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.

scholarly journals Computational Method for Simulating Thermoset Polymer Curing and Prediction of Thermophysical Properties

2020 ◽  
Author(s):  
Jeffrey Sanders ◽  
Carla E. Estridge ◽  
Matthew B Jackson ◽  
Thomas JL Mustard ◽  
Samuel J. Tucker ◽  
...  
Keyword(s):  
High Throughput ◽  
Thermophysical Properties ◽  
High Throughput Screening ◽  
Simulation Analysis ◽  
Low Cost ◽  
Polymer Network ◽  
Thermomechanical Properties ◽  
Computational Method ◽  
Cross Linking ◽  
Automated Simulation

Thermoset polymers are an area of intense research due to their low cost, ease of processing, environmental resistance, and unique physical properties. The favorable properties of this class of polymers have many applications in aerospace, automotive, marine, and sports equipment industries. Molecular simulations of thermosets are frequently used to model formation of the polymer network, and to predict the thermomechanical properties. These simulations usually require custom algorithms that are not easily accessible to non-experts and not suited for high throughput screening. To address these issues, we have developed a robust cross-linking algorithm that can incorporate different types of chemistries and leverage GPU-enabled molecular dynamics simulations. Automated simulation analysis tools for cross-linking simulations are also presented. Using four well known epoxy/amine formulations as a foundational case study and benzoxazine as an example of how additional chemistries can be modeled, we demonstrate the power of the algorithm to accurately predict curing and thermophysical properties. These tools are able to streamline the thermoset simulation process, opening up avenues to in-silico high throughput screening for advanced material development.

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

RSC Advances ◽  
2020 ◽  
Vol 10 (68) ◽  
pp. 41954-41966 ◽  
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.

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.

Thermal and Dielectric Properties of Inorganic-Organic Nanocomposites Involving Epoxy Resin and Polyhedral Oligomeric Silsesquioxanes

2012 ◽  
Vol 476-478 ◽  
pp. 665-669 ◽  
Author(s):  
Li Yang ◽  
Miao Yin ◽  
Xiu Yun Li ◽  
Han Bing Ma
Keyword(s):  
Thermal Stability ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Bisphenol A ◽  
Epoxy Resin ◽  
Functional Groups ◽  
Epoxy Matrix ◽  
Epoxy Resins ◽  
Diglycidyl Ether ◽  
Polyhedral Oligomeric Silsesquioxanes

In this paper, a type of nanoporous polyhedral oligomeric silisesquioxanes (POSS) containing eight functional groups have been synthesized and mixed with diglycidyl ether of bisphenol A (DGEBA) to form epoxy resin networks with nanostructures. The cured octa(aminophenyl) silsesquioxane (1c-POSS) and DGEBA system inherently possesses higher thermal stability and higher char yield than the control epoxy resins. Furthermore, the dielectric constant of the 1c-POSS/DGEBA material (4.36) is substantially lower than that of the neat epoxy resins (4.64) as a consequence the presence of nanoporous POSS cubes in the epoxy matrix.

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

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.

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.

scholarly journals New Biosourced Flame Retardant Agents Based on Gallic and Ellagic Acids for Epoxy Resins

Molecules ◽  
2019 ◽  
Vol 24 (23) ◽  
pp. 4305 ◽  
Author(s):  
Valeriia Karaseva ◽  
Anne Bergeret ◽  
Clément Lacoste ◽  
Hélène Fulcrand ◽  
Laurent Ferry
Keyword(s):  
Phenolic Compounds ◽  
Epoxy Resin ◽  
Epoxy Resins ◽  
Flame Retardants ◽  
Fire Behavior ◽  
Diglycidyl Ether ◽  
Scanning Calorimetry ◽  
Burning Behavior ◽  
Borate Ester ◽  
Thermal Stability Of

The aim of this work was an investigation of the ability of gallic (GA) and ellagic (EA) acids, which are phenolic compounds encountered in various plants, to act as flame retardants (FRs) for epoxy resins. In order to improve their fireproofing properties, GA and EA were treated with boric acid (to obtain gallic acid derivatives (GAD) and ellagic acid derivatives (EAD)) to introduce borate ester moieties. Thermogravimetric analysis (TGA) highlighted the good charring ability of GA and EA, which was enhanced by boration. The grafting of borate groups was also shown to increase the thermal stability of GA and EA that goes up respectively from 269 to 528 °C and from 496 to 628 °C. The phenolic-based components were then incorporated into an epoxy resin formulated from diglycidyl ether of bisphenol A (DGEBA) and isophorone diamine (IPDA) (72, 18, and 10 wt.% of DGEBA, IPDA, and GA or EA, respectively). According to differential scanning calorimetry (DSC), the glass transition temperature (Tg) of the thermosets was decreased. Its values ranged from 137 up to 108 °C after adding the phenolic-based components. A cone calorimeter was used to evaluate the burning behavior of the formulated thermosets. A significant reduction of the peak of heat release rate (pHRR) for combustion was detected. Indeed, with 10 wt.% of GA and EA, pHRR was reduced by 12 and 44%, respectively, compared to that for neat epoxy resin. GAD and EAD also induced the decrease of pHRR values by 65 and 33%, respectively. In addition, a barrier effect was observed for the resin containing GAD. These results show the important influence of the biobased phenolic compounds and their boron derivatives on the fire behavior of a partially biobased epoxy resin.

