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Magnetic-conductive bi-gradient structure design of CP/PGFF/Fe 3 O 4 composites for highly absorb e d EMI shielding and balanced mechanical strength

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Journal of Materials Science & technology 2023年第2期133卷 102-110页

作者： Qiang Peng Meng Ma Si Chen Yanqin Shi Huiwen He Xu Wang College of Materials Science and Engineering Zhejiang University of TechnologyHangzhou 310014China Key Laboratory of Plastic Modification and Processing Technology in Zhejiang Province Hangzhou 310014China

Developing excellent absorption-dominant electromagnetic interference(EMI)shielding composites is an urgent demand for the rapid development of 5 G technology and electronic ***,a simple strategy is employed to fabricate carbon nanotubes-polypropylene fibers(CP)/polypropylene-glass fibers felt(PGFF)/Fe 3 O 4 composites with superior EMI shielding effectiveness and low reflection due to the magnetic-conductive bi-gradient structure which is naturally formed by deposition during the vacuum-assisted filtration *** difference in dimensionality between one-dimensional CNT with outstand-ing electrical conductivity and zero-dimensional magnetic Fe 3 O 4 nanoparticles is the theoretical basis for the successful construction of the magnetic-conductive bi-gradient structure in a gap-rich PGFF matrix that endows the composites with“absorb-reflect-reabsorb”EMI ***-magnetic waves are incident from the magnetic layer,the EMI shielding effectiveness(SE)reaches 48.9 dB as the weight percentage of the conductive layer increases,more importantly,the reflection coefficients are reduced by more than 0.32 compared with that of another incident ***’s more,the re-sultant composites exhibit an outstanding signal shielding function in the *** work paves a convenient pathway for designing a magnetic-conductive bi-gradient structure and efficient absorbing EMI shielding composites applied in the next-generated electronic information and communication field.

关键词： Electromagnetic interference shielding Magnetic-conductive bi-gradient structure Absorption-dominant Dimensionality Polypropylene-glass fibers felt

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Ag anchored mesoporous carbon hollow sphere in Cellulose nanofibers/MXene composite films for high-performance electromagnetic interference shielding

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Nano Materials Science 2025年第1期7卷 65-73页

作者： Wenting Tao Wenqin Shao Meng Ma Si Chen Yanqin Shi Huiwen He Yulu Zhu Xu Wang College of Materials Science and Engineering Zhejiang Key Laboratory of Plastic Modification and Processing TechnologyZhejiang University of TechnologyHangzhou310014PR China State Key Laboratory of Polymer Materials Engineering Sichuan UniversityChengdu610065PR China

The increasingly serious electromagnetic(EM)radiation and related pollution effects have gradually attracted people's attention in the information ***,it's crucial to develop adaptive shielding materials with minimum EM waves(EMW)*** this paper,Ag nanoparticles loaded mesoporous carbon hollow spheres(MCHS@Ag)were synthesized by chemical reduction method,and cellulose nanofibers(CNF)/MXene/MCHS@Ag homogeneous composites were *** total EM interference shielding efficiency(SET)of CNF/MXene/MCHS@Ag composite film was 32.83 dB(at 12.4 GHz),and the absorption effectiveness(SEA)was improved to 26.6 dB,which was 63.1%and 195.5%higher than that of CNF/MXene/MCHS composite *** low dielectric property of MCHS effectively optimized the impedance matching between the composites and *** hollow porous structure prolonged the transmission path of EMW and increased the absorption loss of the *** the same time,Ag nanoparticles located the MCHS were helpful to construct the internal conductive path overcoming the damage of the conductive property caused by the low dielectric of *** research adopts a straightforward method to construct a lightweight,pliable,and mesoporous composites for EMI shielding,which serves a crucial role in the current era of severe EM pollution.

关键词： EMI shielding Porous structure Low reflection Film Ag anchored

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CO_(2)-Sourced Poly(chloropropylene carbonate) with High Flame-Retardant Performance

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Chinese Journal of Polymer Science 2025年第1期43卷 110-119,I0010页

作者： Yue Gong Xiao-Feng Zhu Guan-Wen Yang Meng Ma Xu Wang Jie Xu Xin Shu Guang-Peng Wu MOE Key Laboratory of Macromolecular Synthesis and Functionalization Key Laboratory of Adsorption and Separation Materials&Technologies of Zhejiang ProvinceDepartment of Polymer Science and EngineeringZhejiang UniversityHangzhou 310058China Zhejiang Key Laboratory of Plastic Modification and Processing Technology College of Materials Science and EngineeringZhejiang University of Technology Hangzhou 310014China Shanxi Coal Chemical Industry Technology Research Institute Co Ltd.Xi'an 710100China

