Free volume, thermal and morphological properties of photo-crosslinked thiol-Ene/ nanodiamond hybrid network

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Aslı Beyler Cigil ◽  
Seyfullah Madakbaş ◽  
Cumali Tav ◽  
Uğur Yahşi ◽  
Memet Vezir Kahraman
Keyword(s):  
Thermal Properties ◽  
Free Volume ◽  
Volume Fraction ◽  
Polymer Networks ◽  
Attenuated Total Reflection ◽  
Hybrid Network ◽  
Morphological Properties ◽  
Content Type ◽  
Free Volume Fraction ◽  
The Impact

Purpose The purpose of this research paper is to investigate the changes in free volume by adding acrylate modified nanodiamond particles. In this study, a cross-linked thiol-ene (T) network was obtained under ultraviole light. The changes in free volume were analyzed when acrylate-modified nanodiamond (M-ND) particles were added to the nanocomposites obtained. Positron annihilation lifetime spectroscopy (PALS), a well-established method, was used for this analysis. In addition, the effect of nanocomposites containing different ratios of acrylate M-ND particles (1, 2, 3 and 5 Wt. %) on the surface and the thermal properties were also examined. Design/methodology/approach The impact of different quantities of acrylate M-ND on the free volume and surface morphological properties of thiol-ene polymer networks were studied by using scanning electron microscopy, differential scanning calorimetry, attenuated total reflection, Fourier transform infrared spectroscopy, PALS and thermogravimetric analysis measurements. Findings The thermal properties of T/M-ND were found to depend on the weight percentages of the M-ND content. For increasing weight percentages of M-ND added to thio-lene polymer networks, the glass transition temperature (Tg) increased from 103°C to 154°C. The ortho-positronium (o-Ps) lifetime (free volume) and free volume fraction characterization of T/M-ND nanocomposites were investigated using PALS. Increasing temperature caused both the o-Ps lifetime (free volume) to change with increasing saturation and to linearly increase the intensity; however, an increasing weight percentage of M-ND caused no change at all for the o-Ps lifetime (free volume) and the free volume fraction. Originality/value According to published literature, and to the best of the authors’ knowledge, this is the first time a study examining the free volume properties in a thiol-ene system has been carried out.

scholarly journals Shape and Temperature Expansion of Free Volume Holes in Some Cured Polybutadiene-Polyisoprene Rubber Blends

2021 ◽  
Vol 22 (3) ◽  
pp. 1436
Author(s):  
Giovanni Consolati ◽  
Eros Mossini ◽  
Dario Nichetti ◽  
Fiorenza Quasso ◽  
Giuseppe Maria Viola ◽  
...  
Keyword(s):  
Free Volume ◽  
Radial Direction ◽  
Volume Fraction ◽  
Spherical Shape ◽  
Suitable Model ◽  
Positron Annihilation Lifetime ◽  
Rubber Blends ◽  
Free Volume Fraction ◽  
Hole Model ◽  
Best Fit

The free volume fraction of a macromolecular structure can be assessed theoretically by using a suitable model; however, it can also be evaluated from experimental data obtained from dilatometry and positron annihilation lifetime spectra. In this second case, a regular geometry of the sub-nanometric cavities forming the free volume has to be assumed, although in fact they are irregularly shaped. The most popular approach is to guess spherical holes, which implies an isotropic growth of these last with temperature. In this work, we compared the free volume fraction, as obtained from experiments in a set of polybutadiene and polyisoprene cured rubbers and their blends, with the analogous quantity expected by using the lattice-hole model. The results allowed us to obtain insights on the approximate shape of the holes. Indeed, a cylindrical flattened geometry of the cavities produced a better agreement with the theory than the spherical shape. Furthermore, the best fit was obtained for holes that expanded preferentially in the radial direction, with a consequent decrease of the aspect ratio with temperature.

scholarly journals Thermal, mechanical and morphological properties of polyurethane–zirconia loading

2020 ◽  
Author(s):  
Ali J Salman ◽  
Ali Assim Al-Obaidi ◽  
Dalya H Al-Mamoori ◽  
Lina M Shaker ◽  
Ahmed A Al-Amiery
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Thermal Properties ◽  
Material Science ◽  
Morphological Properties ◽  
Flexural Stress ◽  
Renewable Materials ◽  
Sem Images ◽  
The Impact ◽  
Scanning Electron

