在环境中,塑料碎片的风化是次级微塑料(MP)的主要来源之一。它不同于主要的MP,因为它不是故意设计的,并呈现由尺寸范围为1μm-1mm的塑料碎片组成的高度异质分析物。要检测辅助MP,方法必须用适当的参考材料来开发。这些应该共享环境MP的特征,这是一个广泛的范围,多种形状(碎片,球体,电影,纤维),在水中的悬浮性,和通过老化改性的颗粒表面(额外的OH,C=O,和COOH)。为了生产这样的材料,我们提出了一种基于快速超声处理的聚苯乙烯(PS)碎裂方法,聚对苯二甲酸乙二醇酯(PET),和聚乳酸(PLA),可分散的产量高达105/15毫升,在水介质中的高纯度MP颗粒。为了满足参考材料的要求,关键性质-组成和尺寸分布,以确保样品的均匀性,以及形状,悬念性,和老化-重复分析(N=3)以确保稳健的生产程序。该程序产生100nm-1mm范围内的碎片(<20μm,所有颗粒的54.5±11.3%)。通过拉曼显微光谱法(颗粒=500-1,000)和反射型显微傅立叶变换红外分析(颗粒=10)对尺寸范围为10μm-1mm的碎片进行了定量表征。通过扫描电子显微镜(SEM)对100nm-20μm的较小颗粒进行定性表征。光学显微镜和SEM分析表明,碎片是所有聚合物的主要形状,但纤维也存在。此外,使用紫外可见光谱法研究了纯MilliQ水中的悬浮性和沉降性,结果表明,所产生的碎片根据其密度进行沉降,并且避免了与玻璃的附着。最后,通过超声处理和自然老化的MP产生的片段的红外光谱的比较表明,在OH中的颗粒表面添加了极性基团,C=O,和COOH地区,使这些颗粒适用于二次MP的参考材料。
In the environment the weathering of plastic debris is one of the main sources of secondary microplastic (MP). It is distinct from primary MP, as it is not intentionally engineered, and presents a highly heterogeneous analyte composed of plastic fragments in the size range of 1 μm-1 mm. To detect secondary MP, methods must be developed with appropriate reference materials. These should share the characteristics of environmental MP which are a broad size range, multitude of shapes (fragments, spheres, films, fibers), suspensibility in water, and modified particle surfaces through aging (additional OH, C=O, and COOH). To produce such a material, we bring forward a rapid sonication-based fragmentation method for polystyrene (PS), polyethylene terephthalate (PET), and polylactic acid (PLA), which yields up to 105/15 mL dispersible, high purity MP particles in aqueous media. To satisfy the claim of a reference material, the key properties-composition and size distribution to ensure the homogeneity of the samples, as well as shape, suspensibility, and aging -were analyzed in replicates (N = 3) to ensure a robust production procedure. The procedure yields fragments in the range of 100 nm-1 mm (<20 μm, 54.5 ± 11.3% of all particles). Fragments in the size range 10 μm-1 mm were quantitatively characterized via Raman microspectroscopy (particles = 500-1,000) and reflectance micro Fourier transform infrared analysis (particles = 10). Smaller particles 100 nm-20 μm were qualitatively characterized by scanning electron microcopy (SEM). The optical microscopy and SEM analysis showed that fragments are the predominant shape for all polymers, but fibers are also present. Furthermore, the suspensibility and sedimentation in pure MilliQ water was investigated using ultraviolet-visible spectroscopy and revealed that the produced fragments sediment according to their density and that the attachment to glass is avoided. Finally, a comparison of the infrared spectra from the fragments produced through sonication and naturally aged MP shows the addition of polar groups to the surface of the particles in the OH, C=O, and COOH region, making these particles suitable reference materials for secondary MP.