Poly(lactic acid)와 Nanomer^®I.44P를 이용한 친환경 나노복합체 개발

조원주,황기,김준태,Cho, Won-Ju,Whang, Key,Kim, Jun Tae 한국포장학회 2014 한국포장학회지 Vol.20 No.3

Biodegradable nanocomposites were fabricated with poly (lactic acid) (PLA) and Nanomer$^{(R)}$ I.44P using ultrasonication (US). Processing conditions were optimized to obtain the maximum tensile properties of the nanocomposites. Poly (ethylene glycol) (PEG) was used as a plasticizer to avoid the brittleness of nanocompsoties. In order to disperse nanoclay into the PLA matrix, PEG and Nanomer$^{(R)}$ I.44P were firstly mixed and dispersed in the chloroform and followed by ultrasonication for 1 min With 10% PEG 400, tensile stress and Young's modulus of the nanocomposites decreased from 53.5 MPa and 2225 MPa to 37.0 MPa and 1757 MPa, respectively, while the elongation was increased from 4% to 21%. Tensile stress, Young's modulus, and elongation of nanocomposites were also increased with nanoclay concentration up to 2% (w/w) and were decreased with further increase in the nanoclay concentration. Transmittance of nanocomposites were significantly decreased from 62.5% for pure PLA film to 7.8% for 5% nanoclay containing nanocomposites. Water vapor permeability of the nanocomposites was also significantly decreased with nanoclay concentration and the minimum WVP of $3.5{\times}10^{-11}g{\cdot}m/m^2{\cdot}s{\cdot}Pa$ was obtained with 5% (w/w) nanoclay concentration. The PLA/Nanomer$^{(R)}$ I.44P nanocomposites showed a great potential as a environmental friendly food packaging material. PLA와 nanoclay인 Nanomer$^{(R)}$ I.44P를 이용한 환경 친화적인 nanocomposites을 개발하였다. PLA/Nanomer$^{(R)}$ I.44P nanocomposites의 상온 건조 후 잔존하는 용매를 제거하기 위해 진공건조를 하였으며, 진공건조 시간이 8시간 까지는 신장율이 크게 감소하였으며, 그 이후에는 유의적인 차이가 없었다. Nanoclay가 PLA matrix내에서 균일하게 분산시키기 위해 초음파 처리를 하였으며, 초음파 처리시간이 5분까지는 인장강도 및 영모듈러스가 증가하는 경향을 보였으나 5분 이상의 초음파 처리에서는 시간이 증가함에 따라 인장 특성도 점차 감소하였고, 특히 15분 이상 초음파 처리를 하였을 때에는 nanoclay가 뭉치는 현상이 관찰 되었다. Nanoclay의 양이 증가할수록 nanocomposites의 가시광선 영역에서의 투과성(trasmittance)은 62.5%에서 7.8%로 크게 감소하였다. Water vapor permeability (WVP)는 nanoclay의 첨가량에 따라 감소하는 경향을 보이며, 5%의 nanoclay 첨가 시 $3.5{\times}10^{-11}g{\cdot}m/m^2{\cdot}s{\cdot}Pa$로 control에 비해 약 43%가 감소하였다.

