanocomposite film. Investigation of the stabilization and nonstabilization of SeNPs over several cycles has shown that the effect of the polymer matrix of Na‐CMC on the stabilization of nanoparticles was achieved for 672 h, which was confirmed by the unchanged size distribution and resistance to change of the SeNPs synthesized in Na‐CMC solutions. In this study, selenium nanoparticles (SeNPs) were synthesized and stabilized by reducing sodium selenite using ascorbic acid in an aqueous solution of sodium carboxymethylcellulose (Na-CMC) with a degree of substitution of 0.97 and a degree of polymerization of 810. IR-Fourier spectroscopy revealed that coordination bonds between functional groups in Na-CMC and SeNPs resulted in the development of polymer-metal complexes. UV–Vis spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), and dynamic light scattering (DLS) methods were used to determine the SeNP sizes in the structure of the nanocomposite film. Investigation of the stabilization and nonstabilization of SeNPs over several cycles has shown that the effect of the polymer matrix of Na-CMC on the stabilization of nanoparticles was achieved for 672 h, which was confirmed by the unchanged size distribution and resistance to change of the SeNPs synthesized in Na-CMC solutions.

중합도에 따른 저점도 실리콘유의 유전 특성

조경순,Cho, Kyung-Soon 한국전기전자재료학회 2014 전기전자재료학회논문지 Vol.27 No.12

The characteristics of dielectric constant and $tan{\delta}$ of low viscosity silicone oils with changing degree of polymerization were investigated. The result shows dipole loss mechanism at low temperature range. The dielectric loss in the range of low frequencies are predominantly of ionic nature with temperature increase. The peak of dielectric loss is the detrapping of the electrons which is were trapped in the localized level of the silicone oils at the frequency of 30 kHz. The increase of ionic conduction is attributed to the presence of ionizable oxidation products and their increased dissociation feature. The activation energy ${\Delta}H$ and dipole moment ${\mu}_d$ were increased whit increasing degree of polymerization.

Characterization of highly sulfonated PEEK based membrane for the fuel cell application

Kim, D.J.,Lee, B.N.,Nam, S.Y. Pergamon Press ; Elsevier Science Ltd 2017 International journal of hydrogen energy Vol.42 No.37

In this study, poly(bisphenol-A-ether ketone) (PBAEK) is synthesized via nucleophilic aromatic substitution poly condensation between bisphenol A and 4,4-difluorobenzophenone, and the synthesized polymers are sulfonated using chlorosulfuric acid and suitable synthesis conditions for the temperature and sulfonating reagent content. The sulfonation degree of polymer is calculated using element analyses. The prepared sulfonated polymers are characterized for potential fuel cell applications through determining their water uptake, proton conductivity, and thermal stability. The significant advantage of the synthesized sulfonated PBAEK (sPBAEK) is its better solubility relative to commercial PEEK in various solvents, because sPBAEK backbones contain bisphenol A. The water uptake of the membrane increases with increases in the sulfonation degree. The sPBAEK membrane exhibits increased proton conductivity compared with the PBAEK membrane at 100% relative humidity conditions. As the sulfonation degree increases, the proton conductivity increases due to the increasing content in the hydrophilic domain. This property allows the prepared membranes to be potential candidates for proton exchange membrane fuel cells.

Surface functionalization of commercially available polyolefin-based non-woven fabric via ionizing radiation-induced graft polymerization

한동석,홍랑기,박석영,황인태,손준용,정찬희,최재학,신관우,신준화 한국공업화학회 2020 한국공업화학회 연구논문 초록집 Vol.2020 No.-

In this research, the surface functionalization of chemically-stable polyolefin-based non-woven fabric was studied by ionizing radiation graft polymerization. To investigate the optimal conditions for the functionalization, polypropylene fabric (PP) was irradiated by electron beam under the nitrogen atmosphere at the different absorbed doses, and then acrylic acid as a functional monomer was graft polymerized under various conditions of solvent, monomer concentration, reaction time and temperature. The functionalized PP was characterized in terms of grafting degree, chemical structure, thermal decomposition temperature, and morphology. The analytical results reveals that the polyacrylic acid-grafted PP with the grafting degree of 40 ~ 200% can be produced under the optimum condition, and leading to the homogeneously surface-functionalized PP.

