scholarly journals Synthesis and thermal properties of silicon-containing benzoxazine

2019 ◽  
Vol 32 (1) ◽  
pp. 59-64 ◽  
Author(s):  
Kai Zeng ◽  
Hui Li ◽  
Haixia Shi ◽  
Jiayu Wu ◽  
Jilei Xu ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Nuclear Magnetic Resonance ◽  
Fourier Transform ◽  
Thermal Properties ◽  
Main Chain ◽  
Proton Nuclear Magnetic Resonance ◽  
In Situ Ftir ◽  
Degradation Temperature ◽  
Thermal Stability Of

A novel benzoxazine, containing silicon (Si) in the main chain and bonded to two benzene ring, was synthesized from aniline, bis( p-hydroxyphenyl)dimethylsilane, and paraformaldehyde. The structure was characterized by proton nuclear magnetic resonance and Fourier transform infrared (FTIR) spectra. The curing behavior of the benzoxazine was evaluated by differential scanning calorimeter and in situ FTIR. The thermal stability of the resulting polybenzoxazine was studied by thermogravimetric analysis under nitrogen and air atmospheres. The results indicated that the Si-containing polybenzoxazine possessed significantly higher initial degradation temperature and char yield than conventional bisphenol A/aniline-based polybenzoxazine.

Synthesis and thermal properties of phenol- and amine-capped main-chain benzoxazine oligomers with multiple methyl substitutions

2020 ◽  
Vol 32 (7) ◽  
pp. 823-834
Author(s):  
Lei Zhang ◽  
Jiale Mao ◽  
Shuang Wang ◽  
Yiting Zheng
Keyword(s):  
Thermal Stability ◽  
Thermal Properties ◽  
Main Chain ◽  
Chemical Shifts ◽  
Char Yield ◽  
Curing Temperature ◽  
Proton Nuclear Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
Chemical Structures ◽  
End Capping

A series of main-chain benzoxazine oligomers with different methyl substitutions are successfully synthesized. Chemical structures are analyzed by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, and gel permeation chromatography. Effects of methyl substitutions on chemical shifts of protons in oxazine ring and thermal properties, including glass transition temperature, thermal stability, and char yield, are discussed. The influences of methyl substitutions on different positions are demonstrated: (i) substitution on phenols induces obvious increase in curing temperature while substitution on amine does not show apparent impact; (ii) substitution at different positions results in T g variation, following the sequence of none-substitution > substitution at end-capping > substitution on diamines in main-chain > substitution on bisphenols in main-chain; and (iii) substitution at end-capping would cause apparent deterioration in thermal stability while substitution on diamines in main-chain would benefit thermal stability and char yield. Experimental results and related explanations are provided in detail.

Dielectric and thermal properties of thermoplastic elastomer gels in the presence of nanographite

e-Polymers ◽  
2011 ◽  
Vol 11 (1) ◽  
Author(s):  
Marissa A. Paglicawan ◽  
Jin Kuk Kim
Keyword(s):  
Thermal Stability ◽  
Dielectric Constant ◽  
Thermal Properties ◽  
Thermoplastic Elastomer ◽  
Expandable Graphite ◽  
Distinct Region ◽  
Graphite Nanoplatelets ◽  
Degradation Temperature ◽  
Exfoliated Graphite Nanoplatelets ◽  
Thermal Stability Of

AbstractIn this work, the effect of different nanographite such as expandable graphite (EG) and exfoliated graphite nanoplatelets (xGnP) on the electrical and thermal properties of nanocomposite thermoplastic elastomer gels prepared from a poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) imbibed with an EBcompatible paraffin oil was investigated. The electrical properties have been studied as a function of variation of nanoparticles in the frequency range of 52 to 107 Hz. For all the nanoparticles studied, the dielectric constant increases as the volume content of the nanoparticles in the TPE gels increases. The increase in dielectric constant was fairly smooth with no clear dielectric singularity in the concentration range studied. However, the percolation threshold in the dielectric spectra was clearly seen. The incorporation of a small quantity of nanographite improved the thermal stability of the swollen midblock of TPEGS, since the particles dispersed in this region, thereby increasing the distinct region of oil degradation temperature but no improvement on SEBS matrix. The results showed that size, shape and agglomeration of the particles with high amount of oil in SEBS system played a role in the dielectric properties and thermal stability.

