scholarly journals Structure, stability, and properties of phenolic fibers modified by phenyl molybdate

2020 ◽  
pp. 096739112092780
Author(s):  
Yang Kai ◽  
Jiao Mingli ◽  
Zhang Xiaomei ◽  
Jia Wanshun ◽  
Diao Quan ◽  
...  
Keyword(s):  
Melt Spinning ◽  
Main Chain ◽  
Phenol Formaldehyde ◽  
Gel Permeation Chromatography ◽  
Decomposition Temperature ◽  
Nitrogen Atmosphere ◽  
Molecular Structures ◽  
Structure Stability ◽  
Initial Decomposition Temperature ◽  
Heat Curing

Phenyl molybdate-modified phenolic fibers (PMoPFs) were prepared by melt spinning from the corresponding resin which was polymerized from phenol, formaldehyde, and phenyl molybdate, followed by solution curing and then heat curing processes. The molecular structures, including characteristic groups and molecular weight, were examined by nuclear magnetic resonance, Fourier transform infrared spectroscopy, and gel permeation chromatography. The influences of the curing processes were demonstrated by mechanical properties, scanning electron microscopy, and thermogravimetric analysis characterization. PMoPF with 8 wt% molybdic acid and cured in an oven possessed a tensile strength as high as 187 MPa, initial decomposition temperature of 300°C, and a char yield under nitrogen atmosphere at 800°C as high as 66.0%, with the molybdate (MoO4 2−) groups being introduced into the phenolic main chain.

Halogenated methacrylate-based aluminum oxide (Al2O3) nanocomposites

2015 ◽  
Vol 30 (6) ◽  
pp. 762-772
Author(s):  
Kathikar Abdul Wasi ◽  
Sakvai Mohammed Safiullah ◽  
Kottur Anver Basha
Keyword(s):  
Aluminum Oxide ◽  
Polymer Matrix ◽  
Glycidyl Methacrylate ◽  
Morphological Changes ◽  
Thermal Studies ◽  
Gel Permeation Chromatography ◽  
Decomposition Temperature ◽  
Scanning Calorimetry ◽  
Initial Decomposition Temperature ◽  
Mixing Techniques

The aim of the work is to prepare the halogenated methacrylate-based polymer nano-aluminum oxide (Al2O3) composites and to study the effect of incorporated nano-Al2O3 on morphological and thermal studies. A functional 2,4,6-tribromophenyl methacrylate- co-glycidyl methacrylate copolymer microspheres (poly(TBPMA- co-GMA); pTG) by emulsion solvent evaporation techniques, whereas (2,4,6-tribromophenyl methacrylate- co-glycidyl methacrylate)-Al2O3 nanocomposites (pTG-Al2O3 nanocomposites) were prepared by solution mixing techniques. The pTG and its Al2O3 nanocomposites were structurally characterized by Fourier transform infrared (FTIR) spectroscopy. Thermal studies of pTG and its Al2O3 nanocomposites were carried out by thermogravimetric analysis and differential scanning calorimetry . The molecular weight of the pTG was determined by gel permeation chromatography. The size distribution and morphology of the pTG and its Al2O3 nanocomposites were determined by scanning electron microscopy (SEM). The FTIR results reveal that there is no significant interaction between the polymer matrix and Al2O3 nanoparticle. The significant increase in the initial decomposition temperature and glass transition temperature of pTG-Al2O3 nanocomposites compared to its polymer was due to the incorporation of nano-Al2O3 in the polymer matrix. The SEM observation provides the information about the morphological changes that arise in polymer matrix due to the incorporation of nano-Al2O3.

Study on Preparation and Property of High Thermal Oxidation Stability PPS/SiO2 Fiber

2014 ◽  
Vol 789 ◽  
pp. 249-254 ◽  
Author(s):  
Si Meng ◽  
Ze Xu Hu ◽  
Xue Yu Xing ◽  
Qiu Xu Lu ◽  
Zhe Zhou ◽  
...  
Keyword(s):  
Thermal Oxidation ◽  
Melt Spinning ◽  
Fiber Strength ◽  
Oxidation Stability ◽  
Decomposition Temperature ◽  
Thermal Ageing ◽  
Initial Decomposition Temperature ◽  
Ageing Treatment ◽  
Thermal Oxidation Stability ◽  
Retention Strength

