Neat Diglycidyl Ether Of Bisphenol A Research Articles

Studies on the Modification of Commercial Bisphenol-A-Based Epoxy Resin Using Different Multifunctional 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.

Preparation and properties of a novel fluorinated epoxy resin/DGEBA blend for application in electronic materials

A novel epoxy monomer 4-trifluoromethyl phenylhydroquinone epoxy resin (4-TFMEP) was synthesized via a multistep procedure including the Meerwein arylation reaction and followed by nucleophilic reaction. The chemical structure of 4-TFMEP was confirmed by proton nuclear magnetic resonance and Fourier-transform infrared spectrum. Then a mixed system (DGEBA/4-TFMEP x%) composed of diglycidyl ether of bisphenol A (DGEBA) and 4-TFMEP was prepared by a melting method without any solvent. After curing, the properties of this series of mixed epoxy resins were measured and compared with the neat DGEBA. As a result, the blend resins exhibited good thermal stability, excellent hydrophobic and low dielectric properties with 4-TFMEP content increasing. Furthermore, the material of DGEBA/4-TFMEP 40% achieves higher glass transition temperature of 104°C and char yield 33% than DGEBA (char yield = 22%) possessed. In the contact angle testing, DGEBA/4-TFMEP 40% shows 127.2° satisfied the standard of hydrophobic material. In addition, by the test of dielectric properties, DGEBA/4-TFMEP x% materials show lower than DGEBA/boron trifluoride ethylamine (BF3MEA) material, because of the introduced side group of fluorine content into the material improves the electronegativity of epoxy material and reduced the polarizability of molecules efficient. Herein, we believe the novel mixed epoxy system (DGEBA/4-TFMEP x%) has a potential application in electronic industries.

One-Step Preparation of Hyperbranched Polyether Functionalized Graphene Oxide for Improved Corrosion Resistance of Epoxy Coatings

In this paper, hyperbranched polyether functionalized graphene oxide (EHBPE-GO) was prepared by a facile one-step method. Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD), thermogravimetric analyzer (TGA), and trans-mission electron microscopy (TEM) results confirmed the formation of EHBPE-GO. Then, EHBPE-GO was cured with phenolic amides at room temperature to prepare epoxy coatings. The corrosion resistance of epoxy coatings was investigated systematically by using electrochemical and traditional immersion methods. Results show that a small amount of EHBPE-GO (8 wt % of Diglycidyl ether of bisphenol A (DGEBA)) in epoxy coating achieves 50% higher improvement in acid-resistance than unmodified neat DGEBA resin. For the nanocomposite epoxy coating, the superior acid-resistance is attributed to the increased crosslink density and the impermeable 2D structure of EHBPE-GO. This work provides a facile strategy to develop the effective improved corrosion resistance nanofiller for epoxy coating.

Preparation of hyperbranched polymeric ionic liquids for epoxy resin with simultaneous improvement of strength and toughness

The present work is based on a study of methylhexahydrophthalic anhydride (MHHPA) cured diglycidyl ether of bisphenol A (DGEBA) in the presence of a hyperbranched ionic liquid (HBP-Mim). Differential scanning calorimetry studies confirmed that the curing reaction was accelerated by HBP-Mim. The impact strength of DGEBA (17.1 kJ/m2) increased to 39.5 kJ/m2 after the addition of 9 phr HBP-Mim-2. Tensile and flexural properties also showed a significant improvement as the incorporation of 9 phr HBP-Mim-2 resulted in 63.1% and 135.2% increase in the tensile and flexural strengths of epoxy thermosets, respectively, compared with neat DGEBA. Thermal stability and thermomechanical properties of the HBP-Mim modified epoxy thermosets also showed a significant improvement. The simultaneous improvements in the mechanical and thermal properties could be attributed to increased free volume and cross-link density.

