How much particle surface corrugation is sufficient to improve aerosol performance of powders?
How much particle surface corrugation is sufficient to improve aerosol performance of powders?
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DOI：
10.1007/s11095-004-9020-4
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发表时间：
2005-01-01
影响因子：
3.7
通讯作者：
Raper, JA
中科院分区：
文献类型：
--
作者：
Chew, NYK;Tang, P;Raper, JA
目的.目前的研究旨在量化不同程度的颗粒表面粗糙度，并将其与粉末的气溶胶性能相关联。在不同条件下，通过喷雾干燥制备不同表面粗糙度的粉末。对粉体的粒度、形貌、晶型、真密度、含水率等固态性能进行了表征。通过光散射获得的表面分形维数（D-S）来量化表面粗糙度。通过使用Rotahaler以60 L/min将粉末分散到多级液体撞击器中来研究气溶胶性能。细颗粒分数（FPF）表示为气溶胶中尺寸小于或等于5 μ m的BSA颗粒的重量%。制备了四种颗粒表面波纹度增加的粉末，D-S范围从最小波纹的2.06到最大波纹的2.41。粉末具有相似的尺寸分布（VMD 3 μ m，跨度1.4-1.5）和固态性质。增加表面张力，D-S。从2.06到2.18略微提高了FPF，从27%显著提高到41%。这可以通过减少接触面积和增加颗粒之间的分离距离来解释。进一步增加D-S（D-S ≥ 2.18）并不能改善FPF。通过喷雾干燥成功地获得了具有不同粗糙度的粉末，并通过分形分析对其表面粗糙度进行了量化。结果表明，只有一个相对较小程度的表面粗糙度是足以实现相当大的改善，在粉末的气溶胶性能。
Purpose. The current study aimed to quantify the different degree of particle surface corrugation and correlate it to the aerosol performance of powders.Methods. Powders of different degree of surface corrugation were prepared by spray drying under varying conditions. The solid-state properties of the powders including particle size, morphology, crystal form, true density, and moisture content were characterized. The degree of surface corrugation was quantified by the surface fractal dimension (D-S) obtained by light scattering. The aerosol performance was studied by dispersing the powders using the Rotahaler at 60 L/min into a multi-stage liquid impinger. Fine particle fraction (FPF) was expressed as the wt% of BSA particles of size less than or equal to 5 mum in the aerosol.Results. Four powders of increasing degree of particle surface corrugation were prepared, with D-S ranging from 2.06 for the least corrugated to 2.41 for the most corrugated. The powders had a similar size distribution (VMD 3 mum, span 1.4-1.5) and solid-state properties. Increasing the surface corrugation, D-S. slightly from 2.06 to 2.18 enhanced the FPF significantly from 27 % to 41 %. This was explained by the reduced area of contacts and increased separation distance between the particles. Further increase of corrugation (D-S greater than or equal to 2.18) did not improve FPF.Conclusions. Powders with varying degrees of corrugation were successfully obtained by spray drying with their surface roughness quantified by fractal analysis. It was shown that only a relatively small degree of surface corrugation was sufficient to accomplish a considerable improvement in the aerosol performance of the powder.