Abstract This work proposes an approach to fabricate flexible transparent ultraviolet (UV)-shielding membrane by casting method, which uniformly disperses pristine zinc oxide nanoparticles (NPs) in low-density polyethylene (LDPE). The critical conditions for film fabrication, such as casting temperature, LDPE concentration in the solution, dissolution time, NP concentration, and post hot press cooling processes, are systematically studied. It is found that the casting temperature needs to be close to the melting temperature of LDPE, namely, 115°C, so that transparent film formation without cracks can be guaranteed. NP agglomerates are suppressed if the polymer concentration is controlled below 6%. For good dispersion of NPs, LDPE has to be swelled or unentangled enough in the solution (close to 200 h dissolution time), and then the NP agglomerates can be diminished due to the diffusion of the NPs into the polymer gel (322 h dissolution time). When the NPs are well-dispersed in the LDPE film, the film can completely shield UV light while allowing high transmissivity for the visible light. As the concentration of NPs in the film increases from 4 to 6%, the transmissivity of the film decreases, the tensile strength increases, and the tensile failure strain decreases.

中文翻译：

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由原始氧化锌纳米粒子分散在低密度聚乙烯中制成的透明紫外线屏蔽复合膜

摘要 这项工作提出了一种通过浇铸法制造柔性透明紫外线 (UV) 屏蔽膜的方法，该方法将原始氧化锌纳米粒子 (NPs) 均匀地分散在低密度聚乙烯 (LDPE) 中。系统地研究了薄膜制造的临界条件，如流延温度、溶液中的 LDPE 浓度、溶解时间、NP 浓度和热压后冷却过程。发现流延温度需要接近LDPE的熔化温度，即115℃，才能保证无裂纹的透明成膜。如果聚合物浓度控制在 6% 以下，则可抑制 NP 团聚。为了 NPs 的良好分散，LDPE 必须在溶液中充分溶胀或解缠结（接近 200 小时的溶解时间），然后由于纳米颗粒扩散到聚合物凝胶中（溶解时间为 322 小时），纳米颗粒团聚体可以减少。当 NPs 在 LDPE 薄膜中良好分散时，薄膜可以完全屏蔽紫外线，同时允许对可见光的高透射率。随着薄膜中纳米颗粒的浓度从 4% 增加到 6%，薄膜的透射率降低，拉伸强度增加，拉伸破坏应变减小。