Synthesis and characterization of amino-terminated hyperbranched polymer and its effect on impact resistance of epoxy resin thermosets

Amino-terminated hyperbranched polymer (HBP-NH2) was synthesized from diethylenetriamine (DETA) and methyl acrylate (MA) by melt polycondensation through AB3 and AB2 route, and its chemical structure was characterized by attenuated total internal reflectance infrared spectroscopy (ATR-IR) and 1H nuclear magnetic resonance (1H-NMR) spectroscopy. Then, the influence of HBP-NH2 content on the toughness improvement and fractural surface morphology of diglycidyl ether of bisphenol A (DGEBA) cured systems was investigated through impact resistance test and field emission scanning electron microscopy (FESEM), respectively. The results indicated that HBP-NH2 can enhance the toughness of epoxy cured system near 61 % than the neat DGEBA cured thermosets. FESEM images show that the toughness enhancement of epoxy system should be based on shearing deformation mechanism (the thermosets modified with low content of HBP-NH2) and the second phase toughening mechanism (the thermosets modified with high content of HBP-NH2).

Toughening of aromatic epoxy via aliphatic epoxy copolymers

While aromatic diglycidyl ether of bisphenol A (DGEBA) based epoxy polymer matrix systems are important for high-performance applications, their brittle nature is an issue that needs to be addressed. In this paper the authors show that small additions of a more flexible aliphatic epoxy copolymers, both di- and tri-functional, can significantly increase the notched Izod impact strength (56–77%) over the neat DGEBA, while not detrimentally affecting other mechanical properties such as glass transition temperature and flexural properties. In fact, at 1 wt% concentrations, the tri-functional epoxy shows a slight increase (∼2%) in the glass transition temperature compared to neat DGEBA. The improvement in impact toughness is attributed to the more flexible backbone of the aliphatic epoxy molecules. The total miscibility of the aromatic and aliphatic epoxies within the investigated concentration range (up to 20 wt%) allows for this toughening approach to be directly applied to current composite production methods, such as resin transfer molding (RTM).

Integration of biobased functionalized feedstock and plastisol in epoxy resin matrix toward developing structural jute biocomposites with enhanced impact strength and moisture resistance properties

Epoxy resin matrix based on diglycidyl ether of bisphenol A (DGEBA) was modified with addition of epoxidized soybean oil (ESBO). Structural jute composites prepared with ESBO modified DGEBA resin showed a decrease in tensile strengths, owing to reduced cross linking density. Percentage elongation of the samples increased with addition of ESBO. An optimized composition was identified, at which the composite showed increase in tensile strength, modulus and elongation. Interestingly, impact strengths increased initially with incorporation of ESBO, but with further increase in ESBO, impact strengths decreased. Structural Jute composites were also prepared by incorporating polyvinyl (chloride) (PVC) plastisol into the modified matrix which showed an increase in both tensile and impact strengths. Fourier transform infrared spectroscopy (FT‐IR) analysis indicated the curing state of the composites. The spectrum peaks became increasingly stronger in the OH band with increasing ESBO quantities. This could be attributed to the hydrophilic nature of ESBO, a result that was well supported by the moisture absorption test. Although, water uptake capacity of ESBO/DGEBA modified matrix composites recorded increasing trend with increased ESBO content, with inclusion of plastisol, the water uptake values dropped. Composite with DGEBA/ESBO/plastisol modified matrix actually recorded water uptake capacity comparable to composite with neat DGEBA, possibly owing to improved interfacial adhesion and hydrophobic nature of PVC plastisol. POLYM. COMPOS., 37:391–397, 2016. © 2014 Society of Plastics Engineers

Synthesis of polysiloxane‐type multifunctional flame retardant and its application in epoxy systems

AbstractPolymethyl(3‐glycidyloxypropyl)siloxane (PMGS) was synthesized as a flame‐retardant additive, which were cocured with diglycidyl ether of bisphenol‐A (DGEBA) using 4,4′‐diaminodiphenylsulfone as a curing agent. The structure of PMGS was confirmed through Fourier transform infrared and 1H‐NMR spectra. The cured products were characterized with dynamic mechanical thermal analysis, thermogravimetric analysis, and oxygen index analyzer. With PMGS incorporated, the cured epoxy resin showed better thermal stability, higher limited oxygen index, and higher char yield. At moderate loading of PMGS, the storage modulus and glass transition temperature of the cured epoxy resin based on neat DGEBA were obviously improved. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Epoxy toughening using low viscosity liquid diglycidyl ether of ethoxylated bisphenol‐A

