scholarly journals Direct Measurement of Temperature Diffusivity of Nanocellulose-Doped Biodegradable Composite Films

Micromachines ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 738 ◽  
Author(s):  
Hiroki Fujisawa ◽  
Meguya Ryu ◽  
Stefan Lundgaard ◽  
Denver P. Linklater ◽  
Elena P. Ivanova ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Direct Measurement ◽  
Cross Sections ◽  
Polymer Films ◽  
Composite Films ◽  
Polymer Nanocomposite ◽  
Optical Transmittance ◽  
Nanocomposite Films ◽  
Contact Method ◽  
Resistance Change

The thermal properties of novel nanomaterials play a significant role in determining the performance of the material in technological applications. Herein, direct measurement of the temperature diffusivity of nanocellulose-doped starch–polyurethane nanocomposite films was carried out by the micro-contact method. Polymer films containing up to 2 wt%. of nanocellulose were synthesised by a simple chemical process and are biodegradable. Films of a high optical transmittance T≈80% (for a 200 μm thick film), which were up to 44% crystalline, were characterised. Two different modalities of temperature diffusivity based on (1) a resistance change and (2) micro-thermocouple detected voltage modulation caused by the heat wave, were used for the polymer films with cross sections of ∼100 μm thickness. Twice different in-plane α‖ and out-of-plane α⊥ temperature diffusivities were directly determined with high fidelity: α‖=2.12×10−7 m2/s and α⊥=1.13×10−7 m2/s. This work provides an example of a direct contact measurement of thermal properties of nanocellulose composite biodegradable polymer films. The thermal diffusivity, which is usually high in strongly interconnected networks and crystals, was investigated for the first time in this polymer nanocomposite.

scholarly journals Direct Measurement of Temperature Diffusivity of Nanocellulose Composite Films

2020 ◽  
Author(s):  
Hiroki Fujisawa ◽  
Meguya Ryu ◽  
Stefan Lundgaard ◽  
Denver Linklater ◽  
Elena Ivanova ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Direct Measurement ◽  
Cross Sections ◽  
Polymer Films ◽  
Composite Films ◽  
Optical Transmittance ◽  
Nanocomposite Films ◽  
Contact Method ◽  
Resistance Change ◽  
Out Of Plane

The thermal properties of novel nanomaterials play a significant role in determining the performance of the material in technological applications. Herein, direct measurement of the temperature diffusivity of cellulose nanocomposite films was carried out by the micro-contact method. Polymer films containing up to 2%wt. of nanocellulose were synthesised by a simple chemical process. Films of a high optical transmittance T ≈ 80 % (for a 200- μ m-thick film), which were up to 44% crystalline, were characterised. Two different modalities of temperature diffusivity based on: 1) a resistance change and 2) micro-thermocouple detected modulation of a heat wave, were used for the polymer films with cross-sections of ∼ 100 μ m thickness. Twice different in-plane α ‖ and out-of-plane α ⊥ temperature diffusivities were directly determined with high fidelity: α ‖ = 2 . 12 × 10 − 7 m 2 /s and α ⊥ = 1 . 13 × 10 − 7 m 2 /s. An amorphous polyethylene terephthalate (PET) fiber was measured for comparison α ‖ = 1 . 15 × 10 − 7 m 2 /s. This work provides an example of a direct contact measurement of thermal properties of nanocellulose composite films. The thermal diffusivity, which is usually high in strongly interconnected networks and crystals, was investigated for the first time in this composite.

scholarly journals Polymer-Single Wall Carbon Nanotube Composites for Potential Spacecraft Applications

2001 ◽  
Vol 706 ◽  
Author(s):  
Cheol Park ◽  
Zoubeida Ounaies ◽  
Kent A. Watson ◽  
Kristin Pawlowski ◽  
Sharon E. Lowther ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Carbon Nanotube ◽  
Composite Films ◽  
Polymeric Materials ◽  
Polymer Nanocomposite ◽  
Weight Percent ◽  
Nanocomposite Films ◽  
Mechanical And Thermal Properties ◽  
Single Wall Carbon Nanotube ◽  
Single Wall Carbon

AbstractPolymer-single wall carbon nanotube (SWNT) composite films were prepared and characterized as part of an effort to develop polymeric materials with improved combinations of properties for potential use on future spacecraft. Next generation spacecraft will require ultra-lightweight materials that possess specific and unique combinations of properties such as radiation and atomic oxygen resistance, low solar absorptivity, high thermal emissitivity, electrical conductivity, tear resistance, ability to be folded and seamed, and good mechanical properties. The objective of this work is to incorporate sufficient electrical conductivity into space durable polyimides to mitigate static charge build-up. The challenge is to obtain this level of conductivity (10-8 S/cm) without degrading other properties of importance, particularly optical transparency. Several different approaches were attempted to fully disperse the SWNTs into the polymer matrix. These included high shear mixing, sonication, and synthesizing the polymers in the presence of pre-dispersed SWNTs. Acceptable levels of conductivity were obtained at loading levels less than one tenth weight percent SWNT without significantly sacrificing optical properties. Characterization of the nanocomposite films and the effect of SWNT concentration and dispersion on the conductivity, solar absorptivity, thermal emissivity, mechanical and thermal properties were discussed. Fibers and non-woven porous mats of SWNT reinforced polymer nanocomposite were produced using electrospinning.

