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.

Pitch precursors affording excellent spinnability, high-level oxidation-resistance, and good carbonization yields were prepared by bromination–dehydrobromination of various ratios of pyrolyzed fuel oil and coal tar pitch. The pitches exhibited spinnabilities that were much better than those of pitches prepared via simple distillation. A pitch prepared using a 1:2 ratio of fuel oil and coal tar pitch exhibited the best tensile strength. Pitch fibers of diameter 8.9 ± 0.1 μm were stabilized at 270 °C without soaking time after heating at a rate of 0.5 °C/min and carbonized at 1100 °C for 1 h after heating at 5 °C/min. The resulting carbon fibers exhibited a tensile strength, elongation, Young’s modulus, and average diameter of 1700 ± 170 MPa, 1.6 ± 0.1%, 106 ± 37 GPa, and 7.1 ± 0.2 μm, respectively.

Isotactic polyacrylonitrile (PAN) with triad isotacticity of 0.53, which was determined by 13C NMR, using dialkylmagnesium as an initiator, was successfully synthesized. Isothermal treatment of iso-PAN was conducted in air at 200, 220, 250 and 280℃. Structural evolutions and chemical changes were studied with Fourier transformation infrared and wide-angle X-ray diffraction during stabilization. A new parameter CNF=I2240cm-1/ (I1595cm-1+f*I1595cm-1) was defined to evaluate residual nitrile groups. Crystallinity and crystal size were calculated with X-ray diffraction dates. The results indicated that the nitrile groups had partly converted into a ladder structure as stabilization proceeded. The rate of reaction increased with treatment temperature; crystallinity and crystal size decreased proportionally to pyrolysis temperature. The iso-conversional method coupled with the Kissinger and Flynn-Wall-Ozawa methods were used to determine kinetic parameters via differential scanning calorimetry analysis with different heating rates. The active energy of the reaction was 171.1 and 169.1 kJ/mol, calculated with the two methods respectively and implied the sensitivity of the reaction with temperature.

Polyacrylonitrile (PAN) fibers were pre-oxidized in a temperature range of 180-275℃. The effects of positive and negative stretching on the structure and morphology of PAN fiber in the pre-oxidation process were studied by FTIR spectroscopy, XRD, and SEM. Mechanical property changes were also investigated. No changes in the movement and intensity of functional groups of PAN fibers were caused by positive stretching of up to 10% and negative stretching down to -8%. The crystal structure can be affected by the positive stretching and negative stretching. The maximum strength is 479.81 MPa when the stretching is positive, and the maximum strength is 420.55 MPa when the stretching is negative.

The blue-green algae which caused odor problem in the tap water are difficult to precipitate in sedimentation basin and clogged the filter void rapidly. The studies of this paper were not only oxidation, coagulation and sedimentation processes for effectively removing blue-green algae but yellow clay and polyamine for verification as coagulants aids. The results of this research are summarized as follows: Higher ozone dose(C) and longer contact time(T) were needed for a high degree of removing blue-green algae efficiency. the removal rate of blue-green algae was proportional to the C×T value. The removal percent of chlorophyll-a by sedimentation and filter without pre-ozonation was about 75% but 1 mg/L pre-ozonation could increase the removal percent of chlorophyll-a to 99% and more pre-ozonation could remove completely. Though the removal efficiency of turbidity could increased by high dose of chlorination, the dissolved organic carbon was increased. More chlorine dose from 4 to 10 mg/L dissolved organic carbon was decreased. Using yellow clay as coagulant aids increased density of floc so the settling velocity of floc become rising but polyamine could not increase settling velocity of floc though it could formated large floc.