Analysis of the effect and mechanism of microwave curing on the chemical shrinkage of epoxy resins

The microwave cure–induced chemical shrinkage of epoxy resins in composite materials was researched in this article. Four kinds of epoxy resins were cured using the microwave and thermal heating process. An improved device containing fiber Bragg grating sensors was applied to accurately measure the chemical shrinkage–induced linear strains in those samples. Experimental results indicated that the chemical shrinkage of diglycidyl ether of bisphenol A (DGEBA)/polyetheramine (PEA) and tetraglycidyl diaminodiphenylmethane/4,4′-diaminodiphenyl sulfone epoxy resins was significantly reduced by microwave curing, and the reductions about 37.1 and 38.4% were achieved compared with the thermal-cured counterparts. However, the chemical shrinkage of the thermal- and microwave-cured samples was almost the same for DGEBA/methyl tetrahydrophthalic anhydride and DGEBA/dicyandiamide epoxies. In order to analyze the influencing mechanism of microwaves on the chemical shrinkage, the chemical structure of various samples was characterized by using Fourier-transform infrared spectroscopy, and the free volume was measured by positron annihilation lifetime spectrometer. It was found that microwaves can greatly decrease the contents of hydroxyl groups in epoxy resins, leading to the reduction of the chemical shrinkage. Furthermore, the mechanical properties of both microwave- and thermal-cured DGEBA/PEA epoxies were studied, and the results showed that the microwave-cured specimens have a higher impact strength but a lower tensile strength.

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MECHANICAL CHARACTERISTICS FOR COMPOSITE MATERIALS USING COMMERCIAL EPOXY RESINS AND DIFFERENT FILLERS

Journal of Southwest Jiaotong University ◽

10.35741/issn.0258-2724.56.5.17 ◽

2021 ◽

Vol 56 (5) ◽

pp. 179-185

Author(s):

Omar A. Amin ◽

S. A. Hassan ◽

M. A. Sadek ◽

M. A. Radwan ◽

Hany A. Elazab

Keyword(s):

Mechanical Properties ◽

Epoxy Resin ◽

Epoxy Resins ◽

Three Dimensional ◽

Mechanical Tests ◽

Diglycidyl Ether ◽

Dimensional Structure ◽

Polymeric Chain ◽

Hydroxyl Groups ◽

Different Types

Epoxy resins are thermoset polymers that consist of epoxide groups in their molecular structure. It shows many attractive characteristics like strong adhesion, excellent mechanical strength, low shrinkage, excellent insulator, excellent chemical stability for acidic and basic environments, and microbial resistance due to the presence of hydroxyl groups and ether bonds and its three-dimensional structure. Many of these characteristics can be modified by adding strong bindings in the polymeric chain to give more improved characteristics. This research aims to prepare a composite material using epoxy resin and different types of fillers to achieve resistance to high kinetic energy impact. Experimental work is focused on preparing cured epoxy resin samples by using diglycidyl ether of bisphenol A (DGEBA) resin with tertiary amine as a hardener. In order to obtain different samples with different properties, we add different types of fillers, then mechanical tests are used to measure the mechanical properties of the samples. The results have proved that fiberglass is the best filler added to epoxy resins to improve its mechanical properties.

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Polymerization of diglycidyl ether of bisphenol A/ diaminodiphenyl sulfone epoxy resins using radio frequency fields

Journal of Applied Polymer Science ◽

10.1002/1097-4628(19991213)74:12<2917::aid-app17>3.0.co;2-u ◽

1999 ◽

Vol 74 (12) ◽

pp. 2917-2923 ◽

Cited By ~ 2

Author(s):

Angus Forysth ◽

Andrew K. Whittaker

Keyword(s):

Bisphenol A ◽

Radio Frequency ◽

Epoxy Resins ◽

Diglycidyl Ether ◽

Diaminodiphenyl Sulfone

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Recyclable High-Performance Epoxy-Anhydride Resins with DMP-30 as the Catalyst of Transesterification Reactions

Polymers ◽

10.3390/polym13020296 ◽

2021 ◽

Vol 13 (2) ◽

pp. 296

Author(s):

Wenzhe Zhao ◽

Le An ◽

Shujuan Wang

Keyword(s):

Epoxy Resins ◽

High Performance ◽

Low Cost ◽

Epoxy Oligomer ◽

Diglycidyl Ether ◽

Hydroxyl Groups ◽

Excellent Performance ◽

Simple Method ◽

Amine Groups ◽

Alcoholic Hydroxyl

Epoxy-anhydride resins are widely used in engineering fields due to their excellent performance. However, the insolubility and infusibility make the recycling of epoxy resins challenging. The development of degradable epoxy resins with stable covalent networks provides an efficient solution to the recycling of thermosets. In this paper, 2,4,6-tris(dimethylaminomethyl)phenol (DMP-30) is incorporated into the epoxy-glutaric anhydride (GA) system to prepare high-performance epoxy resins that can be recycled below 200 °C at ordinary pressure via ethylene glycol (EG) participated transesterification. The tertiary amine groups in DMP-30 can catalyze the curing reaction of epoxy and anhydride, as well as the transesterification between ester bonds and alcoholic hydroxyl groups. Compared with early recyclable anhydride-cured epoxy resins, the preparation and recycling of diglycidyl ether of bisphenol A (DGEBA)/GA/DMP-30 systems do not need any special catalysts such as TBD, Zn(Ac)2, etc., which are usually expensive, toxic, and have poor compatibility with other compounds. The resulting resins have glass transition temperatures and strengths similar to those of conventional epoxy resins. The influences of GA content, DMP-30 content, and temperature on the dissolution rate were studied. The decomposed epoxy oligomer (DEO) is further used as a reaction ingredient to prepare new resins. It is found that the DEO can improve the toughness of epoxy resins significantly. This work provides a simple method to prepare readily recyclable epoxy resins, which is of low-cost and easy to implement.