PPS/SiO2 composite was studied to enhance the thermal oxidation stability of PPS. In order to improve the dispersity of SiO2 in PPS matrix, the SiO2 was modified by silane coupling agent, KH-570. The fractured surface morphologies, thermal properties and rheological property of PPS/SiO2 composite were researched. The high thermal oxidation stability PPS/SiO2 fibers were prepared by melt spinning. The thermal ageing treatment was carried out, and the strength and retention strength, before and after ageing treatment, of two kinds of fibers (PPS fibers and PPS/SiO2 fibers) were compared. The results of SEM showed the good dispersity of the modified SiO2 in PPS matrix. After adding modified SiO2, the initial decomposition temperature increased. At the same time, the fiber strength and retention strength were improved, which can be found by comparing. Compared with pure PPS, after adding 1.0 wt%, which was proved to be the optimum dosage by the research, modified SiO2 into PPS, the initial decomposition temperature was increased by 15.3°C, the retention strength was increased from 60.3% to 85.1% after ageing treat.

scholarly journals Synthesis and Characterization of Easily Processable Polyaramides Containing Pendent Diamantan Moiety in the Main Chain

2008 ◽  
Vol 5 (2) ◽  
pp. 257-262 ◽  
Author(s):  
M. K. Mukul ◽  
P. K. Srivastava
Keyword(s):  
Main Chain ◽  
Gel Permeation Chromatography ◽  
Nitrogen Atmosphere ◽  
Direct Polycondensation ◽  
Molecular Weights ◽  
Gel Permeation ◽  
Thermal Stability Of ◽  
Tga Analysis ◽  
Carboxy Methyl

Three new polyamides were synthesized by direct polycondensation of 1-6 bis(carboxy methyl diamantan with three different aromatic amines in Nmethyl 2-pyrrolidine containing lithium chloride using triphenyl phosphate and pyridine as condensing agent. 1-6 bis(carboxy methyl)diamantan was prepared from 1-6 dibromo diamantan and structure was conformed by1H and13C NNR spectroscopy. A comparison of the effect for introducing bulky side group in the diamine contribution was evaluated. This polyamide had inherent viscosity of 0.57-1.18dL/g. It was found that all polyamides were soluble in polar aprotic solvents. Thermal stability of polymer was evaluated by TGA analysis. Molecular weights of all polyamides were determined by gel permeation chromatography. These have been found to be thermally stable up to 400°C with 1320% weight loss under nitrogen atmosphere.

New Route to Improve Thermal Property of Phenolic Resin

2012 ◽  
Vol 246-247 ◽  
pp. 1047-1051
Author(s):  
Guang Wen Cheng
Keyword(s):  
Thermal Property ◽  
Room Temperature ◽  
Phenolic Resin ◽  
Main Chain ◽  
Zirconium Oxychloride ◽  
Decomposition Temperature ◽  
Nitrogen Atmosphere ◽  
Side Chain ◽  
Condensation Polymerization ◽  
Preceramic Polymer

A new route for improving the thermal property of phenolic resin was described. Firstly, a soluble preceramic polymer was synthesized by condensation polymerization of zirconium oxychloride, salicyl alcohol and acetylacetone in the presence of triethylamine at room temperature. A modified phenolic resin was then obtained via blending the preceramic polymer and phenolic resin in solution. The preceramic polymer was characterized by FTIR, NMR and GPC. The thermal property of the modified phenolic resin was also investigated by TGA. It was found that the preceramic polymer was composed of Zr-O-Zr as the main chain and the ligands (salicyl alcohol and acetylacetone) as the side chain. It pyrolyzed completely at 600°C and formed ZrO2 in nitrogen atmosphere. The results of TGA indicated that 5 wt% preceramic polymer could increase the thermal decomposition temperature and the char yield of the modified phenolic resin by 18°C and 25%, respectively. Moreover, the preceramic polymer allowed the char formation from phenolic resin at relatively low temperature.

scholarly journals A Novel Synergistic Flame Retardant of Hexaphenoxycyclotriphosphazene for Epoxy Resin

Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3648
Author(s):  
Jiawei Jiang ◽  
Siqi Huo ◽  
Yi Zheng ◽  
Chengyun Yang ◽  
Hongqiang Yan ◽  
...  
Keyword(s):  
Flame Retardant ◽  
Epoxy Resin ◽  
Hydrothermal Reaction ◽  
Halloysite Nanotubes ◽  
Decomposition Temperature ◽  
Nitrogen Atmosphere ◽  
Initial Decomposition Temperature ◽  
Cone Calorimeter Test ◽  
Metal Organic ◽  
Synergistic Flame Retardant

Hexaphenoxycyclotriphosphazene (HPCP) is a common flame retardant for epoxy resin (EP). To improve the thermostability and fire safety of HPCP-containing EP, we combined UiO66-NH2 (a kind of metal-organic frame, MOF) with halloysite nanotubes (HNTs) by hydrothermal reaction to create a novel synergistic flame retardant (H-U) of HPCP for EP. For the EP containing HPCP and H-U, the initial decomposition temperature (T5%) and the temperature of maximum decomposition rate (Tmax) increased by 11 and 17 °C under nitrogen atmosphere compared with those of the EP containing only HPCP. Meanwhile, the EP containing HPCP and H-U exhibited better tensile and flexural properties due to the addition of rigid nanoparticles. Notably, the EP containing HPCP and H-U reached a V-0 rating in UL-94 test and a limited oxygen index (LOI) of 35.2%. However, with the introduction of H-U, the flame retardant performances of EP composites were weakened in the cone calorimeter test, which was probably due to the decreased height of intumescent residual char.

