Curing and thermal behavior of resin matrix for composites based on epoxidized soybean oil/diglycidyl ether of bisphenol A (original) (raw)
Related papers
Curing and mechanical characterization of a soy-based epoxy resin system
Journal of Applied Polymer Science, 2004
A potentially inexpensive alternative epoxy resin system based on soybean oil has been developed for polymer composite applications. Epoxidized methyl soyate (EMS) and epoxidized allyl soyate (EAS) have been synthesized at the University of Missouri-Rolla. These materials consist of mixtures of epoxidized fatty acid esters. The epoxidized soy-based resins provide better intermolecular crosslinking and yield materials that are stronger than materials obtained with commercially available epoxidized soybean oil (ESO). The curing behavior and glass transition have been monitored with differential scanning calorimetry. Neat resin test samples have been fabricated from resin systems containing various amounts of EMS, EAS, and ESO. Standardized tests have shown that the addition of EAS enhances the tensile and flexural properties of the base epoxy resin system. Therefore, epoxidized soy ester additives hold great potential for environmentally friendly and lower cost raw materials for the fabrication of epoxy composites for structural applications.
Effect of structure on thermal behaviour of epoxy resins
European Polymer Journal, 2003
The paper deals with the curing behaviour of diglycidyl ether of bisphenol-A (DGEBA) using three novel multifunctional aromatic amines having phosphine oxide and amide-acid linkages. The amines were prepared by reacting tris(3-aminophenyl)phosphine oxide (TAP) with 1,2,4,5-benzenetetracarboxylic acid anhydride (P)/4,4 0-(hexafluoroisopropylidene)diphthalic acid anhydride (F)/3,3 0 ,4,4 0-benzophenonetetracarboxylic acid dianhydride (B). Amide-acid linkage in these amines is converted to thermally stable imide linkage during curing reaction. Curing temperatures of DGEBA were higher with phosphorylated amines than the conventional amine 4,4 0-diamino diphenyl sulphone (D). A decrease in initial decomposition temperature and higher char yields were observed when phosphorus containing amide-acid amines were used as curing agents for DGEBA.
Curing and thermal behavior of epoxy resins of hexafluoro - bisphenol –A and bisphenol-A
Polímeros, 2016
This paper describes the synthesis and characterization of epoxy resins based on (hexafluoroisopropylidene)diphenol (EFN) and p,p'-isopropylidenebisphenol (EBN), respectively and 4, 4'-(hexafluoroisopropylidene)dipthalic-imideamine (IMAM), a curing agent. The synthesized epoxy resins and IMAM curing agent were characterized by Fourier Transform Infrared (FTIR) and 1 H Nuclear Magnetic Resonance (NMR) spectroscopy. 13 C NMR technique was also used to characterize IMAM. Study of curing behavior of EFN and EBN with stoichiometric amount of aromatic 4,4'-diaminodiphenylmethane (DDM), 4,4'-diaminodiphenylsulfone (DDS) and IMAM by using Differential Scanning Calorimetery (DSC) indicated that IMAM was least reactive curing agent towards both epoxy resins as compared to DDS and DDM. The investigation of thermal decomposition of the cured compounds by thermogravimetric analyzer (TGA) indicated the higher thermal stability of EFN and EBN resins initially with DDS and at elevated temperatures with IMAM. It was also observed that EFN resins were thermally more stable than EBN resins cured with corresponding curing agents.
Journal of Applied Polymer Science, 2017
A novolac epoxy resin based on 4,4 0-dihydroxybenzophenone (BZPNE) was synthesized via epoxidation of 4,4 0-dihydroxybenzophenone novolac resin (BZPN). BZPN was obtained by strong mineral acid catalyzed reaction of 4,4 0-dihydroxybenzophenone (BZP) and paraformaldehyde. The formation of BZPNE and BZPN was confirmed by Fourier transform infrared spectroscopy, proton and carbon nuclear magnetic resonance spectroscopy, gel permeation chromatography, and epoxy equivalent weight. Different blends of BZPNE with diglycidyl ether of bisphenol-A (DGEBA; EEW $180) were cured using dicyandiamide were characterized by thermogravimetric analysis, thermomechanical analysis, dynamic mechanical analysis, and interfacial property between aluminum adherends at ambient and elevated temperature. Thermal properties were found to improve on increasing quantity of BZPNE in DGEBA as it is evidenced from glass transition temperature (T g). Likewise, no deterioration in interfacial properties was observed with the highest quantity of BZPNE (30%) in DGEBA blend, when tested at 150 8C. Cure kinetics of compositions were studied by nonisothermal differential scanning calorimetry and Kissinger method was used to compute the kinetic parameters such as frequency factor (A), activation energy (E a) followed by the dependency of rate constant (k) on temperature of different blends. V
Journal of Applied Polymer Science, 2009