Poly(lactic acid)와 Nanomer®I.44P를 이용한 친환경 나노복합체 개발

조원주,황기,김준태 한국포장학회 2014 한국포장학회지 Vol.20 No.3

PLA와 nanoclay인 Nanomer® I.44P를 이용한 환경 친 화적인 nanocomposites을 개발하였다. PLA/Nanomer® I.44P nanocomposites의 상온 건조 후 잔존하는 용매를 제 거하기 위해 진공건조를 하였으며, 진공건조 시간이 8시간 까지는 신장율이 크게 감소하였으며, 그 이후에는 유의적인 차이가 없었다. Nanoclay가 PLA matrix내에서 균일하게 분산시키기 위해 초음파 처리를 하였으며, 초음파 처리시간 이 5분까지는 인장강도 및 영모듈러스가 증가하는 경향을 보였으나 5분 이상의 초음파 처리에서는 시간이 증가함에 따라 인장 특성도 점차 감소하였고, 특히 15분 이상 초음 파 처리를 하였을 때에는 nanoclay가 뭉치는 현상이 관찰 되었다. Nanoclay의 양이 증가할수록 nanocomposites의 가 시광선 영역에서의 투과성(trasmittance)은 62.5%에서 7.8% 로 크게 감소하였다. Water vapor permeability (WVP)는 nanoclay의 첨가량에 따라 감소하는 경향을 보이며, 5%의 nanoclay 첨가 시 3.5×10-11g·m/m2·s·Pa로 control에 비해 약 43%가 감소하였다. Biodegradable nanocomposites were fabricated with poly (lactic acid) (PLA) and Nanomer® I.44P using ultrasonication (US). Processing conditions were optimized to obtain the maximum tensile properties of the nanocomposites. Poly (ethylene glycol) (PEG) was used as a plasticizer to avoid the brittleness of nanocompsoties. In order to disperse nanoclay into the PLA matrix, PEG and Nanomer® I.44P were firstly mixed and dispersed in the chloroform and followed by ultrasonication for 1 min With 10% PEG 400, tensile stress and Young’s modulus of the nanocomposites decreased from 53.5 MPa and 2225 MPa to 37.0 MPa and 1757 MPa, respectively, while the elongation was increased from 4% to 21%. Tensile stress, Young’s modulus, and elongation of nanocomposites were also increased with nanoclay concentration up to 2% (w/w) and were decreased with further increase in the nanoclay concentration. Transmittance of nanocomposites were significantly decreased from 62.5% for pure PLA film to 7.8% for 5% nanoclay containing nanocomposites. Water vapor permeability of the nanocomposites was also significantly decreased with nanoclay concentration and the minimum WVP of 3.5×10-11g·m/m2·s·Pa was obtained with 5% (w/w) nanoclay concentration. The PLA/Nanomer® I.44P nanocomposites showed a great potential as a environmental friendly food packaging material.

Rheology of PP/Clay Hybrid Produced by Supercritical $CO_2$ Assisted Extrusion

Lee, Sang-Myung,Shim, Dong-Cheol,Lee, Jae-Wook The Polymer Society of Korea 2008 Macromolecular Research Vol.16 No.1

Polypropylene (PP)-layered silicate nanocomposites were developed using a new processing method involving a supercritical carbon dioxide ($scCO_2$)-assisted co-rotating twin-screw extrusion process. The nanocomposites were prepared through two step extrusion processes. In the first step, the PP/clay mixture was extruded with $CO_2$ injected into the barrel of the extruder and the resulting foamed extrudate was cooled and pelletized. In the second step, the foamed extrudate was extruded with venting to produce the final PP/clay nanocomposites without $CO_2$. In this study, organophilic-clay and polypropylene matrix were used. Maleic anhydride grafted polypropylene (PP-g-MA) was used as a compatibilizer. This study focused on the effect of $scCO_2$ on the dispersion characteristics of the clays into a PP matrix and the rheological properties of the layered silicate based PP nanocomposites. The dispersion properties of clays in the nanocomposites as well as the rheological properties of the nanocomposites were examined as a function of the PP-g-MA concentration. The degree of dispersion of the clays in the nanocomposites was analyzed by X-ray diffraction and transmission electron microscope. Various rheological properties of the nanocomposites were measured using a rotational rheometer. In the experimental results, the $scCO_2$ assisted continuous manufacturing extrusion system was used to successfully produce the organophilic-clay filled PP nanocomposites. It was found that $scCO_2$ had a measurable effect on the clay dispersion in the polymer matrix and the melt intercalation of a polymer into clay layers.

