用於氣溶膠過濾的聚(偏氟乙烯–三氟乙烯)靜電紡絲之奈米纖維濾材研發

Abstract

本論文以靜電紡絲聚(偏氟乙烯-三氟乙烯)(Polyvinylidene fluoride-trifluoroethylene, P(VDF-TrFE))纖維及其與聚苯乙烯(Polystyrene, PS)纖維複合的濾材應用於氣膠過濾為主軸。P(VDF-TrFE)具有高可撓性、高化學抗性、高熱穩定性及高極性晶體結構的性質，靜電紡絲纖維則有高表面體積比的特性，對於過濾材來說，可以提升濾材的過濾穩定性及過濾效率。 本研究先以靜電紡絲不同的溶劑組成、溶液供給速率、P(VDF-TrFE)濃度、於溶液中添加表面活性劑控制表面張力，探討溶液特性對纖維結構的影響，並以掃描式電子顯微鏡觀測其纖維結構，佐以量測其溶液性質變化，探討影響靜電紡絲P(VDF-TrFE)纖維表面形貌的因素，以此製備出奈米尺度約180 nm的P(VDF-TrFE)纖維。 過濾量測使用以氯化鈉微粒為測試材料的穿透率量測系統，量測P(VDF-TrFE)在不同線徑組成下的纖維過濾效率，其中以所量測濾材中纖維線徑183 nm纖維過濾效率最為傑出，再以此纖維探討不同靜電紡絲收集時間下製備的纖維過濾效率，發現過濾膜品質隨著收集時間增加而下降。為了進一步提升P(VDF-TrFE)纖維的過濾效能，以雙針靜電紡絲的方式將P(VDF-TrFE)纖維與PS粗纖維複合，利用PS纖維使P(VDF-TrFE)纖維間距增加以降低壓損，並經由電暈放電的方式駐電，使複合濾材具有較佳的帶電性，以不增加壓損的前提下，提升P(VDF-TrFE)/PS濾材的過濾效能，使其在壓損39.55 Pa有92.17 %的過濾效率，對於低耗能需求的過濾系統中，有其應用的潛力。

The main goal of this thesis is to apply a fiber composite composed of electrospun poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) fibers and P(VDF-TrFE)/polystyrene (PS) fibers to aerosol filtration. The advantages of P(VDF-TrFE) are its high flexibility, good chemical resistance, high thermal stability and polarization capability. Electrospun P(VDF-TrFE) fibers with characteristics of P(VDF-TrFE) polymer and high surface-to-volume ratio may enhance the stability and efficiency of the filtration. A series of studies are conducted to study the structure of the electrospun P(VDF-TrFE) fiber filters fabricated with different processing parameters, including solvent composition, solution feeding rate, P(VDF-TrFE) concentration, and addition of surfactant. The electrospun P(VDF-TrFE) nanofibers are developed with fiber diameter ranging from 780 nm to 180 nm. The filtration efficiency of P(VDF-TrFE) filter under different fiber diameter is quantified by challenging with sodium chloride particles. Among the measured filters of different fiber diameters, the finest fiber diameter of 183 nm has the best filtration performance. The P(VDF-TrFE) filters fabricated by different electrospinning collection time are also studied and compared. It is found that the quality factor decreased along with a longer collection time. In order to further improve the filtration efficiency of P(VDF-TrFE) filter, a P(VDF-TrFE)/PS composite filter is fabricated by a well-developed double-needle electrospinning method. P(VDF-TrFE)/PS composite filter has 92.17% filtration efficiency and 39.55 Pa pressure drop after corona charge treatment. Finally, the air filter developed in this thesis potentially can be applied for low energy consumption filtration system.