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Polymerization of diglycidyl ether of bisphenol A/ diaminodiphenyl sulfone epoxy resins using radio frequency fields

Journal of Applied Polymer Science ◽

10.1002/(sici)1097-4628(19991213)74:12<2917::aid-app17>3.0.co;2-u ◽

1999 ◽

Vol 74 (12) ◽

pp. 2917

Author(s):

Angus Forysth ◽

Andrew K. Whittaker

Keyword(s):

Bisphenol A ◽

Radio Frequency ◽

Epoxy Resins ◽

Diglycidyl Ether ◽

Diaminodiphenyl Sulfone

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Allergic contact dermatitis from non-diglycidyl-ether-of-bisphenol-A epoxy resins

Contact Dermatitis ◽

10.1111/j.1600-0536.1991.tb01725.x ◽

1991 ◽

Vol 24 (4) ◽

pp. 293-300 ◽

Cited By ~ 34

Author(s):

Lassi Kanerva ◽

Riitta Jolanki ◽

Tuula Estlander

Keyword(s):

Contact Dermatitis ◽

Bisphenol A ◽

Allergic Contact Dermatitis ◽

Epoxy Resins ◽

Diglycidyl Ether ◽

Allergic Contact

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Study of the Infrared Spectral Features of an Epoxy Curing Mechanism

Applied Spectroscopy ◽

10.1366/000370208786049204 ◽

2008 ◽

Vol 62 (10) ◽

pp. 1129-1136 ◽

Cited By ~ 30

Author(s):

Liang Li ◽

Qili Wu ◽

Shanjun Li ◽

Peiyi Wu

Keyword(s):

Correlation Analysis ◽

Near Infrared ◽

Nir Spectroscopy ◽

Diglycidyl Ether ◽

Hydroxyl Groups ◽

Spectral Correlation ◽

Derivative Analysis ◽

Curing Mechanism ◽

Infrared Spectral ◽

Epoxy Groups

In this work, the isothermal curing process of diglycidyl ether of bisphenol A(DGEBA) cured with 4,4′-diaminodiphenylmethane (DDM) was monitored in situ by mid-infrared (MIR) and near-infrared (NIR) spectroscopy. With the help of generalized two-dimensional (2D) correlation analysis, the results obtained showed that, during curing, the change of amine and epoxy groups was simultaneous, taking place prior to the change of hydroxyl groups, followed by the change of CH2/CH groups, resulting from the ring-opening reaction of epoxy groups. In addition, 2D MIR×NIR hetero-spectral correlation analysis and second-derivative analysis were also employed, by means of which direct evidence of the curing mechanism could be obtained and obscure NIR band assignments in the overlapped CH combination region could be made.

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Sustainable access to fully biobased epoxidized vegetable oil thermoset materials prepared by thermal or UV-cationic processes

RSC Advances ◽

10.1039/d0ra07682a ◽

2020 ◽

Vol 10 (68) ◽

pp. 41954-41966 ◽

Cited By ~ 1

Author(s):

Samuel Malburet ◽

Chiara Di Mauro ◽

Camilla Noè ◽

Alice Mija ◽

Marco Sangermano ◽

...

Keyword(s):

Bisphenol A ◽

Epoxy Resin ◽

Vegetable Oil ◽

Epoxy Resins ◽

Diglycidyl Ether

Beyond the need to find a non-toxic alternative to DiGlycidyl Ether of Bisphenol-A (DGEBA), the serious subject of non-epichlorohydrin epoxy resins production remains a crucial challenge that must be solved for the next epoxy resin generations.

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Effect of Epoxy Resin Addition on the Moisture Sensitivity of Macro Defect Free Polymer-Cement Composites

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.466.65 ◽

2011 ◽

Vol 466 ◽

pp. 65-72 ◽

Cited By ~ 3

Author(s):

Ozgur Ekincioglu ◽

M. Hulusi Ozkul ◽

Yoshihiko Ohama ◽

Silvia Patachia ◽

Georgeta Moise

Keyword(s):

Bisphenol A ◽

Epoxy Resins ◽

Production Method ◽

Diglycidyl Ether ◽

Poly Vinyl Alcohol ◽

Cement Pastes ◽

Force Microscopy ◽

Atomic Force ◽

Roll Mill ◽

Mdf Cements

Macro-defect-free (MDF) cements are cement-polymer composites and were developed by Birchall et al. three decades ago. The composites are produced by mixing small amounts of polymer and water with cement. However, they have a different production method than that of cement pastes, which was inspired by rubber production. Mixtures of cement, polymer and water are processed by using a two-roll mill. The composites are known with their high flexural strengths. Unfortunately, there are not any known commercial products using MDF cements because of their poor durability under moisture. In this study, MDF cements were prepared by using poly(vinyl alcohol--vinyl acetate) PVA, calcium aluminate cements and two different types of epoxy resins. Epoxy resins were a diglycidyl ether of bisphenol A and a mixture of a diglycidyl ethers of bisphenol A and F. Durability performance was compared with respect to biaxial flexural strengths, contact angle and atomic force microscopy (AFM) for the specimens stored in water.

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