다시마 alginate와 bile acids의 결합능에 미치는 추출조건의 영향

유병진,임영선,정인학,이강호,YOU Byeong-Jin,IM Yeong-Sun,JEONG In-Hak,LEE Kang-Ho 한국수산과학회 1997 한국수산과학회지 Vol.30 No.1

추출조건에 따른 다시마 alginate의 성질을 조사하기 위하여 추출용매인 $Na_{2}CO_{3}$의 농도를 1, 3, 및 $5\%$로 각각 조절하고 추출시간을 각각 1, 3, 5 및 10시간으로 하였을때 각 추출조건에서 추출된 alginate의 bile acids 결합능과 물리화학적 특성을 조사한 결과는 다음과 같다. 건조다시마를 미세하게 마쇄할수록, $Na_{2}CO_{3}$ 농도와 추출시간이 증가할수록 alginate 추출량은 증가하였다. alginate의 bile acids와의 결합능은 저 농도의 $Na_{2}CO_{3}$ 용액으로 단시간에 추출한 것일수록 높게 나타났다. alginate에 의한 bile acids 결합능은 cholic acid에서 가장 높게 나타났고, taurocholic acid, glycocholic acid, deoxycholic acid 순으로 조사되었다. 다시마로 부터 alginate를 추출하고 남은 잔사(RAEA)의 bile acids와의 결합능은 alginate의 경우와 같이 추출 용액의 농도가 높을수록 추출시간이 길어질수록 감소하는 경향을 보였다. Bile acids와의 결합능은 cholic acid, taurocholic acid의 경우 alginate보다 다소 낮은 값을 나타냈고, glycocholic acid의 경우 alginate와 비슷한 값을 보였으나 deoxycholic acid와의 결합능은 추출된 alginate보다도 오히려 높은 값을 보였다. 추출된 alginate의 점도와 중합도는 추출용액의 농도가 증가하고 추출시간이 길어짐에 따라 감소하였으며 이에 비례하여 bile acid와의 결합능도 감소하였다. Changes in bile acid binding rapacity in vitro and physical properties of alginate extracted from sea tangle (Laminaria spp.) and residue after extracting alginate (RAEA) were investigated. For the purpose, extraction conditions controlled under 1, 3 and $5\%$ of sodium carbonate solution, and 1, 3, 5 and 10 hours of extraction time at $60^{\circ}C$. The less sea tangle had particle size and the higher concentration of sodium carbonate solution increseded, the more yield of alginate gained. High concentration of sodium carbonate solution and long extraction time resulted in weakly binding capacity in vitro by alginate. Among four bile acids, binding capacites with alginate were in the order of cholic, taurocholic acid>glycocholic acid>deoxycholic acid. The binding capacity of RAEA was rated at almost same degree of alginate. For increasing the binding capacity of bile acids by alginate, it was subject to high viscosity and degree of polymerization.

Composition-structure-property relationships of CaO-MO-SiO₂ (M=Mg²⁺, Mn²⁺) systems derived from micro-Raman spectroscopy

North-Holland 2012 Journal of non-crystalline solids Vol.358 No.23

The effect of Mn<SUP>2+</SUP> and Mg<SUP>2+</SUP> ions on the distribution of silicate anionic species (Q<SUP>n</SUP> units, n=0, 1, 2, 3) in CaO-MO-SiO<SUB>2</SUB> (M=Mn<SUP>2+</SUP>, Mg<SUP>2+</SUP>) systems was compared by employing micro@?Raman spectroscopic analysis. The Q<SUP>3</SUP>/Q<SUP>2</SUP> ratio in both systems decreased as the content of MO increased, indicating that the substitution of MO for CaO resulted in depolymerization of the silicate networks, especially in the wollastonite primary area. The Q<SUP>3</SUP>/Q<SUP>2</SUP> ratio of the MgO@?containing system was higher than that of the MnO@?containing system due to the larger ionization potential of Mg<SUP>2+</SUP> ions than Mn<SUP>2+</SUP> ions. Thermophysical properties of the silicate melts, such as viscosity, activation energy of viscous transportation, density, and electrical conductivity of the silicate melts, had a good linear relationship to the Q<SUP>3</SUP>/Q<SUP>2</SUP> ratio, indicating that the Q<SUP>3</SUP>/Q<SUP>2</SUP> ratio is a good index for the degree of polymerization. The methodology outlined in the present study can be extended to predict the physical properties of silicate melts in glass science, metallurgical slags, and chemical geology.

