Improvement of fracture toughness and glass transition temperature of DGEBA-based epoxy systems using toughening and crosslinking modifiers

2018 ◽  
Vol 59 (1) ◽  
pp. 86-95 ◽  
Author(s):  
Katja Utaloff ◽  
Martin Heinz Kothmann ◽  
Michael Ciesielski ◽  
Manfred Döring ◽  
Thomas Neumeyer ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Epoxy Systems

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.

Mechanics and nanovoid nucleation dynamics: effects of polar functionality in glassy polymer networks

Soft Matter ◽  
2018 ◽  
Vol 14 (44) ◽  
pp. 8895-8911 ◽  
Author(s):  
Robert M. Elder ◽  
Tyler R. Long ◽  
Erich D. Bain ◽  
Joseph L. Lenhart ◽  
Timothy W. Sirk
Keyword(s):  
Fracture Toughness ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Glassy Polymer ◽  
Polymer Networks ◽  
Molecular Simulations ◽  
High Glass Transition Temperature

We use molecular simulations and experiments to rationalize the properties of a class of networks based on dicyclopentadiene (DCPD), a polymer with excellent fracture toughness and a high glass transition temperature (Tg), copolymerized with 5-norbornene-2-methanol (NBOH).

Curing of epoxy systems at sub-glass transition temperature

2006 ◽  
Vol 99 (6) ◽  
pp. 3669-3676 ◽  
Author(s):  
Irena Kroutilová ◽  
Libor Matějka ◽  
Antonín Sikora ◽  
Kamil Souček ◽  
Lubomír Staš
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Epoxy Systems

scholarly journals 1-Butyl-3-methylimidazolium Salts as New Catalysts to Produce Epoxy-anhydride Polymers with Improved Properties

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Mikhail S. Fedoseev ◽  
Matvey S. Gruzdev ◽  
Lubov F. Derzhavinskaya
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Epoxy Resin ◽  
Catalytic Action ◽  
Curing Process ◽  
Tertiary Amines ◽  
Epoxy Oligomers ◽  
Epoxy Systems ◽  
Active Formation

We report the curing process of epoxy oligomers by using isomethyltetrahydrophthalic anhydride catalyzed with 1-butyl-3-methylimidazolium salts. Catalytic action has been ascertained to be dependent on the nature of anion. Salts with(Br-)and(PO4-)anions appeared to be most active. Formation of salt adducts with epoxy resin and anhydride is shown. Polymers having higher values of strength and glass transition temperature—as compared with similar epoxy systems cured in the presence of tertiary amines as catalysts—are prepared.

scholarly journals Study on Toughness Improvement of a Rosin-Sourced Epoxy Matrix Composite for Green Aerospace Application

2020 ◽  
Vol 4 (4) ◽  
pp. 168
Author(s):  
Dongyuan Hu ◽  
Xvfeng Zhang ◽  
Xiaoling Liu ◽  
Zhen Qin ◽  
Li Hu ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Carbon Fiber ◽  
Matrix Composite ◽  
Resin Matrix ◽  
Potential Candidate ◽  
Interlaminar Fracture Toughness ◽  
Interlaminar Fracture

A high temperature epoxy resin was formulated by using a rosin-sourced anhydride-type curing agent, i.e., maleopimaric acid (RAM), and a two-component epoxy consisting of an E51-type epoxy and a solid phenolic epoxy to form a bio-sourced green matrix resin. The glass transition temperature of the final resin was 238 °C Carbon fiber composite prepreg and was manufactured and laminated into composite specimens. Interleaving Toughening Technology (ITT) was applied to the laminates by using Polyamide interleaf veils. The interlaminar fracture toughness and compression after impact (CAI) strength were investigated and showed that the opening Mode I interlaminar fracture toughness GIC and the Mode II interlaminar fracture toughness GIIC of the specimens with interleaves were significantly improved from 227.51 J/m2 to 509.22 J/m2 and 1064.3 J/m2 to 1510.8 J/m2, respectively. Correspondingly, the drop-weight impact test shows that the interleaves reduced the impact damage area from 20.9% to 11.3% of the total area, and the CAI residual strength was increased from 144 MPa to 191 MPa. Meanwhile, mechanical tests showed that the in-plane properties of the interleaved laminates were slightly reduced due to carbon fiber volume fraction reduction. In conclusion, the high glass transition temperature, fracture toughness and CAI behaviour make the green resin matrix composite a potential candidate for aerospace applications.

scholarly journals Toughening studies on an ABS/PC blend-modified epoxy resin system

1994 ◽  
Vol 6 (3) ◽  
pp. 241-248 ◽  
Author(s):  
K Natarajan ◽  
R M V G K Rao
Keyword(s):  
Fracture Toughness ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Epoxy Resin ◽  
Diglycidyl Ether ◽  
Particle Dispersion ◽  
Scanning Electron Micrographs ◽  
Epoxy Resin System ◽  
Modified Epoxy

Studies were carried out on the toughening of a bifunctional epoxy (diglycidyl ether of bisphenol-A) matrix system with an ABS/PC thermoplastic blend. The thermoplastic blend was incorporated into the epoxy matrix by particle dispersion and melt-mix methods. The unmodified and modified epoxy resin systems were cured with a stoichiometric quantity of diamino diphenyl methane (DDM). The cured castings were characterized by measurement of glass transition temperature (Tg) by DsC, evaluation of plane strain fracture toughness (Klc) by three-point bending tests and SEM analysis of non-etched and base/acid etched fracture surfaces. In genera] ABS/PC-modified (15% w/w) epoxy-resin-cured systems showed enhanced fracture toughness without lowering the glass transition temperature. The melt-mix method yielded higher fracture toughness than the particle dispersion method; this conclusion was also supported by scanning electron micrographs.

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