scholarly journals Curing Kinetics and Thermal Stability of Epoxy Composites Containing Newly Obtained Nano-Scale Aluminum Hypophosphite (AlPO2)

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 644 ◽  
Author(s):  
Farimah Tikhani ◽  
Shahab Moghari ◽  
Maryam Jouyandeh ◽  
Fouad Laoutid ◽  
Henri Vahabi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
High Performance ◽  
Frequency Factor ◽  
Curing Temperature ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Nano Scale ◽  
Aluminum Hypophosphite ◽  
Thermal Stability Of

For the first time, nano-scale aluminum hypophosphite (AlPO2) was simply obtained in a two-step milling process and applied in preparation of epoxy nanocomposites varying concentration (0.1, 0.3, and 0.5 wt.% based on resin weight). Studying the cure kinetics and thermal stability of these nanocomposites would pave the way toward the design of high-performance nanocomposites for special applications. Scanning electron microscopy (SEM) and transmittance electron microscopy (TEM) revealed AlPO2 particles having domains less than 60 nm with high potential for agglomeration. Excellent (at heating rate of 5 °C/min) and Good (at heating rates of 10, 15 and 20 °C/min) cure states were detected for nanocomposites under nonisothermal differential scanning calorimetry (DSC). While the dimensionless curing temperature interval (ΔT*) was almost equal for epoxy/AlPO2 nanocomposites, dimensionless heat release (ΔH*) changed by densification of polymeric network. Quantitative cure analysis based on isoconversional Friedman and Kissinger methods gave rise to the kinetic parameters such as activation energy and the order of reaction as well as frequency factor. Variation of glass transition temperature (Tg) was monitored to explain the molecular interaction in the system, where Tg increased from 73.2 °C for neat epoxy to just 79.5 °C for the system containing 0.1 wt.% AlPO2. Moreover, thermogravimetric analysis (TGA) showed that nanocomposites were thermally stable.

scholarly journals Corrosion Resistance of Mild Steel Coated with Phthalimide-Functionalized Polybenzoxazines

Coatings ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1114
Author(s):  
Kamal I. Aly ◽  
Abdulsalam Mahdy ◽  
Mohamed A. Hegazy ◽  
Nayef S. Al-Muaikel ◽  
Shiao-Wei Kuo ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Mild Steel ◽  
High Performance ◽  
Functional Group ◽  
Curing Temperature ◽  
Resonance Spectroscopy ◽  
Scanning Calorimetry ◽  
Mannich Reactions ◽  
Polymerization Behavior ◽  
Thermal Stability Of

Herein, we synthesized two new phthalimide-functionalized benzoxazine monomers, pPP-BZ and oPP-BZ, through Mannich reactions of 2-(4-hydroxyphenyl)isoindoline-1,3-dione (pPP) and 2-(2-hydroxyphenyl)isoindoline-1,3-dione (oPP), respectively, with p-toluidine and paraformaldehyde. The structures of these two monomers were confirmed using Fourier transform infrared (FTIR) and nuclear magnetic resonance spectroscopy. We used differential scanning calorimetry, FTIR spectroscopy, and thermogravimetric analysis to study the polymerization behavior and thermal stability of the monomers and their corresponding polybenzoxazines. Poly(pPP-BZ) and poly(oPP-BZ) were formed on mild steel (MS) through spin-coating and subsequent thermal curing polymerization. We used various corrosion testing methods to examine the effect of the curing temperature on the corrosion resistance of the coated MS samples in 3.5 wt.% aqueous solution of NaCl. Among our tested systems, the corrosion rate reached a low of 2.78 µm·Y−1 for the MS coated with poly(pPP-BZ)180 (i.e., the coating that had been cured at 180 °C); this value is much lower than that (4.8 µm·Y−1) reported for a maleimide-based benzoxazine compound (MI-Bz)/33 wt.% ACAT (amine-capped aniline trimer) blend. Thus, the incorporation of the imide functional group into the PBZ coatings is an effective strategy for affording high-performance corrosion resistance.

