Trifunctional Epoxy Research Articles

A renewable resveratrol-based epoxy resin with high Tg, excellent mechanical properties and low flammability

Preparing low-flammable biobased epoxy resins with a high glass transition temperature (Tg) and excellent mechanical properties is significant for the rapid growing electronics and microelectronics industry. In this research, a resveratrol-based epoxy resin (REEP) with well-designed chemical structures possessing trifunctional epoxy groups and rigid conjugate structures was prepared through the one-pot method and was then cured by methyl hexahydrophthalic anhydride (MeHHPA). The conventional petroleum-based epoxy resin (DGEBA) was cured by the same kind of curing agent. Results showed that Tg of REEP/MeHHPA was up to 210.8 °C, much higher than that of DGEBA/MeHHPA (only 146.5 °C). The tensile strength and modulus of REEP/MeHHPA were 73.5 MPa and 3.0 GPa, respectively. More importantly, REEP/MeHHPA exhibited exceptional low permittivity (about 3.5) and low flammability with high char yield of 19.0% (800 °C). Therefore, the resveratrol-based epoxy resin could be a promising candidate for DGEBA and has great potential application in electronics and microelectronics industry.

Nanofiltration membranes from crosslinked Troger's base Polymers of Intrinsic Microporosity (PIMs)

Novel membrane separation technologies are highly sought after to meet the needs for improved energy efficiency in industrial separations. Polymers of intrinsic microporosity (PIMs) are a valuable class of polymers for membrane separations as their porosity originates from their unique highly rigid backbone structure. In this work, for the first time, we demonstrate that low defectivity membranes could be obtained from hydroxy functional branched Troger's base (TB-OH) PIM. Further, we utilize a tri-functional epoxy crosslinker Tris(4-hydroxyphenyl)methane triglycidyl ether (TGE) to crosslink the branched TB-OH layer and demonstrate that the membrane stability was improved significantly after the crosslinking.

The Application of a Tri-Functional Epoxy Resin as a Crosslinking Agent in Extruded Polyamide-6 Foam

A tri-functional epoxy resin was used to cross-link polyamide-6 (PA6) during chemical extrusion foam molding and its loading-dependent effect on the melting, crystallization properties, crosslinking degree, and melt strength of PA6 as well as the cell morphology of extruded foam specimens was determined. As the tri-functional epoxy resin loading increased the crystallization and melting temperatures of PA6 decreased whereas the area of the melting peak and crystallinity of PA6 first increased and then decreased. Incorporation of epoxy resin also reduced the PA6 processing temperature. Increased tri-functional epoxy resin loading enhanced melt viscosity, the crosslinking degree and melt strength of PA6. Scanning electron microscopy revealed that the foamability of PA6 was obviously improved by the addition of the epoxy resin.

Improved Mechanical and Thermal Properties of Trifunctional Epoxy Resins through Controlling Molecular Networks by Ionic Liquids

A heterogeneous molecular network of trifunctional epoxy resins was designed by using a two-step polymerization strategy to improve the toughness and thermal properties without sacrificing the modu...

Design, synthesis, and theoretical analysis of thermal stability epoxy resins obtained through a facile and cost-effective approach

• Several novel silicon-containing imidazole and thiazole derivative curing agents were designed and successfully synthesized through a facile and cost-effective approach and utilized as a modifier for epoxy resins. • The thermal stability and possible curing mechanism were proposed and discussed. • The dissipative particle dynamics (DPD) method was further used to get insight into the mechanism of the thermal stability and predict the mechanical properties. A trifunctional epoxy resin (TGPAP) with excellent thermal stability was cured by several novel curing agents through a facile and cost-effective approach. The temperature of maximum weight loss rate ( T peak ) of cured TGPAP were up to 370 °C and 330 °C under N 2 and air atmospheres, which attributed to the synergistic effects between curing agents and TGPAP. The dissipative particle dynamics simulations also reveal that the curing agents with more functional groups and higher reactivity induce the higher cross-linking density, leading to better mechanical properties. The simulations well reproduced the experimental results and also predicted the effect of the curing agents on mechanical properties.

