多功能聚丙烯柔性碳纸，用于可穿戴电子设备

1成果简介

随着5G通信、物联网和可穿戴电子设备的飞速发展，电磁干扰（EMI）污染日益严重，对高性能EMI屏蔽材料的需求急剧增长。理想的EMI屏蔽材料应同时具备高屏蔽效能、轻质、柔性、可穿戴舒适性以及多功能集成（如焦耳加热、疏水、透气）。然而，传统金属基屏蔽材料笨重且不耐腐蚀，现有碳基柔性屏蔽材料往往面临导电性与力学柔性难以兼顾、制备成本高、功能单一等瓶颈。同时，大量废弃聚丙烯塑料和碳纤维预氧化废料的环境处置问题亟待解决。

本文，大连理工大学陈友汜 研究员在《Small》期刊发表题为"Bionic Engineering Strategy for Preparing Flexible Carbon Paper From Waste Polypropylene: Excellent Electromagnetic Shielding Performance and Multifunctional Integration"的研究论文。研究受珍珠层（Nacre）层状砖-泥微结构启发，以回收聚丙烯（rPP）和废弃预氧化纤维为双废料前驱体，通过液相磺化过程中PP基体的"异质溶胀"（heterogeneous swelling）效应，成功构建了PP衍生碳与短切碳纤维（SCF）的高强度柔性互穿网络结构。

本研究利用PP衍生碳与短切碳纤维（SCF）构建了高强度的柔性互穿网络结构。由SCF与PP衍生微裂纹形成的协同三维导电网络，使材料展现出高达7735 S m−1的电导率。PP-CP在X波段展现出高达58.8 dB的电磁干扰屏蔽效能（EMI SE）和6642 dB·cm²/g的厚度平均比屏蔽效能（SSE/t），同时具备优异的焦耳热效应、疏水性和透气性。PP-CP 卓越的多功能集成特性不仅满足了新一代可穿戴电子设备的需求，同时也为聚丙烯和碳纤维资源的可持续利用开辟了一条新途径。

2图文导读

图1、(a) Schematic diagram of PP-CP preparation, (b) Potential application scenarios of PP-CP, (c) SEM images of PP-CF1300 treated by sulfuric acid for (c1) 0 h, (c2) 0.5 h, (c3) 1 h, (c4) 2 h, (d) SEM images of (d1–d3) CPP-CF1300-900 and (d4) digital photographs of PP-CF1300, SPP-CF1300 and PP-CP.

图2、(a) XRD curves of CPP-CFX-900, Raman spectra of (b) PP-derived carbon and (c) carbon fiber, (d) XPS spectra of CPP-CFX-900, (e) C1s, (f) O1s, (g) N1s, and (h) S2p high-resolution peak spectra of CPP-CF1300-900。

图3、(a) SET of CPP-CFX-900 in the X-band, (b) Average SE of CPP-CFX-900 in the X-band, (c) SET of CPP-CF1300-Y in the X-band, (d) Conductivity of CPP-CF1300-1300, (e) SET, (f) Average SE, (g) SEA/SET, and (h) Power factor of CPP-CF1300-1300 in the X-band with different contents of SCF, (i) Reported shielding efficiency of advanced electromagnetic shielding materials, (j) Schematic diagram of PP-CP for EMI shielding application and (k) Electromagnetic shielding mechanism of PP-based carbon paper.

图4、(a) Schematic diagram of PP-CP joule heating performance test, (b) Curves of surface temperature for PP-CP over time under different input voltages, (c) Surface temperature of PP-CP under different input voltages, (d) Linear fitting of PP-CP surface temperature to U2, (e) Curves of PP-CP surface temperature over time with gradient voltage, (f) Electric heating curve at 3.5 V switching cycle, (g) Temperature stability of PP-CP at an input voltage of 3.5 V, (h) Electrothermal conversion mechanism of PP-CP, (i) Heating water at an input voltage of 3.5 V, and (j) Ice melting and oil absorption at an input voltage of 3.5 V.

图5、(a) Tensile strength of PP-CP, (b)Tensile strength and tensile modulus of carbon fibers, (c) SEM image and digital photograph of PP-CP in a bent state, Static contact angle of PP-CP with (d) water, coffee, milk, and juice, (e) Hydrophobicity demonstrated by digital photos and static contact angle images, (f) Self-cleaning performance, (g) Breathability, and (h) Flame retardancy of PP-CP.

3小结

在本研究中，利用再生聚丙烯（rPP）通过硫酸磺化及高温碳化工艺，制备了一种柔性聚丙烯基碳纸。再生聚丙烯（rPP）相的异质膨胀诱导了基体内的微裂纹形成和结构重排。结合SCF的桥接效应，形成了一种致密的“砖瓦式”碳结构，这既提高了电磁屏蔽性能，又增强了结构柔韧性。得益于由异质碳源形成的三维导电网络，PP-CP在保持优异柔韧性的同时，实现了58.8 dB的最佳电磁干扰屏蔽值（EMI SE）。与此同时，相互连接的碳网络还赋予了PP-CP多种集成功能，包括焦耳热效应、应变传感、疏水性、透气性和阻燃性。再生聚丙烯与废纤维的结合不仅为碳纸制备提供了可持续的前驱体体系，同时也为调控柔性电磁屏蔽材料的微观结构和整体性能开辟了一条有效途径。

文献：
https://doi.org/10.1002/smll.73607

来源：材料分析与应用