scholarly journals The regulatory effects of the number of VP(N-vinylpyrrolidone) function groups on macrostructure and photochromic properties of polyoxometalates/copolymer hybrid films

e-Polymers ◽  
2019 ◽  
Vol 20 (1) ◽  
pp. 1-7
Author(s):  
Zong-lai Liu ◽  
Tong-tong Yue ◽  
Wen-tian Sun ◽  
Feng-jun Zhang ◽  
Wei Feng
Keyword(s):  
Methyl Acrylate ◽  
Reduction Process ◽  
Covalent Bond ◽  
Esr Spectra ◽  
Nanocomposite Films ◽  
Hybrid Films ◽  
Photochromic Properties ◽  
Ft Ir ◽  
Regulatory Effects ◽  
Thermal Stability Of

AbstractNanocomposite films were synthesized by introducing phosphotungstic acid (PWA) into the poly (vinylpyrrolidone and methyl acrylate) (P (VP(N-vinylpyrrolidone)coMA(methyl acrylate))). FT-IR curves illustrated that non-covalent bond interaction was built between PWA particles and organic matrixes. In combination the results of SEM, TG-DTA and DSC, it was conducted that the ratio of functional groups of VP had a critical effect on the surface morphology, thermal stability of the hybrid films. Irradiated with ultraviolet light, the transparent thin hybrid films change from colorless to blue. Stored in air, the hybrid films could recover colorless gradually. The analysis of kinetics told us that higher VP content within the different systems always accompanied more superior photochromic performance, faster coloring and fading speed. Appearance of W5+ in ESR spectra indicated that the photo-reduction process between PWA and copolymer matrix occurred.

scholarly journals Thermal and electrical properties of polyimide/PANI nanofiber composites prepared via in situ polymerization

2018 ◽  
Vol 36 (2) ◽  
pp. 283-287
Author(s):  
Aseel A. Kareem
Keyword(s):  
In Situ Polymerization ◽  
Composite Films ◽  
Nanocomposite Films ◽  
X Ray Diffraction ◽  
Nanofiber Composite ◽  
X Ray ◽  
Thermal And Electrical Properties ◽  
Ft Ir ◽  
Thermal Stability Of

Abstract Polyimide/polyaniline nanofiber composites were prepared by in situ polymerization with various weight percentages of polyaniline (PANI) nanofibers. X-ray diffraction (XRD) and Fourier transform infrared spectra (FT-IR), proved the successful preparation of PANI nanofiber composite films. In addition, thermal stability of PI/PANI nanofiber composites was superior relative to PI, having 10 % gravimetric loss in the range of 623 °C to 671 °C and glass transition temperature of 289 °C to 297 °C. Furthermore, the values of the loss tangent tanδ and AC conductivity σAC of the nanocomposite films were notably higher than those of pure polyimide. The addition of 5 wt.% to 15 wt.% PANI nanofiber filler enhanced the activation energy of PI composites from 0.37 eV to 0.34 eV.

Spectral Investigation on the Growth and Characterization of NLO Crystals of Thiourea Succinic Acid Single Crystal.

2015 ◽  
Vol 2 (2) ◽  
pp. 70-73
Author(s):  
Kannan.P ◽  
Thambidurai.S ◽  
Suresh.N
Keyword(s):  
Single Crystal ◽  
Succinic Acid ◽  
Slow Evaporation Technique ◽  
Absorption Studies ◽  
Dta Analysis ◽  
Evaporation Technique ◽  
Ft Ir ◽  
Ir Spectroscopic ◽  
Thermal Stability Of

Growth of optically transparent single crystals of thiourea succinic acid (TUSA) was grown successfully from aqueous solution by slow evaporation technique. The crystal structure was elucidated using the single crystal XRD. The various functional groups and the modes of vibrations were identified by FT-IR spectroscopic analysis. The optical absorption studies indicate that the optical transparency window is quite wide making its suitable for NLO applications. Thermal stability of the crown crystal carried out by TGA-DTA analysis.

Sonochemical Synthesis of Poly (Methyl Acrylate)

2008 ◽  
Vol 136 ◽  
pp. 175-190 ◽  
Author(s):  
M.A. Jothi Rajan ◽  
T. Mathavan ◽  
T.S. Vivekanandam ◽  
S. Umapathy ◽  
V. Ganesan ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Methyl Acrylate ◽  
Radical Addition ◽  
Thermal Method ◽  
Sonochemical Synthesis ◽  
Aqueous Sodium ◽  
Addition Polymerization ◽  
Clean Environment ◽  
Free Radical Addition ◽  
Thermal Stability Of

Polymers are prepared by various methods. The method of preparation plays an important role in deciding many of the physical properties of polymers. In this work Poly (Methyl Acrylate), PMA, is synthesized by free radical addition polymerization in the presence a monomer, an initiator under the influence of ultrasound. Methyl Acrylate (E-Merck, India) of proper strength is mixed with aqueous sodium peroxodisulphate solution of known strength and the time of passage of ultrasound is varied in steps of 30 minutes and 10 samples of solid PMA are obtained for 10 different periods of passage of ultrasound. Solid PMA samples are purified and air-dried under clean environment. TGA, DTA measurements are done on all the 10 PMA samples. The thermal stability of PMA with the change in the time of passage of ultrasound is discussed quantitatively. The thermal stability of PMA, synthesized sonochemically shows better results over the thermal method of synthesis. However in this paper we report the measurements made on PMA samples synthesized at 30 and 300 minutes sonication periods respectively.

