The presence of inorganic particles gives high mechanical properties to the epoxy resin, and its strength, stiffness, toughness, and heat resistance are greatly improved, which is manifested in the increase in the impact strength, tensile strength, and elastic modulus of the material. Glass temperature increase. Epoxy resin is a thermosetting resin with excellent overall performance and has been widely used. However, epoxy resin cured products are brittle, have poor impact resistance, are easy to crack, and are not resistant to fatigue. Various modifications are made to improve their performance as rings. Oxygen resin research hotspots. The combination of nano-inorganic particles and epoxy resin can combine the stiffness, dimensional stability and thermal stability of inorganic materials with the toughness and processability of epoxy resin, exhibiting the synchronization effect of toughening and reinforcement. What are the properties and mechanism of inorganic nanoparticle-filled modified epoxy resins?
With the addition of nanoparticles, the impact strength of composites has been greatly improved. The generally accepted mechanism of action is that after the nano-particles are uniformly dispersed in the epoxy resin, if the matrix resin is impacted by an external force, there will be a gap between the particles and the matrix. The silver grains are generated, and the matrix resin between the nanoparticles also undergoes plastic deformation and absorbs a certain impact energy. As the particles become finer, the specific surface area will further increase, and the contact surface between the nanoparticles and the matrix resin will also increase; When the material is impacted by external force, it will produce more silver lines and plastic deformation, and absorb more impact energy to achieve the toughening effect. If too much nano-particles are added, larger silver lines and plastic deformation will occur when the external force is applied, and macro-cracking will occur, and the impact strength will decrease.
The presence of rigid nano-particles is prone to stress concentration and causes silvering of the surrounding matrix resin, which absorbs certain deformation work. On the other hand, the presence of rigid nano-particles causes the expansion of the silver streaks in the matrix resin to be hindered and passivated, eventually stopping the cracking. Do not develop destructive cracking, resulting in toughening effects. The addition of nanoparticles all increase the tensile strength of the matrix. The increase in tensile strength may be due to the physical or chemical bonding of the inorganic particles to the epoxy resin through the coupling agent, which enhances the interfacial adhesion, so that the nanoparticles can take a certain load and make the tensile strength of the composite material. increase. The addition of nanoparticles all increase the basic flexibility. For particle-reinforced composites, the load is shared by the matrix and the particles. The particles mechanically constrain the deformation of the matrix to produce reinforcement. The tethering effect of the particles limits the movement and deformation of the matrix, and the degree of the tethering effect is related to the particle gap, particle properties, and matrix properties.
The reason why the glass transition temperature of the epoxy resin is increased due to the addition of nanoparticles, there is a strong interaction between the nanoparticles and the epoxy resin, and the glass transition temperature increases. The surface-treated nano-particles actually act as cross-linking sites in the matrix. On the one hand, the surface is favorable for entanglement of the epoxy resin chains to form physical crosslinks; on the other hand, the surface treatment agent and the matrix bond of the surface are Together, it forms a good interface between the filler particles and the matrix and acts as a chemical crosslinking point. Therefore, with the addition of nanoparticles, the crosslink density increases to increase the glass transition temperature. It can be seen that the addition of nanoparticles can significantly increase the glass transition temperature of the system and improve the heat resistance of the system.
Therefore, the modification mechanism of nanoparticles has obvious characteristics. Inorganic nanoparticles have the energy transfer effect, so that the matrix resin crack propagation is blocked and passivation, and eventually stop the crack, will not develop into destructive cracking; with the reduction of the particle size of nanoparticles, The specific surface area of ​​the particles increases, the contact area between the nanoparticles and the substrate increases, the material generates more micro-cracks when impacted, and absorbs more impact energy; the inorganic nanoparticles have a balance effect of stress concentration and stress radiation, and absorb shocks. The energy causes no obvious stress concentration on the substrate and achieves the mechanical equilibrium state of the composite material. If the amount of nano particles is too large or the particle size of the filler is large, the stress concentration of the composite material is more obvious, and the micro crack easily develops into macro cracking, resulting in compounding. The performance of the material is degraded; the inorganic nanoparticles in the matrix, as the cross-linking point of the polymer molecular chains, contribute to the improvement of the tensile strength and the glass transition temperature of the composite material.
