Cure Kinetics Of TGDDM Epoxy Resins Toughened With Polysulfone

Epoxy resins are the main matrix for high-performance composites. After cure epoxy resins converte into three-dimensional, cross-linked network stucture which results in brittle behavior of epoxy resins. It is important to understand the reaction kinetics of the epoxy resins in these blends. To predict and controll the properties of cured epoxy resins, it is essential to develop suitable kinetic models to simulate the curingreaction for invesigating the cure mechanism.The aim of this work was to investigate the cure behavior of an epoxy resin 4,4'-diamiodiphenyl methane(TGDDM) cured with 4,4'-diaminodiphenyl sulfone(DDS) respectively toughened with Polysulfone(PSF) nanofibers and PSF films.PSF nanofibers were produced by electrospinning. In order to optimize the technics of electro-spinning, some processing parameters were studied respectively. SEM shows that the average diameter of PSF nanofibers is 231nm.The thickness of the PSF thermoplastic films can be controlled by altering the concentration of the PSF solution. In this paper, the thickness of the films added to the epoxy resins is 30um which is suitable.The cure kinetics and mechanisms of epoxy resin system TGDDM toughened with nano PSF fibers and PSF films were respectively studied with differential scanning calorimetry (DSC) under non- isothermal and isothermal conditions. The results show that the reaction mechanism as well as the orders of the two kinds of toughening epoxy resins remained the same as that of the neat epoxy resins.With the increasing of nano PSF fibers and PSF films, the reaction rate and the conversion of toughening epoxy resin systems increased. The same result can also be obtained when the reaction temperature increase. However it can be found that under the same cure temperature, the parameter of nano PSF fibers toughened epoxy resins were higher than that of PSF, including the reaction rate, the conversion as well as the cure extend.Phase separation takes place in the epoxy resins modified. Phase morphology, phase distributing, phase development and the chemical reaction between epoxy resins and thermoplastic during cure progress. In this study the phase morphology of the PSF nanofibers and PSF films modifying epoxy resins were monitored by AFM. The microstructures of modified epoxy resins and the toughening mechanisms of PSF nanofibers and PSF films in epoxy resins were studied. It was found that the nano PSF fibers modifying epoxy resin system existed two phase structure, the irregularly deformed PSF particles dispersing in the epoxy resin matrix. However, only one phase structure was found in the epoxy resins modified by the PSF films.