Polyaniline Composites Using Three Different Acid as a Secondary Dopant: Preparation and Properties

2014 ◽  
Vol 1022 ◽  
pp. 22-25 ◽  
Author(s):  
Hong Hua Qi ◽  
Jiao Chen ◽  
Na Li Chen ◽  
Hui Xia Feng ◽  
Jian Hui Qiu
Keyword(s):  
Thermal Stability ◽  
Fourier Transform ◽  
Chemical Oxidation ◽  
In Situ Chemical Oxidation ◽  
Chemical Oxidation Polymerization ◽  
Secondary Doping ◽  
Polyaniline Composites ◽  
Thermal Stability Of ◽  
Better Than

In this paper, the preparation of PANI was investigated via in secondary doping in-situ chemical oxidation polymerization. We use NH2SO3H as dopant, and HP3O4, H2SO4or HCl as secondary dopant, respectively. The influencing of products conductivity was discussed about difference secondary dopant with changing concentration. The synthesized polymer composites are characterized by Fourier Transform Infrared Spectroscopy (FTIR) and four probe conductivity apparatus. The results show that in redoping process, the conductivity of PANI was 3.1746 S/cm when the concentration of HCl was 1.0 mol/L. Meanwhile, the thermal stability of PANI prepared with HP3O4or H2SO4as secondary dopant was better than HCl as secondary dopant.

Improvement of Electrical Conductivity of Polyamide 6/Polyaniline Blends by Graphene

2020 ◽  
Vol 831 ◽  
pp. 117-121
Author(s):  
Sirikunya Suksanit ◽  
Prasit Pattananuwat ◽  
Pranut Potiyaraj
Keyword(s):  
Thermal Stability ◽  
Electrical Conductivity ◽  
Fourier Transform ◽  
Synthesis Method ◽  
Polyamide 6 ◽  
Reduced Graphene ◽  
The Fourier Transform ◽  
Thermal Stability Of ◽  
Scanning Electron

Polymer composites of polyaniline (PANI)/polyamide 6 (PA6) blends and reduced graphene oxide (rGO) were prepared via the in situ synthesis method in order to improve formability and electrical properties. Polymer blends and composites were characterized by the Fourier transform infrared spectroscopy, scanning electron microscopy, and thermal gravimetric analysis. It was found that the composites prepared by the in situ synthesis method have better compatibility between polymer blends and matrix than that prepared by the conventional dry-mix method as investigated by scanning electron microscope (SEM). The Fourier-transform infrared (FT-IR) spectrograms indicate the presence of covalent bonds between functional groups between polyaniline and reduced graphene oxide. The PA6/PANI-rGO films show the electrical conductivity of 2.970×10-6 S/cm while PA6/PANI-GtO show electrical conductivity of 4.082×10-7 S/cm. Thermal stability of polymer blend was characterized by the thermogravimetric analysis. The thermal stability of polyamide 6 after blending is not changed significantly.

Chemistry at Polyimide-Metal Interfaces: In Situ FTIR Studies of Polymer Curing Processes and Thermal Stability

1992 ◽  
Vol 282 ◽  
Author(s):  
Jiong-Ping Lu ◽  
David Volfson ◽  
Fred Trusell ◽  
Klavs F. Jensen
Keyword(s):  
Thermal Stability ◽  
Elevated Temperatures ◽  
In Situ Ftir ◽  
Ftir Studies ◽  
Absorption Studies ◽  
Polymer Curing ◽  
Cu Substrates ◽  
Metal Interfaces ◽  
Thermal Stability Of

ABSTRACTWe report in-situ Fourier transform infrared (FTIR) reflection-absorption studies of curing chemistry of polyimide thin films on Crand Cu surfaces, and of the thermal stability of the resulting thin film interfaces when exposed to air at elevated temperatures. The polyimide investigated is based on 4,4'-(hexafluoroisopropylidene)bis(phthalicanhydride)-4,4'-bis(4-aminophenoxy)-biphenyl. The imidization process takes place at temperatures higher than 90°C anda small amount of anhydride is generated during curing. This by-product is converted to imide at temperatures above 250°C. Complete imidization is achieved after curing at 300°C on Cr substrates, while evidence for incomplete curing on Cu is observed under the same conditions. Thermal stability studies with Cr and Cu substrates show that thermal decomposition of thin (∼1000Å) polyimide filmsoccurs on Cu when the film is exposed to air at 200°C, while the polyimide is stable on Cr.

scholarly journals Organo-montimorillonites containing a reactive thiophene group for polythiophenes nanocomposites

Cerâmica ◽  
2016 ◽  
Vol 62 (362) ◽  
pp. 133-139
Author(s):  
J. C. Macêdo-Fonsêca ◽  
A. A. A. Tino ◽  
M. P. A. Silva-Alves ◽  
R. M. Souto-Maior
Keyword(s):  
Thermal Stability ◽  
Fourier Transform ◽  
Montmorillonite Clay ◽  
Polymerization Reaction ◽  
Ammonium Bromide ◽  
X Ray Diffraction ◽  
X Ray ◽  
Before And After ◽  
Thermal Stability Of