Abstract The polyurethane (PU) has been showing a dramatic increase in applications related to material science and technology. However, the mechanical, physical and thermal properties could be further improved by loading PU with zirconia (Zr) to create renewable materials known as polyurethane–zirconia (PUZ) composites. In this study, PU matrix was treated with wt.% Zr at 0.5, 1.0, 1.5 and 2.0. In this study, the thermo-mechanical properties and the morphology were investigated of PU and PUZ nano-samples. The images of the scanning electron microscope (SEM) were the prime tool in investigating PU and PUZ surfaces and fractured surfaces showing vanishing the cracks and formation of agglomeration on the sample PUZ-1.5%. In addition, the tensile strength, Young’s modulus and maximum loading were improved by 36.7, 31.8 and 39.1%, respectively, at Zr loading of 1.5 wt.%. The flexural stress and the load were improved by 94.3% and 93.6%, respectively, when Zr loading was 1.5 wt.%. The impact without and with a notch was improved by 110.7% and 62.6%, respectively, at Zr loading of 1.5 wt.%. The the morphologies of the PU surface and Zr surface supported by SEM images. Regarding the storage modulus ability of PU and PUZ composites, Zr loading has negatively influenced E. The E functioning temperature was observed to move from 142 to 183°C. Another effect was determined by adding a small amount of Zr. This small amount was enough to shift the crystallization temperature (${T}_c$) and the melting temperature (${T}_m$) of PU from 125 to 129°C and from 150 to 144°C, respectively.

scholarly journals Effect of Free Volume on Curcumin Release from Various Polymer-Based Composite Films Analyzed Using Positron Annihilation Lifetime Spectroscopy

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5679
Author(s):  
Jong-Whan Rhim ◽  
Saygin Kuzeci ◽  
Swarup Roy ◽  
Necmettin Akti ◽  
Cumali Tav ◽  
...  
Keyword(s):  
Positron Annihilation ◽  
Free Volume ◽  
Bioactive Compounds ◽  
Polymer Matrix ◽  
Volume Fraction ◽  
Composite Films ◽  
Positron Annihilation Lifetime Spectroscopy ◽  
Positron Annihilation Lifetime ◽  
Biocomposite Films ◽  
Free Volume Fraction

This work reports the effects of free volume on curcumin release in various polymer-based composite films. Curcumin-reinforced biocomposite films were fabricated with natural biopolymers (carrageenan and chitosan) and bioplastics (poly(lactide) (PLA) and poly (butylene adipate-co-terephthalate) (PBAT)) via the solvent casting method. The curcumin release test was performed using an aqueous medium, and it was found that it was released the fastest in the carrageenan film, followed by the chitosan, PLA, and PBAT films, presumably owing to the dissimilarity of the polymer matrix. The free volume of the polymer films was determined using positron annihilation lifetime spectroscopy (PALS) to understand the release phenomena of curcumin. The free volume fraction was varied and reliant on the type of polymer, with the highest in the PBAT-based film followed by the PLA-, chitosan-, and carrageenan-based films. The free volume method helps analyze the release of bioactive compounds in a polymer matrix and may help to achieve a better understanding of the release of bioactive compounds.

scholarly journals Numerical study of heat transfer in 90° bend tube by AI2O3 nano fluids using fluid injection

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hadi Mahdizadeh ◽  
Nor Mariah Adam
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Reynolds Number ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Volume Fraction ◽  
Fluid Injection ◽  
Content Type ◽  
Nano Fluid ◽  
The Impact

Purpose This paper aims to investigate increasing heat transfer in bend tube 90° by fluid injection using nano fluid flow that was performed by expending varying Reynolds number. This paper studies the increased heat transfer in the bent tube that used some parameters to examine the effects of volume fraction, nanoparticle diameter, fluid injection, Reynolds number on heat transfer and flow in a bend pipe. Design/methodology/approach Designing curved tubes increases the thermal conductivity amount between fluid and wall. It is used the finite volume method and simple algorithms to solve the conservation equations of mass, momentum and energy. The results showed that the nanoparticles used in bent tube transfusion increase the heat transfer performance by increasing the volume fraction; it has a direct impact on enhancing the heat transfer coefficient. Findings Heat transfer coefficient enhanced 1.5% when volume fraction increased from 2 % to 6%, the. It is due to the impact of nanoparticles on the thermal conductivity of the fluid. The fluid is injected into the boundary layer flow due to jamming that enhances heat transfer. Curved lines used create a centrifugal force due to the bending and lack of development that increase the heat transfer. Originality/value This study has investigated the effect of injection of water into a 90° bend before and after the bend. Specific objectives are to analyze effect of injection on heat transfer of bend tube and pressure drop, evaluate best performance of mixing injection and bend in different positions and analyze effect of nano fluid volume fraction on injection.

