多功能聚丙烯柔性碳紙，用于可穿戴電子設備

1成果簡介

隨著5G通信、物聯網和可穿戴電子設備的飛速發展，電磁干擾（EMI）污染日益嚴重，對高性能EMI屏蔽材料的需求急劇增長。理想的EMI屏蔽材料應同時具備高屏蔽效能、輕質、柔性、可穿戴舒適性以及多功能集成（如焦耳加熱、疏水、透氣）。然而，傳統金屬基屏蔽材料笨重且不耐腐蝕，現有碳基柔性屏蔽材料往往面臨導電性與力學柔性難以兼顧、制備成本高、功能單一等瓶頸。同時，大量廢棄聚丙烯塑料和碳纖維預氧化廢料的環境處置問題亟待解決。

本文，大連理工大學陳友汜 研究員在《Small》期刊發表題為"Bionic Engineering Strategy for Preparing Flexible Carbon Paper From Waste Polypropylene: Excellent Electromagnetic Shielding Performance and Multifunctional Integration"的研究論文。研究受珍珠層（Nacre）層狀磚-泥微結構啟發，以回收聚丙烯（rPP）和廢棄預氧化纖維為雙廢料前驅體，通過液相磺化過程中PP基體的"異質溶脹"（heterogeneous swelling）效應，成功構建了PP衍生碳與短切碳纖維（SCF）的高強度柔性互穿網絡結構。

本研究利用PP衍生碳與短切碳纖維（SCF）構建了高強度的柔性互穿網絡結構。由SCF與PP衍生微裂紋形成的協同三維導電網絡，使材料展現出高達7735 S m?1的電導率。PP-CP在X波段展現出高達58.8 dB的電磁干擾屏蔽效能（EMI SE）和6642 dB·cm2/g的厚度平均比屏蔽效能（SSE/t），同時具備優異的焦耳熱效應、疏水性和透氣性。PP-CP 卓越的多功能集成特性不僅滿足了新一代可穿戴電子設備的需求，同時也為聚丙烯和碳纖維資源的可持續利用開辟了一條新途徑。

2圖文導讀

圖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.

圖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。

圖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.

圖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.

圖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小結

在本研究中，利用再生聚丙烯（rPP）通過硫酸磺化及高溫碳化工藝，制備了一種柔性聚丙烯基碳紙。再生聚丙烯（rPP）相的異質膨脹誘導了基體內的微裂紋形成和結構重排。結合SCF的橋接效應，形成了一種致密的“磚瓦式”碳結構，這既提高了電磁屏蔽性能，又增強了結構柔韌性。得益于由異質碳源形成的三維導電網絡，PP-CP在保持優異柔韌性的同時，實現了58.8 dB的最佳電磁干擾屏蔽值（EMI SE）。與此同時，相互連接的碳網絡還賦予了PP-CP多種集成功能，包括焦耳熱效應、應變傳感、疏水性、透氣性和阻燃性。再生聚丙烯與廢纖維的結合不僅為碳紙制備提供了可持續的前驅體體系，同時也為調控柔性電磁屏蔽材料的微觀結構和整體性能開辟了一條有效途徑。

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

來源：材料分析與應用