Study On The Properties And Preparation Of Polyether Sulfone Toughened Epoxy Prepreg

Currently, most composite materials are prepared by prepreg layup. Therefore, research on prepreg is becoming increasingly important. Ensuring storage time of prepreg, reducing the cost of composite materials and achieving moderate temperature curing is the direction of the researchers which they have been working on. However, due to the heaby density of cured epoxy resin crosslink, it shows a high degree of brittleness. With the development of composite materials in aircraft, ships and other fields, the demand on epoxy prepreg is on the increase.Therefore, it has been a hot issue of composites researchers' work on toughening epoxy prepreg research based on the moderate temperature curing,In this paper, while meeting the performance requirements of the hot melt prepreg, solid epoxy resin E20, and liquid epoxy phenolic epoxy NPCN704 NPEL128 are choosed as a matrix resin system, and the state of the resin system at room temperature is studied. The optimum ratio of the resin matrix is determined by viscosity-temperature – curve. Non-isothermal DSC and DMA are used to determine the optimal ratio of dicyandiamide / diureas curing system to achieve moderate temperature curing Ultimately curing system is that, 100?/1h+130?/2h+180?/2h. The effect of molding process for composites on performance of composites are studied by the preparation of composites. Through optimizationas, molding process is determined as initial temperature 100 ?, 20 min incubation pressure, a pressure of about 4MPa. After the molding process, subsequently curing carry out by curing system 130 ? / 2h + 180 ? / 2h. In this paper, the dynamics of epoxy curing reaction is studied by a combination use of non-isothermal DSC and isothermal The kinetics equation of curing reaction is studied and the kinetic parameters are calculated by non-isothermal DSC.The curing system dynamics model is researched by isothermal DSC and he model parameters calculated by pattern matching. Finalize the autocatalytic reaction model to meet the characteristics of autocatalytic model and dominant position in the reaction.In this paper, medium temperature curing system is toughened by PES. The effects of the content of PES on viscosity of resin and mechanical properties of the casting resin are studied and ultimately the amount of PES is slected as 8%. The glass transition temperature of the composite material which 8% PES is added in is studied by DMA. Data shows that before and after the modification of PES, the glass transition temperature of the system was maintained at about 150 ? while the latter increased slightly; only one peak emerge on curves showing that the compatibility of base resin system and PES is excellent; the elastic deformation capacity of the system is enhanced after toughening. The curing reaction mechanism is studied by infrared testing. Infrared test shows that dicyandiamide have not been broken down into cyanamide to participate in the reaction and the open-loop reaction occurs between active hydrogen and cyano group on dicyandiamide and epoxy group when dicyandiamide curing epoxy resin. Finally, the toughening effect PES can be observed from the scanning electron micrographs which verifies thepossibility that PES improved the mechanical properties of the composites.