• Food Science and Biotechnology
• /
• v.16 no.5
• /
• pp.691-709
• /
• 2007

Concerns on environmental waste problems caused by non-biodegradable petrochemical-based plastic packaging materials as well as consumer's demand for high quality food products has caused an increasing interest in developing biodegradable packaging materials using annually renewable natural biopolymers such as polysaccharides and proteins. However, inherent shortcomings of natural polymer-based packaging materials such as low mechanical properties and low water resistance are causing a major limitation for their industrial use. By the way, recent advent of nanocomposite technology rekindled interests on the use of natural biopolymers in the food packaging application. Polymer nanocomposites, especially natural biopolymer-layered silicate nanocomposites, exhibit markedly improved packaging properties due to their nanometer size dispersion. These improvements include increased mechanical strength, decreased gas permeability, and increased water resistance. Additionally, biologically active ingredients can be added to impart the desired functional properties to the resulting packaging materials. Consequently, natural biopolymer-based nanocomposite packaging materials with bio-functional properties have huge potential for application in the active food packaging industry. In this review, recent advances in the preparation and characterization of natural biopolymer-based nanocomposite films, and their potential use in food packaging applications are addressed.

• Journal of Sensor Science and Technology
• /
• v.22 no.6
• /
• pp.400-403
• /
• 2013

The piezoelectric composite film of ferroelectric PZT ceramic ($PbZr_xTi_{1-x}O_3$) and polymer (PDMS, Polydimethylsiloxane) was prepared to improve the flexibility of piezoelectric material. The bar coating method was applied to fabricate flexible nanocomposite film with large surface area by low cost process. In the case of using metal electrode on the composite film, although there is no problem by bending process, the electrode is usually broken away from the film by stretching process. However, the well-attached, flexible CNT electrode on PZT/PDMS film improved flexibility, especially stretchability. PZT particles was usually settled down into polymer matrix due to gravity of the weighty particle, so to improve the dispersion of PZT powder in polymer matrix, small amount of additives (CNT powder, Carbon nanotube powder) was physically mixed with the matrix. By stretching the film, an output voltage of PZT(70 wt%)/PDMS with CNT (0.5 wt%) was measured.

• Membrane and Water Treatment
• /
• v.6 no.4
• /
• pp.309-321
• /
• 2015

We report in this study the synthesis of mixed matrix reverse osmosis membranes by interfacial polymerization (IP) of thin film nanocomposite (TFNC) on porous polysulfone supports (PS). This paper investigates the synthesis of ZnO nanoparticles (NPs) using the sol-gel processing technique and evaluates the performance of mixed matrix membranes reached by these aerogel NPs. Aqueous m-phenyl diamine (MPD) and organic trimesoyl chloride (TMC)-NPs mixture solutions were used in the IP process. The reaction of MPD and TMC at the interface of PS substrates resulted in the formation of the thin film composite (TFC). NPs of ZnO with a size of about 25 nm were used for the fabrication of the TFNC membranes. These membranes were characterized and evaluated in comparison with neat TFC ones. Their performances were evaluated based on the water permeability and salt rejection. Experimental results indicated that the NPs improved membrane performance under optimal concentration of NPs. By changing the content of the filler, better hydrophilicity was obtained; the contact angle was decreased from $74^{\circ}$ to $32^{\circ}$. Also, the permeate water flux was increased from 26 to 49 L/m2.h when the content of NPs is 0.1 (wt.%) with the maintaining of lower salt passage of 1%.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.278.1-278.1
• /
• 2014

Organic materials have been explored as the gate dielectric layers in thin film transistors (TFTs) of backplane devices for flexible display because of their inherent mechanical flexibility. However, those materials possess some disadvantages like low dielectric constant and thermal resistance, which might lead to high power consumption and instability. On the other hand, inorganic gate dielectrics show high dielectric constant despite their brittle property. In order to maintain advantages of both materials, it is essential to develop the alternative materials. In this work, we manufactured nanocomposite gate dielectrics composed of organic material and inorganic nanoparticle and integrated them into organic TFTs. For synthesis of nanocomposite gate dielectrics, polyimide (PI) was explored as the organic materials due to its superior thermal stability. Candidate nanoprticles (NPs) of halfnium oxide, titanium oxide and aluminium oxide were considered. In order to realize NP concentration dependent electrical characteristics, furthermore, we have synthesized the different types of nanocomposite gate dielectrics with varying ratio of each inorganic NPs. To analyze gate dielectric properties like the capacitance, metal-Insulator-metal (MIM) structures were prepared together with organic TFTs. The output and transfer characteristics of organic TFTs were monitored by using the semiconductor parameter analyzer (HP4145B), and capacitance and leakage current of MIM structures were measured by the LCR meter (B1500, Agilent). Effects of mechanical cyclic bending of 200,000 times and thermally heating at $400^{\circ}C$ for 1 hour were investigated to analyze mechanical and thermal stability of nanocomposite gate dielectrics. The results will be discussed in detail.