First Principles Calculations of Electronic, Structural and Optical Properties of (PMMA–ZrO2 –Au) and (PMMA–Al 2O3 –Au) Nanocomposites for Optoelectronics Applications

Angham Hazim,Hayder M. Abduljalil,Ahmed Hashim 한국전기전자재료학회 2021 Transactions on Electrical and Electronic Material Vol.22 No.2

This study focuses on the quantum mechanical treatment of the geometrical optimization and the electronic structure problems of a nanomaterial PMMA and nanocomposites. The hybrid functional B3LYP/6-31G level of DFT is used to investigate four molecules divided into two groups, they are PMMA as an original basis molecule and (PMMA–Au), (PMMA–Al 2 O 3 –Au), (PMMA–ZrO 2 –Au) nanocomposites as the two group. The DFT calculations have been performed using Gaussian 09 package of programs. The geometrical optimization included both bonds in °A and angles in deg. The calculated electronic properties included the total energy, HOMO and LUMO energies, energy gap, ionization energy, electron affi nity, electronegativity, electrochemical hardness, electronic softness and Electrophilic index. The geometrical optimization of PMMA and nanocomposites has been found in good agreement with the experimental data because of its relaxed geometrical parameters. One of the important results was obtain in this study, is the decreasing of the energy gap. This states that these nanocomposites arethe nearest to semiconductor due to the both HOMO and LUMO levels become more adjacent. These consequences mention to construct new structures with new electronic properties. All nanocomposites need small energy to become cationdue to ionization potential is decrease with addition nanoparticles to the pure PMMA, but the electronic affinity is an increase with with addition nanoparticles to the pure PMMA. The total ground state energy of the PMMA have largest value of total energy compared for other nanocomposites, where E T decreased with addition nanoparticles to pure PMMA. The hardness decrease with addition nanoparticles to the pure PMMA, therefore all the nanocomposites are softer, and this reduces the resistance of a species to lose electrons. Good relax for the structures of the studied PMMA was obtained theoretically, in which, the angles C–C, C=O and C–H in pure PMMA are remain in the same ranges for other nanocomposites. In general, most of the studied nonocomposites direct electronic transition from the valence to conduction band with wave length lies in the range of solar spectrum. The obtained results showed that the (PMMA–ZrO 2 –Au) and (PMMA–Al 2 O 3 –Au) nanocomposites have huge applications in electronics and photo-electronics fi elds.

Structural, Optical and Electronic Properties of Novel (PVA–MgO)/SiC Nanocomposites Films for Humidity Sensors

Hind Ahmed,Hayder M. Abduljalil,Ahmed Hashim 한국전기전자재료학회 2019 Transactions on Electrical and Electronic Material Vol.20 No.3

The polyvinyl alcohol (PVA) and magnesium oxide (MgO) nanocomposites and (PVA–MgO) nanocomposites doped by Silicon carbide (SiC) nanoparticles have been fabricated with diff erent concentrations of Silicon carbide and (PVA–MgO) nanocomposites. Both experimental and theoretical studies on structural and optical properties of novel (PVA–MgO–SiC) nanocomposites for humidity sensors were examined for fi rst time with low cost, fl exible and high sensitivity. The (PVA–MgO–SiC) nanocomposites were intended with various concentrations of Silicon carbide nanoparticles. The experimental results of optical properties for (PVA–MgO–SiC) nanocomposites indicated that the absorbance, absorption coeffi cient, extinction coeffi cient, refractive index, imaginary and real dielectric constants and optical conductivity of (PVA–MgO) nanocomposites increase with an increase in Silicon carbide nanoparticles concentrations. The absorbance increases from 0.432 to 2.55 a.u while the transmittance decreases from 0.779 to 0.230 a.u. The energy gap decreases from 4.4 to 2.1 eV. The energy gap theoretically decreases from 7.07 to 3.04 eV. The experimental results of novel (PVA–MgO–SiC) nanocomposites applications showed that (PVA–MgO–SiC) nanocomposites have high sensitivity for relative humidity. The results obtained were compared with theoretic results obtained by using Gaussian 09 program and Gaussian view 5.0.8 program and using density functional theory (DFT) at B3LYP level with 6 - 31G basis set.

