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Journal ArticleDOI: 10.1007/S10973-021-10630-8

Thermal and bonding properties of epoxy asphalt bond coats

02 Mar 2021-Journal of Thermal Analysis and Calorimetry (Springer International Publishing)-pp 1-13
Abstract: Epoxy asphalt bond coat (EABC) is one of the thermosetting polymer-modified asphalts, which has been widely employed as a strong waterproof bonding layer between the asphalt concrete and the orthotropic steel bridge deck. In the present work, the influences of asphalt content on the phase separation, viscosity, thermal stability, viscoelastic behavior, mechanical performance, pull-off strength, and adhesive performance of EABCs were characterized by various instruments. Laser scanning confocal microscopy observations showed that phase separation occurring in EABCs depended on the curing time. The asphalt merged to form large spherical particles in the continuous epoxy phase during the cure reaction. The size of asphalt particles increased in the asphalt content. Viscosities of EABCs were higher than that of the pure epoxy and increased with the asphalt content in the initial curing stage. However, the opposite trend was observed in the latter curing stage. The presence of asphalt slightly improved the glass transition temperature and the damping properties of the pristine epoxy. For EABCs, the damping behaviors slightly increased with the asphalt content. The thermal stability of the pristine epoxy was enhanced by the incorporation of asphalt. The addition of asphalt decreased the mechanical, adhesive properties, and pull-off strength of the pristine epoxy. What’s more, these properties of EABCs decreased in the asphalt content.

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Topics: Asphalt concrete (65%), Epoxy (57%), Asphalt (53%) ... read more
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Journal ArticleDOI: 10.1016/J.CONBUILDMAT.2021.122752
Ru Chen1, Ruikang Zhao1, Ya Liu1, Zhonghua Xi1  +4 moreInstitutions (1)
Abstract: Epoxy asphalt binder is flammable and plenty of fumes are produced during its high-temperature pavements in tunnels. To improve fire retardancy and reduce asphalt fumes, eco-friendly flame-retarded warm-mix epoxy asphalt binders (WEABs) for road tunnel pavements were developed by incorporation of reactive polymeric flame retardant (RPFR), which was composed of a reactive polymeric brominated epoxy oligomer (BEO) and antimony oxide. The influence of RPRF on flame retardancy, rotational viscosity, microstructures, thermal properties and mechanical performance of the pure WEAB was investigated using various techniques: oxygen index instrument, Brookfield viscometer, confocal microscope, differential scanning calorimeter, thermogravimetric analyzer and universal testing machine. The presence of RPFR significantly improved the limited oxygen index (LOI) of the pure WEAB. The LOI of RPFR modified WEABs increased in the flame retardant loading. The reaction of epoxide groups of RPFR with the curing agents of epoxy asphalt reduced the viscosity of the pure WEAB and extended the allowable construction time of the WEAB mixture. The inclusion of RPFR increased the glass transition temperature (Tg) of the pure WEAB. For modified WEABs, the Tg increased in the RPFR loading. RPFR reacted into the epoxy asphalt backbone through the reaction between epoxy groups and curing agents. The incorporation of RPFR improved the thermal stability of the pure WEAB. The addition of 8 wt% RPFR increased the tensile strength of the pure WEAB, while the inclusion of RPFR slightly decreased the break elongation of the pure WEAB. Double phase separation occurred in RPFR modified WEAB: the main phase separation included the continuous epoxy phase and the discontinuous asphalt domains, in which the secondary phase separation formed with asphalt as the continuous phase and spherical BEO domains as the discontinuous phase. The particle size of BEO domains decreased with the increase of the RPFR loading.

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Topics: Epoxy (53%)