The molecular dynamics of different relaxation modes in asymmetric chlorinated butyl rubber/petroleum resin blends

RSC Advances ◽  
2014 ◽  
Vol 4 (40) ◽  
pp. 20620-20625 ◽  
Author(s):  
Fengshun Zhang ◽  
Guansong He ◽  
Kangming Xu ◽  
Hong Wu ◽  
Shaoyun Guo
Keyword(s):  
Molecular Dynamics ◽  
Free Volume ◽  
Volume Fraction ◽  
Butyl Rubber ◽  
Segmental Motion ◽  
Petroleum Resin ◽  
Free Volume Fraction ◽  
Relaxation Modes ◽  
Chlorinated Butyl Rubber

The PR plays a role like an anti-plasticizer in decreasing the free volume fraction of the CIIR/PR blend. The mobility of Rouse modes is confined significantly more than that of local segmental motion.

Influence of microstructure morphology on multi-scale modeling of low-alloyed TRIP-steels

2018 ◽  
Vol 35 (2) ◽  
pp. 499-528 ◽  
Author(s):  
Stefan Prüger ◽  
Ashutosh Gandhi ◽  
Daniel Balzani
Keyword(s):  
Volume Fraction ◽  
Measurement Techniques ◽  
Content Type ◽  
Systematic Assessment ◽  
Microstructural Parameters ◽  
Multi Scale ◽  
Scale Modeling ◽  
Macro Scale ◽  
Microstructure Morphology ◽  
The Impact

Purpose The purpose of this study is to quantify the impact of the variation of microstructural features on macroscopic and microscopic fields. The application of multi-scale methods in the context of constitutive modeling of microheterogeneous materials requires the choice of a representative volume element (RVE) of the considered microstructure, which may be based on some idealized assumptions and/or on experimental observations. In any case, a realistic microstructure within the RVE is either computationally too expensive or not fully accessible by experimental measurement techniques, which introduces some uncertainty regarding the microstructural features. Design/methodology/approach In this paper, a systematical variation of microstructural parameters controlling the morphology of an RVE with an idealized microstructure is conducted and the impact on macroscopic quantities of interest as well as microstructural fields and their statistics is investigated. The study is carried out under macroscopically homogeneous deformation states using the direct micro-macro scale transition approach. Findings The variation of microstructural parameters, such as inclusion volume fraction, aspect ratio and orientation of the inclusion with respect to the overall loading, influences the macroscopic behavior, especially the micromechanical fields significantly. Originality/value The systematic assessment of the impact of microstructural parameters on both macroscopic quantities and statistics of the micromechanical fields allows for a quantitative comparison of different microstructure morphologies and a reliable identification of microstructural parameters that promote failure initialization in microheterogeneous materials.

A fabrication and characterization of luffa/PANI/PEO biocomposite nanofibers by means of electrospinning

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Gözde Konuk Ege ◽  
Hüseyin Yüce ◽  
Özge Akay ◽  
Hasbi Öner ◽  
Garip Genç
Keyword(s):  
Thermal Properties ◽  
Alkali Treatment ◽  
Natural Fibers ◽  
Weight Ratio ◽  
Morphological Structure ◽  
Film Structure ◽  
Morphological Properties ◽  
Dsc Analysis ◽  
Scanning Calorimetry ◽  
Content Type

Purpose This paper aims to address the production of biocomposite nanofibers using luffa natural fibers and polyaniline conductive polymer/polyethylene oxides (PANI/PEO). Design/methodology/approach In this study, luffa natural fibers are extracted by chemical method. After mixing the treated luffa (TL) with the PANI/PEO solution, TL/PANI/PEO nanofibers were produced by electrospinning (ES) method under different ES parameters to examine the optimal conditions for nanofiber production. Then TL/PANI/PEO biocomposite nanofibers prepared in different weight ratios were produced to analyze the effects of luffa in the morphology and thermal properties of the biocomposite nanofibers. The characterization analysis of TL/PANI/PEO biocomposite nanofibers was performed by scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) analysis methods. Findings The analysis shows that different weight ratios of TL to PANI/PEO changed the morphology of the membrane. When increasing the weight ratio of TL, the morphological structure of TL/PANI/PEO transformed from nanofiber structure to thin film structure. The appearance of O—H peaks in the FTIR results proved the existence of TL in PANI/PEO nanofibers (membrane). Moreover, an increase in the weight ratio of luffa from 2% to 7.5% leads to an increase in the peak intensity of the O—H group. Regarding DSC analysis, biocomposite nanofibers improved the thermal properties. According to all results, 2%wt TL/PANI/PEO showed optimal morphological properties. Originality/value Plant cellulose was extracted from the luffa, one of the natural fibers, by method of alkali treatment. A new type of biocomposite nanofibers was produced using TL blend with PANI via electrospinning method.

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