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The composite PAN fibers which incorporated with CNTs and Titania were prepared by mean of wet spinning. These fibers were then pre-oxidized with microwave heating in an air atmosphere. A combination of characterizations was carried out to study the impact of nanoparticles fillers on the properties of as-spun fibers and their performance during the microwave pre-oxidation. The addition of an equal amount of fillers made obvious changes in the chemical and crystalline structure, consequently improves the strength, and this could lower the capability to creep over a wide range of temperatures in the subsequent processes. FTIR and NMR analyses results of the pre-oxidized fibers exhibited clear changes in the PAN structure, where the dehydrogenation reaction and the degree of cyclization were investigated. Additional confirmation of the occurrence of cyclization reaction was achieved by XRD and thermal analysis. According to the TGA results, the pre-oxidized CNT1/Ti-PAN fibers exhibit greater thermal stability suggesting high carbon content and good quality could result in the dependent carbon fibers.

In this paper, hydroxyl terminated polyethersulfone(PES) was used as a toughening agent to modify the monocomponent high performance epoxy resin by blending. The solubility of PES in epoxy resin and the curing performance, mechanical properties, morphology, viscoelastic properties and thermal properties of epoxy/PES blends were investigated, respectively. The dissolution experiment results showed that the hydroxyl terminated PES had a good compatibility with the epoxy resin and could be dissolved in epoxy resin under controlled conditions. FT-IR studies showed that the addition of PES did not affect the result of epoxy resin curing reaction. The results of the mechanical properties of the epoxy/PES blends indicated a 32% and 9% enhancement in fracture toughness and impact strength respectively, which can be ascribed to the bicontinuous phase structure of the epoxy/PES blends. Reaction induced phase separation was observed in the epoxy/PES blends during the curing process of epoxy resin, which presented dispersed particles, bicontinuous and phase inverted structures with the increase of the PES content. Thermogravimetric analysis revealed that the thermal stability of the epoxy/PES blends were slightly increased compared to that of the pure epoxy resin. Thus, the hydroxyl terminated PES could be used to improve the mechanical and thermal properties of the monocomponent high performance epoxy resin.

The effective use of single walled carbon nanotubes (SWCNT) for improving mechanical properties of polymers is the key to the efficient diffusion of carbon nanotubes into organic solvents to form a stable single solution. The single walled carbon nanotubes in dimethylacetamide (DMAc) with different dispersion methods (including homogenizer, ball mill, micro jet machine) were studied in this paper, adding different organic compounds (dispersant, polyacrylonitrile) and different chemical treatment methods (acid purification, etc.) affect the dispersion of single wall carbon nanotubes were also discussed. The best dispersing time, the effects of different conditions on the basic properties of Single-walled carbons and on the dispersed state of carbon nanotubes were determined by using optical microscopy, scanning electron microscopy, Raman and elemental analysis, in order to get the optimal dispersion conditions of single-walled carbon nanotubes in DMAc.