Shao Wenqin, Zhang Xutao, Liang Xiao, Tao Wenting, Ma Meng, Chen Si, Shi Yanqin, He Huiwen, Zhu Yulu, Wang Xu
College of Materials Science and Engineering, Zhejiang Key Laboratory of Plastic Modification and Processing Technology, Zhejiang University of Technology, Hangzhou 310014, PR China.
State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065, PR China.
ACS Appl Mater Interfaces. 2024 Aug 14;16(32):42674-42686. doi: 10.1021/acsami.4c10660. Epub 2024 Aug 1.
Cellulose nanofiber (CNF) has been widely used as a flexible and lightweight polymer matrix for electromagnetic shielding and thermally conductive composite films because of its excellent mechanical strength, environmental performance, and low cost. However, the lack of flame retardancy seriously hinders its further application. Herein, renewable and biomass-sourced l-arginine (AR) was used to surface-modify ammonium polyphosphate (APP) and an environmentally friendly biobased flame retardant was synthesized by the coordination of zinc sulfate heptahydrate (ZnSO·7HO), which was named AAZ. AAZ was deposited on the surface of CNF by electrostatic adsorption and Zn complexation. The biobased compatibilizer Triton X-100 was employed to assist the exfoliation of graphene nanoplatelets (GNPs) and their dispersion in the CNF matrix. Due to the formation of a dense lamellar layer resembling a shell structure, the CNF/GNPs composite films with a tensile strength of 52 MPa were obtained via vacuum-assisted filtration. Because the phosphorus-containing group produces a protective layer of PO compound and promotes the formation of a carbon layer by CNF and the combustion releases ammonia gas, the fire-resistant performance of the composite films was greatly improved. Compared with the pure CNF film, the composite film exhibits 33% reduction in PHRR value and 40% reduction in THR. In addition, the CNF/GNPs composite film with 20 wt % GNPs possessed high conductivity (2079.2 S/m) and electromagnetic interference (EMI) shielding effectiveness (37 dB). The ultrathin CNF/GNPs composite films have excellent potential for use as efficient flame retardant and EMI shielding materials.
纤维素纳米纤维（CNF）因其优异的机械强度、环境性能和低成本，已被广泛用作电磁屏蔽和导热复合薄膜的柔性轻质聚合物基体。然而，缺乏阻燃性严重阻碍了其进一步应用。在此，采用可再生且来源于生物质的L-精氨酸（AR）对聚磷酸铵（APP）进行表面改性，并通过七水合硫酸锌（ZnSO·7H₂O）配位合成了一种环保型生物基阻燃剂，命名为AAZ。AAZ通过静电吸附和锌络合沉积在CNF表面。使用生物基增容剂Triton X-100辅助石墨烯纳米片（GNPs）的剥离及其在CNF基体中的分散。由于形成了类似壳结构的致密层状层，通过真空辅助过滤获得了拉伸强度为52 MPa的CNF/GNPs复合薄膜。由于含磷基团产生PO化合物保护层并促进CNF形成碳层且燃烧释放氨气，复合薄膜的耐火性能得到极大提高。与纯CNF薄膜相比，复合薄膜的热释放速率峰值（PHRR）值降低了33%，热释放总量（THR）降低了40%。此外，含有20 wt% GNPs的CNF/GNPs复合薄膜具有高电导率（2079.2 S/m）和电磁干扰（EMI）屏蔽效能（37 dB）。超薄的CNF/GNPs复合薄膜作为高效阻燃和EMI屏蔽材料具有优异的应用潜力。
