| Summary: | 碩士 === 國立臺灣大學 === 高分子科學與工程學研究所 === 101 === In this study, we synthesized micron-sized carbon black/polymer composites by heterocoagulation. First of all, we fabricated the polymeric latex with narrow size distribution and positive surface charge. Secondly, carbon black surface modification with silane coupling agent by sol-gel process had been achieved. In the last part, polymeric latex and surface-modified carbon black were mixed in water then we adjusted the pH value of the solution to a certain level and heated above the glass transition temperature of the polymeric latex to form carbon black/polymer composites.
In the first part, we studied some experimental parameters that may affect the polydispersity, zeta potential, isoelectric point or Tg of the polymeric latex fabricated by dispersion polymerization. Dynamic light scattering zetasizer had been used to measure the zeta potential of the polymeric latex. We also used scanning electron microscopy(SEM) to measure the size of the latex particles. Glass transition temperature was measured by differential scanning calorimeter.
In the second part, carbon black surface modification with various functional group on the silane coupling agents via sol-gel process had been studied. The size and its distribution of the modified carbon black were measured by dynamic light scattering and thermogravimetric analysis, then Fourier transform infrared spectrometer was used to confirm the results.
In the last part, we fabricated the carbon black/polymer composites via heterocoagulation method. Appropriate pH values were controlled to achieve good heterocoagulation results. By heating up the polymeric latex to above its Tg, the surface of polymeric latex will become soft to form the stable composites with heterocoagulated carbon black on their surfaces. The composites were purified with centrifuge and the amount of the heterocoagulated carbon black was tested by thermogravimetric analysis. The morphologies of the cross section of the composites were observed via transmitting electron microscope ultra-thin sectioning technique.
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