scholarly journals Analogy and Comparative Study of Hydroxypropyl Methylcellulose (HPMC) Biopolymer with Graphene Oxide and Zinc Oxide Nano Fillers

2021 ◽  
Vol 33 (7) ◽  
pp. 1513-1518
Author(s):  
Sanoop Padinhattayil ◽  
K. Sheshappa Rai
Keyword(s):  
Zinc Oxide ◽  
Graphene Oxide ◽  
Comparative Study ◽  
Hydroxypropyl Methylcellulose ◽  
Composite Films ◽  
Polymer Nanocomposite ◽  
Thermal Characterization ◽  
Xrd Analysis ◽  
Nanocomposite Films ◽  
Mechanical Study

Present study describes the analogy and comparative study of polymer nanocomposites with the known polymer matrix hydroxypropyl methylcellulose (HPMC) incorporated with graphene oxide (GO) and zinc oxide (ZnO) nanoparticles as nano fillers. The polymer nanocomposite films were carried out using solution casting method and characterized by IR spectroscopy, XRD analysis, mechanical properties, thermal characterization and optical microscopy analysis. There were several changes in the HPMC polymer by the addition of nanoparticles of GO and ZnO in structural, thermal, mechanical and optical properties. The thermal stability of the composite films increased as compared with the pure HPMC whereas the mechanical study shows a variation of down values.

scholarly journals Spectral Studies on Impact of Alkali Perchlorate (Li/Na/K-ClO4) Salts on the Properties of PVA-Ag-Cr3+ Polymer Nanocomposite Films

2021 ◽  
Vol 2070 (1) ◽  
pp. 012077
Author(s):  
M Hemalatha ◽  
V Krishna Vinay ◽  
D Siva Raju ◽  
Ch Linga Raju
Keyword(s):  
Polymer Films ◽  
Polymer Nanocomposite ◽  
Intramolecular Hydrogen Bonding ◽  
Nanocomposite Films ◽  
Degree Of Crystallinity ◽  
Spectral Studies ◽  
Poly Vinyl Alcohol ◽  
X Ray Diffraction ◽  
Intramolecular Hydrogen ◽  
Metal Nanocomposites

Abstract Poly (Vinyl alcohol) metal (PVA-Ag-Cr) nanocomposites were prepared by a slow evaporation method with the help of a refluxing procedure. The effect of alkali perchlorate (Li/Na/K-QlO4) salts embedded in PVA-metal nanocomposites were analysed with SEM, XRD, EPR, and optical techniques. The surface structure and topology of the synthesized composites were studied using scanning electron microscopy. The crystallinity of the prepared polymer films has been determined using the X-ray diffraction pattern. Existing changes in some diffraction angle with the alkali salts results the fluctuations in the degree of crystallinity. EPR studies reveal the ‘g’ values at 1.96, 1.93, and 1.98 due to the oxidation exchange-coupled pair. The observed absorption spectra of Cr3+ ions corresponding to Li, Na & KClO4 salts in PVAAgSe polymer films revealed the band positions centered at 220, 275, 480, 535, and 1030 nm of all the alkali chlorates with small shifting in-band positions. This may be due to the inter/intramolecular hydrogen bonding.

Effect of SnO2 Nanoparticle Doping on Structural, Morphological and Thermal Properties of PVA-PVP Polymer Blend

2019 ◽  
Vol 962 ◽  
pp. 82-88
Author(s):  
B. Guruswamy ◽  
V. Ravindrachary ◽  
C. Shruthi ◽  
M. Mylarappa
Keyword(s):  
Thermal Properties ◽  
Polymer Blend ◽  
Doping Level ◽  
Polymer Nanocomposite ◽  
Nitrogen Atmosphere ◽  
Nanocomposite Films ◽  
Average Roughness ◽  
Casting Technique ◽  
Dsc Studies ◽  
Type Semiconductor

The n-type semiconductor SnO2 nanoparticles were synthesised using standard route and the effect of this nanoparticle doping on structural, morphological and thermal properties of PVA-PVP polymer blend has been investigated. Pure and PVA-PVP/SnO2 Nanocomposite films were prepared using solution casting technique. The powder X-ray diffraction result shows that the crystalline nature of the blend increases with doping level. FESEM study shows that the surface morphology of the polymer nanocomposite varies with doping level. AFM study reveals that in the nanocomposite films, the average roughness changes with dopant concentration. The DSC studies on the samples were performed from 40°C to 400°C under nitrogen atmosphere and it shows that the thermal properties of the blend changes with doping concentration.

