| Summary: | 碩士 === 中國文化大學 === 材料科學與製造研究所 === 90 === Emulsifier-free emulsion copolymerization of styrene and methacrylic acid is studied, with the increase of hydrophilic comonomer of methacrylic acid is quicker to attain saturated concentration then to begin the reaction in the first stage, after the styrene supply nucleation mechanism. On the other hand, by enriching the methacrylic acid chain growing in the first stage, these growing chains gain their hydrophobic by increasing the ratio of styrene in the chain, when achieving some degree of saturation a precipitating to form a new particle. The mechanism of particle formation is homogeneous nucleation.
The reaction rate becomes faster with the increasing hydrophilic comonomer ratio and the increasing initiator concentration. When hydrophilic comonomer ratio is fixed and the initiator concentration increased, the system produces a lot of particles. In contrast, the particle size will decrease. The particle size becomes lost with the increasing initiator concentration. The particle number becomes gain at the increasing hydrophilic comonomer concentration. The density of the particle number reduces as the reaction time increases, then achieves a constant.
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