Synthesis, characterization and rheological properties of epoxy monomers derived from bifunctional aromatic amines

Several new epoxy monomers were synthesized from glycidylation of functional aromatic amines containing hydroxyl or thiol groups. The epoxy monomers were triglycidyl-2-aminophenol, triglycidyl-2-aminothiophenol, tetraglycidyl-1,2-phenylenediamine and tetraglycidyl-4-methyl-1,2-phenylenediamine. The characterization of the epoxy monomers was carried out by FTIR and 1H NMR spectroscopy. Rheological properties of solutions of the epoxy monomers in ethanol were evaluated using an advanced rheometer. The effect of solution concentration and temperature on the viscosity of the epoxy solution was evaluated. The shear rheology study at various temperatures of the epoxy resins solutions in ethanol was carried out on solutions with concentrations ranges form 0.5 to 5 wt% and temperatures (20–70 °C). The results revealed that the tetra-functional epoxy resins behave as Newtonian liquids and its viscosity is independent on the shear rate. However, the solutions of tri-functional epoxy resins are non-Newtonian liquids, and their viscosities are shear rate dependent. The activation energy of the epoxy monomers was calculated from the Arrhenius equation using solution with concentrations ranges of 0.5–5 wt%.

Heat-Resistant Polymers and Composites on the Basis of Epoxy–Isocyanate Binding Agents

The polymerization reaction of bi- and trifunctional epoxy resins with di- and polyisocyanates with different structures is studied via differential scanning calorimetry and IR spectroscopy. Polymers and composite materials (organic plastics) with high values of glass transition point, modulus of elasticity, and strength are obtained.

Bio-based tri-functional epoxy resin (TEIA) blend cured with anhydride (MHHPA) based cross-linker: Thermal, mechanical and morphological characterization

ABSTRACTA novel renewable resource based tri-functional epoxy resin from itaconic acid (TEIA) was blended with petroleum based epoxy resin (DGEBA) and fabricated at different ratios. Then, it was by thermally cured with methylhexahydrophthalic anhydride (MHHPA) in presence of 2-methylimidazole (2-MI) catalyst. The tensile, modulus, strength of virgin epoxy resin (41.97 MPa, 2222 MPa) increased to 47.59 MPa, 2515 MPa, respectively, with the addition of 30% of TEIA. The fracture toughness parameter, critical stress intensity factor (KIC) revealed enhancement of toughness in the TEIA bio-based blends system. The thermomechanical properties of TEIA (tri-functional epoxy resin from itaconic acid) modified petroleum-epoxy networks were investigated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). The fracture morphology was also studied by the scanning electron microscopy and atomic force microscopy respectively.

Highly crosslinked and uniform thermoset epoxy microspheres: Preparation and toughening study

A new type highly crosslinked and uniform thermoset epoxy microspheres (EMs) was prepared through the thermal curing between a trifunctional epoxy resin (TGPAP) and an aromatic amine hardener (DETDA), by precipitation polymerization in a low molecular weight polypropylene glycol (PPG-600) medium. The formation of EMs and the phase separation process were investigated in detail. The structure and thermal properties of EMs were characterized, and the result showed that EMs was active microspheres with hydroxyl and amino groups on its surface, and it had a high glass transition temperature Tg of 205 °C and high thermal stability. EMs was further used to toughen brittle epoxy resins. The effect of EMs on the curing behavior, mechanical and thermal properties of epoxy resins was studied. EMs accelerated the curing and the effect reached maximum till 5 wt% amount. Mechanical and thermal performance measurements exhibited that EMs not only significantly improved the toughness of epoxy matrix, but also increased the Tg. When 5 wt% EMs was introduced, the impact strength rose from 17.8 kJ m−2 to 42.4 kJ m−2 and Tg increased more than 10 °C. The excellent toughening performance of EMs was attributed to its high stiffness and active surface.

Trifunctional Epoxy Resin Composites Modified by Soluble Electrospun Veils: Effect on the Viscoelastic and Morphological Properties.

Electrospun veils from copolyethersulfones (coPES) were prepared as soluble interlaminar veils for carbon fiber/epoxy composites. Neat, resin samples were impregnated into coPES veils with unmodified resin, while dry carbon fabrics were covered with electrospun veils and then infused with the unmodified epoxy resin to prepare reinforced laminates. The thermoplastic content varied from 10 wt% to 20 wt%. TGAP epoxy monomer showed improved and fast dissolution for all the temperatures tested. The unreinforced samples were cured first at 180 °C for 2 h and then were post-cured at 220 °C for 3 h. These sample showed a high dependence on the curing cycle. Carbon reinforced samples showed significant differences compared to the neat resin samples in terms of both viscoelastic and morphological properties.

Toward simultaneous toughening and reinforcing of trifunctional epoxies by low loading flexible reactive triblock copolymers.