Study on Synthesis and Thermal Property of Polyvinylamine

2010 ◽  
Vol 150-151 ◽  
pp. 1500-1503 ◽  
Author(s):  
Hong Chi Zhao ◽  
Qi Li ◽  
Wen Yu Xu ◽  
Fan Huang
Keyword(s):  
Decomposition Temperature ◽  
Characteristic Peak ◽  
Initial Decomposition Temperature ◽  
Nmr Spectrum ◽  
X Ray ◽  
Nuclear Magnetic Resonance Spectrometer ◽  
Chemical Structures ◽  
Thermogravimetric Analyzer ◽  
Infrared Spectrometer ◽  
Thermal Stability Of

Polyvinylamine (PVAm) and polyvinylamine chloride (PVAm•HCl) were synthesized by Hofmann degradation of polyacrylamide (PAM). The reaction condition is gentle and the operation is safe, simple and economical so that it is a good reaction method. The chemical structures and thermal properties of the polymers were studied by Fourier transform infrared spectrometer (FTIR), nuclear magnetic resonance spectrometer (NMR), X-ray diffractmeter (XRD) and thermogravimetric analyzer (TGA). Synthesis of PVAm•HCl was confirmed by the intensities of the characteristic peak of -CONH2 decreased and the appearance of a new absorption peak at 1530cm-1 (due to N-H bond of -NH3+ ) in the FTIR spectrum, the appearance of the characteristic absorption peaks of carbon atoms in the 13C NMR spectrum, the appearance of chemical shift assignments of proton in 1H NMR spectrum and the appearance of characteristic dispersing diffraction peak between 22.5° to 25.2° in the XRD spectrum, respectively. PAM had three decomposing stages, but PVAm•HCl had two decomposing stages. TG curve of PAM and PVAm•HCl showed that the initial decomposition temperature were 190oC and 140oC, respectively. The thermal stability of PVAm•HCl was poorer than that of PAM.

scholarly journals Experimental Study of Thermal and Catalytic Pyrolysis of Plastic Waste Components

2018 ◽  
Vol 10 (11) ◽  
pp. 3979 ◽  
Author(s):  
Azubuike Anene ◽  
Siw Fredriksen ◽  
Kai Sætre ◽  
Lars-Andre Tokheim
Keyword(s):  
High Density Polyethylene ◽  
Catalytic Pyrolysis ◽  
Batch Reactor ◽  
Decomposition Temperature ◽  
Nitrogen Atmosphere ◽  
Waste Plastics ◽  
Molecular Weight Range ◽  
Thermal Pyrolysis ◽  
Pp Blends ◽  
Hydrocarbon Distribution

Thermal and catalytic pyrolysis of virgin low-density polyethylene (LDPE), high-density polyethylene (HDPE), polypropylene (PP) and mixtures of LDPE/PP were carried out in a 200 mL laboratory scale batch reactor at 460 °C in a nitrogen atmosphere. Thermogravimetric analysis (TGA) was carried out to study the thermal and catalytic degradation of the polymers at a heating rate of 10 °C/min. The amount of PP was varied in the LDPE/PP mixture to explore its effect on the reaction. In thermal degradation (TGA) of LDPE/PP blends, a lower decomposition temperature was observed for LDPE/PP mixtures compared to pure LDPE, indicating interaction between the two polymer types. In the presence of a catalyst (CAT-2), the degradation temperatures for the pure polymers were reduced. The TGA results were validated in a batch reactor using PP and LDPE, respectively. The result from thermal pyrolysis showed that the oil product contained significant amounts of hydrocarbons in the ranges of C7–C12 (gasoline range) and C13–C20 (diesel range). The catalyst enhanced cracking at lower temperatures and narrowed the hydrocarbon distribution in the oil towards the lower molecular weight range (C7–C12). The result suggests that the oil produced from catalytic pyrolysis of waste plastics has a potential as an alternative fuel.

