scholarly journals Determination of the cross-linking degree of unmodified epoxy resin by cycloaliphatic polyamine and polyamidamin hardeners by ftir spectroscopy

2003 ◽  
Vol 57 (11) ◽  
pp. 563-567 ◽  
Author(s):  
Sasa Zlatkovic ◽  
Goran Nikolic ◽  
Jakov Stamenkovic
Keyword(s):  
Epoxy Resin ◽  
Epoxy Resins ◽  
Optimal Time ◽  
Cross Linking ◽  
Stoichiometric Ratio ◽  
Film Hardness ◽  
Epoxy Groups ◽  
Epoxy Systems ◽  
Unmodified Epoxy

Unmodified epoxy resin GY250 was crosslinked by the cycloaliphatic polyamino hardener HY847 and polyamidamine hardener HY848 in the different mass ratios. The degree of crosslinking of the epoxy resin and the quantity of unreacted epoxy groups were determined by a spectroscopic FTIR method. The optimal time of complete crosslinking, as a criterion of the degree, was determined by measuring the film hardness indirectly (JUS H.C8.055). The optimal stoichiometric ratio of 100:18:32 (GY250:HY847:HY848) was defined by correlating parameters which directly depend on the degree of crosslinking and the period of application of the epoxy resins, as a prerequisite for forming 2-component epoxy systems which are comparatively more elastic adhesive and waterproof.

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.

scholarly journals Bending and Compressive Analysis of Epoxy Resins Modified with Low-polar Solvent Solution of Polysulphone

2018 ◽  
Vol 55 (3) ◽  
pp. 295-298
Author(s):  
Vasile Bria ◽  
Cristian Muntenita ◽  
Iulia Graur
Keyword(s):  
Energy Storage ◽  
Epoxy Resin ◽  
Epoxy Resins ◽  
Polar Solvent ◽  
High Porosity ◽  
Three Point Bending ◽  
Mobility Of Charge Carriers ◽  
Bio Compatibility ◽  
Epoxy Systems ◽  
Excellent Stability

The memory shape materials seem to be extremely promising materials for medical applications especially as inserts to support the muscular system. In the case of memory shape polymers a supplementary issue is related to their bio-compatibility such as they can be rejected by the organism even their properties are fitting the requirements. Present study started from the hypothesis that mixing the epoxy resin with other polymers some valuable materials could be obtained especially for energy storage. The epoxy resins possess extraordinary properties (relatively to other thermoset polymers) but they also show an excellent stability that generates problems when this type of materials should be neutralized. Epoxy resins also show low water or other liquids absorption due to their low porosity and they cannot be used for energy storage applications when mobility of charge carriers is ensured by liquid phase. A polymer with high porosity used for membrane formation is the polysulfone and, in this regard, tests were performed to analyse the ways to mix an epoxy resin with polysulfone. The idea had generated a study regarding the properties of such a mixture together with the condition that had to be reached to successfully get the mixture. Low-polar solvent solution of polysulfone had been obtained with 1-methyl-2-pyrrolidinone. After compatibility tests, 15 and 20% of this solution was added to the components of the epoxy systems -with the epoxy resin -and formed materials were analysed by mechanical means-compressive and three-point bending - the surprise was that some materials had showed memory shape properties.

scholarly journals Optimization of the Curing and Post-Curing Conditions for the Manufacturing of Partially Bio-Based Epoxy Resins with Improved Toughness

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1354 ◽  
Author(s):  
Diego Lascano ◽  
Luis Quiles-Carrillo ◽  
Sergio Torres-Giner ◽  
Teodomiro Boronat ◽  
Nestor Montanes
Keyword(s):  
Epoxy Resin ◽  
Epoxy Resins ◽  
Polymer Network ◽  
Thermomechanical Properties ◽  
Diglycidyl Ether ◽  
Polymer Chains ◽  
Cross Linking ◽  
Reactive Diluent ◽  
Gel Time ◽  
Curing Conditions