4 Citations


Journal ArticleDOI: 10.1007/S10973-021-10689-3
Xiaocheng Han1, Wufeng Su1, Jie Gong1, Zhonghua Xi1  +4 moreInstitutions (1)
Abstract: Asphaltenes tend to aggregate to nanoparticles or clusters in crude oil and solvents over a wide concentration and temperature range. In the present paper, asphaltenes extracted from the base asphalt was used as a filler to introduce into epoxy resin. The microstructure and evolution of asphaltenes aggregation in the epoxy resin were observed using laser scanning confocal microscopy. Furthermore, the effect of asphaltenes on the viscosity, dynamic mechanical behavior, thermostability, mechanical properties of epoxy resin was evaluated by Brookfield rotational viscometer, dynamic mechanical analysis, thermogravimetric analysis and universal testing machine. The presence of asphaltenes increased the viscosity of the neat epoxy during all stages of cure reaction. The viscosity of epoxy/asphaltenes composites increased with the filler concentration. Fractal asphaltenes aggregation formed in the composites with 1 mass% asphaltenes. Network microstructures of asphaltenes aggregation appeared in the epoxy phase with a further increase of asphaltenes content. Moreover, the increase of asphaltenes loading resulted in denser network microstructures in the epoxy matrix. Aggregation evolution revealed that asphaltenes particles redispersed evenly in the epoxy resin in the form of some aggregates at the beginning of curing. During the cure reaction of epoxy, asphaltenes aggregates started to agglomerate and grow to network microstructures. The presence of asphaltenes led to the enhancement of the storage modulus of the neat epoxy at the rubbery stage. The glass transition temperature (Tg) of the epoxy composites slightly increased with the increase of asphaltenes loading. The epoxy composite with 5 mass% asphaltenes had higher Tg than the neat epoxy. The inclusion of asphaltenes had a negligible effect on the damping properties and thermal stability of the neat epoxy. The aggregation and heterogeneous dispersion of asphaltenes resulted in the decrease of the tensile strength and elongation at break of the neat epoxy. However, the inclusion of asphaltenes significantly enhanced Young’s modulus of the neat epoxy. Young’s modulus of the neat epoxy was increased by more than fourfold with the addition of 5 mass% asphaltenes.

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Topics: Epoxy (57%), Asphaltene (55%), Dynamic mechanical analysis (51%)

3 Citations


Journal ArticleDOI: 10.1617/S11527-021-01744-4
Yongjia Jiang1, Ruikang Zhao1, Zhonghua Xi1, Jun Cai1  +4 moreInstitutions (1)
Abstract: Brittleness is an inherent shortcoming of epoxy resin which results in the longitudinal fatigue cracking of mixtures during the long service time of orthotropic steel deck bridges. In this paper, this problem was addressed by introducing a reactive thermoplastic elastomer, epoxidized styrene–butadiene–styrene copolymer (ESBS) into epoxy asphalt binder (EAB). Epoxy ESBS modified asphalts (EESBAs) with various epoxidation degrees were prepared. Double phase separation occurred in the EESBAs. In the EESBAs with 18% and 31% epoxidation degrees, most of ESBS domains dispersed on the edge of the secondary asphalt phase and in the epoxy phase. Furthermore, the size and number of ESBS domains decreased in the epoxidation degree. However, un-epoxidized SBS domains completely dispersed the asphalt phase and all ESBS domains moved to the epoxy phase when the epoxidation degree increased to 39%. In EESBAs, the average diameters of asphalt domains increased in the epoxidation degree. The inclusion of ESBS increased the viscosity of the pure EAB and the viscosity of EESBAs increased in the epoxidation degree. Nevertheless, all EESBAs had at least a 150-min allowable construction time. By adding 2 wt% ESBS with 39% epoxidation degree, the glass transition temperature (Tg) decreased. The Tg of EESBAs decreased in the epoxidation degree. The inclusion of ESBS greatly enhanced the damping properties of the pure EAB. The elongation at break and toughness of the pure EAB were remarkably increased by 263% and 93%, respectively, with the incorporation of 2 wt% ESBS with 39% epoxidation degree. Furthermore, the toughness of EESBAs increased in the epoxidation degree.

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Topics: Epoxy (50%)

2 Citations


Journal ArticleDOI: 10.1016/J.CONBUILDMAT.2021.123598
Hongfeng Xie1, Ruikang Zhao1, Rui Wang1, Zhonghua Xi1  +3 moreInstitutions (1)
Abstract: B-staged epoxy bond coat (BEBC) has been widely applied as a waterproof adhesive layer in the pavements of orthotropic steel bridges. During its application, the uncured BEBC layer was first paved on the surface of the steel deck or the bituminous surfacing and hot bituminous mixture would be constructed until the BEBC layer became touch-dry. In this paper, the impacts of thermal shock on the degree of cure (DOC), pull-off strength, hydrophilicity, glass transition temperature (Tg), damping performance, thermal stability and mechanical behaviors of the touch-dry BEBC were investigated. Thermal shock greatly increased the DOC of the touch-dry BEBC and the touch-dry BEBC turned to be nearly fully cured after the thermal shock at a higher temperature. The pull-off strength of the touch-dry BEBC was remarkably improved by the thermal shock. After the thermal shock at 160 °C, the pull-off strengths at room temperature and at 60 °C of the touch-dry BEBC were increased by 584% and 914%, respectively. After the thermal shock, the contact angle of the touch-dry BEBC was greatly increased and the hydrophilicity of the touch-dry BEBC was converted to hydrophobicity. Thermal shock significantly increased the Tg of the touch-dry BEBC. Furthermore, the Tg of thermally shocked BEBCs slightly increased in the temperature. Thermal shock improved the damping performance of the fully cured BEBC. The tensile strength and toughness of the touch-dry BEBC were greatly improved by the thermal shock. However, thermal shock lowered the elongation at break of touch-dry BEBC. In the case of thermally shocked BEBCs, the temperature had a limited effect on the tensile strength, while the elongation at break increased in the temperature. The fracture energy first decreased in the temperature and increased after 150 °C. Maximum fracture energy appeared at 160 °C. After the thermal shock, the tensile strength of the touch-dry BEBC was increased by as much as 3-fold. The fracture energy of the BEBC thermally shocked at 160 °C was 182% greater than that of the touch-dry BEBC.

