Two-Dimensional Correlation Study of Uniaxially Drawn Poly(Ethylene Terephthalate) Films by Using Attenuated Total Reflection Based Dynamic Compression Modulation Step-Scan Fourier Transform Infrared in Combination with Spectral Simulation Analysis by Density Functional Theory

2006 ◽  
Vol 60 (2) ◽  
pp. 145-154 ◽  
Author(s):  
Yuji Nishikawa ◽  
Tatsuhiko Nakano ◽  
Isao Noda
Keyword(s):  
Density Functional ◽  
Simulation Analysis ◽  
Dynamic Compression ◽  
Correlation Study ◽  
Attenuated Total Reflection ◽  
Spectral Simulation ◽  
Functional Theory ◽  
Poly Ethylene Terephthalate ◽  
Poly Ethylene ◽  
Modulation Step

Two-Dimensional Correlation Analysis of Polyimide Films Using Attenuated Total Reflection-Based Dynamic Compression Modulation Step-Scan Fourier Transform Infrared Spectroscopy

2007 ◽  
Vol 61 (8) ◽  
pp. 873-881 ◽  
Author(s):  
Yuji Nishikawa ◽  
Tatsuhiko Nakano ◽  
Isao Noda
Keyword(s):  
Dynamic Response ◽  
Intermolecular Interactions ◽  
Density Functional ◽  
Sequential Analysis ◽  
Dynamic Compression ◽  
Correlation Study ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Two Dimensional ◽  
Spectral Simulation

Attenuated total reflection (ATR)-based dynamic compression modulation two-dimensional (2D) correlation study of poly(p-phenylene biphenyltetracarboximide) film is carried out in combination with spectral simulation analysis by density functional theory (DFT). The dynamic 2D infrared (IR) correlation spectra in the region of imide I (C=O stretching mode) show three distinct correlation peaks located around 1777, 1725, and 1708 cm−1. The band at 1708 cm−1 is the lower wavenumber shift component of 1777 or 1735 cm−1 peaks and is attributed to the results from intermolecular interactions, according to the DFT analysis. The 1708 cm−1 band also shows the largest dynamic response, suggesting that these intermolecular interactions may enhance the dynamic response. The dynamic 2D IR correlation spectra in the region of imide II (C–N–C axial stretching mode) vibrations also show three correlation peaks located around 1335, 1355, and 1370 cm−1, although the imide II band is shown to consist substantially of one component by the DFT analysis. These multiple peaks may be attributed to the compression-induced wavenumber shift of the band in the backbone structures. The sequential analysis of 2D correlation data show that, upon applying the dynamic compression, the response of the backbone regions (imide II) occurs first, followed by that of the side-chain regions (imide I, C=O).

Density Functional Theory Study: Interactions of Lithium-Montmorillonite with Poly(Ethylene Oxide) as Preliminary Investigation of Lithium Polymer Conductivity

2014 ◽  
Vol 893 ◽  
pp. 790-793
Author(s):  
Muhammad Naufal Lintangpradipto ◽  
Triati Dewi Kencana Wungu ◽  
Ahmad H. Lubis ◽  
Hermawan Kresno Dipojono ◽  
Nugraha
Keyword(s):  
Density Functional Theory ◽  
Ethylene Oxide ◽  
Potential Energy ◽  
Density Functional ◽  
Preliminary Investigation ◽  
Energy Curve ◽  
Functional Theory ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
Good Agreement

In this study, the interactions between poly (ethylene oxide) (PEO) and lithium-montmorillonite (LiMMT) have been investigated using density functional theory (DFT) calculation. The results of calculations show that the adsorption process of PEO on the LiMMT surface is physisorption with adsorption energy of -0.063 eV. This observation is consistent with the results of our calculations on PES (Potential Energy Surface) and PEC (Potential Energy Curve). The formation of space between PEO and LiMMT are found in range of 3.4 - 4.2 Å which are in good agreement with experimental results.

scholarly journals ATR-FTIR Spectroscopy Combined with Chemometric Methods for the Classification of Polyethylene Residues Containing Different Contaminants

2021 ◽  
Author(s):  
Daniel José da Silva ◽  
Hélio Wiebeck
Keyword(s):  
Predictive Ability ◽  
Principal Component ◽  
Plastic Waste ◽  
Attenuated Total Reflection ◽  
Least Squares Regression ◽  
Chemometric Methods ◽  
Poly Ethylene Terephthalate ◽  
Terrestrial Environments ◽  
Poly Ethylene ◽  
Main Components