Graphene-reinforced elastomeric nanocomposites: A review

Mensah, Bismark,Gupta, Kailash Chandra,Kim, Hakhyun,Wang, Wonseok,Jeong, Kwang-Un,Nah, Changwoon Elsevier 2018 POLYMER TESTING -LONDON- Vol.68 No.-

<P><B>Abstract</B></P> <P>The development of graphene nanosheets and/or their derivatives (GSDs) has sparkled worldwide overwhelming industrial and academic research interests, due to their unique and potentially useful properties. This review is written to highlight the state of art of GSDs/elastomer nanocomposites and their applications in various fields of technologies. It begins with reviewing the recent progress made in GSDs/elastomer nanocomposites in comparison to elastomer nanocomposites based on carbon nanotubes. The role of GSDs structures, functionalization, type of matrices, and content of fillers on properties of GSDs/elastomer composites has been reviewed systematically. The basic properties of various GSDs/elastomer nanocomposites including; morphology, curing behavior, mechanical properties such as Young's modulus (E), tensile strength (σ<SUB>s</SUB>) and elongation at break (E<SUB>b</SUB>), electrical percolation threshold, and thermal stability have been discussed in details. Finally, an attempt has been made to identify the critical challenges, which still need to be addressed for improving the processing of GSDs/elastomer nanocomposites and to explore their prospects for advanced applications. The article has been concluded by summarizing the key facts of GSDs that play significant role in developing GSDs/elastomer nanocomposites for technological applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> This review article covers every aspect of elastomer nanocomposites based on graphenes and graphenes derivatives(GSD). </LI> <LI> Characterization of GSD structure, morphology functionalization, matrix type, and various properties of GSD/elastomer composite have been systematically reviewed. </LI> <LI> Challenges for further improving the processing of GSD/elastomeric nanocomposites and for exploring future advanced applications of elastomer nanocomposites.. </LI> </UL> </P>

Structural, Optical and Electronic Properties of Novel (PVA–MgO)/SiC Nanocomposites Films for Humidity Sensors

Hind Ahmed,Hayder M. Abduljalil,Ahmed Hashim 한국전기전자재료학회 2019 Transactions on Electrical and Electronic Material Vol.20 No.2

The polyvinyl alcohol (PVA) and magnesium oxide (MgO) nanocomposites and (PVA–MgO) nanocomposites doped by Silicon carbide (SiC) nanoparticles have been fabricated with diff erent concentrations of Silicon carbide and (PVA–MgO) nanocomposites. Both experimental and theoretical studies on structural and optical properties of novel (PVA–MgO–SiC) nanocomposites for humidity sensors were examined for fi rst time with low cost, fl exible and high sensitivity. The (PVA–MgO–SiC) nanocomposites were intended with various concentrations of Silicon carbide nanoparticles. The experimental results of optical properties for (PVA–MgO–SiC) nanocomposites indicated that the absorbance, absorption coeffi cient, extinction coeffi cient, refractive index, imaginary and real dielectric constants and optical conductivity of (PVA–MgO) nanocomposites increase with an increase in Silicon carbide nanoparticles concentrations. The absorbance increases from 0.432 to 2.55 a.u while the transmittance decreases from 0.779 to 0.230 a.u. The energy gap decreases from 4.4 to 2.1 eV. The energy gap theoretically decreases from 7.07 to 3.04 eV. The experimental results of novel (PVA–MgO–SiC) nanocomposites applications showed that (PVA–MgO–SiC) nanocomposites have high sensitivity for relative humidity. The results obtained were compared with theoretic results obtained by using Gaussian 09 program and Gaussian view 5.0.8 program and using density functional theory (DFT) at B3LYP level with 6 - 31G basis set.