scholarly journals Origin of Magnetically Induced Optical Transmission of Magnetic Nanocomposite Films

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2533
Author(s):  
Qiushu Zhang ◽  
Bei Peng ◽  
Jintao Xu ◽  
Mengqi Chu
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Film Thickness ◽  
Optical Transmission ◽  
Light Transmission ◽  
Composite Films ◽  
Optical Transmittance ◽  
Nanocomposite Films ◽  
Magnetic Composite ◽  
Particle Movement

Herein, we present an investigation on the origin of the magnetically induced optical transmission of composite films comprised of polydimethylsiloxane and magnetic nanofillers via experiment and simulation. Structured and unstructured films were used in the study, which were fabricated with and without magnetic fields, respectively. Altered optical transmittance was observed from both types of films when they were subjected to an external magnetic field. Numerical analyses were performed to investigate the effect of the particle movement under magnetic field and the film magnetostriction on the film optical transmittance. The simulation results show that the changed light transmission under magnetic field is mainly due to a variation in the film thickness resulting from the film magnetostriction. The ellipsometric analysis results confirm the altered film thickness in response to the external magnetic field, and the measurements of the film magnetostrictive stresses validate that there is magnetostriction in the magnetic composite films. Additionally, it is indicated that there might be some relationship between the magnetically induced optical transmission and the film magnetostrictive stress under certain conditions.

scholarly journals Thermal Properties of TiO2NP/CNT/LDPE Hybrid Nanocomposite Films

Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1270 ◽  
Author(s):  
Moustafa Zagho ◽  
Mariam AlMaadeed ◽  
Khaliq Majeed
Keyword(s):  
Thermal Stability ◽  
Thermal Properties ◽  
Composite Films ◽  
Nanocomposite Films ◽  
Filler Concentration ◽  
Gravimetric Analysis ◽  
Melt Mixing ◽  
Hybrid Filler ◽  
Hybrid Fillers ◽  
Multi Walled Carbon Nanotubes

This work aims to investigate the effect of hybrid filler concentration on the thermal stability of low-density polyethylene (LDPE) matrices. LDPE-based composite films were synthesized by melt mixing, followed by compression molding, to study the influence of titanium oxide nanoparticles (TONPs) and/or multi-walled carbon nanotubes (CNTs) on the thermal properties of LDPE matrices. Fourier transform infrared (FTIR) spectroscopy confirmed the slight increase in the band intensities after TONP addition and a remarkable surge after the incorporation of CNTs. The value of crystallization temperature (Tc) was not modified after incorporating TONPs, while an enhancement was observed after adding the hybrid fillers. The melting temperature (Tm) was not changed after introducing the CNTs and CNT/TONP hybrid fillers. The percentage crystallinity (Xc %) was increased by 4% and 6%, after incorporating 1 wt % and 3 wt % CNTs, respectively. The TONP incorporation did not modify the Xc %. Moreover, thermal gravimetric analysis (TGA) thermograms confirmed the increased thermal stability after introducing CNTs and hybrid fillers compared to TONP incorporation.

Influence of ZnO nanoadditives on the structural characteristics and dielectric properties of PVA

2021 ◽  
Author(s):  
E. Abdeltwab ◽  
A. Atta
Keyword(s):  
Dielectric Properties ◽  
Structural Characteristics ◽  
Composite Films ◽  
Polymer Nanocomposite ◽  
Nanocomposite Films ◽  
Energy Storage Devices ◽  
Scanning Calorimetry ◽  
Super Capacitor ◽  
Sem Images ◽  
Wide Range

In this study, different percentages of semiconducting zinc oxide nanoparticles (ZnONPs) are mixed with polyvinyl alcohol (PVA) to create flexible ZnO/PVA polymer nanocomposite films. The characteristics of the prepared films are investigated using differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. The XRD pattern shows that the ZnO/PVA composite films were successfully synthesized; while the SEM images show that the ZnONPs are homogeneously dispersed in the PVA polymer chain. Moreover, the DSC indicates an improvement in the thermal stability behavior with increased of ZnONPs concentration. The electrical conductivity, dielectric properties, electric modulus behavior, and the energy density efficiency of the pristine PVA and ZnO/PVA composite films are determined using an LCR meter in the frequency range 102–106 Hz. The dielectric constant of the composite film increased from 0.185 for pristine PVA to 1.389 for 9%ZnO/PVA, and the conductivity is improved from [Formula: see text] S/cm to [Formula: see text] S/cm. This work would open the road for utilizing ZnO/PVA flexible nanocomposite films for wide range of applications such as batteries, super-capacitor and energy storage devices.

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