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Topics: Thermal shock (54%)

2 Citations


Journal ArticleDOI: 10.1016/J.JCLEPRO.2021.128061
Abstract: The objective of this work is to evaluate the potential of cashew nut shell liquid (CNSL) as a renewable resource and low-cost raw material for the synthesis of bio-based epoxy for asphalt binders. The epoxidized material named ECL was synthesized via chemical modifications in alkyl phenols present in CNSL – a good alternative of petrochemicals based on phenols to replace the toxic bisphenol A, currently used to synthetize epoxidized products. The additive was structurally characterized by Nuclear Magnetic Resonance (1H NMR and 13C NMR), and Fourier Transform Infrared Spectroscopy (FTIR), presenting results in accordance with the epoxidation reactions. Testing was conducted on asphalt binder with 10% and 20% of epoxidized CNSL to explore the influence of bio-epoxidized additives on the properties of binder, both unaged and RTFO-aged conditions. The Rotational Viscosity, Dynamic Shear Rheometer (DSR) and Binder bond strength (BBS) tests were utilized. The viscoelastic behaviour of epoxy modifier asphalt presented higher viscosity than neat asphalt binder. The rheological parameters from DSR showed that the epoxy modifiers enhance the elasticity of the binder, suggesting the presence of polymer elastic networks in modified binders. The rutting resistance of epoxidized modified binder at the high temperature was evaluated by Multiple Stress Creep and Recovery (MSCR) test, while the fatigue life was analysed by Linear Amplitude Sweep (LAS) test. The MSCR results indicated that the 10% of the ECL additive, increasing rutting resistance, while the LAS test showed that fatigue resistance of AB-10% ECL was positively affected by epoxidized CNSL additive. BBS results showed that the aged AB-10% ECL has the highest binder bond strength. Furthermore, the use of renewable energy resources is a strong incentive towards the development of less pollutant technologies.

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Topics: Dynamic shear rheometer (56%), Epoxy (50%)

1 Citations


References
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65 results found


Journal ArticleDOI: 10.1016/J.COMPOSITESB.2008.01.002
Abstract: There have been a number of review papers on layered silicate and carbon nanotube reinforced polymer nanocomposites, in which the fillers have high aspect ratios. Particulate–polymer nanocomposites containing fillers with small aspect ratios are also an important class of polymer composites. However, they have been apparently overlooked. Thus, in this paper, detailed discussions on the effects of particle size, particle/matrix interface adhesion and particle loading on the stiffness, strength and toughness of such particulate–polymer composites are reviewed. To develop high performance particulate composites, it is necessary to have some basic understanding of the stiffening, strengthening and toughening mechanisms of these composites. A critical evaluation of published experimental results in comparison with theoretical models is given.

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Topics: Particle (54%), Polymer nanocomposite (53%), Nanocomposite (52%) ... read more

2,397 Citations


Open accessBook
14 Dec 1997-
Abstract: An Introduction to Dynamic Mechanical Analysis. Basic Rheological Concepts: Stress, Strain, and Flow. Rheology Basic: Creep-Recovery and Stress Relaxation. Thermomechanical Analysis. Dynamic Testing. Time-Temperature Scans Part I: Transitions in Polymers. Time and Temperature Studies: Part II Thermosets. Frequency Scans. DMA Applications to Real Problems: Guidelines.