This research deals with the influence of different curing and post-curing temperatures on the mechanical and thermomechanical properties as well as the gel time of an epoxy resin prepared by the reaction of diglycidyl ether of bisphenol A (DGEBA) with an amine hardener and a reactive diluent derived from plants at 31 wt %. The highest performance was obtained for the resins cured at moderate-to-high temperatures, that is, 80 ° C and 90 ° C , which additionally showed a significant reduction in the gel time. This effect was ascribed to the formation of a stronger polymer network by an extended cross-linking process of the polymer chains during the resin manufacturing. Furthermore, post-curing at either 125 ° C   or 150 ° C yielded thermosets with higher mechanical strength and, more interestingly, improved toughness, particularly for the samples previously cured at moderate temperatures. In particular, the partially bio-based epoxy resin cured at 80 ° C and post-cured at 150 ° C for 1 h and 30 min, respectively, showed the most balanced performance due to the formation of a more homogeneous cross-linked structure.

Organic Aerogels Based on Epoxy Resins: Synthesis and Properties

2020 ◽  
Vol 869 ◽  
pp. 240-245
Author(s):  
Alexey Voytik ◽  
Georgiy V. Malkov ◽  
Artur T. Kapasharov ◽  
Alexey Yu. Kostin
Keyword(s):  
Infrared Spectroscopy ◽  
Epoxy Resin ◽  
Epoxy Resins ◽  
Supercritical Drying ◽  
Curing Conditions ◽  
Solvent Content ◽  
Bet Method ◽  
Catalyst Content ◽  
Organic Aerogels ◽  
Epoxy Groups

The aim of this work was to develop methods for the synthesis of organic aerogels based on epoxy resins and to investigate their properties. Aerogels based on DGEBA-epoxy resin were obtained by CO2-supercritical drying of gel samples prepared from acetone solutions of epoxy resin with different amount of catalyst and solvents. As a result, aerogels of different density were obtained; the dependence of density on the solvent content in the samples was revealed. The aerogels were characterized by infrared spectroscopy to define the degree of conversion of the epoxy groups, by SEM to confirm nanoscale morphology of aerogels, as well as by the BET method to determine the specific surface area of the samples and its dependence on the catalyst content and curing conditions.

Studies on the Properties of Epoxy Resins Modified with Novel Liquid Crystalline Polyurethane

2010 ◽  
Vol 150-151 ◽  
pp. 727-731 ◽  
Author(s):  
Zhi Yi Huang ◽  
Shao Rong Lu ◽  
Zhi You Yang ◽  
Chun He Yu ◽  
Dong Guo
Keyword(s):  
Thermal Decomposition ◽  
Tensile Strength ◽  
Epoxy Resin ◽  
Epoxy Resins ◽  
Liquid Crystalline ◽  
Bending Strength ◽  
Decomposition Temperature ◽  
Thermal Decomposition Temperature ◽  
The Impact ◽  
Unmodified Epoxy

Liquid crystal polyurethane (LCPBI) containing biphenylnate and imide units was synthesized and characterized and used to modify the conventional epoxy resin (E-51). Experimental results revealed that the impact strength of the epoxy resin modified with LCPBI was 2.5 times higher than that of unmodified epoxy resin, and the tensile strength as well as the bending strength was also improved. The thermal decomposition temperature of modified systems was also 15-20oC higher than that of the unmodified system, and the fracture structures of the blends was investigated by SEM.

Epoxy resins thermosetting for mechanical engineering

2021 ◽  
Vol 11 (1) ◽  
pp. 797-814
Author(s):  
Heru Sukanto ◽  
Wijang Wisnu Raharjo ◽  
Dody Ariawan ◽  
Joko Triyono ◽  
Mujtahid Kaavesina
Keyword(s):  
Epoxy Resin ◽  
Research Design ◽  
Epoxy Resins ◽  
Mechanical Engineering ◽  
Cross Linking ◽  
Large Role ◽  
Curing Agents

Abstract This review presents various types of epoxy resins and curing agents commonly used as composite matrices. A brief review of cross-linking formation and the process of degradation or decomposition of epoxy resins by pyrolysis and solvolysis is also discussed. Mechanical engineers are given a brief overview of the types of epoxy resin, which are often applied as composite matrices considering that they currently play a large role in the research, design, manufacturing, and recycling of these materials.

