scholarly journals Influence of antioxidants in epoxy-anhydride resin used for HV applications

2018 ◽  
Author(s):  
Chau Hon Ho ◽  
Emmanuel Logakis ◽  
Andrej Krivda
Keyword(s):  
Thermal Stability ◽  
Glass Transition ◽  
Transition Temperature ◽  
Breakdown Voltage ◽  
Degradation Behavior ◽  
Thermooxidative Degradation ◽  
Thermo Gravimetric ◽  
Chemical Structures ◽  
Stabilizing Effect ◽  
Resin Formulation

<p>In this work, various antioxidants with different chemical structures and functionalities were investigated in respect to their influence in the processibility and properties of a standard epoxyanhydride resin formulation used in HV applications. Such antioxidants are mainly used in thermoplastic materials as they are known for their long- and shortterm stabilizing effect against thermal and thermooxidative degradation. They are also used as UV stabilizers against decomposition and discoloration of the polymer and as metal deactivators by catching and eliminating metal ions. Recently, the use of such antioxidants as voltage stabilizers in cross-linked polyethylene has been reported showing a significant increase in breakdown voltage.</p><p>Our investigations show that the processing requires additional mixing steps in order to completely dissolve antioxidants in the epoxy formulation. While little amounts of antioxidants or voltage stabilizers have a large influence in thermoplastics regarding thermal stability and electrical properties, the studied antioxidants in a concentration range of 1-5 weight-% show surprisingly only little impact in breakdown voltage as well as in dielectric properties and also in degradation behavior as detected by thermo-gravimetric analyses. Only the glass transition temperature of the cured epoxy resin is decreased in a few cases where the antioxidants have a plasticizing effect.</p>

scholarly journals Studies on the Modification of Commercial Bisphenol-A-Based Epoxy Resin Using Different Multifunctional Epoxy Systems

2021 ◽  
Vol 2 (2) ◽  
pp. 419-430
Author(s):  
Ankur Bajpai ◽  
James R. Davidson ◽  
Colin Robert
Keyword(s):  
Mechanical Properties ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Bisphenol A ◽  
Epoxy Resin ◽  
Tensile Fracture ◽  
Chemical Structures ◽  
Amino Phenol ◽  
Epoxy Systems

The tensile fracture mechanics and thermo-mechanical properties of mixtures composed of two kinds of epoxy resins of different chemical structures and functional groups were studied. The base resin was a bi-functional epoxy resin based on diglycidyl ether of bisphenol-A (DGEBA) and the other resins were (a) distilled triglycidylether of meta-amino phenol (b) 1, 6–naphthalene di epoxy and (c) fluorene di epoxy. This research shows that a small number of multifunctional epoxy systems, both di- and tri-functional, can significantly increase tensile strength (14%) over neat DGEBA while having no negative impact on other mechanical properties including glass transition temperature and elastic modulus. In fact, when compared to unmodified DGEBA, the tri-functional epoxy shows a slight increase (5%) in glass transition temperature at 10 wt.% concentration. The enhanced crosslinking of DGEBA (90 wt.%)/distilled triglycidylether of meta-amino phenol (10 wt.%) blends may be the possible reason for the improved glass transition. Finally, the influence of strain rate, temperature and moisture were investigated for both the neat DGEBA and the best performing modified system. The neat DGEBA was steadily outperformed by its modified counterpart in every condition.

Investigating the role of GeO2 in enhancing the thermal stability and proton mobility of proton-conducting phosphate glasses

2021 ◽  
Author(s):  
Takahisa Omata ◽  
Aman Sharma ◽  
Takuya Kinoshita ◽  
Issei Suzuki ◽  
Tomohiro Ishiyama ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Phosphate Glasses ◽  
Proton Mobility ◽  
Proton Conducting

In this study, the effect of GeO2 on the thermal stability and proton mobility (μH) of proton-conducting phosphate glasses was experimentally investigated using 22HO1/2−3NaO1/2−(12−x)LaO3/2−xGeO2−63PO5/2 glasses. Increasing glass transition temperature (Tg)...