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Topics: Dynamic mechanical analysis (55%), Dynamic testing (53%), Thermomechanical analysis (52%) ... read more

1,389 Citations


Journal ArticleDOI: 10.1016/S0022-460X(03)00106-8
Mohan D. Rao1Institutions (1)
Abstract: In this paper, the application of passive damping technology using viscoelastic materials to control noise and vibration in vehicles and commercial airplanes is described. Special damped laminates and spray paints suitable for mass production and capable of forming with conventional techniques are now manufactured in a continuous manner using advanced processes. These are widely used in the automotive and aerospace industry in a variety of applications to reduce noise and vibration and to improve interior sound quality. Many of these recent applications are not readily available for dissemination in academe and archival literature. It is hoped that the material presented in this paper will be useful for instruction and further research in developing new and innovative applications in other industries.

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Topics: Noise control (52%)

498 Citations


Journal ArticleDOI: 10.1016/S0014-3057(01)00194-X
N. Chikhi1, S. Fellahi1, M. Bakar1Institutions (1)
Abstract: Epoxy resins are widely utilised as high performance thermosetting resins for many industrial applications but unfortunately some are characterised by a relatively low toughness. In this respect, many efforts have been made to improve the toughness of cured epoxy resins by the introduction of rigid particles, reactive rubbers, interpenetrating polymer networks and engineering thermoplastics within the matrix. In the present work liquid amine-terminated butadiene acrylonitrile (ATBN) copolymers containing 16% acrylonitrile is added at different contents to improve the toughness of diglycidyl ether of bisphenol A epoxy resin using polyaminoimidazoline as a curing agent. The chemical reactions suspected to take place during the modification of the epoxy resin were monitored and evidenced using a Fourier transform infrared. The glass transition temperature ( T g ) was measured using a differential scanning calorimeter. The mechanical behaviour of the modified epoxy resin was evaluated in terms of Izod impact strength (IS), critical stress intensity factor, and tensile properties at different modifier contents. A scanning electron microscope (SEM) was used to elucidate the mechanisms of deformation and toughening in addition to other morphological features. Finally, the adhesive properties of the modified epoxy resin were measured in terms of tensile shear strength (TSS). When modifying epoxy resin with liquid rubber (ATBN), all reactivity characteristics (gel time and temperature, cure time and exotherm peak) decreased. The infrared analysis evidenced the occurrence of a chemical reaction between the two components. Addition of ATBN led to a decrease in either the glass transition temperature and stress at break accompanied with an increase in elongation at break and the appearance of some yielding. As expected, the tensile modulus decreased slightly from 1.85 to about 1.34 GPa with increasing ATBN content; whereas a 3-fold increase in Izod IS was obtained by just adding 12.5 phr ATBN compared to the unfilled resin. It is obvious that upon addition of ATBN, the Izod IS increased drastically from 0.85 to 2.86 kJ/m 2 and from 4.19 to 14.26 kJ/m 2 for notched and unnotched specimens respectively while K IC varies from 0.91 to 1.49 MPa m 1/2 (1.5-fold increase). Concerning the adhesive properties, the TSS increased from 9.14 to 15.96 MPa just by adding 5 phr ATBN. Finally SEM analysis results suggest rubber particles cavitation and localised plastic shear yielding induced by the presence of the dispersed rubber particles within the epoxy matrix as the prevailing toughening mechanism.

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Topics: Epoxy (60%), Diglycidyl ether (55%), Thermosetting polymer (54%) ... read more

364 Citations


Journal ArticleDOI: 10.1016/0079-6700(94)00032-W
Takashi Inoue1Institutions (1)
Abstract: Spinodal decomposition induced by chemical reaction is observed in an epoxy/ polyethersulphone (PES) system having a lower critical solution temperature (LCST) type phase diagram. The binary mixture is homogeneous at its curing temperature (< LCST). When the cure reaction proceeds, the system is thrust into a two-phase regime by the LCST depression caused by a molecular weight increase and phase separation then takes place via spinodal decomposition. Reaction-induced spinodal decomposition yields a variety of two-phase structures: interconnected globule structures, isolated domain structures with uniform domain size, and bimodal domain structures, depending on the relative rates of the chemical reaction and the phase separation. This cured epoxy/PES is a tough thermoset material which has been used as a matrix resin for CFRP. A new high-impact poly(methyl methacrylate) (PMMA) (PMMA particles/poly(ethylene-covinylacetate) (EVA) matrix), can be obtained by radical polymerization of an 80/20 MMA/EVA mixture. Polyimide/silica hybrid materials with excellent heat resistances were also obtained by the sol-gel method. A very high strength rubber (~60 MPa) was obtained by peroxide cure of a hydrogenated nitrile rubber/zinc dimethacrylate mixture. Structure formation in reaction-induced spinodal decomposition has been modelled by computer simulation of the growth of a concentration fluctuation under a successive increase in thermodynamic quench depth.

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353 Citations