Imine Bond Characterization and Properties for Controlled Release Drugs of Collagen Protein Cross-Linked Cotton Fiber

2011 ◽  
Vol 175-176 ◽  
pp. 214-219 ◽  
Author(s):  
Yun Hui Xu ◽  
Zhao Fang Du ◽  
Yu Yue Chen
Keyword(s):  
Controlled Release ◽  
Cotton Fiber ◽  
Sodium Periodate ◽  
Covalent Bond ◽  
Subsequent Treatment ◽  
Aqueous Acetic Acid ◽  
Cotton Thread ◽  
Collagen Protein ◽  
Ft Ir ◽  
Imine Bond

For exploiting the novel multifunctional ecological cotton fibers, a new cotton fiber with the collagen protein cross-linking (CPCCF) was prepared by the limited selective oxidation of a cotton thread with sodium periodate solution and subsequent treatment with a solution of collagen protein at 40°C in aqueous acetic acid. FT-IR spectra of the CPCCF suggested that the imine covalent bond between the collagen protein and the oxidized cotton fiber was formed through a series of reaction. X-ray diffractograms analysis showed that the crystallinity of oxidized cotton fiber after collagen protein treatment increased slightly. Meanwhile, Scanning electron microscopy photographs illuminated that the modification with collagen protein occurred on the surface of cotton fiber. Kjeldahl nitrogen analysis of the CPCCF showed that the maximum percentage of collagen protein introduced into cotton fiber was 1.68% (w/w). However, the breaking strength of the cotton thread oxidized partially by sodium periodate at the concentration of less than 2.0 mg ml-1 did not decrease much. Furthermore, a model experiment for the controlled release drugs was performed using aloe anthraquinone, components of a Chinese medicine, suggested potential usefulness of the CPCCF as a carrier for the controlled release drugs.

Synthesis of biomass based plasticizer from linoleic acid and cardanol for preparing durable PVC material

2021 ◽  
Author(s):  
Hongying Chu ◽  
Huabei Li ◽  
Xiaoyan Sun ◽  
Yaowang Zhang
Keyword(s):  
Thermal Stability ◽  
Linoleic Acid ◽  
Chemical Structure ◽  
Dioctyl Phthalate ◽  
H Nmr ◽  
Plasticized Pvc ◽  
Migration Resistance ◽  
Ft Ir ◽  
And Migration ◽  
Thermal Stability Of

Abstract In this paper, we synthesized a kind of bio-based plasticizer epoxidized linoleic acid cardanol ester(ELCE) from cardanol and linoleic acid. Its chemical structure was characterized with FT-IR and 1H NMR. Polyvinyl chloride(PVC) blends plasticized with ELCE were prepared via thermoplastic blending with torque rheometer. The performance including torque, mechanical property, thermal stability, plasticizing property and migration resistance of plasticized PVC blends were investigated and compared with plasticized PVC blends with commercial plasticizer dioctyl phthalate(DOP). The results showed that ELCE improved thermal stability of PVC blends. ELCE played more excellent plasticizing effect on PVC blends than DOP. The better solvent extraction resistance and volatile resistance of ELCE make it impossible to completely replace DOP in PVC products.

Enhanced Thermal Stability of Esterified Lignin in Different Solvent Mediums

2018 ◽  
Vol 9 (1) ◽  
pp. 39-49 ◽  
Author(s):  
Sharifah Nurul Ain Syed Hashim ◽  
Sarani Zakaria ◽  
Chin Hua Chia ◽  
Sharifah Nabihah Syed Jaafar
Keyword(s):  
Thermal Stability ◽  
Alkaline Solution ◽  
Room Temperature ◽  
Hydroxyl Groups ◽  
Aqueous Alkaline Solution ◽  
Alkali Lignin ◽  
Weight Percentage ◽  
H Nmr ◽  
Ft Ir ◽  
Thermal Stability Of

In this study, soda alkali lignin from oil palm empty fruit bunch (EFB-AL) and kenaf core (KC-AL) are esterified with maleic anhydride under two different conditions, namely i) pyridine at temperature of 120°C for 3h and ii) aqueous alkaline solution at room temperature for 4h. As a result, the weight percentage gain (WPG) of the esterified EFB-AL (EFB-EL) and esterified KC-AL (KC-EL) in pyridine demonstrated a higher compared to aqueous alkaline solution. The FT-IR results of EFB-EL and KC-EL in both solvents exhibited some changes at the carbonyl and hydroxyl groups. Furthermore, the esterification process induced the carboxylic peak to appear in both alkali lignin samples. The outcome is confirmed by conducting H-NMR analysis, which demonstrated ester and carboxylic acid peaks within the spectral analysis. Finally, the TGA results showed both EFB-EL and KC-EL that are exposed to aqueous alkaline actually possessed better thermal stability and higher activation energy (Ea) compared to the esterified samples in pyridine.