Flexible reactive poly(glycidyl methacrylate)-b-poly(propylene glycol)-b-poly(glycidyl methacrylate) (GPG) and nonreactive poly(ethylene glycol)-b-poly(propylene glycol)-b-poly(ethylene glycol) (EPE80) were utilized to toughen a trifunctional epoxy (diglycidyl 4, 5-epoxycyclohexane-1, 2-dicarboxylate, TDE-85). In comparison with the nonreactive EPE80 and reactive GPG92 with long reactive blocks (Lreactive), the incorporation of reactive GPG83 with short Lreactive improved the comprehensive mechanical properties of the epoxy. Upon an optimal GPG83 loading of 2.5 wt%, the tensile strength, elongation at break and critical strain energy release rate (G1c) increased by ca. 31%, 45.9% and 130.8%, respectively, without sacrificing the modulus and thermal stability. Morphology characterization evidenced that micro-scale domains and nanosized vesical micelles coexisted in the nonreactive EPE80 toughened systems. However, homogeneous morphologies were formed in reactive GPG83 and GPG92 toughened systems. Fracture morphology analysis suggested that GPG can toughen epoxy thermosets by incorporating flexible PPG blocks into the epoxy network, thereby enabling an energy dissipation mechanism. The good balance between the mobility of flexible PPG and degree of cross-link density leads to the simultaneous toughening and reinforcing effect of GPG83 toward the trifunctional epoxy.

Synthesis and characterization of itaconic‐based epoxy resins

A trifunctional epoxy resin from itaconic acid (TEIA) was synthesized from a renewable resource‐based itaconic acid by allylation of itaconic acid to form diallyl itaconate by using m‐chloroperoxybenzoic acid as oxidizing agents followed by epoxidation of allylic C═C bond of diallyl itaconate methylhexahydropthalic anhydride as curing agent in the presence of 2‐methyl imidazole as a catalyst. The chemical structure of the synthesized resins was confirmed by Fourier transform infrared and nuclear magnetic resonance (1H‐NMR and13C‐NMR) spectroscopy analysis. The mechanical, thermal, and rheological performances of the TEIA were also investigated and compared with diglycidyl ether of bisphenol A and a plant‐based epoxidized soybean oil bioresin cured with the same curing agent. The higher epoxy value of 1.02, lower viscosity (0.96 Pa s at 25°C), higher mechanical, and higher curing reactivity toward methylhexahydropthalic anhydride of TEIA as compared with epoxidized soybean oil and comparable with diglycidyl ether of bisphenol A demonstrated significant evidence to design and develop a novel bio‐based epoxy resin with high performance to substitute the petroleum‐based epoxy resin.

Flame retardancy of glucofuranoside based bioepoxy and carbon fibre reinforced composites made thereof

Flame retarded bioepoxy resins and carbon fibre reinforced composites were prepared from a novel glucofuranoside based trifunctional epoxy monomer (GFTE) cured with aromatic amine hardener. 4% phosphorus (P)-containing samples were prepared using liquid resorcinol bis(diphenyl phosphate) (RDP), solid ammonium polyphosphate (APP), and their combination. The common application of the inorganic APP and the organophosphorus RDP had two main advantages: APP compensated the plasticizing effect of low P-containing RDP, resulting in increased glass transition and storage modulus values compared to RDP-containing sample, while RDP added gas phase flame retardant action to the APP acting only in the solid phase, resulting in self-extinguishing, V-0 UL-94 rated bioepoxy matrix and composite specimens.

Flammability and acoustic absorption of alumina foam/tri-functional epoxy resin composites manufactured by the infiltration process

Abstract Ceramic-polymer composites with an interpenetrating network structure have a lot of advantages, which can be achieved by connecting two quite different phases. Infiltration of liquid epoxy resin into the cellular alumina matrix is the most suitable way of producing this type of materials and offers an opportunity for a precise and simple fabrication method of ceramic-based interpenetrating composites. Alumina foams manufactured by “gel-casting” method were infiltrated by new tri-functional epoxy resin (triglycidylized para-aminophenol) designed for special aircraft applications. Combination of this new epoxy resin with high-porous alumina foams causes higher compressive strength and better flammability of ceramic/polymer composite than either individual component. Additionally, alumina/epoxy composites with partial pores filling ratio showed satisfactory acoustic absorption characteristics. Development of this type of composites is a result of need to research new, lightweight materials with increased mechanical strength, non-inflammable and another functional features, e.g. noise reduction ability, design for the aerospace industry. Therefore, presented paper investigates flammability, acoustic absorption and mechanical properties of resulted composites.

Synthesis, Structural, Viscosimetric, And Rheological Study, of A New Trifunctional Phosphorus Epoxyde Prepolymer , Tri-Glycidyl Ether Tri-Mercaptoethanol Of Phosphore (TGETMEP)

The aim of our work is to synthesize a new phosphorus tri-functional epoxy resin tri-glycidyl ether tri-mercaptoethanol of phosphorus (TGETMEP) in two stages. In the first stage, we got the precursor molecule of the epoxy matrix tri-mercaptoethanol phosphate (METR). The second step led us to the synthesis of tri-functional resin TMEP condensation with epichlorohydrin. The standard TGETMEP resin was characterized by the Fourier infrared transformation (FTIR) and nuclear magnetic resonance (NMR), on one hand. The viscosimetric analysis was investigated by the Hebbelod capillary viscometer and rheometer Rheomat 01, on the other hand. The cross-linked resins and tertiary formulated composites have been studied by the rheometer 01 which was observed by means of SEM.

