1成果簡介

隨著5G通信、物聯(lián)網(wǎng)和可穿戴電子設(shè)備的飛速發(fā)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(yīng)同時具備高屏蔽效能、輕質(zhì)、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(tǒng)金屬基屏蔽材料笨重且不耐腐蝕，現(xiàn)有碳基柔性屏蔽材料往往面臨導(dǎo)電性與力學(xué)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(yù)氧化廢料的環(huán)境處置問題亟待解決。

本文，大連理工大學(xué)陳友汜 研究員在《Small》期刊發(fā)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(jié)構(gòu)啟發(fā)，以回收聚丙烯（rPP）和廢棄預(yù)氧化纖維為雙廢料前驅(qū)體，通過液相磺化過程中PP基體的"異質(zhì)溶脹"（heterogeneous swelling）效應(yīng)，成功構(gòu)建了PP衍生碳與短切碳纖維（SCF）的高強度柔性互穿網(wǎng)絡(luò)結(jié)構(gòu)。

本研究利用PP衍生碳與短切碳纖維（SCF）構(gòu)建了高強度的柔性互穿網(wǎng)絡(luò)結(jié)構(gòu)。由SCF與PP衍生微裂紋形成的協(xié)同三維導(dǎo)電網(wǎng)絡(luò)，使材料展現(xiàn)出高達7735 S m?1的電導(dǎo)率。PP-CP在X波段展現(xiàn)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(yōu)異的焦耳熱效應(yīng)、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(shè)備的需求，同時也為聚丙烯和碳纖維資源的可持續(xù)利用開辟了一條新途徑。

2圖文導(dǎo)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(jié)

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(zhì)膨脹誘導(dǎo)了基體內(nèi)的微裂紋形成和結(jié)構(gòu)重排。結(jié)合SCF的橋接效應(yīng)，形成了一種致密的“磚瓦式”碳結(jié)構(gòu)，這既提高了電磁屏蔽性能，又增強了結(jié)構(gòu)柔韌性。得益于由異質(zhì)碳源形成的三維導(dǎo)電網(wǎng)絡(luò)，PP-CP在保持優(yōu)異柔韌性的同時，實現(xiàn)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(wǎng)絡(luò)還賦予了PP-CP多種集成功能，包括焦耳熱效應(yīng)、應(yīng)變傳感、疏水性、透氣性和阻燃性。再生聚丙烯與廢纖維的結(jié)合不僅為碳紙制備提供了可持續(xù)的前驅(qū)體體系，同時也為調(diào)控柔性電磁屏蔽材料的微觀結(jié)構(gòu)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(yīng)用