Polyimide nanocomposites with functionalized graphene sheets

2017 ◽  
Vol 31 (6) ◽  
pp. 837-861 ◽  
Author(s):  
Jin-Hae Chang
Keyword(s):  
Electrical Conductivity ◽  
Filler Content ◽  
Coefficient Of Thermal Expansion ◽  
Barrier Properties ◽  
Decomposition Temperature ◽  
Graphene Sheets ◽  
Functionalized Graphene ◽  
Hybrid Films ◽  
Initial Decomposition Temperature ◽  
Transmission Electron Microscopy Analysis

Polyimide (PI) nanocomposites containing two different functionalized graphene sheets (FGSs) were synthesized, and their thermal properties, morphology, oxygen permeability, and electrical conductivity were compared. Hexadecylamine–graphene sheets and 4-amino- N-hexadecylbenzamide–graphene sheets were utilized. Hybrid films were obtained from blended solutions of PI and FGSs, with the filler content with respect to the PI varying from 0 wt% to 10 wt%. The differences in the properties of the PI matrix were then analyzed with respect to filler content. Transmission electron microscopy analysis confirmed that the two FGSs were dispersed homogeneously throughout the polymer matrix, although some FGS aggregates were also formed. Furthermore, it was observed that the addition of small amounts of FGS nanofiller was sufficient to improve the coefficient of thermal expansion, the gas barrier properties, and the electrical conductivity of the hybrid films. In contrast, the glass transition temperature and the initial decomposition temperature of the PI hybrid films continued to decrease with increasing FGS content.

scholarly journals Preparation of Few-Layered WS2 and Its Thermal Catalysis for Dihydroxylammonium-5,5′-Bistetrazole-1,1′-Diolate

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Yiping Shang ◽  
Wu Yang ◽  
Yabei Xu ◽  
Siru Pan ◽  
Huayu Wang ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Thermal Decomposition ◽  
Analysis Data ◽  
Decomposition Temperature ◽  
Thermal Excitation ◽  
Layered Semiconductor ◽  
Initial Decomposition Temperature ◽  
Thermal Decomposition Behavior ◽  
Decomposition Behavior ◽  
Catalytic Effects

In this study, few-layered tungsten disulfide (WS2) was prepared using a liquid phase exfoliation (LPE) method, and its thermal catalytic effects on an important kind of energetic salts, dihydroxylammonium-5,5′-bistetrazole-1,1′-diolate (TKX-50), were investigated. Few-layered WS2 nanosheets were obtained successfully from LPE process. And the effects of the catalytic activity of the bulk and few-layered WS2 on the thermal decomposition behavior of TKX-50 were studied by using synchronous thermal analysis (STA). Moreover, the thermal analysis data was analyzed furtherly by using the thermokinetic software AKTS. The results showed the WS2 materials had an intrinsic thermal catalysis performance for TKX-50 thermal decomposition. With the few-layered WS2 added, the initial decomposition temperature and activation energy (Ea) of TKX-50 had been decreased more efficiently. A possible thermal catalysis decomposition mechanism was proposed based on WS2. Two dimensional-layered semiconductor WS2 materials under thermal excitation can promote the primary decomposition of TKX-50 by enhancing the H-transfer progress.

scholarly journals Effect of PEEK degradation on commingled fabrics consolidation

2021 ◽  
Author(s):  
Lisa Feuillerat ◽  
Olivier De Almeida ◽  
Jean-Charles Fontanier ◽  
Fabrice Schmidt
Keyword(s):  
Melt Spinning ◽  
Molar Mass ◽  
Degradation Kinetics ◽  
Gel Permeation Chromatography ◽  
Raw Material ◽  
High Porosity ◽  
Absorption Bands ◽  
Mass Distributions ◽  
Key Factor ◽  
Lower Molar

The effects of PEEK degradation on consolidation of commingled semi-finished products have been investigated. Two commingled semi-finished products provided by two different suppliers have been studied and compared to a powdered fabric based on the same PEEK grade. Both were manufactured from aligned AS4 carbon and PEEK yarns but the first product referred as the NCF1 has a lower commingling level than the second one identified as the NCF2. Contrary to what could be expected, under the same processing conditions, consolidation of the NCF1 and the NCF2 systematically results in a high porosity content, above 10%. Fourier Transform Infrared spectrophotometry (FTIR) in ATR mode and Gel Permeation Chromatography (GPC) have shown small molecular structure modifications of PEEK yarns compared to the raw material, such as a shift of molar mass distributions towards lower molar mass and the appearance of C-H absorption bands attributed to non-aromatic alkanes. These modifications have been attributed to sizing of PEEK filament. Calorimetric (DSC) and rheological analyses have demonstrated that the presence of sizing in the semi-finished products have huge consequences on the degradation kinetics. The crystallization temperature decreases and the viscosity increases significantly. This acceleration of the degradation kinetics is the reason of the poor consolidation behavior during composite manufacturing. The conditions of melt spinning extrusion under which the neat PEEK is transformed into filament are therefore a key factor of PEEK degradation.

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