Application Of The Isoconversional Methods On Thermal Analysis Of Polymers

The polymer aggregated structure is the direct factor to influence the properties of polymer material. All kinds of physical and chemical state as well as releasing and absorption to heat are involved in the formation and variation process of aggregated structure (such as crystallization, Curing Process). The analysis to the change of thermal is an important method to study polymer materials. This paper analyses activation energy of polymer materials and nano-composites material in thermal transition process by using the thermal analysis method of isoconversional. The relation between polymer and nano filler in the process of isoconversional can be deduced. Then the formation and evolution of polymer nanocomposites aggregated structure is relatively thorough realized.In this paper, nano Si3N4particles are selected as nano filler which often apply to ceramics not widely to polymer materials. At first, Coupling agent γ-GLlycidoxypropyl trimethoxysilane is used in making surface modification of nano Si3N4particles which makes better combination between nanoparticles and polymer materials. Then, the modified nano Si3N4particles are filled into the polymer matrix by the method of high speed mix, sonic oscillation and banburying. We choose some typical polymer to research which forms composites together with nano Si3N4particles. These polymers are PET with relatively slow crystallization,PA-6with relatively quick crystallization and E-51. Based on the common analysis method of isoconversional such as Friedman Flynn-Wall-Ozawa (FWO), Coats-Redfern methods, the those typical polymer and changing regularity to activation energy in the crystallization and solidify process of the composites can be studied, which has unique advantage with respect to general analysis method such as Avrami, Kisssinger.The analysis for PET-Si3N4particle system discovers that PET with1wt%nano particle crystallizes at higher rate, but when the content of nano particle is more than2wt%, the crystallization of PET is impeded. nano particle has less impact on the crystallization of PA6than PET. The rate of PA6crystallization is slightly increased only when cooling rate is relative low. Although crystallization activation energy for two kinds of thermoplastic materials increases as relative crystallinity increases, crystallization activation energy of PET-Si3N4system is larger than that of PA6-Si3N4system. However, Si3N4nano particle whose content is less than0.45wt%promotes the curing reaction of epoxy resin E-51/DDM/Si3N4system of which curing activation energy goes down firstly, then up with the reaction degree increase.