AbstractTwo new epoxy resins, diglycidyl ether of ethoxylated bisphenol‐A (BPA) with two and six oxyethylene units (DGEBAEO‐2 and DGEBAEO‐6) were synthesized and characterized. DGEBAEO‐6 was used to toughen the conventional epoxy resin diglycidyl ether of BPA (DGEBA). The blends of DGEBA with different amounts of DGEBAEO‐6 were cured by 4,4′‐diamino diphenylmethane (DDM), and their thermal and mechanical properties were examined. The DSC and DMA results presented that DGEBA/DGEBAEO‐6 blends exhibited a homogenous phase, and the glass transition temperature of the blends was inversely proportional to the content of DGEBAEO‐6. The impact strength of the cured blends was directly proportional to the content of DGEBAEO‐6, and reached five times higher than that of the neat DGEBA when 50 wt % DGEBAEO‐6 was used; the same impact strength was achieved for DDM‐cured DGEBAEO‐2. The viscosities of the blends decreased with increasing the DGEBAEO‐6 content, whereas the tensile and flexural strength and the thermal stabilities were not obviously affected. Scanning electron microscopic results confirmed that the plastic deformation inducing by the incorporated flexible oxyethylene units was responsible for the toughness improvement. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Synthesis and characterization of P/Si flame retardant and its application in epoxy systems

In this report, a novel phosphorus/silicon‐containing reactive flame retardant, hexa(3‐triglycidyloxysilylpropyl)triphosphazene (HGPP), was synthesized and characterized by Fourier transform infrared spectrometry and nuclear magnetic resonance spectra (1H, 31P, and 29Si), respectively. To prepare cured epoxy, HGPP had been co‐cured with diglycidyl ether of bisphenol‐A (DGEBA) via 4,4‐diaminodiphenylsulfone as a curing agent. The mechanical, thermal, and flame retardant properties of the cured epoxy were evaluated by dynamic mechanical analysis, thermogravimetric analysis, and limiting oxygen index (LOI). According to these results, it could be found that incorporation of HGPP in the cured epoxy system showed good thermal stability, high LOI values, and high char yield at high temperature. As moderate loading of HGPP in the epoxy system, its storage modulus and glass transition temperature were higher than those of neat DGEBA. Copyright © 2011 John Wiley & Sons, Ltd.

Thermal and mechanical properties of anhydride‐cured epoxy resins with different contents of biobased epoxidized soybean oil

AbstractThermosetting resins were synthesized by the partial replacement of the synthetic epoxy prepolymer based on diglycidyl ether of bisphenol A (DGEBA) with increasing amounts of epoxidized soybean oil (ESO) with methyltetrahydrophthalic anhydride as a crosslinking agent and 1‐methyl imidazole as an initiator. Calorimetric studies showed a drop in the reaction heat with ESO content; this was associated with the lower reactivity of oxirane rings in ESO due to steric constrains. The effects of the replacement of increasing amounts of synthetic DGEBA with ESO on the network properties, such as the storage modulus (E′) in the glassy and rubbery regions, glass‐transition temperature (Tg), and impact and compressive properties were examined. All formulations were transparent, although phase‐separated morphologies were evidenced by scanning electron microscopy observations. The intensity of the transmitted light passed to a minimum at a short reaction time associated with the cloud point and then increased continuously until the refractive index of the dispersed phase approximated that of the continuous phase at complete conversion. The combination of DGEBA with 40 wt % ESO resulted in a resin with an optimum set of properties; E′ in the glassy state was 93% of that of the neat DGEBA resin, Tg decreased only about 11°C, and the impact strength increased about 38% without a loss of transparency. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

New epoxy thermosets modified with hyperbranched poly(ester-amide) of different molecular weight

The influence of hydroxy-functionalized hyperbranched poly(ester-amide) (HBP) of different molecular weight on the curing process of diglycidylether of bisphenol A (DGEBA) was studied using methyltetrahydrophthalic anhydride (MTHPA) as curing agent. By Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FTIR) the curing reaction was monitored and the covalent incorporation of the modifier in the matrix was proved. By thermomechanical analysis (TMA) the reduction of the contraction after gelation on changing the HBP proportion was observed. The incorporation of HBP increased the glass transition temperature ( T g) and reduced the overall shrinkage. The modified materials showed a higher thermal degradability than neat DGEBA thermosets allowing reworkability. Thermal expansion coefficient, Young’s modulus, impact strength and microhardness were improved. The water uptake behavior was also evaluated.

