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In this paper, the rheological, electrical and mechanical properties of silver paste with different blends of epoxy resin and polyester resin were studied. The thixotropy and thixotropy recovery rate of resin silver paste were studied by rheometer, and the effect of rheology on printing film was discussed. In situ curving resistance test method was used to monitor the change of thermal curing resistance of silver resin paste. The results showed that the content of epoxy resin in silver paste had great influence on the resistance. The adhesion strength of resin silver paste on Al2O3 substrate was evaluated by the thrust test method, and the thermal impact performance of resin silver paste was evaluated. The results showed that when the ratio of epoxy resin to polyester resin was 1:0.6, the viscosity of C-1 silver paste was moderate, the thixotropic recovery rate was 58.03% after 10 s, and the printing surface was flat. After curing at 200 ℃ for 30 min, the resistance is about 2 Ω, the adhesion strength is about 10 N/mm², and the adhesion strength is not significantly deteriorated after thermal shock at 260 ℃. The comprehensive performance is better, and it is suitable for the process requirements of electronic components. [ABSTRACT FROM AUTHOR]

Tn this paper, different contents (0.25%, 0.5%, 0.75% and 1%) of graphene nanoplatelets (GNP) were used to modify epoxy resin adhesive. Through double-sided shear tests of carbon fiber reinforced concrete structures, the change of adhesive properties before and after GNP modification under different time of immersion aging (2, 4, 6, 8 weeks) was studied, and the influence of graphene nanoplatelets modification on the durability of adhesive joint was investigated. The test results show that both the interfacial bonding strength and the maximum slip displacement increase first and then decrease with the increase of GNP content under the nonimmersion and immersion aging tests, and 0.5% GNP has the largest increase rate for interfacial bonding strength under each working condition. After 8 weeks of immersion aging, ().5% GNP increases the bonding strength and maximum slip by 54.1 % and 53.66% respectively. After 8 weeks of aging, the bonding strength of unmodified adhesive decreases by 15.19% compared with the non-aging environment, while 0.5% GNIVEpoxy adhesive only decreases by 10.47%. The GNP reinforced adhesive could not only improve the adhesive joints strength, but also reduce the diffusion of water molecules into adhesive and interface. This paper provides some reference for the application of GNP reinforced adhesive to enhance durability of the carbon fiber bonded concrete structure. [ABSTRACT FROM AUTHOR]

The introduction of phosphorus elements inside the epoxy resin by chemical modification can effectively improve its liquid oxygen compatibility, and this will also change the chemical properties of the epoxy resin, but the change of chemical properties remains to be studied. Since it is difficult to characterize some chemical properties in experimental studies, this paper made an in-depth study of the chemical properties of 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phospha-phenanthrene-10-oxide (ODOPB) modified epoxy resin molecules based on the density functional theory (DFT). In order to analyze the effect of chemical properties on grafting ODOPB functional groups into the epoxy resin molecules, the relevant properties of unmodified epoxy resin molecules were also studied and compared. The results showed that the bond dissociation energy and Laplace bond order on the main chain of the epoxy resin molecule increased after ODOPB modification, and the maximum values of the electrostatic potential and average local ionization energy decreased, indicating that grafting ODOPB can improve the thermal stability and liquid oxygen compatibility of the epoxy resin. This study provides the theoretical basis for the study of the ODOPB modified epoxy resin liquid oxygen compatibility mechanism on the molecular level. [ABSTRACT FROM AUTHOR]

In recent years, some halogen-based flame retardants have been gradually eliminated out for consideration of the environment， and phosphorus-containing flame retardants have received extensive attention as substitutes for halogen-based flame retardants. However, efficient phosphorus-based flame retardants usually produce more smoke while improving flame retardancy, therefore, they need to be used in combination with synergists. This paper introduced the flame-retardant mechanism of phosphorus-containing flame retardants in epoxy resin. The latest research progress of synergists， including inorganic， organic， and organic-inorganic hybrid synergistic agents， with phosphorus-based flame retardants in epoxy resin was summarized. We look forward to the future development trend of the synergistic system of phosphorus-containing flame retardants in epoxy resin. [ABSTRACT FROM AUTHOR]

