Experimental Parameter Simulation And Preparation Study Of Latent Microcapsule Curing Agent

Prepreg is a storable semi-finished product of fiber-reinforced composite material.If the matrix resin is thermosetting resin,curing agent should be added to form prepreg together with the reinforcing material and other additives.Prepreg is normally stored at low temperatures and thawed when used.Moreover,if the curing temperature of prepreg is high,there will be problems such as high internal stress of curing,poor quality of finished products and high energy consumption.If low temperature curing prepreg is used,the curing speed is fast and the prepreg is not suitable for more than 10 days at room temperature.In this paper,the microcapsule technology is applied to the preparation of a latent curing agent,so that it has high reaction activity and better storage performance at room temperature.In this paper,the formation process of microcapsules was simulated by a specific simulation method.Specific simulation methods are the Dissipative Particle Dynamics simulation(DPD)and Molecular Dynamics simulation(MD).In the DPD simulation,the stability of emulsion formation was explored,the beads in the system were coarsely granulated,the interfacial tension of the system under different conditions was calculated,and the microscopic mechanism was explained.The diffusion capacity of small molecules in the volatile process in PMMA was simulated by MD simulation method,and the diffusion capacity of small molecules in solvent and curing agent was compared.By means of simulation,the influence of water content,surfactant,and temperature on the stability of the emulsion is summarized.The influence of temperature on the movement performance of each molecule in the polymer shell material in the solvent volatilization process is also summarized,which could provide parameters for experimental preparation and simplify the experimental process.In this paper,based on the above simulation,but also the control variable method by changing the simulation more difficult than shell core,stirring rate and the content of stabilizer three conditions for the preparation of microcapsule,summarize the microcapsules morphology characteristics and the influence of particle size,also of PMMA coating and two kinds of different imidazoles core material(2-MI,2-PZ)microcapsules of curing agent to identify the composition of FT-IR,TG core content test,and the microcapsule storage life at room temperature curing agent/epoxy resin system of the measurement.Morphology analysis showed that the microcapsules were characterized by high sphericity,no holes on the surface,no adhesion between each other,average size between 8-25 ?m,shell thickness between 1.5-2 ?m,and fish-scale uneven surface.The optimum preparation technology of microcapsule was obtained by analyzing the influence of morphology and particle size.Microcapsule was verified by infrared spectra.By thermo-gravimetric curve measured with 2-MI/PMMA ? 2-PZ/PMMA microcapsule,the core material were 16% and 33% respectively,shows the microcapsule shell material effect on the protection of the core material,and indicates that O/W emulsion solvent evaporation method is more suitable for coating oil soluble core material.The protected by microcapsule PMMA shell material of imidazole curing agent 2-PZ contact with epoxy resin storage,incubation period at room temperature for more than 3 months,showed the excellent performance of latent.