This article describe the influence of phenolphthalein poly (ether ketone) (PEK-C) on the cure behaviors and thermal properties of the diglycidyl ether of bisphenol A (DGEBA) epoxy resin with cyanate ester as curing agent. The curing kinetics and reaction pathways were monitored using dynamic differential scanning calorimeter and Fourier transform infrared spectroscopy. The dependence of activation energy on the conversion degree for all the studied systems was calculated in the light of Ozawa-Flynn-Wall method. Furthermore, the thermomechanical properties and the thermal stability of the cured resins were also evaluated by dynamic mechanical analysis and thermogravimetric analysis, respectively. Conclusions can be drawn as follows: the main reaction pathways did not vary with the inclusion of PEK-C, but the reaction rate of the blend was found to be higher than that of the neat epoxy. The glass transition temperature of the blend was not changed by the addition of PEK-C, while the initial decomposition temperature slightly decreased with increase in PEK-C content. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation, curing kinetics, and thermal properties of bisphenol fluorene epoxy resin
Journal of Applied Polymer Science, 2007
Diglycidyl ether of 9,9-bis(4-hydroxyphenyl) fluorene (DGEBF) was synthesized to introduce more aromatic structures into an epoxy resin system. The structure of DGEBF was characterized with Fourier transform infrared and 1 H-NMR. 4,4 0 -Diaminodiphenylmethane (DDM) was used as the curing agent for DGEBF, and differential scanning calorimetry was applied to study the curing kinetics. The glass-transition temperature of the cured DGEBF/DDM, determined by dynamic mechanical analysis, was 2608C, which was about 1008C higher than that of widely used diglycidyl ether of bisphenol A (DGEBA). Thermogravimetric analysis was used to study the thermal degradation behavior of the cured DGEBF/ DDM system: its onset degradation temperature was 3708C, and at 7008C, its char yield was about 27%, whereas that of cured DGEBA/DDM was only 14%.
Polymer Engineering & Science, 2013
The present work was aimed at studying the effects of incorporation of epoxidized soybean oil (ESO) in a standard bisphenol A-type epoxy resin (EP) cured by anhydride hardener. The EP/ESO ratio was set for 100/0, 75/25, 50/50, 25/75 and 0/100 (wt.%/wt.%). The investigations performed covered the curing, rheology (gelling), thermomechanical (TMA) and thermogravimetric analysis (TGA) of the EP/ESO compositions. The results showed that the dilution of EP with ESO was accompanied with marked changes in the curing, gelling behavior and final properties. Differential scanning calorimetry (DSC) revealed that the crosslinking of EP/ESO≥50/50 occurred in two steps. This has been considered for the cure schedule set. The gel time of EP/ESO, determined at T=100, 120, 140 o C, respectively, increased with increasing ESO content. The activation energy of gelling increased with increasing ESO content. The glass transition temperature decreased with increasing ESO content of the transparent samples. According to TMA the coefficient of thermal expansion in the glassy state increased with increasing ESO content but was independent of the latter in the rubbery stage. TGA indicated that with increasing ESO content the thermal degradation started earlier and the char yield decreased. The Ozawa, Flynn and Wall (OFW) approach was adapted to TGA tests to calculate
Study of the Curing Process of DGEBA Epoxy Resin Through Structural Investigation
Macromolecular Chemistry and Physics, 2015
In this work, a multi-scale approach with different analytical methods is applied to study the curing process and the structural properties of a diglycidyl ether of bisphenol A (DGEBA) epoxy resin. This monomer, thermally cured using 4,4′-diaminodiphenilsulfone (DDS) as hardener, is analyzed after 10, 45, 90, and 120 min of reaction time at 180 °C to obtain information on samples with different cross-linking densities. Samples are also characterized after extraction in acetone in order to obtain structural information on the insoluble parts. For this purpose, differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), solid-state nuclear magnetic resonance (ss-NMR), and positron annihilation lifetime spectroscopy (PALS) are employed. The importance of this multi-method approach lies in the possibility to obtain a more complete knowledge of the investigated system, overcoming the limits inherent to the use of a single technique, through the correlation among results obtained from different structural investigation methodologies.
Epoxidized Glycidyl Ester of Soybean Oil as Reactive Diluent for Epoxy Resin
Epoxidized glycidyl esters of soybean oil (EGS) have been synthesized and used as reactive diluents for partial replacement of a commercial, bisphenol A-based epoxy resin (DGEBA). The EGS merits include a higher epoxy content and lower viscosity than the epoxidized triglyceride soybean oil (ESO). Thermosetting resins were fabricated from DGEBA systems blended with various amounts of EGS and ESO, using 4-methyl-1,2-cyclohexanedicarboxylic anhydride as a curing agent and 2-ethyl-4-methylimidazole as catalyst. The curing behavior and glass transition were monitored by differential scanning calorimetry (DSC), the performance of thermosetting resins was studied by measurement of thermal stability and flexural properties. The results indicate that EGS resins provide better compatibility, intermolecular crosslinking, and yield materials that are stronger than materials obtained using ESO. However, the EGS resin systems significantly reduce viscosity compared to either pure DGEBA or ESO-ble...