광에너지 총량에 따른 광중합 콤포짓트레진과 콤포머의 중합도에 관한 연구

황경란,이용근,임범순,김철위 대한치과기재학회 2000 대한치과재료학회지 Vol.27 No.4

Dental composite resin is filler added, particle reinforced composite material, and the usage range had been enlarged in the posterior restoration through improvement of physical properties. Recently, resin modified glassionomer and compomer are used for various purposes. The degree of polymerization of cross-liked polymer has great importance in determining the mechanical properties and clinical availability of materials. Residual carbon-carbon double bonds have been implicated in causing reduced wear resistance, strength and color stability. The degree of polymerization is an important factor for longevity of a restoration. However the higher the degree of polymerization in resin composites, the higher the shrinkage will result. It has been elucidated that the degree of polymerization was significantly affected by the intensity of the curing light, wavelength of light and irradiation time. In this experiment, 16 kinds of restorative materials such as five kinds of universal composite resin, five kinds of condensable composite resin, two kinds of flowable composite resin, and four kinds of compomer were used. This study examined the effect of light intensity and irradiation time on the polymerization behavior such as the heat release during polymerization and the rate of polymerization by DSC (differential scanning calorimeter), and the degree of double bond conversion by FT-IR. With DSC, the irradiation modes were three different light intensity of 300, 400, 600 ㎽/㎠ and for 40 seconds. With FT-IR, the levels of irradiation energy were 1,500, 40,000, 8,000, 16,000 and 24,000 mJ/㎠ by combining the light intensity of 300, 400, 600 ㎽/㎠ and irradiation time of 5, 10, 20 and 40 seconds. From this experiment, The following results were obtained : 1.In the DSC result, heat of polymerization of composite resin was 23.22∼55.17J/gram and exothermic energy of compomer was 26.50∼52.68 J/gram 2.At the isothermal condition of 27℃, there were exothermal peaks at 40.812∼44.724 seconds from the start of irradiation. The percentage of polymerization by released heat was 19.12∼49.44% after 18 seconds, 37.23∼82.07% after 36 seconds, and 93.57∼98.53% after 54 seconds from the start of irradiation. 3.From FT-IR, the degree of polymerization of composite resin was 17.17∼60.91% and that of compomer was 7.74∼40.82%, and the degree of final conversion was influenced by the kinds of restorative materials and the irradiation energy(p<0.01). 4.As the irradiation energy was increased from 1,500 mJ/㎠ to 16,000 mJ/㎠, the degree of conversion was increased also. However, the degree of final conversion was no significant differences with the irradiation energy of 24,000 mJ/㎠ and 16,000 mJ/㎠(p>0.05). The wavenumber of absorbance peak of aromatic double bond was similar regardless of the restorative materials, and appeared around 1606.67∼1610.67 cm-1. The absorbance peak of aliphatic double bond appeared around 1636.64∼1638.52 cm-1 from FT-IR.

