Synthesis of waterborne epoxy resin with diethanolamine-assisted succinimide for improving the strand integrity of polyimide filament

A water-soluble epoxy resin emulsion was synthesized by diethanolamine-assisted succinimide modified epoxy resin (DSEP) and used to reinforce the strand integrity of polyimide filament (PI). FTIR, XPS, and 1H NMR provide an evidence for the succinimide (SI) and diethanolamine (DEA) bonded onto the epoxy resin (EP) structure in the form of C-N-C. The DSEP emulsion shows high storage and dilution stability, with its particle size distribution and PDI of 118∼232 nm and 0.106∼0.638, respectively. Compared with DEA modified EP, DSEP exhibits better strand integrity for PI filament. The breaking strength of PI filament infiltrated by DSEP can reach 2.59 GPa, which is increased by 47.04% than that of PI filament, and is close to that of commercially available water-soluble polyimide resin (2.63 GPa). In addition, the fracture microstructure of PI filament further confirms that DSEP significantly reinforces the aggregation of PI filament. Importantly, there is no wire splitting phenomenon of DSEP reinforced PI filament after more than 200 times of friction. These benefit from the similar material groups of imide ring and benzene ring between DSEP and PI filament structure, as well as the strong hydrogen bonding interaction between them, as further confirmed by FTIR and SEM analysis.

Preparation Optimization and Performance Evaluation of Waterborne Epoxy Resin for Roads

To further improve the road performance of waterborne epoxy resin, it was prepared by using the phase inversion method. The tensile properties, bending properties, impact resistance, and storage stability of waterborne epoxy resin were determined. The bonding properties of waterborne epoxy resin were analyzed. At the same time, their properties were compared with those of waterborne epoxy resin prepared by using the curing agent emulsification method. The performance of waterborne epoxy resin was comprehensively evaluated based on multi-index grey target decision model. The results show that the optimum preparation parameters for the preparation of waterborne epoxy resin by phase inversion method are shear time 1.5 h, shear temperature 60°C, and shear rate 1300–1500 r/min. The suitable contents of emulsifier A and B are 18% and 16%, respectively. The tensile strength, elongation at break, bending strength, bending deformation, and impact strength of waterborne epoxy resin prepared by emulsifier A can reach 34.46 MPa, 12.96%, 85.37 MPa, 19.42 mm, and 15.66 kJ/m2, respectively. It shows improved mechanical strength, deformation ability, impact resistance, and bonding performance. The comprehensive properties of waterborne epoxy resin prepared by emulsifier A are the best. It is suggested to use phase inversion method to prepare waterborne epoxy resin for roads.