Abstract A sodium montmorillonite clay (Na+MMT) was modified with different contents of a reactive salt derived from thiophene (trimethyl-(2-thiophen-3-yl-ethyl)-ammonium bromide) (TMETA). The thiophene salt in the organoclay (xtioMMT) was oxidatively polymerized in situ, giving rise to montmorillonite clay intercalated with a polythiophene salt (xpoltioMMT). Analysis by Fourier transform infrared spectroscopy shows a difference in organization of the salt inside the clay lamellae, before and after its polymerization. X-ray diffraction indicates that the salts, whether polymeric or not, are arranged as a monolayer for all compositions. Differently to the expected, the thermal stability of the organoclays decreases upon polymerization suggesting degradation of TMETA in the polymerization reaction.

scholarly journals Preparation of poly(MPAEMA)/halloysite Nanocomposites and Investigation of Antiproliferative Activity

2021 ◽  
Vol 65 (2) ◽  
Author(s):  
Nevin Çankaya ◽  
Serap Yalçın ◽  
Nevin Turan
Keyword(s):  
Thermal Stability ◽  
Thermal Analysis ◽  
Thermal Properties ◽  
Cytotoxic Effect ◽  
In Situ Polymerization ◽  
Clay Content ◽  
Xtt Assay ◽  
Research Areas ◽  
Thermal Stability Of

Abstract. In this present work, the synthesis, characterization, and thermal properties of poly(2-(4-methoxyphenylamino)-2-oxoethyl methacrylate) (MPAEMA) polymer/clay-based nanocomposites were investigated by in-situ polymerization. At the characterizations of nanomaterials FTIR, XRD, SEM, and TGA techniques were used. It was determined from XRD and SEM measurements that the morphology of nanocomposites was exfoliated when the clay content in the polymer matrix was kept at 3% and 5%. From thermal analysis, a positive correlation was observed between the clay ratio and thermal stability of nanomaterials. Also, the cytotoxic effect of halloysite and its nanocomposites was investigated using XTT assay on HeLa cells. According to the results, nanocomposites showed a non-cytotoxic response and thus they may use safety in many research areas such as medicine, agriculture, cosmetics.   Resumen. En este trabajo, se reporta la síntesis, caracterización y propiedades térmicas de nanocompuestos de polímero / arcilla poli(2-(4-metoxifenilamino)-2-oxoetil metacrilato) (MPAEMA), obtenidos mediante polimerización in situ. Para caracterizar los nanomateriales se utilizaron las siguientes técnicas: FTIR, XRD, SEM y TGA. A partir de las mediciones de XRD y SEM se determinó que la morfología de los nanocompuestos muestra exfoliación, cuando el contenido de arcilla en la matriz de polímero se mantiene en 3% y 5%. Estudios mediante análisis térmico muestran una correlación positiva entre la relación de arcilla y la estabilidad térmica de los nanomateriales. También se investigó el efecto citotóxico de la halloysita y sus nanocompuestos utilizando el ensayo XTT en células HeLa. Los resultados muestran que los nanocompuestos tienen una respuesta no citotóxica y, por lo tanto, pueden utilizarse con seguridad en muchas áreas de investigación en disciplinas como la medicina, la agricultura y la cosmética.

An in situ TEM observation on the thermal stability of a nanocrystalline FeBSi alloy

1993 ◽  
Vol 16 (5) ◽  
pp. 260-264 ◽  
Author(s):  
H.Y. Tong ◽  
B.Z. Ding ◽  
H.G. Jiang ◽  
Z.Q. Hu ◽  
L. Dong ◽  
...  
Keyword(s):  
Thermal Stability ◽  
In Situ Tem ◽  
Thermal Stability Of

Study of Configurational Sequence Structures of Poly(Butadiene)s by Carbon-13 Proton Decoupled Fourier Transform Nuclear Magnetic Resonance Spectroscopy

1973 ◽  
Vol 46 (2) ◽  
pp. 350-358 ◽  
Author(s):  
Yasuhide Alaki ◽  
Toshio Yoshimoto ◽  
Mamoru Imanari ◽  
Makoto Takeuchi
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Fourier Transform ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Polymer Chains ◽  
Proton Nuclear Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
Sequence Structure ◽  
Nmr Method ◽  
Nuclear Magnetic

Abstract Carbon-13 proton nuclear magnetic resonance (NMR) of poly(butadiene) s consisting of various ratios of cis-1,4-, trans-1,4- and 1,2-structures were measured by the pulsed Fourier transform NMR method. The spectra of poly(butadiene)s with two or three kinds of butadiene configurations show several new signals which were not observed for homopolymers comprising merely one kind of butadiene configuration. All of these peaks are ascribed to the carbons linked by different kinds of configurations. From these results, the configurational sequence structure of butadiene units in polymer chains has been revealed.

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