Solution Blow Spun High Performance Co-Polyimide Nanofibers

2017 ◽  
Vol 898 ◽  
pp. 2181-2186
Author(s):  
Jing Li ◽  
Jun Rong Yu ◽  
Jing Zhu ◽  
Yan Wang ◽  
Zu Ming Hu ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Tensile Property ◽  
High Performance ◽  
Nanofiber Membrane ◽  
High Productivity ◽  
Thermal Imidization ◽  
Solution Blow Spinning ◽  
Ft Ir ◽  
Biphenyltetracarboxylic Dianhydride ◽  
Thermal Stability Of

Solution blow spinning (SBS) is an innovative nanofiber fabricating method with high productivity. 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) / p-phenylenediamine (PDA) / 4,4'-oxydianiline (ODA) co-polyimide nanofiber membrane was efficiently produced by SBS followed by imidization from precursor polyamic acid (PAA) nanofiber membrane in the paper. The morphologies and structures of the obtained PAA and PI nanofiber membrane were examined by SEM and FT-IR. The effect of thermal imidization temperature on the tensile property was investigated. The thermal stability of polyimide nanofiber membrane was also characterized by TGA.

scholarly journals Se-O Bond Is Unique to High Se Enriched Sweet Potato Stem Protein with Better Antioxidant Ability

Foods ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3064
Author(s):  
Qi Gao ◽  
Jia-Le Wu ◽  
Lan-Ping Jiang ◽  
Su-Qi Sun ◽  
Xue-Jun Gu ◽  
...  
Keyword(s):  
Sweet Potato ◽  
Energy Dispersive Spectrometry ◽  
Structural Characteristics ◽  
Radical Scavenging ◽  
Dpph Radical ◽  
Enrichment Method ◽  
Potato Plants ◽  
Ft Ir ◽  
Dpph Radical Scavenging ◽  
Thermal Stability Of

Sweet potato plants were treated with selenium (Se). Spraying Se on the sweet potato leaves was an effective Se enrichment method and proteins were extracted from the sweet potato stem. The structural characteristics of the protein were investigated. Fourier transform infrared spectroscopy (FT-IR) detected more signals from the Se-enriched sweet potato stem protein (SSP), and the number of forms of Se chemical bonds gradually increased with increasing Se content, such as the Se-O bond in high Se-enriched SSP, indicating altered secondary structures.Scanning electron microscopy-energy dispersive spectrometry (SEM-EDS) indicated more Se atoms in the Se-enriched SSPs (SSSPs). The DSC results revealed that Se enrichment enhanced the thermal stability of the samples. Moreover, selenomethionine (SeMet), selenocystine (SeCys2), and methylselenocysteine (MeSeCys) were determined to be the main Se forms in the SSSPs. Furthermore, the SSSPs showed relatively higher superoxide anion radical and DPPH radical scavenging activities than the blank, which indicates that SSSPs can be used as antioxidants. By recovering the proteins, the agricultural by-product—sweet potato stem can be further utilized, and the obtained Se-enriched proteins may contribute to human health.

scholarly journals Polymerization of Ethylene Glycol Dimethacrylate (EGDM), Using An Algerian Clay as Eco-catalyst (Maghnite-H+ and Maghnite-Na+)

2020 ◽  
Vol 15 (1) ◽  
pp. 221-230 ◽  
Author(s):  
Sara Haoue ◽  
Hodhaifa Derdar ◽  
Mohammed Belbachir ◽  
Amine Harrane
Keyword(s):  
Ethylene Glycol ◽  
Exchange Process ◽  
Ethylene Glycol Dimethacrylate ◽  
Glycol Dimethacrylate ◽  
Green Catalyst ◽  
Ion Exchange Process ◽  
Ft Ir ◽  
Uv Visible ◽  
Thermal Stability Of ◽  
End Group

In this paper we have explored a novel and green method to synthesis and polymerize ethylene glycol dimethacrylate (EGDM). This technique consists on using Maghnite (Algerian clay) as a green catalyst to replace toxic catalysts. The Algerian clay has been modified using two ion exchange process to obtain Maghnite-H+ (proton exchanged process) and Maghnite-Na+ (sodium exchanged process). Synthesis experiments of EGDM and Poly (EGDM) are performed in bulk respecting the principles of green chemistry. The structure of the obtained monomer and the obtained polymer was confirmed by FT-IR, 1H-NMR and 13C-NMR, where the methacrylate end groups are clearly visible. The presence of unsaturated end group in the structure of monomer was confirmed by UV-Visible analysis. Thermogravimetric analysis (TGA) was used to study the thermal stability of these obtained products. Copyright © 2020 BCREC Group. All rights reserved 

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