scholarly journals Investigation of the functional network modifier loading on the stoichiometric ratio of epoxy resins and their dielectric properties

2021 ◽  
Author(s):  
Istebreq A. Saeedi ◽  
Sunny Chaudhary ◽  
Thomas Andritsch ◽  
Alun S. Vaughan
Keyword(s):  
Glass Transition ◽  
Dielectric Properties ◽  
Electrical Properties ◽  
Epoxy Resins ◽  
Functional Network ◽  
Cross Linking ◽  
Network Modifier ◽  
Epoxy Resin System ◽  
The Cross ◽  
The Impact

AbstractReactive molecular additives have often been employed to tailor the mechanical properties of epoxy resins. In addition, several studies have reported improved electrical properties in such systems, where the network architecture and included function groups have been modified through the use of so-called functional network modifier (FNM) molecules. The study reported here set out to investigate the effect of a glycidyl polyhedral oligomeric silsesquioxane (GPOSS) FNM on the cross-linking reactions, glass transition, breakdown strength and dielectric properties of an amine-cured epoxy resin system. Since many previous studies have considered POSS to act as an inorganic filler, a key aim was to consider the impact of GPOSS addition on the stoichiometry of curing. Fourier transform infrared spectroscopy revealed significant changes in the cross-linking reactions that occur if appropriate stoichiometric compensation is not made for the additional epoxide groups present on the GPOSS. These changes, in concert with the direct effect of the GPOSS itself, influence the glass transition temperature, dielectric breakdown behaviour and dielectric response of the system. Specifically, the work shows that the inclusion of GPOSS can result in beneficial changes in electrical properties, but that these gains are easily lost if consequential changes in the matrix polymer are not appropriately counteracted. Nevertheless, if the system is appropriately optimized, materials with pronounced improvements in technologically important characteristics can be designed.

Planarization and Dielectric Properties of Thin Photosensitive and Nonphotosensitive BCB

2004 ◽  
Vol 1 (2) ◽  
pp. 47-52
Author(s):  
Brian Dusch ◽  
Paul A. Kohl
Keyword(s):  
Thin Films ◽  
Dielectric Properties ◽  
Thick Films ◽  
Cross Linking ◽  
Low Loss ◽  
The Cross

Thin films (0.2 μm to 1.8 μm) of photosensitive and nonphotosensitive BCB were fabricated and the degree of planarization (DOP) and dielectric properties were investigated. It was found that a high DOP for wide spaces (>20 μm spaces with 1 μm of BCB) was possible with nonphotosensitive BCB but not photosensitive BCB because of the cross-linking reaction during the photo-process. Thin films (as thin as 0.2 μm) exhibited dielectric properties similar to thick films. The dielectric properties of the photosensitive BCB were slightly higher than nonphotosensitive BCB. Low loss properties were observed at all thickness.

scholarly journals Synthesis of epoxy resins derivatives of naphthalene-2,7-diol and their cross-linked products

2019 ◽  
Vol 138 (6) ◽  
pp. 4349-4358 ◽  
Author(s):  
K. Fila ◽  
M. Gargol ◽  
M. Goliszek ◽  
B. Podkościelna
Keyword(s):  
Fourier Transform ◽  
Epoxy Resins ◽  
Attenuated Total Reflectance ◽  
Cross Linking ◽  
Total Reflectance ◽  
Before And After ◽  
Ft Ir ◽  
The Cross ◽  
Derivatives Of ◽  
Epoxy Groups

Abstract The aim of this study was the synthesis of three different epoxy compounds based on naphthalene-2,7-diol (2,7-NAF.EP, 2,7-NAF.WEP, 2,7-NAF.P.EP) and then their cross-linking by triethylenetetramine (TETA). All epoxides were prepared by the reaction of naphthalene-2,7-diol with epichlorohydrin but under different conditions and with other catalysts. The structures of the obtained compounds before and after the cross-linking reactions were confirmed by the attenuated total reflectance Fourier transform infrared spectroscopy (ATR/FT-IR). The ATR/FT-IR spectra of cross-linked compounds show disappearance of the C–O–C bands (about 915 cm−1) derived from the epoxy groups. DSC and TG/DTG measurements indicated that the obtained materials possess good thermal resistance; they are stable up to about 250 °C. The hardness of the cross-linked products was determined using the Shore D method. The highest value of hardness was obtained for the 2,7-NAF.EP-POL. Additionally, the UV–Vis absorption spectra of the obtained polymers were registered and evaluated.

Chemiluminescence measurement of gel times for amine-cured epoxy resins

1995 ◽  
Vol 7 (2) ◽  
pp. 219-236 ◽  
Author(s):  
K A Kozielski ◽  
N C Billingham ◽  
G A George ◽  
D C L Greenfield ◽  
J M Barton
Keyword(s):  
Chemical Reactions ◽  
Epoxy Resins ◽  
Physical State ◽  
Glycidyl Ether ◽  
Cross Linking ◽  
Gel Time ◽  
The Matrix ◽  
Effect Of Impurities ◽  
The Cross

The cross-linking reactions of 4,4'-diaminodiphenyl sulphone (DDS) with stoichiometric quantities of glycidyl ether- or tetraglycidyl amine-based epoxy resins were monitored using chemiluminescence (CL) and rheometry. It was found that, when a sample was cured isothermally in air, the CL profile increased to a maximum, then decreased again. The maximum was found to correspond well with the gel time (tgel), as measured by rheometry. This observation is discussed in relation to the chemical reactions occurring within the material and the physical state of the matrix. The effect of impurities in DDS on the gel time of these epoxy resins is reported.

