Light scattering techniques (static and dynamic) are commonly used to analyze the particle size distributions (PSDs) of polymer emulsions. Both techniques need specialized mathematical algorithms to invert either the scattered light time profiles or the scattered light patterns to obtain the PSDs. As a result of the ensemble nature of these techniques, they are low in resolution and sensitivity making them vulnerable to artifacts and instabilities. This article describes the ability of the Nicomp algorithm - employed only in the Nicomp 380 - to provide accurate and realistic PSDs for emulsion samples that have comparatively wide distributions.
Limitations of Light Scattering Techniques
分析乳液是光散射技术的具有挑战性的任务。通常，生产目的是产生特定平均直径的乳液和相对窄的宽度或多分散性。除了具有大量大颗粒的乳液之外，光散射技术可以快速和准确地测量平均直径。欧洲杯猜球平台这些大颗粒倾向于“混蛋”分欧洲杯猜球平台布到更大的平均直径，导致结果不准确。
The size of nearly 99% of the solids fraction has been reduced by the homogenization process. However, the emulsion still has 1-2% of the solids fraction in particles larger than 1µm. It has been demonstrated by numerous studies that such a small percentage of solids fraction can still lead to stability problems. Nevertheless, the amount of material in the tail is not adequate to be detected by light scattering techniques.
Capabilities of Single Particle Optical Sizing (SPOS) Technique
SPOS is a powerful and highly sensitive particle sizing technique capable of detecting trace amounts of large particles. This technique is utilized by theAccusizer 780.，这可以为乳液中最大的球状提供更准确和明确的结果。这些小球与乳液安全和稳定性密切相关。
SPOS is a single particle counter capable of counting particles down to 0.5µm. The AccuSizer 780 is ideal for applications demanding the quantification of the coarse particle tail of a primarily sub-micron distribution. Unlike light scattering ensemble techniques, the AccuSizer 780 does not assume the shape of a PSD.
检测技术结构PSD的计数and sizing hundreds of thousands of particles and placing them into very narrow size bins. It can handle broad distributions as it is not an ensemble technique. Furthermore, no artifacts are generated as the distribution is not computed.
Representative Results
Figure 1a consists of the Volume-Weighted PSD acquired by the Nicomp 380 on a PVD emulsion, showing a single Gaussian peak with a mean diameter of roughly 0.68µm and width of 18%. Figure 1b consists of the Volume-Weighted results from the same sample acquired by the AccuSizer 780.
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图1。一种。Volume-Weighted PSD of PVC Emulsion from Nicomp 380; b. Volume-Weighted PSD of PVC Emulsion from Accusizer 780.
从380和780枚管_获得的结果证明了主峰的平均直径。由于380型号的分辨率，380产生的主峰略宽。相反，780型型号检测到大约30μm的颗粒，由于光散射方法固有的低灵敏度欧洲杯猜球平台，380模型未检测到。
图2显示了从具有宽分布的不稳定乳液获得的结果。图2a包括从第二乳液获得的体积加权380结果。该分析产生了两个峰，一个在0.27μm，秒为1.3μm。第一峰可以用乳液峰鉴定，而第二峰是聚集尾的代理峰。这种分布可以对集合测量构成挑战。
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图2。一种。Nicomp 380的宽PVC乳液的体积加权PSD;湾来自Accusizer 780的宽PVC乳液的体积加权PSD。
The larger particles have the tendency to obscure or shift the contribution from the main peak. Nonetheless, the Nicomp algorithm can ‘separate out’ the contribution from the larger particles, thereby allowing the stabilization of the main peak to the correct mean diameter. The analysis yields a mean diameter that is in correlation with the expected value. Figure 2b consists of the Volume-weighted PSD acquired by the AccuSizer 780. The true particle size is represented by the second peak observed by the 380 model, further validating the accuracy of the Nicomp algorithm and its ability to deal with complex distributions.
Conclusion
结果清楚地证明了NICOMP 380模型的能力，可以使用专利的NICOMP配件算法精确地尺寸窄和多分散的PVC乳液。NICOMP 380模型能够正确地确定多分散的乳液中存在的两种模式。然而，只有单个粒子计数器的装甲780'能够确定存在的最大粒子。欧洲杯猜球平台
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