Nanocomposite Epoxy Resin for SiC Module

2011 ◽  
Vol 2011 (HITEN) ◽  
pp. 000196-000200 ◽  
Author(s):  
Kenji Okamoto ◽  
Yuji Takematsu ◽  
Miyako Hitomi ◽  
Yoshinari Ikeda ◽  
Yoshikazu Takahashi
Keyword(s):  
Thermal Stability ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Epoxy Resin ◽  
Molecular Motion ◽  
Experimental Results ◽  
Power Module ◽  
Operation Temperature ◽  
Thermal Stability Of

There is a demand to improve the thermal stability of epoxy molding resins used in the power module of SiC power chips operating at temperatures of 200°C or more. This paper describes a technique for increasing the thermal stability of the resin by decreasing molecular motion through the addition of nanofiller. The experimental results showed that the glass transition temperature (Tg) of the epoxy resin increased by approximately 30°C when the silica nanofiller was added. The epoxy resin added nanofiller was investigated in order to achieve the operation temperature 200°C of power module.

scholarly journals Melt Stable Functionalized Organosolv and Kraft Lignin Thermoplastic

Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1108
Author(s):  
Shubhankar Bhattacharyya ◽  
Leonidas Matsakas ◽  
Ulrika Rova ◽  
Paul Christakopoulos
Keyword(s):  
Thermal Stability ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Kraft Lignin ◽  
Added Value ◽  
Lignin Valorization ◽  
1H Nuclear Magnetic Resonance ◽  
Ft Ir ◽  
Viable Biomass

A shift towards an economically viable biomass biorefinery concept requires the use of all biomass fractions (cellulose, hemicellulose, and lignin) for the production of high added-value products. As lignin is often underutilized, the establishment of lignin valorization routes is highly important. In-house produced organosolv as well as commercial Kraft lignin were used in this study. The aim of the current work was to make a comparative study of thermoplastic biomaterials from two different types of lignins. Native lignins were alkylate with two different alkyl iodides to produce ether-functionalized lignins. Successful etherification was verified by FT-IR spectroscopy, changes in the molecular weight of lignin, as well as 13C and 1H Nuclear Magnetic Resonance (NMR). The thermal stability of etherified lignin samples was considerably improved with the T2% of organosolv to increase from 143 °C to up to 213 °C and of Kraft lignin from 133 °C to up to 168 °C, and glass transition temperature was observed. The present study shows that etherification of both organosolv and Kraft lignin with alkyl halides can produce lignin thermoplastic biomaterials with low glass transition temperature. The length of the alkyl chain affects thermal stability as well as other thermal properties.

Reinforcement of NR with ENR Modified RHA

2012 ◽  
Vol 581-582 ◽  
pp. 663-667
Author(s):  
Zong Qiang Zeng ◽  
Hong Chao Liu ◽  
He Ping Yu
Keyword(s):  
Thermal Stability ◽  
Glass Transition ◽  
Transition Temperature ◽  
Natural Rubber ◽  
Rice Husk Ash ◽  
Dynamic Properties ◽  
Natural Rubber Latex ◽  
Morphological Structure ◽  
Rubber Latex ◽  
Tga Analysis

The rice husk ash (RHA) was first modified with epoxidized natural rubber latex (ENRL) and then blended with natural rubber latex (NRL) to prepare NR/RHA composite. The morphological structure, thermal stability and dynamic properties were studied with multiple instruments. FTIR and TGA analysis showed that ENR was grafted onto the surface of RHA. The composite prepared with modified RHA showed better dispersity and reinforcement compared to the composite with unmodified RHA, and the glass-transition temperature tended to be higher.

