采用非对称场流分离技术(Asymmetrical flow field-flow fractionation,AF4)对标准聚苯乙烯颗粒粒径进行表征.利用非对称场流分离仪以0.1％ SDS(十二烷基磺酸钠)和0.02％ NaN3的水溶液为流动相,测定标准的聚苯乙烯纳米颗粒在流体流场作用下通过分离腔室的保留时间,以确定纳米颗粒的平均粒径.优化了聚焦时间、横向流速、进样量、主体流速等实验条件,建立了利用AF4准确表征纳米颗粒的方法,并与扫描电镜(Scanning electron microscope,SEM)的表征结果进行比较.结果表明,AF4的表征结果比SEM更接近于聚苯乙烯颗粒的标准粒径,具有更高的稳定性和准确度.本方法可作为纳米粒径表征的一种准确方法.%This study introduced the general method of asymmetrical flow field-flow fractionation for the particle size measurement of polystyrene latexes.The separation took place under the influence of flow field generated by a cross flow where 0.1％ SDS and 0.02％ NaN3 aqueous solution as cartier phase.Several experimental parameters were optimized including focusing time,cross flow rate,injection mass and channel flow rate,which was important for quantification.It was found that AF4 was particularly useful and simple for the determination of particle size,because the elution profile could be converted to the particle size on the basis of the equation directly.Each sample was injected ten times and the relative standard deviation was less than 1％,which showed that AF4 had high stability.The comparison results of mean diameter determined by AF4 and scanning electron microscope (SEM) showed that the mean diameter of SEM was lower than those obtained from AF4 or provided by manufacturers,therefore AF4 was more accuracy and precise than SEM,which could be developed as an accurate method for size characterization.
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