Photocatalytic oxidation for removal of gases toluene by TiO₂-CeO₂ nanocomposites under UV light irradiation

Koli, Valmiki B.,Kim, Jung-Sik Elsevier 2019 Materials science in semiconductor processing Vol.94 No.-

<P><B>Abstract</B></P> <P>Simple sol-gel method has used to synthesize TiO<SUB>2</SUB>-CeO<SUB>2</SUB> nanocomposites. XRD analysis carried out to determine the phase and structural properties of the synthesized nanocomposites. Thermal and gravimetric stability of the samples were determined by TGA. The optical spectroscopic study revealed that the nanocomposites show the shifting of band edge towards higher wavelength with an increase in the CeO<SUB>2</SUB> content in nanocomposites as compared to pure TiO<SUB>2</SUB>. Morphology of the synthesized nanocomposites was confirmed by FE-SEM and TEM analysis. Synthesized nanomaterials are in spherical with particle sizes in the range 10–20 nm. The HR-TEM image showed the formation of the heterojunction between CeO<SUB>2</SUB> and TiO<SUB>2</SUB> NPs and their elemental composition was confirmed by EDS. Surface chemical bonding states and the electronic valence band positions of the elements in nanocomposites were determined by XPS analysis. Photoluminescence study revealed the effect of CeO<SUB>2</SUB> concentration on photogenerated electron-hole pairs in TiO<SUB>2</SUB> nanoparticles. Photocatalytic activity of synthesized nanomaterials was studied by decomposition of toluene gas with irradiation of UV light. Revealed that nanocomposites with TiO<SUB>2</SUB>:CeO<SUB>2</SUB> ratio of 3:1 had the highest photocatalytic efficiency as compared to the other nanocomposites and pure TiO<SUB>2</SUB> and CeO<SUB>2</SUB> nanoparticles. Therefore, the results confirmed that the coupling of TiO<SUB>2</SUB> with CeO<SUB>2</SUB> absorb the photon energy and generates reactive oxygen species, which are easily transferred to CeO<SUB>2</SUB>, causing enhances the separation of the electron-hole pair and an improved the photocatalytic activity of the nanocomposites.</P>

나노복합재료의 전기/역학적 특성과 예측을 위한 멀티스케일 모델링의 최신 연구 분석

길태건,배진호,윤현노,이행기 한국전산구조공학회 2023 한국전산구조공학회논문집 Vol.36 No.2

Nanocomposites have been considered innovative composite materials that have multi-functionality and high performance. Because the incorporation of nanoscale fillers may significantly improve the electrical, mechanical, and thermal properties of composites, numerous extensive studies on the characterization of nanocomposites with nanoscale fillers have been performed. In particular, the development of nanocomposites using carbon-based nanoscale fillers (e.g., carbon nanotubes, carbon black, graphene nanoplates) have attracted much interest in the composite field. This paper provides a review of recent advances in the electrical/mechanical characteristics of nanocomposites, which are essential for their practical applications. Furthermore, this paper revisits the recent research on multi-scale modeling, which is a promising approach for predicting the characteristics of nanocomposites. The current challenges and future development potentials for multi-scale modeling are also discussed.

Experimental and Theoretical Study on Shear Flow Behavior of Polypropylene/Layered Silicate Nanocomposites

Lee, Seung-Hwan,Youn, Jae-Ryoun The Korean Society for Composite Materials 2008 Advanced composite materials Vol.17 No.3

Polypropylene/layered silicate nanocomposites containing maleic anhydride grafted polypropylene were prepared by melt compounding and their rheological behavior was investigated in shear flow. Transient and steady shear flows were simulated numerically by using the K-BKZ integral constitutive equation along with experimentally determined damping functions under dynamic oscillatory and step strain shear flows. Nonlinear shear responses were predicted with the K-BKZ constitutive equation using two different damping functions such as the Wagner and PSM models. It was observed that PP-g-MAH compatibilized PP/layered silicate nanocomposites have stronger and earlier shear thinning and higher steady shear viscosity than pure PP resin or uncompatibilized nanocomposites at low shear rate regions. Strong damping behavior of the PP/layered silicate nanocomposite was predicted under large step shear strain and considered as a result of the strain-induced orientation of the organoclay in the shear flow. Steady shear viscosity of the pure PP and uncompatibilized nanocomposite predicted by the K-BKZ model was in good agreement with the experimental results at all shear rate regions. However, the model was inadequate to predict the steady shear viscosity of PP-g-MAH compatibilized nanocomposites quantitatively because the K-BKZ model overestimates strain-softening damping behavior for PP/layered silicate nanocomposites.