• Korean Chemical Engineering Research
• /
• v.51 no.3
• /
• pp.382-387
• /
• 2013

Biodegradable polyurethane (PU)/clay nanocomposite films were prepared via extrusion compounding process followed by casting film process. Organically modified montmorillonite (denoted as C30B) with a large amount of hydroxyl groups on its surface was used for the formation of strong bonding with PU resin. From both XRD analysis and TEM observations, the intercalated and exfoliated structure, and dispersion state of silicate platelets in the compounded nanocomposite films were confirmed. In addition, the rheological and tensile properties, optical transparency, oxygen permeability of the prepared nanocomposites were investigated as a function of added nanoclay content, and moreover based on these results, the corelation between the morphology and the resulting properties of the nanocomposites could be presented. The inclusion of nanoclays at appropriate content resulted in remarkable improvement in the nanocomposite performance including tensile modulus, elongation, transparency, and oxygen barrier property, however at excess amount of nanoclays, reduction or very slight increase was observed due to poor dispersion. The biodegradability of the prepared nanocomposite film was evaluated by examining the deterioration in the barrier and tensile properties during degradation period under compost.

• Polymer(Korea)
• /
• v.28 no.6
• /
• pp.551-555
• /
• 2004

Cellulose diacetate (CDA) nanocomposite films were prepared by using various plasticizer and montmorillonite nanofiller in methylene chloride/ethanol (9:1 w/w) mixed solution. The thermal property (T$_{g}$) of prepared CDA films was observed by DSC and T$_{g}$ of the films was decreased with the increase in the plasticizer content. The degree of dispersion of MMT in the CDA film was observed by XRD and mechanical property of CDA film was measured by tensile strength and Young's modulus. When the plasticizer was added into the CDA film upto 30 wt%, the Young's modulus of film was decreased from 1930 MPa to 1131 MPa but was increased from 1731 MPa to 2272 MPa when the MMT was added into the film upto 7 wt%. The mechanical properties of CDA films were decreased by addition of plasticizer but strengthened by the incorporation of MMT.

• Membrane Journal
• /
• v.28 no.1
• /
• pp.75-82
• /
• 2018

Forward osmosis (FO) desalination system has been highlighted to improve the energy efficiency and drive down the carbon footprint of current reverse osmosis (RO) desalination technology. To improve the trade-off between water flux and salt rejection of thin film composite (TFC) desalination membrane, thin film nanocomposite membranes (TFN), in which nanomaterials as a filler are embeded within a polymeric matrix, are being explored to tailor the separation performance and add new functionality to membranes for water purification applications. The objective of this article is to develop a graphene nanocomposite membrane with high performance of water selective permeability (high water flux, high salt rejection, and low reverse solute diffusion) as a next-generation FO desalination membrane. For advances in fabrication of graphene oxide (GO) membranes, layer-by-layer (LBL) technique was used to control the desirable structure, alignment, and chemical functionality that can lead to ultrahigh-permeability membranes due to highly selective transport of water molecules. In this study, the GO nanocomposite membrane fabricated by LBL dip coating method showed high water flux ($J_w/{\Delta}{\pi}=2.51LMH/bar$), water selectivity ($J_w/J_s=8.3L/g$), and salt rejection (99.5%) as well as high stability in aqueous solution and under FO operation condition.

• Membrane Journal
• /
• v.31 no.1
• /
• pp.35-51
• /
• 2021

Advancements in thin-film nanocomposite (TFN) membrane technology for nanofiltration is crucial for removing pollutants from natural resources. In recent years, various metal-organic framework (MOF) modifications have been tested to overcome the drawbacks that are inevitable with conventional thin-film composite (TFC) and TFN membranes. In general, MIL-101(Cr), UiO-66, ZIF-8, and HKUST-1 [Cu3(BCT2)] are MOFs that were proven to exhibit excellent membrane performance in terms of solvent permeability and solute rejection; their respective studies are reviewed in this article. Other novelties, such as the simultaneous use of different MOFs and unique MOF layering techniques (e.g., dip-coating, spray pre-disposition, Langmuir-Schaefer film, etc.) are also discussed as they present alternate solutions for membrane enhancement and/or preparation convenience. Not only are these MOF-modified TFN membranes frequently shown to improve separation performance from their respective TFC and TFN membranes, but many reports also explain their potential for a cost-effective and environmentally friendly process. In this review the thin film nanocomposite nanofiltration membrane is discussed.

• The monthly packaging world
• /
• s.214
• /
• pp.46-57
• /
• 2011

• Journal of Korean Society on Water Environment
• /
• v.30 no.3
• /
• pp.292-297
• /
• 2014

We synthesized the self-organized nanoporous oxide with potentiostatic anodization of iron foil. The iron oxide nanocomposite (INCs) were fabricated in 1M $Na_2SO_4$ containing 0.5wt% NaF electrolyte holding the potential at 20, 40 and 60 V for 20min, respectively. Field Emmision Scanning Electron Microscopy (FESEM) and X-ray Diffractometer (XRD) were used to evaluate the micromorphology and crystalline structure of INC film. Also, this study was performed to evaluate the fenton reaction using INC film with hydroperoxide for degradation of cyanide dissolved in water. In case of INC-40V in the presence of $H_2O_2$ 3%, the first-order rate constant was found to be $1.7{\times}10^{-2}min^{-1}$, and indicated to be $1.2{\times}10^{-2}min^{-1}$ on commercial hematite powder. This result is shown to be good performance enough to replace the powder type for treatment of wastewater.