School of River and Ocean Engineering, Chongqing Jiaotong University, Chongqing 400074, China.
School of River and Ocean Engineering, Chongqing Jiaotong University, Chongqing 400074, China.
Sci Total Environ. 2022 Sep 10;838(Pt 3):156369. doi: 10.1016/j.scitotenv.2022.156369. Epub 2022 May 30.
During service or on discarding in the environment, solar ultraviolet radiation (UVR) and mechanical abrasion (MA) often act on plastic surface in combination, which cause the surface of plastics deterioration and micro- and nano- plastics release. Here, we examined how the set conditions (UVR, MA and UVR+MA (i.e., UVR combined with MA)) and polymer composition affected plastic degradation and microplastics (MPs) release. The surface degradation process and release of MPs of two types of plastic films (polyethylene (PE) and thermoplastic polyurethane (TPU)) under the action of UVR, MA and UVR+MA were analyzed and compared. The main results are as follow: First, the surface change of PE and TPU films by UVR+MA was observed more prominently than by UVR and MA. UVR+MA resulted in the accelerated surface degradation compared to UVR and MA. A large number of MPs were released from both PE and TPU films and significant differences were observed between UVR, MA and UVR+MA conditions. The UVR+MA treatment led to the generation of the largest amount of MPs with a smallest particle size, followed by MA and UVR. Second, plastics with different compositions exhibited different levels of resistance to UVR and MA. PE films released more MPs than TPU under the three set conditions. Finally, optical microscopy provided a direct and non-invasive method to assess the plastics degradation and the observed change in relative transmittance as a function of exposure time could be fitted linearly in some circumstances, which can be used to quantify the release of MPs. This study provided a basis for better understanding the degradation mechanisms of plastics surface and the relationship with MPs release during use and into the environment.
在使用过程中或在环境中丢弃时，太阳紫外线辐射（UVR）和机械磨损（MA）通常会同时作用于塑料表面，导致塑料表面恶化和微塑料和纳米塑料的释放。在这里，我们研究了设定条件（UVR、MA 和 UVR+MA（即 UVR 与 MA 结合））和聚合物组成如何影响塑料降解和微塑料（MPs）的释放。分析和比较了 UVR、MA 和 UVR+MA 作用下两种类型的塑料薄膜（聚乙烯（PE）和热塑性聚氨酯（TPU））的表面降解过程和 MPs 的释放。主要结果如下：首先，观察到 UVR+MA 作用下 PE 和 TPU 薄膜的表面变化比 UVR 和 MA 更明显。与 UVR 和 MA 相比，UVR+MA 导致表面降解加速。大量的 MPs 从 PE 和 TPU 薄膜中释放出来，并且在 UVR、MA 和 UVR+MA 条件之间观察到显著差异。UVR+MA 处理导致产生的 MPs 数量最多，粒径最小，其次是 MA 和 UVR。其次，具有不同组成的塑料对 UVR 和 MA 表现出不同的抵抗力。在三种设定条件下，PE 薄膜释放的 MPs 比 TPU 多。最后，光学显微镜提供了一种直接和非侵入性的方法来评估塑料的降解，并且在某些情况下，可以将观察到的相对透光率随暴露时间的变化拟合为线性，可以用于量化 MPs 的释放。这项研究为更好地理解塑料表面的降解机制以及在使用和进入环境过程中与 MPs 释放的关系提供了依据。
