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The research and development trend demands of high-performance carbon fiber precursor of the high purification and structure homogenised From the outset, however, in the polymer to join the second termonomer to broaden the exothermic nature of the polymer and to improve spinnability. Therefore, how the structure of the polymer, while only the addition of a comonomer meet the polymer cyclization the exothermic and into fiber demand related research has been difficulties with one of the hot research field of carbon fiber first acrylonitrile monomers, methyl acrylate, itaconic acid as a comonomer, and azobis-iso-butyronitrile as an initiator, by adjusting the experimental parameters in N, N-dimethylformamide (DMF) was synthesized polyacrylonitrile ( PAN) dope. On the monomer conversion, molecular weight, and the analysis of the differential scanning calorimeter (DSC) (e.g., monomer concentration, polymerization time, initiator concentration and polymerization temperature), discuss the experimental parameters on the conversion rate, molecular weight and copolymerization PAN thermal performance, and application of infrared spectroscopy, proton nuclear magnetic resonance spectroscopy means of a preliminary analysis of the structure of PAN copolymerization. The results show that: the experimental time up to 48h, the experimental parameters, although a slight change in the rate of monomer conversion of at most reach about 50%; initiator concentration and monomer concentration in the solution of the molecular weight of the main factors, by adjusting these two experiment parameters, can significantly change the molecular weight; comonomer join the thermal performance of the PAN, the copolymerizable PAN exothermic peak significantly wider, and the exothermic than homopolymerization PAN significantly reduced. Then, itaconic acid, and methanol, ethanol, propanol, butanol, isopropanol, iso-butanol as a substrate, by selective esterification reaction to synthesize a corresponding series β-itaconic acid monoester. 70 ℃ AIBN as initiator in DMF to the Fineman-Ross method and Kelen-Tudos method were measured β-itaconic acid monoester with acrylonitrile apparent reactivity ratios. Found Fineman-Ross method the β-itaconic acid monoisobutyl measured butyl (MIBI) and acrylonitrile (AN) copolymerization reaction between the apparent reactivity ratios were rAN = 0.523, rMIBI = 2.001 rAN × rMIBI = 1.047 ≈ 1 AN / MIBI copolymerization system close to the general ideal copolymerization. Application of differential scanning calorimetry (DSC), β-itaconic acid mono Dioxide content, the atmosphere, the heating rate on the P (AN-co-MIBI) copolymer heat stabilized. The results show that the, the MIBI the exotherm starting temperature of the copolymer decreased significantly broaden exothermic peak heat release rate decreases, but the atmosphere is little influence of the starting temperature of the exothermic peak of P (AN-co-MIBI). This shows that the ionic mechanism in the thermal stabilization process triggered cyclization reaction, and then the oxidation reaction occurs. With the increase of heating rate, the initial reaction temperature gradually move to the high temperature zone, the heat release gradually smaller peak type by widening two peaks gradually to a peak. With MIBI content increases, the angle of contact between the copolymer and water from 62.5 ° to 80.5 °, which showed MIBI hydrophilicity failed to improve the copolymerization of PAN. The wide angle X-ray diffraction data obtained the copolymer ratio homopolymer of a small degree of crystallinity, grain size is small, much MIBI possible to improve the regularity of the molecular chain, to increase the flexibility of the chain, to improve the spinnability .
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