An easy approach to fabricating HgS/chitosan nanocomposite films and their ability to sense triethylamine

2014 ◽  
Vol 34 (4) ◽  
pp. 339-344 ◽  
Author(s):  
Shan Wang ◽  
Minyan Zheng
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Scanning Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Fluorescence Emission ◽  
Nanocomposite Films ◽  
Scanning Calorimetry ◽  
Sem Image ◽  
Thermal Stability Of ◽  
Scanning Electron

Abstract A chitosan (CS)–HgS nanocomposite was synthesized by a simulating biomineralization method. The effect of HgS nanoparticles on the physical properties of the composite was studied by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The glass transition temperature (Tg) of the composite was 22°C higher than that of CS. The thermal stability of the composite was higher than that of CS, which was evidenced by the shift of onset temperature of degradation by 22°C as measured by DSC. The SEM image of the HgS/CS nanocomposite film shows that the nanoparticle size was 100 nm. The fluorescence emission of nanocomposite films was found to be very sensitive to the presence of triethylamine; even a small amount of triethylamine dramatically increased emissions. By contrast, emission was hardly affected by other common ions in water. The films are predicted to have the potential to be developed into excellent sensing films for triethylamine.

Preparation and Thermal Properties of Polybenzoxazine/TiC Hybrids

2014 ◽  
Vol 887-888 ◽  
pp. 49-52 ◽  
Author(s):  
Noureddine Ramdani ◽  
Jun Wang ◽  
Wen Bin Liu
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Thermal Properties ◽  
High Performance ◽  
Phenolic Resin ◽  
Scanning Calorimetry ◽  
New Class ◽  
Solution Blending ◽  
Tic Nanoparticles ◽  
Thermal Stability Of

In this work, typical polybenzoxazine, as new class of phenolic resin, has been used as a matrix for preparing a series of high performance hybrid materials using various amounts of titanium carbide (TiC) ranging between 0-10 wt% as fillers, via a solution blending technique. The thermal properties of bisphenol A-aniline base benzoxazine monomers (BA-a) and TiC mixtures have been studied by differential scanning calorimetry (DSC). The thermal stability of their cured hybrids has been tested by means of thermogravimetric analysis (TGA). The result showed that the glass transition temperature of the prepared composites increased with increasing the amount of TiC to reach a higher value at 194°C. Also, the incorporation of TiC nanoparticles has considerably improved the thermal stability of the hybrids including the char yield which increase by 50 % at 10 wt% TiC content.

Kinetic Analysis of UV-Curable Epoxy Resins for Micromachining Applications

2009 ◽  
Vol 74 ◽  
pp. 299-302 ◽  
Author(s):  
Voytekunas Vanda Yu ◽  
Ng Feng Lin ◽  
Koh Chai Ling ◽  
Abadie Marc
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Epoxy Resins ◽  
High Performance ◽  
Moisture Absorption ◽  
Scanning Calorimetry ◽  
Uv Curable ◽  
Mechanical And Electrical Properties ◽  
Multifunctional Epoxy Resin ◽  
Thermal Stability Of

Multifunctional epoxy resin series Epiclon HP-7200 is classified under the high performance series and is well known for its application in electrical encapsulation as it exhibits excellent mechanical and electrical properties. In addition, they have an advantage of an ultra low moisture absorption compared to other conventional cresol novolac (ECN) and biphenyl epoxy resins, which potentially makes it the next new mainstream of epoxy resins in electronics application. In this paper, kinetic study of various concentration of Epiclon HP-7200 (40-70 wt %) with divinyl ether (DVE) as the reactive solvent has been performed by Photo-Differential Scanning Calorimetry (DPC). The thermal stability of the Epiclon HP-7200 solutions has been analyzed by DSC and TGA.

Thermally Stable Polyimide/Silica Hybrid: Synthesis, Characterization and Optical Nonlinearity

2010 ◽  
Vol 123-125 ◽  
pp. 1275-1278
Author(s):  
Guang Yu Wu ◽  
Cheng Yao ◽  
Feng Xian Qiu
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
High Performance ◽  
Nonlinear Optical ◽  
Sol Gel ◽  
Optical Nonlinearity ◽  
29Si Nmr ◽  
Scanning Calorimetry ◽  
Excellent Thermal Stability ◽  
Electro Optic

An intercalation nonlinear-optical (NLO) polyimide was synthesized based on the 3,3’, 4,4’- Bisphenyltetracarboxylic (BPDA) and [(6-nitrobenzothiazole-2-yl)diazenyl]phenyl-1,3- diamine (NBADA). Then, hybrid polymer was synthesized by the sol-gel technique. FT-IR spectroscopy and 29Si NMR were used to characterize the structure of the hybrid. The results revealed that Q3, Q4 and T3 are the major microstructure elements in forming a network structure. The surface morphology, particle size, crystallinity and the thermal stability of the hybrid were investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). DSC and TGA results showed that the glass transition temperature (Tg) and the decomposition temperature (Td) at 5% mass loss were 243, 359°C and 355, 456°C, respectively. These results showed that the hybrid material had excellent thermal stability than the pure polyimide. The electro-optic coefficients of nonlinear optical polyimide and hybrid were measured at the wavelength of 832 nm. The electro-optic coefficients were 22 and 19pm/V (poling voltage of 3.8KV, 210°C) and the values remained well (retained＞93% for more than 100h). The results suggest that the materials have potential applications for high performance optical device.