In view of the technical difficulties in plugging and protecting fractured reservoirs, based on the analysis of the selfdegradation mechanism of epoxy resin materials, this paper developed a new type of epoxy resin self-degradation plugging agent, and experimentally explored the influence of the dosage of curing agent and modifier on the performance of the new type of epoxy resin self-degradation plugging agent. With the help of pressure bearing strength experiment, long fracture plugging simulation experiment device, reservoir protection tester, etc., the compressive strength, fracture plugging and reservoir protection performance were systematically tested. The experimental results show that the newly developed epoxy resin self-degradable plugging agent has good degradation performance. The final degradation rate can reach more than 90% at all temperatures, and the degradation rate is more than 95% at 120 ℃ for 96 h. The environmental temperature and pH can promote its degradation; At the same time, the selfdegradable plugging agent has a high elastic modulus and a good compression crushing rate, and the compression crushing rate is only 6.2% under 30 MPa. Combined with the particle size grading optimization, the new epoxy resin self-degradable plugging agent can effectively block the cracks between 0.5-4 mm, and has a good crack pressure bearing sealing effect, the result of reservoir protection experiment shows that after 8 days of degradation of self-degradable plugging agent, the core permeability recovery rate reaches 99.1%, and the reservoir protection effect is good. [ABSTRACT FROM AUTHOR]

Aiming at the problems of insufficient flexural strength and low durability of cement concrete, this paper prepared concrete with different content of epoxy resin（0%, 3 wt%, 6 wt%, 9 wt%） by using epoxy resin as doping phase, and analyzed the influence of epoxy resin on the mechanical properties, micro appearance and durability of cement concrete. The results show that the doping of epoxy resin accelerates the hydration reaction, reduces the number of cracks and pores, and improves the density of concrete. The compressive strength and flexural strength both increased first and then decreased with the increase of resin doping. The compressive strength and flexural strength of the concrete with 6 wt% epoxy resin doping reached the maximum values of 43.8 and 7.9 Mpa respectively when cured for 28 d, which increased by 18.70% and 29.51% respectively compared with the concrete without resin doping. The chloride ion diffusion coefficient of concrete decreases first and then increases with the increase of resin doping amount. The chloride ion diffusion coefficient of concrete with 6 wt% epoxy resin doping content for 28 d is the lowest of 7.7×10-8 cm/s, and the chloride ion corrosion resistance is the best. When the number of freeze-thaw cycles reaches 80, the concrete with 6 wt% epoxy resin doping has the lowest mass loss rate of-0.13%, the highest relative dynamic elastic modulus of 94.86%, the lowest wear amount of 0.66 kg/m², and the wear amount reduction rate of 46.77%. It has excellent durability. [ABSTRACT FROM AUTHOR]

In order to reduce the thermal expansion coefficient of epoxy resin, in this paper a low thermal expansion LaFe10.5Co1.0Si1.5/epoxy resin composite material is prepared based on the negative thermal expansion filler LaFe10.5Co1.0Si1.5. Then the influence of LaFe10.5Co1.0Si1.5 filler content on the mechanical properties and thermal expansion properties of the materials is studied. And the gradient distribution of filler particles in the resin matrix is induced by the magnetic field driving method to prepare functional materials with gradient thermal expansion. The results show that LaFe10.5Co1.0Si1.5 can effectively reduce the linear expansion coefficient of epoxy resin-based composites between 228-323 K, and the linear expansion coefficient of the composites can be reduced by 58% when adding 70% LaFe10.5Co1.0Si1.5 filler. In addition, the variation regularities of TGA, thermal conductivity, tensile strength and other properties prove that LaFe10.5Co1.0Si1.5 particles show a gradient distribution along the direction of the magnetic field driven by an external magnetic field. Meanwhile, the thermal expansion properties of the composite materials also show a significant gradient change. These prove that the magnetic field driving method is an effective and simple method for preparing low thermal expansion epoxy gradient materials. [ABSTRACT FROM AUTHOR]