Poly(Binaphthalenevinylene-alt-Phenylenevinylene) Derivatives: Novel Luminescent Polymers for Light-Emitting Devices

1999 ◽  
Vol 598 ◽  
Author(s):  
Lixin Zheng ◽  
Xuezhong Jiang ◽  
Michelle S. Liu ◽  
Alex K-Y. Jen
Keyword(s):  
Thermal Stability ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Model Compound ◽  
Condensation Reaction ◽  
Spectral Characteristics ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Luminescent Polymers

ABSTRACTNovel conjugated light-emitting polymers were synthesized via a Wittig-Horner condensation reaction between a binaphthyl dicarbaldehyde and a series of electron-rich or electron-deficient aryl diphosphonates. After comparing these materials with the model compound, 4c, it was revealed that the introduction of a twisted, non-coplanar binaphthyl structure provided an effective approach for tailoring the spectral characteristics of the polymers and improving their solubility and thermal stability (glass transition temperature, Tg, 200°C). Furthermore, the band structures of the polymers could be fine-tuned by changing the electronic properties of the bridging aromatic units. The electroluninescence (EL) and device characteristics were also reported in this paper.

scholarly journals Recycled Glass Fibres from Wind Turbines as a Filler for Poly(Vinyl Chloride)

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Krzysztof Lewandowski ◽  
Katarzyna Skórczewska ◽  
Kazimierz Piszczek ◽  
Włodzimierz Urbaniak
Keyword(s):  
Thermal Stability ◽  
Glass Transition ◽  
Transition Temperature ◽  
Composite Materials ◽  
Glass Transition Temperature ◽  
Impact Strength ◽  
Vinyl Chloride ◽  
Turbine Blades ◽  
Wind Turbine Blades ◽  
Poly Vinyl Chloride

This paper presents the method of using glass fibre with carbon deposit (GFCD), derived from the recycling of wind turbine blades, for production of composite materials based on poly(vinyl chloride) (PVC). Composite materials containing from 1 to 15 wt% of GFCD were produced by plasticising with a plastographometer and then by pressing. The processability and performance were studied. Mechanical properties in static tension, impact strength, and thermal stability were determined. Glass transition temperature was also determined by means of the dynamic mechanical thermal analysis (DMTA). The GFCD percentage of up to 15 wt% was found not to slightly affect the change in the processability, thermal stability, and glass transition temperature. PVC/GFCD composite materials are characterised by a definitely greater elastic modulus with simultaneous decrease of tensile strength and impact strength. An analysis with scanning electron microscopy revealed good adhesion between the filler and the polymer matrix.

Design of low dielectric constant polybenzoxazine nanocomposite using mesoporous mullite

2016 ◽  
Vol 29 (2) ◽  
pp. 141-150 ◽  
Author(s):  
K Ilango ◽  
P Prabunathan ◽  
E Satheeshkumar ◽  
P Manohar
Keyword(s):  
Thermal Stability ◽  
Dielectric Constant ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Thermal Studies ◽  
Microscopic Analysis ◽  
Low Dielectric Constant ◽  
Low Dielectric ◽  
Porous Morphology

In this present work, porous mullites (PM0–5) were synthesized through a template-assisted method using various weight percentages of pluronic (P-123). PM5 obtained using 10 wt% of P-123 was found to show maximum porosity (3.8 Å) and low dielectric constant value (2.4). PM5 was functionalized using glycidyl-terminated silane and denoted as FPM and various weight percentages of FPM were reinforced with polybenzoxazine (PBZ) matrix in order to develop FPM/PBZ nanocomposites. The thermal studies indicate that 1.5 wt% of FPM/PBZ nanocomposite showed improved thermal stability with 34% char yield at 800°C and 162°C as glass transition temperature. It also exhibits low dielectric constant (2.6) than that of the neat PBZ matrix and other FPM/PBZ nanocomposites. The microscopic analysis confirms the homogenous dispersion of FPM into the PBZ polymer that has a porous morphology. The results suggest that the as-synthesized mesoporous mullite with low dielectric constant ( k), synthesized via template-assisted method can be used as a reinforcement to decrease the dielectric constant of polymeric material, which is of industrial significance.

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