Characterization of Solution Treatment on AA7A55 Alloy

2015 ◽  
Vol 817 ◽  
pp. 185-191
Author(s):  
Xin Yu Lv ◽  
Er Jun Guo ◽  
Li Juan Wang ◽  
Xing Han ◽  
Xiang Jie Wang
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Scanning Electron Microscopy ◽  
Solution Treatment ◽  
Solution Temperature ◽  
Scanning Calorimetry ◽  
Solution Treated ◽  
Thermal Stability Of ◽  
Scanning Electron

The thermal stability of constituent particles in both as-rolled and solution treated in AA7A55 has been investigated by means of scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). Three types of solution treatments were used to dissolve particles constituents. Whereas the degree of recrystallization aggravates which deteriorates the properties with increasing the solution temperature, a significant amount of recrystallization exists after utilizing 480°C solution treatment whereas a much smaller extent from 480°C to 490°C. And electrochemical and exfoliation corrosion matched with the degree of recrystallization. With increasing the recrystallization the corrosion become worse.

A new resin with improved processability and thermal stability

2016 ◽  
Vol 29 (1) ◽  
pp. 13-25 ◽  
Author(s):  
Liping Sheng ◽  
Jingcheng Zeng ◽  
Suli Xing ◽  
Changping Yin ◽  
Jinshui Yang ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Synergistic Effect ◽  
Curing Temperature ◽  
Proton Nuclear Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
Curing Time ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Cure Reaction ◽  
Excellent Thermal Stability

To maintain outstanding thermal stability, amino- and hydroxyl-containing phthalonitrile monomers, 4-(4-aminophenoxy)-phthalonitrile (APN) and 4-(4-hydroxyphenoxy)-phthalonitrile (HPN) were selected and synthesized. Their structures were confirmed by proton nuclear magnetic resonance spectroscopy. Their curing polymers were characterized by Fourier transform infrared spectroscopy. The self-catalytic curing behaviors of the monomers were investigated by differential scanning calorimetry (DSC) at different heating rates. From the results, APN exhibits a higher curing temperature, while HPN exhibits a longer curing time. Then, mixtures of these monomers were investigated by DSC. The result shows that the 50/50 mixture exhibits different autocatalytic behaviors: the curing temperature is lower than that of APN and the curing time of the mixture is shorter than that of HPN. Furthermore, thermogravimetric analysis shows that the polymer from the mixture exhibits higher temperature of 5% weight loss ( T5%) and char yield value at 800°C than those of the polymers from each monomer. All these results indicate that the new mixture resin exhibits improved processability with excellent thermal stability, attributed to the synergistic effect between similar monomers; the synergistic effect optimizes the cure reaction kinetics and promotes cross-linking reactions, thereby producing an excellent resin; this approach is a new method for improving the processability without sacrificing thermal stability.

Thermal stability of CaCO3/polyethylene (PE) nanocomposites

2019 ◽  
Vol 27 (7) ◽  
pp. 371-382
Author(s):  
S Sahebian ◽  
MT Hamed Mosavian
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Thermal Stability ◽  
Morphological Structure ◽  
Thermomechanical Analysis ◽  
Scanning Calorimetry ◽  
Weight Percentage ◽  
Transmission Electron ◽  
Crystallization Experiments ◽  
Thermal Stability Of

Calcium carbonate (CaCO3) nanoparticles in polymer matrix cause to improvement in polymer performance, including thermal stability and mechanical properties. The main goal of this article is to investigate the effect of different weight percentage of nanoparticles of CaCO3 on thermal stability and mechanical properties of polyethylene (PE) nanocomposites. The morphological structure of CaCO3 nanoparticles and nanocomposites was investigated by transmission electron microscopy and scanning electron microscopy. The thermal stability of PE and its nanocomposites was also determined by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and thermomechanical analysis. Nonisothermal crystallization experiments by DSC test showed that the incorporation of nanoparticles increased the crystallinity, glass transition temperature, and the effective energy barrier for crystallization process. Besides, degradation behavior was evaluated by TGA. The onset mass loss temperature shifted to higher value in the presence of nanoparticles.

Sign in / Sign up

Export Citation Format

Share Document