저점도 및 고점도 Bulk-fill Giomer 복합레진과 Bulk-fill 복합레진의 전환율과 중합수축

김희라,이제식,김현정,권태엽,남순현 대한소아치과학회 2019 大韓小兒齒科學會誌 Vol.46 No.1

The aim of this study was to compare the degree of conversion and polymerization shrinkage of low and high viscosity bulk-fill giomer-based and resin-based composites. Two bulk-fill giomer (Beautifil Bulk Restorative (BBR), Beautifil Bulk Flowable (BBF)), two bulk-fill (Tetric N-Ceram Bulk-fill (TBF), SureFil SDR flow (SDR)) and two conventional resin composites (Tetric N-Ceram (TN), Tetric N-flow (TF)) were selected for this study. The degree of conversion was measured by using Fourier transform infrared spectroscopy. Polymerization shrinkage was measured with the linometer. For all depth, BBR had the lowest degree of conversion and SDR had the highest. At 4 mm, the degree of conversion of low and high viscosity bulk-fill giomer resin composites was lower than that of bulk-fill resin composites (p < 0.05). At the depth between 2 mm and 4 mm, there were significant difference with TBF, TN and TF (p < 0.05), while no significant difference in the degree of conversion was measured for BBR, BBF and SDR. Polymerization shrinkage of six resin composites decreased in the following order: TF > SDR > BBF > TBF > TN and BBR (p < 0.05). Polymerization shrinkage of bulk-fill giomer resin composites was lower than that of bulk-fill resin composites (p < 0.05). From this study, it is found that the bulk-fill giomer resin composites and TBF were not sufficiently cured in 4 mm depth. The degree of conversion of low and high viscosity bulk-fill giomer resin composites was significantly lower than bulk-fill resin composites in both 2 mm and 4 mm depths. Therefore, such features of bulk-fill giomer resin composites should be carefully considered in clinical application. 이번 연구에서는 저점도 및 고점도 bulk-fill giomer 복합레진의 전환율과 중합수축을 기존 bulk-fill 복합레진 및 전통적 복합레진과비교 평가해보고자 하였다. Bulk-fill giomer 복합레진 2종류(Beautifil Bulk Restorative(BBR), Beautifil Bulk Flowable(BBF)), bulk-fill 복합레진 2종류(Tetric N-Ceram Bulk-fill(TBF), SureFil SDR flow(SDR)), 전통적 복합레진 2종류(Tetric N-Ceram(TN), Tetric N-flow(TF))를 사용하였다. 중합도 측정은 Fourier transform infrared spectroscopy을 사용하였으며, 중합수축은 linometer을 이용하여 측정하였다. 복합레진 하면의 전환율 측정 결과 2 mm와 4 mm 깊이 모두 BBR에서 가장 낮게 나왔으며, SDR에서 가장 높게 나왔다. 4 mm 깊이에서 고점도 및 저점도 bulk-fill giomer 복합레진의 전환율은 bulk-fill 복합레진에 비해 유의하게 낮은 값을 보였다(p < 0.05). 깊이에따른 전환율 비교 시 TBF, TN, TF는 유의차를 보였으며(p < 0.05), BBR, BBF, SDR는 유의차를 보이지 않았다. 중합수축은 TF > SDR > BBF > TBF > TN, BBR 순서로 감소 했으며(p < 0.05), bulk-fill giomer 복합레진은 bulk-fill 복합레진보다 낮은 중합수축량을 보였다(p < 0.05). 이번 연구 결과 4 mm 깊이에서 bulk-fill giomer 복합레진 및 TBF는 불충분한 중합을 나타냈으며, 2 mm와 4 mm 모두에서 고점도및 저점도 bulk-fill giomer 복합레진은 bulk-fill 복합레진에 비해 낮은 전환율을 보였다. 그러므로 bulk-fill giomer 복합레진의 임상적인적용을 위해서는 이에 대한 충분한 고찰 및 주의가 필요할 것으로 생각된다.

콤포짓트 레진의 중합체계에 따른 중합률 및 잔류단량체 유출

문현정,임범순,이용근,송재경,김철위 대한치과기재학회 2001 대한치과재료학회지 Vol.28 No.2

Newly developed curing units for the dental composite resins are claimed to result in optimum properties and short curing time. The purpose of this study was to detemine the curing effectiveness of the curing units, and to evaluate the relationship between the degree of polymerization and leachability of residual monomer. Three composite resins were tested (Z100; z100, Herculite XRV; HX, Heliomolar; HM). Disk specimens of 2 mm in thickness and 6 mm in diameter were cured with a plasma arc [Apollo 95E; at 1370 mW/㎠, for 5 sec.(A5), 10 sec.(A10), 15sec(A15)], halogen lamp [VIP; at 500 mW/㎠, for 13 sec.(V13), 26 sec.(V26), 40 sec.(V40)] and custom made light emitting diode [LED; at 500 mW/㎠, for 13 sec.(L13), 26 sec.(L26), 40 sec.(L40)]. Specimens were immersed in 75% ethanol for 7 days. Eluates of the composites were analyzed by a high-performance liquid chromatography, and the degree of polymerization of composites were determined by a Fourier transform infrared spectroscopy. To obtain the sufficient curing by a plasma arc, the curing time should be longer than 10 sec. When the same light energy was irradiated, LED showed similar curing performance to halogen lamp. The light energy and the degree of polymerization was not correlated (p>0.05), but the light energy and the leachability of residual monomer was correlated (p<0.05). The leachability of residual monomer (TEGDMA+BisGMA) depended on the degree of polymerization.

치과용 폴리머의 중합도에 관한 연구

최기열 대한치과기재학회 1998 대한치과재료학회지 Vol.25 No.3

The degree of polymerization of dental polymers has much influences on the physical and mechanical properties, such as hardness, tensile strength, compressive strength abrasion resistance, disintegrity and discoloration. Five kinds of composite resins and five kinds of pit and fissure sealants were used in this study. The size of KBr pellets was 13 mm in diameter and 0.05 mm in thickness and the degree of polymerization was measured with IR spectrophotomer(Hitachi 270-30, Japan). The obtained results were as follows : 1. The degree of polymerization of composite resins was 53∼72%, and that of pit and fissure sealants was 66∼73%. 2. The degree of polymerization varied to the shade of composite resins and the more translucent comosites showed much higher value relatively. 3. The fluoride containing pit and fissure sealants were polymerized much less than not containing sealants.