Abstract Low density polyethylene (LDPE) and high density polyethylene (HDPE) are the principal plastics present in solid plastic waste and are found out as the main components of microplastics in marine and terrestrial environments. Currently, efforts have been made to develop new and effective methods to ensure the identification and separation of plastics in waste, ensuring the necessary purity to obtain quality and economically competitive recycled products. In this contribution, we investigated the usage of Fourier-Transform Infrared Spectroscopy in attenuated total reflection mode (ATR-FTIR) combined with Principal Component Analysis (PCA), Linear Partial Least Squares Regression by Intervals (iPLS-R) and Competitive Adaptive Weighted Sampling (CARS/PLS-R) as chemometric methods to classify and determine the compositional fraction of the pristine and recycled mixtures of HDPE and LDPE from plastic waste in São Paulo, Brazil. The 3D PCA plots do not make it possible to classify the different polyethylenes and their polymer blends using the three Principal Components (PC), except for the 2D PCA diagram using PC1 and PC3. The iPLS-R presents the best predictive ability than CARS/PLS-R to determine the LDPE content in HDPE/LDPE recycled blends. However, the presence of different contaminants (in 5 wt%), such as silicon dioxide (SiO2), calcium carbonate (CaCO3), recycled polypropylene (PP), and recycled poly(ethylene terephthalate) (PET), reduces the potential usage of the iPLS-R models as identification tools for LDPE and HDPE sorting in industrial recycling processes.

scholarly journals Epoxy pre-polymers as new and effective materials for corrosion inhibition of carbon steel in acidic medium: Computational and experimental studies

2021 ◽  
Author(s):  
Omar Dagdag ◽  
Zaki Safi ◽  
Rachid Hsissou ◽  
Hamid Erramli ◽  
Mehdi El Bouchti ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Corrosion Inhibition ◽  
Acidic Medium ◽  
Density Functional ◽  
Experimental Studies ◽  
Steel Corrosion ◽  
Attenuated Total Reflection ◽  
Computational Techniques ◽  
Functional Theory ◽  
Different Temperatures

Present study is designed for the synthesis, characterization and corrosion inhibition behavior of two diamine aromatic epoxy pre-polymers (DAEPs) namely, N1,N1,N2,N2-tetrakis (oxiran-2-ylmethyl) benzene-1,2-diamine (DAEP1) and 4-methyl-N1,N1,N2,N2-tetrakis (oxiran-2-ylmethyl) benzene-1,2-diamine (DAEP2) for carbon steel corrosion in acidic medium. Synthesized DAEPs were characterized using spectral (Nuclear magnetic resonance (1H NMR) and Fourier transform infrared-attenuated total reflection (FTIR-ATR)) techniques. Viscosity studies carried out at four different temperatures (20–80 °C) increase in temperature causes significant reduction in their viscosities. The anticorrosive properties of DAEPs differing in the nature of substituents, for carbon steel corrosion in 1 M HCl solution was evaluated using several experimental and computational techniques. Both experimental and computational studies showed that inhibitor (DAEP2) that contains electron releasing methyl (-CH3) showed higher protectiveness as compared to the inhibitor (DAEP1) without substituent (-H). Electrochemical results demonstrate that DAEPs act as reasonably good inhibitors for carbon steel in 1 M HCl medium and their effectiveness followed the sequence: DAEP2 (92.9%) > DAEP1 (91.7%). The PDP results show that the diamine aromatic epoxy pre-polymers molecules (DAEPs) act as mixed type inhibitors. Electrochemical study was also supported using scanning electron microscopy (SEM) method were significant improvement in the surface morphology of inhibited (by DAEPs) metallic specimens was obtained. Results derived from computational density functional theory (DFT) and molecular dynamics (MD) simulationsand studies were consistent with the experimental results derived from SEM, EIS and PDP electrochemical studies. Adsorption of the DAEPs obeyed the Langmuir adsorption isotherm model.