New improved thermosets obtained from DGEBA and a hyperbranched poly(ester-amide)

The influence on the curing process of a commercial hydroxy-functionalized hyperbranched poly(ester-amide) (HBP) Hybrane® S1200 on diglycidylether of bisphenol A (DGEBA) was studied. By Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FTIR) the curing reaction was studied and the covalent incorporation of the modifier in the matrix was proved. By Thermomechanical Analysis (TMA) the reduction of the contraction after gelation on changing the S1200 proportion was observed. The incorporation of S1200 increased the glass transition temperature (Tg) and reduced the overall shrinkage, specially after gelation. The modified materials were more thermally degradable than neat DGEBA thermosets. Thermal expansion coefficient, Young's modulus, impact strength and microhardness were improved without compromising the thermomechanical characteristics. The water uptake behaviour was also evaluated.

Studies on cure behaviors, dielectric characteristics and mechanical properties of DGEBA/poly(ethylene terephthalate) blends

The cure behaviors, dielectric characteristics and fracture toughness of diglycidylether of bisphenol-A (DGEBA)/poly(ethylene terephthalate) (PET) blend system were investigated. The degree of conversion for the DGEBA/PET blend system was measured using Fourier transform infrared (FTIR) spectroscopy. The cure kinetics were investigated by measuring the cure activation energies (Ea) with dynamic differential scanning calorimetry (DSC). The dielectric characteristic was examined by dielectric analysis (DEA). The mechanical properties were investigated by measuring the critical stress intensity factor (KIC), critical strain energy release rate (GIC), and impact strength test. As a result, DGEBA/PET was successfully blended. TheEa of the blend system was increased with increasing PET content to a maximum at 10 phr PET. The dielectric constant was decreased with increasing PET content. The mechanical properties of the blend system were also superior to those of the neat DGEBA. These results were attributed to the increased cross-linking density of the blend system, resulting from the interaction between the epoxy group of DGEBA and the carboxyl group of PET.

Impact-strength improvement of epoxy resins reinforced with a biodegradable polymer

Biobased epoxy materials were prepared from diglycidylether of bisphenol-A (DGEBA) and epoxidized soybean oil (ESO) with a thermally latent initiator. The effects of ESO content on the impact and adhesive strengths of the ESO-reinforced DGEBA epoxy system were investigated using several techniques and the mechanical properties of the DGEBA/ESO blends were studied by means of measurements of the flexural strength ( σ f) and elastic modulus ( E b). In the result, the Izod impact strength of the DGEBA/ESO blends was significantly improved with the addition of ESO, owing to high intermolecular interactions in the DGEBA/ESO blends. The adhesive lap shear strength was increased with increasing ESO content to 40 wt% ESO. The σ f and E b at low ESO contents showed similar values to those of the neat DGEBA.

Isoconversional kinetic analysis of stoichiometric and off-stoichiometric epoxy-amine cures

The curing reaction of stoichiometric and off-stoichiometric diglycidyl ether of bisphenol A (DGEBA) and 1,3-phenylene diamine ( m-PDA) mixtures was studied by differential scanning calorimetry, thermogravimetric analysis and rheological measurements. In order to highlight the side reactions such as etherification and homopolymerization, the neat DGEBA and DGEBA/DMBA ( N, N-dimethylbenzylamine) mixture were examined. The classical model-fitting and the advanced isoconversional methods were used to determine the activation energy of the different reactions. The advanced isoconversional method leads to a good agreement between isothermal, nonisothermal and rheological results. The effective activation energies of primary amine epoxy reaction, etherification and homopolymerization were estimated to about 55–60, 104 and 170 kJ mol −1, respectively.

Thermal Stabilities and Mechanical Interfacial Properties of Polyethresulfone-Modified Epoxy Resin

The thermal stabilities and mechanical interfacial properties of a diglycidyl ether of bisphenol-A (DGEBA) epoxy resin modified with different contents of polyethersulfone (PES) have been investigated. As a result, the curing reaction rate of DGEBA/PES blends was decreased with increasing the PES content. The blends exhibited slight decrease of thermal stabilities compared to the neat DGEBA. The mechanical interfacial properties, characterized by KIC, were significantly increased as the PES content increased.