scholarly journals Synthesis of Benzene Tetracarboxamide Polyamine and Its Effect on Epoxy Resin Properties

Polymers ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 782 ◽  
Author(s):  
Seoyoon Yu ◽  
Wonjoo Lee ◽  
Bongkuk Seo ◽  
Chung-Sun Lim
Keyword(s):  
Epoxy Resin ◽  
Epoxy Resins ◽  
High Performance ◽  
Protective Coatings ◽  
Industrial Applications ◽  
Thermomechanical Properties ◽  
Scanning Calorimetry ◽  
Adhesive Properties ◽  
Cross Sectional ◽  
Value Determination

Epoxy resins have found various industrial applications in high-performance thermosetting resins, high-performance composites, electronic-packaging materials, adhesives, protective coatings, etc., due to their outstanding performance, including high toughness, high-temperature performance, chemical and environmental resistance, versatile processability and adhesive properties. However, cured epoxy resins are very brittle, which limits their applications. In this work, we attempted to enhance the toughness of cured epoxy resins by introducing benzene tetracarboxamide polyamine (BTCP), synthesized from pyromellitic dianhydride (PMDA) and diamines in N-methyl-2-pyrrolidone (NMP) solvent. During this reaction, increased viscosity and formation of amic acid could be confirmed. The chemical reactions were monitored and evidenced using 1H-NMR spectroscopy, FT-IR spectroscopy, water gel-phase chromatography (GPC) analysis, amine value determination and acid value determination. We also studied the effect of additives on thermomechanical properties using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamical mechanical analysis (DMA), thermomechanical analysis (TMA) and by measuring mechanical properties. The BTCP-containing epoxy resin exhibited high mechanical strength and adhesion strength proportional to the amount of BTCP. Furthermore, field-emission scanning electron microscopy images were obtained for examining the cross-sectional morphology changes of the epoxy resin specimens with varying amounts of BTCP.

scholarly journals New Eco-Friendly Synthesized Thermosets from Isoeugenol-Based Epoxy Resins

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 229 ◽  
Author(s):  
Quentin Ruiz ◽  
Sylvie Pourchet ◽  
Vincent Placet ◽  
Laurent Plasseraud ◽  
Gilles Boni
Keyword(s):  
Epoxy Resin ◽  
Storage Modulus ◽  
Epoxy Resins ◽  
Diglycidyl Ether ◽  
Thermal And Mechanical Properties ◽  
Optimum Ratio ◽  
Structural Composites ◽  
Molar Ratios ◽  
Elemental Analyses ◽  
Dsc Analyses

Epoxy resin plays a key role in composite matrices and DGEBA is the major precursor used. With the aim of favouring the use of bio resources, epoxy resins can be prepared from lignin. In particular, diglycidyl ether of isoeugenol derivatives are good candidates for the replacement of DGEBA. This article presents an effective and eco-friendly way to prepare epoxy resin derived from isoeugenol (BioIgenox), making its upscale possible. BioIgenox has been totally characterized by NMR, FTIR, MS and elemental analyses. Curing of BioIgenox and camphoric anhydride with varying epoxide function/anhydride molar ratios has allowed determining an optimum ratio near 1/0.9 based on DMA and DSC analyses and swelling behaviours. This thermoset exhibits a Tg measured by DMA of 165 °C, a tensile storage modulus at 40 °C of 2.2 GPa and mean 3-point bending stiffness, strength and strain at failure of 3.2 GPa, 120 MPa and 6.6%, respectively. Transposed to BioIgenox/hexahydrophtalic anhydride, this optimized formulation gives a thermoset with a Tg determined by DMA of 140 °C and a storage modulus at 40 °C of 2.6 GPa. The thermal and mechanical properties of these two thermosets are consistent with their use as matrices for structural or semi-structural composites.

Study of Thermal Properties of Curing of DGEBA Epoxy Resin with Hexakis-(4-Aminophenoxy)-Cyclotriphosphazene

2011 ◽  
Vol 284-286 ◽  
pp. 365-368 ◽  
Author(s):  
Jing Zhu ◽  
Yong Wu ◽  
Lei Zhao ◽  
Hong Liang Wei ◽  
Hui Juan Chu ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Thermogravimetric Analysis ◽  
Epoxy Resin ◽  
Epoxy Resins ◽  
Chemical Structure ◽  
Diglycidyl Ether ◽  
Flame Retardance ◽  
Curing Agent ◽  
Degradation Behaviors ◽  
Curing Agents

Hexakis-(4-aminophenoxy)-cyclotriphosphazene (PN-NH2) was synthesized through nucleophilic substitution of the chloride atoms of hexachlorocyclotriphosphazene (HCCP) and reduction of the nitro group, and its chemical structure was characterized. As a curing agents for commercial epoxy resin Diglycidyl ether of bisphenol-A (DGEBA) PN-NH2 was compared with conventional curing agents 4,4-diaminodiphenylsulfone(DDS) and 4,4-diaminodiphenylmethane (DDM). The thermal properties and thermal degradation behaviors of these thermosetted resins were investigated by using thermogravimetric analysis (TGA). TGA studies demonstrated that the thermal properties of the PN-NH2-containing cured epoxy resin were higher than those of others. The phosphorus-nitrogen containing curing agent can result in a great improvement of the flame retardance for their thermosetted epoxy resins.

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