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Calcinated tea and cellulose composite films and its dielectric and lead adsorption properties
Jayaramudu, Tippabattini,Varaprasad, Kokkarachedu,Kim, Hyun Chan,Kafy, Abdullahil,Kim, Jung Woong,Kim, Jaehwan Applied Science Publishers 2017 Carbohydrate polymers Vol.171 No.-
<P><B>Abstract</B></P> <P>In this paper, calcinated tea and cellulose composite (CTCC) films were fabricated via solution casting method. Chemical structure, morphology, crystallinity and thermal stability of the fabricated films were characterized by using Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction and thermogravimetric analysis. The effect of calcinated tea loading on the properties of the prepared CTCC films was studied. The results suggest that the prepared CTCC films show higher mechanical properties, thermal stability and dielectric constant than the neat cellulose film. In addition, the CTCC films adsorb Pb<SUP>2+</SUP> ions and its adsorption performance depends on the calcinated tea content and pH level. The CTCC films are useful for sensors, flexible capacitor as well as lead adsorption applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Calcinated tea based cellulose composite (CTCC) film was prepared by blending method. </LI> <LI> The CTCC film shows 4 times higher dielectric constant than the pure cellulose. </LI> <LI> The CTCC film demonstrates lead adsorption, depending on the CT content and pH. </LI> <LI> The CTCC film is useful for sensor, flexible capacitor and metal adsorption. </LI> </UL> </P>
Adhesion properties of poly(ethylene oxide)-lignin blend for nanocellulose composites
Jayaramudu, Tippabattini,Ko, Hyun-U.,Kim, Hyun Chan,Kim, Jung Woong,Choi, Eun Sik,Kim, Jaehwan Elsevier 2019 Composites Part B, Engineering Vol.156 No.-
<P><B>Abstract</B></P> <P>In this paper, poly(ethylene oxide)-lignin (PEO-L) blends were prepared for eco-friendly nanocellulose composites and the effect of lignin content on its adhesion property was studied by using single lap joint test. The PEO-L blends were prepared by blending method using 60% methanol. Cellulose nanofiber (CNF) film, chosen as an adherent material of eco-friendly nanocellulose composites, was prepared by casting CNF emulsion, followed by vacuum filtration and drying. The successful formation of PEO-L blends was confirmed from FTIR, DSC and XRD studies. The shear strength of PEO-L blend increased with the lignin content and the 30% lignin case (442 kPa) showed 189% larger shear strength than the pure PEO (835 kPa). This shear strength improvement is associated with enhanced hydrogen bonds between lignin/PEO and CNF film.</P>
Jayaramudu, Tippabattini,Ko, Hyun-U,Zhai, Lindong,Li, Yaguang,Kim, Jaehwan Taylor Francis 2017 Soft materials Vol.15 No.1
<P>This paper reports polyvinyl alcohol/cellulose-based electroactive hydrogels for actuator applications. The polyvinyl alcohol/cellulose electroactive hydrogels were obtained by physical crosslinking of polyvinyl alcohol and cellulose. The formation of the polyvinyl alcohol/cellulose hydrogel structure, its thermal stability, crystallinity, and mechanical properties were studied by using the Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry, X-ray diffraction, and mechanical test. The studies reveal that the cellulose is uniformly reacted with hydroxyl groups of polyvinyl alcohol by intermolecular bond formation. The cellulose content along with actuation voltage and frequency of electroactive hydrogels influence their displacement behavior.</P>
Poly(Acrylic Acid)-Poly(Vinyl Alcohol) Hydrogels for Reconfigurable Lens Actuators
Tippabattini Jayaramudu,김재환,Yaguang Li,고현우,MD Imrul Reza Shishir 한국정밀공학회 2016 International Journal of Precision Engineering and Vol.3 No.4
Reconfigurable lens provides variable-focus in optics without any moving part. The material for a reconfigurable lens should be deformable in the presence of external stimuli meanwhile maintaining its optical transparency for the lens function. This article reports the fabrication and actuation property of the Poly(acrylic acid)-Poly(vinyl alcohol) (PAP) hydrogels for reconfigurable active lens. The PAP hydrogels were prepared by free radical and freeze-thaw technique using N,N1-methylenebisacrylamaide and potassium persulfate/N,N,N1,N1-tetramethylethylenediamene as crosslinker-initiator pair system. The formation of the hydrogels was conformed form Fourier transform infrared spectra and thermogravimetric analysis. The prepared hydrogels were characterized by swelling studies and optical transparency measured with UV-visible spectroscopy and actuation test in the presence of electric field. There is an optimal concentration of acrylic acid concentration that shows maximum displacement output with less optical transparency loss. Displacement output increased with increasing the voltage and the maximum displacement output of 15.5 µm was achieved in the presence of electrical field. This corresponds to 4% strain.
Ko, Hyun-U,Kim, Hyun Chan,Kim, Jung Woong,Zhai, Lindong,Jayaramudu, Tippabattini,Kim, Jaehwan Institute of Physics Publishing 2017 Smart materials & structures Vol.26 No.8
<P>This paper reports cellulose nanocrystal (CNC) based transparent and electroactive polyurethane (CPPU), suitable for actively tunable optical lens. CNC is used for high dielectric filler to improve electromechanical behavior of CPPU. For high transparency and homogeneous distribution of CNC in polyurethane, CNC-poly[di(ethylene glycol) adipate] is used to play a role of polyol and isocyanate salt. The fabricated CPPU exhibits high transparency (>90%) and 10% of electromechanical strain under 3 V <I>μ</I>m<SUP>−1</SUP> electric field. Mechanical, dielectric properties as well as physical and chemical characteristics are investigated to prove the electromechanical behavior of CPPU.</P>