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首页> 外文期刊>Journal of Applied Polymer Science >Emulksion Polymerization of Tetrafluoroethylene: Effects of Reaction Conditions on the Polymerization Rate and Polymer Molecular Weight
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Emulksion Polymerization of Tetrafluoroethylene: Effects of Reaction Conditions on the Polymerization Rate and Polymer Molecular Weight

机译：四氟乙烯的乳液聚合：反应条件对聚合速率和分子量的影响

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摘要

The emulsion polymerizatio of tetrafluoroethylene (TFE) was carried out in a semibatch reactor using a chemical initiator (amonium persulfate) and a fluorinated surfactant (FC-143). The effects of the reaction condition were investi-gated though the polymerization rate, molecular weight of polytetrafluoroethylene (PTFE), and stability of the dispersion. The emulsion polymerization of TFE was different from conventional emulsion polymerization. The polymerization rate was suppressed when the polymer particles were significantly coagulated. The polymerization rate increased with operating temperature, surfactant concentration, and agitation speed, due to the enhanced stability of the polymer particles. However, once the parameter value was reached, the rate decreased due to the coagulation of the particles. Stable PTFE dispersioin particles were obtained when the surfactant concentration was in the range between 3.48 × 10~(-3) and 32.48 × 10~(-3) mol/liter, which is below critical micelle concentration (CMC). The molecular weight of the PTFE obtained was a function of the surfactant and initiator concentrations, and the polymerization temperature. The molecular weight increased as each parameter decreased. This is against the phenomena observed in a conventional emulsion polymerization. A stable PTFE dispersion polymer having a hgih molecular weight was obtained by optimizing the reaction conditions.
机译：使用化学引发剂（过硫酸铵）和氟化表面活性剂（FC-143）在半间歇式反应器中进行四氟乙烯（TFE）的乳液聚合。通过聚合速率，聚四氟乙烯（PTFE）的分子量和分散体的稳定性研究了反应条件的影响。 TFE的乳液聚合不同于常规乳液聚合。当聚合物颗粒明显凝结时，聚合速率受到抑制。由于聚合物颗粒的稳定性提高，聚合速率随操作温度，表面活性剂浓度和搅拌速度而增加。但是，一旦达到参数值，由于颗粒的凝结，速率降低。当表面活性剂浓度在3.48×10〜（-3）mol / L和32.48×10〜（-3）mol / L之间时，可以获得稳定的PTFE分散粒子，该浓度低于临界胶束浓度（CMC）。所得PTFE的分子量是表面活性剂和引发剂浓度以及聚合温度的函数。分子量随着每个参数的降低而增加。这与常规乳液聚合中观察到的现象相反。通过优化反应条件获得具有hgih分子量的稳定的PTFE分散聚合物。

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