The effect of bis allyl benzoxazine on the thermal, mechanical and dielectric properties of bismaleimide–cyanate blend polymers

RSC Advances ◽  
2015 ◽  
Vol 5 (72) ◽  
pp. 58821-58831 ◽  
Author(s):  
Yiqun Wang ◽  
Kaichang Kou ◽  
Guanglei Wu ◽  
Ailing Feng ◽  
Longhai Zhuo
Keyword(s):  
Mechanical Properties ◽  
Dielectric Properties ◽  
Polymer Composite ◽  
High Performance ◽  
Cross Linking ◽  
Thermal And Mechanical Properties ◽  
High Performance Polymer ◽  
The Cross

A high-performance polymer composite was fabricated using Bz-allyl/BMI/BADCy resin, in which the BMI/BADCy resin was modified with Bz-allyl to improve its dielectric, thermal and mechanical properties and the cross-linking degree after curing.

scholarly journals The Use of the ATD Technique to Measure the Gelation Time of Epoxy Resins

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6022
Author(s):  
Jakub Smoleń ◽  
Piotr Olesik ◽  
Paweł Gradoń ◽  
Mateusz Chudy ◽  
Bogusław Mendala ◽  
...  
Keyword(s):  
Carbon Fibers ◽  
Epoxy Resins ◽  
Gelation Time ◽  
Graphite Powder ◽  
Cross Linking ◽  
Gel Point ◽  
Curing Process ◽  
Carbon Particles ◽  
The Cross ◽  
The Stability

In this paper, we investigated the thermodynamics of the resin curing process, when it was a part of composition with graphite powder and cut carbon fibers, to precisely determine the time and temperature of gelation. The material for the research is a set of commercial epoxy resins with a gelation time not exceeding 100 min. The curing process was characterized for the neat resins and for resins with 10% by weight of flake graphite and cut carbon fibers. The results recorded in the analysis of temperature derivative (ATD) method unequivocally showed that the largest first derivative registered during the test is the gel point of the resin. The innovative approach to measuring the gelation time of resins facilitates the measurements while ensuring the stability of the curing process compared to the normative tests that introduce mechanical interaction. In addition, it was found during the research that the introduction of 10% by weight of carbon particles in the form of graphite and cut carbon fibers rather shortens the gelation time and lowers the temperature peak due to the effective absorption and storage of heat from the cross-linking system. The inhibiting (or accelerating) action of fillers is probably dependent on chemical activity of the cross-linking system.

scholarly journals The Impact of Cross-Linking Effect on the Space Charge Characteristics of Cross-Linked Polyethylene with Different Degrees of Cross-Linking under Strong Direct Current Electric Field

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1149 ◽  
Author(s):  
Shuchao Wang ◽  
Quan Zhou ◽  
Ruijin Liao ◽  
Lai Xing ◽  
Nengcheng Wu ◽  
...  
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Space Charge ◽  
Direct Current ◽  
Cross Linking ◽  
Average Charge ◽  
Electrical Field ◽  
Electrical Field Strength ◽  
The Cross ◽  
The Impact

Cross-linked polyethylene (XLPE) obtained by the crossing-linking reaction of polyethylene (PE) can greatly enhance the mechanical properties and other properties of PE, which makes XLPE widely applied in the field of electric power engineering. However, the space charges can distort the distribution of the electrical field strength in the XLPE applied in the insulation materials, which can shorten the service life of the insulation materials. Therefore, the space charge characteristics of XLPE under the strong direct current (DC) electric field have been the focus of scholars and engineers all over the world. This article has studied the impact of the cross-linking effect on the space charge characteristics of XLPE with different degrees of cross-linking. For this issue, we used dicumyl peroxide (DCP) as the cross-linking agent and low-density polyethylene (LDPE) as the base material for the preparation of samples. Besides, the space charge distribution was measured by the pulsed electro-acoustic method (PEA). In addition, the average charge density as a characteristic parameter was introduced into the experiment, which was used to quantitatively analyze the impact of the cross-linking effect on the space charge characteristics of XLPE with different degrees of cross-linking. Meanwhile, we also explained the impact of the cross-linking effect on XLPE with different degrees of cross-linking from a microscopic point of view. Ultimately, some important conclusions can be obtained. For instance, the cross-linking effect significantly increases the threshold electrical field strength of XLPE, and as the content of cross-linking agent increases, the threshold electrical field strength increases at first and then decreases, and the threshold electrical field strength reaches the maximum value when the content of the cross-linking agent is 1.0% or 2.1%. Besides, the cross-linking effect introduces negative charge traps into the LDPE and increases the densities of the deeper charge traps, and so on. In addition, we have also analyzed the average charge density, and we have summarized the theoretical model of the average charge decay, namely, Q ( t ) = Q 0 + α e − t β , which is very effective for explaining the dissipation characteristics (more conclusive contents can be seen in the conclusion section of this article).

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