A novel comparative study of different layered silicate clay types on exfoliation process and final nanostructure of trifunctional epoxy nanocomposites

The effect of three different organically modified layered silicate clays (Nanomer I.30E, Cloisite 30B and Nanofil SE 3000) on the exfoliation process and on the thermal properties and nanostructure of cured trifunctional epoxy resin based nanocomposites was studied. Optical microscopy showed that the best and poorest qualities of clay distribution in the epoxy matrix were obtained with Nanofil SE 3000 and Nanomer I.30E, respectively. However, the isothermal differential scanning calorimetry scans show that, of the three systems, it is only the Nanomer clay that promotes intra-gallery reaction due to homopolymerisation, appearing as an initial rapid peak prior to the cross-linking reaction. This rapid intra-gallery reaction is not present in the curing curve for the Cloisite and Nanofil systems. This fact implies that the fully cured nanostructure of the Cloisite and Nanofil system is poorly exfoliated, which is confirmed by small angle X-ray scattering which shows a scattering peak for these systems at around 2.53°, corresponding to about 3.5 nm d-spacing.

High Temperature Epoxy Foam: Optimization of Process Parameters.

For many years, reduction of fuel consumption has been a major aim in terms of both costs and environmental concerns. One option is to reduce the weight of fuel consumers. For this purpose, the use of a lightweight material based on rigid foams is a relevant choice. This paper deals with a new high temperature epoxy expanded material as substitution of phenolic resin, classified as potentially mutagenic by European directive Reach. The optimization of thermoset foam depends on two major parameters, the reticulation process and the expansion of the foaming agent. Controlling these two phenomena can lead to a fully expanded and cured material. The rheological behavior of epoxy resin is studied and gel time is determined at various temperatures. The expansion of foaming agent is investigated by thermomechanical analysis. Results are correlated and compared with samples foamed in the same temperature conditions. The ideal foaming/gelation temperature is then determined. The second part of this research concerns the optimization of curing cycle of a high temperature trifunctional epoxy resin. A two-step curing cycle was defined by considering the influence of different curing schedules on the glass transition temperature of the material. The final foamed material has a glass transition temperature of 270 °C.

Synthesis and properties of novel trifunctional epoxy triglycidyl of 4‐(4‐aminophenoxy)phenol with high toughness

ABSTRACTA trifunctional epoxy containing oxyphenylene unit, triglycidyl of 4‐(4‐aminophenoxy)phenol (TGAPP) was synthesized and characterized. The chemical structure of TGAPP was confirmed with FTIR and 1H‐NMR. DSC analysis revealed that the reactivity of TGAPP with curing agent 4, 4′‐diaminodiphenylsulfone (DDS) was significantly lower than that of triglycidyl para‐aminophenol (TGPAP). Rheological analysis showed that the processing window of TGAPP/DDS was 20°C wider compared with that of TGPAP/DDS. The thermal and mechanical properties of cured TGAPP/DDS were investigated and compared with those of the cured TGPAP/DDS. Experimental results showed that, due to the introduction of oxyphenylene unit, the heat resistance and flexural strength were slightly reduced, while the tensile strength and impact strength were enhanced. SEM also confirmed that the introduction of oxyphenylene unit could enhance the toughness of the TGAPP/DDS as evident from ridge formation. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41878.

Non-isothermal cure and exfoliation of tri-functional epoxy-clay nanocomposites

The non-isothermal cure kinetics of polymer silicate layered nanocomposites based on a tri-functional epoxy resin has been investigated by differential scanning calorimetry. From an analysis of the kinetics as a function of the clay content, it can be concluded that the non-isothermal cure reaction can be considered to consist of four different processes: the reaction of epoxy groups with the diamine curing agent; an intra-gallery homopolymerisation reaction which occurs concurrently with the epoxy-amine reaction; and two extra-gallery homopolymerisation reactions, catalysed by the onium ion of the organically modified clay and by the tertiary amines resulting from the epoxy-amine reaction. The final nanos- tructure displays a similar quality of exfoliation as that observed for the isothermal cure of the same nanocomposite system. This implies that the intra-gallery reaction, which is responsible for the exfoliation, is not significantly inhibited by the extra-gallery epoxy-amine cross-linking reaction.

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).