Interaction of carbon monoxide with small metal clusters: a DFT, electrochemical, and FTIR study

2011 ◽  
Vol 89 (12) ◽  
pp. 1445-1456 ◽  
Author(s):  
Brian D. Adams ◽  
Robert M. Asmussen ◽  
Aicheng Chen ◽  
Robert C. Mawhinney
Keyword(s):  
Dft Calculations ◽  
Binding Sites ◽  
Density Functional ◽  
Metal Clusters ◽  
Nanostructured Catalysts ◽  
Attenuated Total Reflection ◽  
Oxidation Of Co ◽  
Functional Theory ◽  
Adsorption Of Co ◽  
D Orbitals

The adsorption of CO molecules onto small metal clusters was studied using density functional theory (DFT) calculations, and experimental electrochemical and attenuated total reflection-Fourier transform infrared spectroscopic (ATR-FTIR) techniques were used to examine CO adsorbed onto nanostructures of similar composition. The adsorption strengths and CO vibrational stretching frequencies were calculated and analyzed for clusters of the form M–CO for all of the period 4, 5, and 6 d-block transition metals. A direct link between the νCO and the population of d orbitals of the metal was observed. All possible binding sites for CO on clusters of the form Pd4–CO, Pd2Pt2–CO, and Pd2Au2–CO were determined and the corresponding adsorption energies and CO stretching frequencies were examined. Pure Pd and bimetallic PdPt and PdAu nanostructures were fabricated and used as catalysts for the adsorption and electrochemical oxidation of CO. The relative quantities of CO molecules adsorbed to surface of the catalysts decrease in the order of PdPt > Pd > PdAu, consistent with our DFT results. The location of νCO bands of CO adsorbed onto the nanostructured catalysts were determined by means of ATR-FTIR spectroscopy and were found to have values close to that predicted by DFT. This paper shows that DFT calculations on very small metal clusters Mn–CO (n ≤ 4) can be a simple but effective way of screening catalysts for their adsorbing properties.

Effect of the flame-retardant 3-hydroxyphenylphosphinyl-propanoic acid on the mechanical, thermal, and flammability properties of poly(ethylene terephthalate) nanofiber mats

2018 ◽  
Vol 31 (8) ◽  
pp. 919-927 ◽  
Author(s):  
Atiyeh Abbasi ◽  
Alireza Shakeri
Keyword(s):  
Thermal Stability ◽  
Flame Retardant ◽  
Ethylene Terephthalate ◽  
Chemical Reactivity ◽  
Attenuated Total Reflection ◽  
Propanoic Acid ◽  
Limiting Oxygen Index ◽  
Poly Ethylene Terephthalate ◽  
Poly Ethylene ◽  
Nanofiber Mats

The structure, thermal stability, and mechanical properties of electrospun nanofiber mats obtained from poly(ethylene terephthalate) (PET) solutions in trifluoroacetic acid/dichloromethane were evaluated. The electrospun PET nanofibers were characterized by means of attenuated total reflection Fourier transform infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry, thermogravimetric analysis, limiting oxygen index, and tensile testing. PET-3-hydroxyphenylphosphinyl-propanoic acid (HPP) copolymer was used as the flame-retardant (FR) agent to improve the thermal stability and flammability of the nanofiber mats. HPP is a commercial FR for polyesters which was studied from the viewpoint of chemical reactivity and reaction mechanism. To enhance the tensile strength of the nanofiber mats, the nanofibers were collected on high-speed rotating drum. The results showed that the nanofibers were oriented, and their strength was enhanced by increasing the velocity of the collector. The average diameter of electrospun nanofibers was in the range of 110–240 nm, decreasing with the increasing drum speed. Also the mean pore size of the mats decreased significantly with increasing orientation of the nanofibers. The results showed that HPP improved the flame retardancy of PET.

Surface Characterization and Antibacterial Evaluation of Poly(Ethylene Terephthalate) Modified by Chitosan-Immobilization

2005 ◽  
Vol 288-289 ◽  
pp. 331-334 ◽  
Author(s):  
Peng Li ◽  
Jin Wang ◽  
W.C. Lu ◽  
H. Sun ◽  
Nan Huang
Keyword(s):  
Photoelectron Spectroscopy ◽  
Bacterial Adhesion ◽  
Surface Characterization ◽  
Ethylene Terephthalate ◽  
Attenuated Total Reflection ◽  
Poly Ethylene Terephthalate ◽  
Modified Surface ◽  
Poly Ethylene ◽  
Pet Films

Biomedical PET films were modified by the approach of chitosan-surface-grafting. Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) revealed that chitosan molecules were successfully grafted on the PET surface. The bacterial adhesion on the modified surface was evaluated by bacteria plate counting in vitro and scanning electron microscopy (SEM). The results testified that chitosan did make the surface of PET become more antibacterial. The free energy of adhesion (∆Fadh) between the bacteria and the chitosan-immobilized surface of PET was calculated. The value of the ∆Fadh was positive, which suggests that the process of bacterial adhesion on the modified PET surface was not thermodynamically favorable, namely, not spontaneous.

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