A novel epoxy-functionalized hyperbranched polysiloxane (HPSi) endowing methyl phenyl silicone resin (Si603)/epoxy systems with enhanced compatibility and fire retardancy performance

RSC Advances ◽  
2015 ◽  
Vol 5 (118) ◽  
pp. 97413-97421 ◽  
Author(s):  
Pei Jia ◽  
Hanchao Liu ◽  
Youchuan Wang ◽  
Xufu Cai
Keyword(s):  
Epoxy Resin ◽  
Silicone Resin ◽  
Fire Retardancy ◽  
Hyperbranched Polysiloxane ◽  
Epoxy Groups ◽  
Epoxy Systems ◽  
Methyl Phenyl

A novel hyperbranched polysiloxane (HPSi) with a great amount of epoxy groups was synthesized as a compatibilizer of epoxy resin (EP)/methyl phenyl silicone resin (Si603) blends.

The Mechanisms of Epoxy Latex Coatings Curing at Ambient Temperature Comparison with Solvent-Type Ones

2010 ◽  
Vol 150-151 ◽  
pp. 1249-1253
Author(s):  
Qing Quan Guo ◽  
Da Guang Li ◽  
Jian Wei Guo ◽  
Huan Qin Chen
Keyword(s):  
Ambient Temperature ◽  
Epoxy Resin ◽  
Water Soluble ◽  
Latex Film ◽  
Curing Agent ◽  
Latex Coatings ◽  
Solvent Type ◽  
And Behavior ◽  
Epoxy Groups

The performance and behavior of epoxy latex coatings are different from solvent-type ones.It is decided by the distinct curing mechanism. The solvent-type epoxy film obtained from epoxy resin and curing agent by homogeneous reaction, namely, the state of epoxy resin and curing agent is uniform. However, epoxy latex film made from epoxy resin emulsion or dispersion and water soluble amine by polyphase reaction. So the determination of potlife of epoxy latex can be showed by film gloss changes with residence time, dissimilar with solvent-type by the index of viscosity. The modern infrared spectrum measure shows that the epoxy groups in the dried epoxy latex film exist even if EEW to HAV proportion is 1.2:1. This also testifies the incomplete polyphase reaction mechanism of epoxy emulsion coating curing at ambient temperature.

Epoxy Resin Embedment

1968 ◽  
Vol 26 ◽  
pp. 100-101
Author(s):  
J. G. Adams ◽  
M. M. Campbell ◽  
H. Thomas ◽  
J. J. Ghldonl
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
Epoxy Resin ◽  
Light Microscope ◽  
Epoxy Resins ◽  
Image Contrast ◽  
Tissue Preservation ◽  
Resin System ◽  
Excellent Quality

Since the introduction of epoxy resins as embedding material for electron microscopy, the list of new formulations and variations of widely accepted mixtures has grown rapidly. Described here is a resin system utilizing Maraglas 655, Dow D.E.R. 732, DDSA, and BDMA, which is a variation of the mixtures of Lockwood and Erlandson. In the development of the mixture, the Maraglas and the Dow resins were tested in 3 different volumetric proportions, 6:4, 7:3, and 8:2. Cutting qualities and characteristics of stability in the electron beam and image contrast were evaluated for these epoxy mixtures with anhydride (DDSA) to epoxy ratios of 0.4, 0.55, and 0.7. Each mixture was polymerized overnight at 60°C with 2% and 3% BDMA.Although the differences among the test resins were slight in terms of cutting ease, general tissue preservation, and stability in the beam, the 7:3 Maraglas to D.E.R. 732 ratio at an anhydride to epoxy ratio of 0.55 polymerized with 3% BDMA proved to be most consistent. The resulting plastic is relatively hard and somewhat brittle which necessitates trimming and facing the block slowly and cautiously to avoid chipping. Sections up to about 2 microns in thickness can be cut and stained with any of several light microscope stains and excellent quality light photomicrographs can be taken of such sections (Fig. 1).

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