Bar-Ilan Institute of Nanotechnology and Advanced Materials, Department of Chemistry, Bar-Ilan University , Ramat Gan 52900, Israel.
ACS Appl Mater Interfaces. 2017 Jan 11;9(1):868-875. doi: 10.1021/acsami.6b12821. Epub 2016 Dec 22.
UV-absorbing nanoparticles (NPs) and microparticles (MPs) were prepared by emulsion and dispersion copolymerization of the vinylic monomer 2-(2'-hydroxy-5'-methacryloxyethylphenyl)-2H-benzotriazole (Norbloc (NB)) with the crosslinking monomer divinylbenzene. The effect of the initiator concentration on the size and size distribution of the polyNB (PNB) particles was elucidated. Thin coatings of the formed PNB NPs or MPs of 19 ± 2 and 200 ± 25 nm dry diameter, respectively, onto polypropylene (PP) films were then prepared and characterized. Increasing the concentration or thickness of the PNB NP or MP thin coatings on the PP films decreased their UV transmittance, up to complete UV blocking with just 2 μm of a 4% NP coating. Migration of the UV-absorbing agents from the coated PP films was not observed during three years of storage at room temperature, offering a unique solution to current problems of migration of UV-absorbing additives. The thin coatings obtained by the PNB NPs were superior to those of the PNB MPs, in that no UV transmittance or loss of optical properties of the PP films were observed for the NP coatings, while the coatings produced by the PNB MPs resulted in damaged optical properties, particularly increasing the haze, and achieved incomplete UV blocking.
UV 吸收纳米粒子 (NPs) 和微粒子 (MPs) 通过乳液和分散共聚方法，由乙烯基单体 2-(2'-羟基-5'-甲基丙烯酰氧乙基苯基)-2H-苯并三唑 (Norbloc (NB)) 与交联单体二乙烯基苯制备而成。探讨了引发剂浓度对聚 NB (PNB) 粒子粒径及其分布的影响。随后在聚丙烯 (PP) 薄膜上制备并表征了分别具有 19 ± 2 nm 和 200 ± 25 nm 干直径的 PNB NPs 或 MPs 的薄膜。结果表明，随着 PP 薄膜上 PNB NP 或 MP 薄膜厚度或浓度的增加，其 UV 透过率降低，仅用 2 μm 厚的 4% NP 涂层即可完全阻挡 UV。在室温下储存三年期间，未观察到涂层中 UV 吸收剂的迁移，为当前 UV 吸收添加剂迁移问题提供了独特的解决方案。与 PNB MPs 相比，PNB NPs 获得的薄膜具有更好的性能，因为 NP 涂层不会导致 PP 薄膜的 UV 透过率或光学性能损失，而 PNB MPs 涂层则会导致光学性能受损，特别是雾度增加，且无法完全阻挡 UV。