With the addition of nanoparticles, the impact strength of composites has been greatly improved. The generally accepted mechanism of action is that after the nano-particles are uniformly dispersed in the epoxy resin, if the matrix resin is impacted by an external force, there will be a gap between the particles and the matrix. The silver grains are generated, and the matrix resin between the nanoparticles also undergoes plastic deformation and absorbs a certain impact energy. As the particles become finer, the specific surface area will further increase, and the contact surface between the nanoparticles and the matrix resin will also increase; When the material is impacted by external force, it will produce more silver lines and plastic deformation, and absorb more impact energy to achieve the toughening effect. If too much nano-particles are added, larger silver lines and plastic deformation will occur when the external force is applied, and macro-cracking will occur, and the impact strength will decrease.
The presence of rigid nano-particles is prone to stress concentration and causes silvering of the surrounding matrix resin, which absorbs certain deformation work. On the other hand, the presence of rigid nano-particles causes the expansion of the silver streaks in the matrix resin to be hindered and passivated, eventually stopping the cracking. Do not develop destructive cracking, resulting in toughening effects. The addition of nanoparticles all increase the tensile strength of the matrix. The increase in tensile strength may be due to the physical or chemical bonding of the inorganic particles to the epoxy resin through the coupling agent, which enhances the interfacial adhesion, so that the nanoparticles can take a certain load and make the tensile strength of the composite material. increase. The addition of nanoparticles all increase the basic flexibility. For particle-reinforced composites, the load is shared by the matrix and the particles. The particles mechanically constrain the deformation of the matrix to produce reinforcement. The tethering effect of the particles limits the movement and deformation of the matrix, and the degree of the tethering effect is related to the particle gap, particle properties, and matrix properties.
The reason why the glass transition temperature of the epoxy resin is increased due to the addition of nanoparticles, there is a strong interaction between the nanoparticles and the epoxy resin, and the glass transition temperature increases. The surface-treated nano-particles actually act as cross-linking sites in the matrix. On the one hand, the surface is favorable for entanglement of the epoxy resin chains to form physical crosslinks; on the other hand, the surface treatment agent and the matrix bond of the surface are Together, it forms a good interface between the filler particles and the matrix and acts as a chemical crosslinking point. Therefore, with the addition of nanoparticles, the crosslink density increases to increase the glass transition temperature. It can be seen that the addition of nanoparticles can significantly increase the glass transition temperature of the system and improve the heat resistance of the system.
Therefore, the modification mechanism of nanoparticles has obvious characteristics. Inorganic nanoparticles have the energy transfer effect, so that the matrix resin crack propagation is blocked and passivation, and eventually stop the crack, will not develop into destructive cracking; with the reduction of the particle size of nanoparticles, The specific surface area of ​​the particles increases, the contact area between the nanoparticles and the substrate increases, the material generates more micro-cracks when impacted, and absorbs more impact energy; the inorganic nanoparticles have a balance effect of stress concentration and stress radiation, and absorb shocks. The energy causes no obvious stress concentration on the substrate and achieves the mechanical equilibrium state of the composite material. If the amount of nano particles is too large or the particle size of the filler is large, the stress concentration of the composite material is more obvious, and the micro crack easily develops into macro cracking, resulting in compounding. The performance of the material is degraded; the inorganic nanoparticles in the matrix, as the cross-linking point of the polymer molecular chains, contribute to the improvement of the tensile strength and the glass transition temperature of the composite material.
7.5M Measuring Tape,Tape Measure Tool,Precision Tape Measure,Tape Measure For Sale
SHANGQIU CHAOYUE MEASURING TOOLS CO., LTD , https://www.calibrateds.com