The alternating copolymer of CO_(2) with epoxide is a green plastic that can efficiently transform CO_(2) into valuable chemicals. Despite the significant advances made, the restricted practical application of CO_(2)-sourced polycarbonates due to their lack of functionality has hindered field development. We successfully demonstrated the flame retardancy of poly(chloropropylene carbonate) (PCPC), a perfectly alternating copolymer of epichlorohydrin (ECH) and CO_(2). This was prepared at a 200-gram scale using a high-efficacy tetranuclear organoborane catalyst. PCPC’s excellent flame-retardant performance has been proven by both the vertical combustion test (UL94 V-0) and the limiting oxygen index (LOI) value (29.1%). The underlaid flame-retardant mechanism of PCPC was clearly elucidated. As a result, we confirmed that the generated cyclic carbonates and concurrently released flame-retardant chlorine radicals, hydrogen chloride, and CO_(2) during combustion render PCPC an excellent flame retardant. Furthermore, we investigated the practicability of PCPC as a halogen-rich polymeric flame retardant by blending it with commercial bisphenol A polycarbonate (BPA-PC). PCPC upgraded the flame retardancy rating of BPA polycarbonate from V-2 to V-0 even with a mere 1 wt% addition. It is our hope that this result will prove useful in future developments of advanced CO_(2)-sourced polymeric materials.

关键词： Carbon dioxide Ring-Opening polymerization Organocatalysis Sustainable materials Flame-retardant polymer

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Catalytic recycling of plastics into value-added products

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Nano Research 2024年第11期17卷 9428-9445页

作者： Tianyu Wei Pengcheng Zhou Wenxian Liu Xijun Liu Tairong Kuang Functional Polymers and Advanced Materials (FPAM) Lab Zhejiang Key Laboratory of Plastic Modification and Processing Technology College of Materials Science and Engineering Zhejiang University of Technology Hangzhou 310014 China State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures Guangxi Key Laboratory of Processing for Nonferrous Metals and Featured Materials MOE Key Laboratory of New Processing Technology for Nonferrous Metals and Materials School of Resources Environment and Materials Guangxi University Nanning 530004 China

The overuse and ineffective management of plastics have led to significant environmental pollution. Catalytic upcycling into value-added chemicals has emerged as a promising solution. This review provides a comprehensive overview of recent advances in catalytic upcycling, focusing on the cleavage of chemical bonds such as carbon-carbon (C-C), carbon-oxygen (C-O), and carbon-hydrogen (C-H) in plastics. It systematically discusses plastics conversion via electrocatalysis, thermal catalysis, and photocatalysis. Additionally, it explores the conversion of plastics into value-added chemicals and functional polymers. The review also addresses the challenges in this field and aims to offer insights for developing sustainable and effective plastics upcycling technologies.

关键词： plastics recycling catalysis chemical recycling value-added chemicals functional polymers

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"Brick-mud" porous impregnated-segregated polymer composites with excellent electrical insulation, high thermal conductivity, and good electromagnetic interference shielding

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Polymer 2025年 316卷

作者： Guo, Hongxin Feng, Huiyao Liu, Tong Kuang, Tairong Lab Zhejiang Key Laboratory of Plastic Modification and Processing Technology College of Materials Science and Engineering Zhejiang University of Technology Hangzhou310014 China

The advancement of 5G communication systems and modern electronic devices has driven the demand for advanced polymer composites with multifunctional capabilities, including electromagnetic interference (EMI) shielding, thermal conductivity, electrical insulation, and mechanical robustness. However, achieving an optimal combination of these properties in a single polymeric material remains challenging. Here, a novel "brick-mud" porous impregnated-segregated structure was developed to address these challenges. This structure consists of polylactic acid/multi-wall carbon nanotubes (PLA/CNTs) microspheres as the "brick" phase and polybutylene succinate/boron nitride (PBS/BN) as the "mud" phase. The interconnected porous PLA/CNTs microspheres were prepared via an emulsion method, which allowed effective infiltration by the PBS/BN matrix during melt blending, resulting in a robust interface. The ratio of "mud" to "brick" was systematically varied, facilitating regulation of the balance between the different multifunctional properties. The resulting composites demonstrated excellent performance, with EMI shielding effectiveness up to ∼41.1 dB, thermal conductivity up to ∼1.37 W m⁻1 K⁻1, volume resistivity exceeding 101⁵ Ω·cm, and mechanical strength as high as ∼54.2 MPa, depending on the composition. Such performance characteristics make these composites particularly suitable for use as casings for 5G communication equipment, where efficient thermal management, EMI shielding, and structural durability are critical. © 2024 Elsevier Ltd

关键词： Electromagnetic shielding

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Well-designed structure of sandwich-like composite films based on hollow polyaniline and MXene with enhanced electromagnetic wave absorption

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Industrial Crops and Products 2023年第1期194卷

作者： Chu, Qindan Tao, Wenting Lin, Hao Ma, Meng Chen, Si Shi, Yanqin He, Huiwen Wang, Xu College of Materials Science and Engineering Key Laboratory of Plastic Modification and Processing Technology in Zhejiang Province Zhejiang University of Technology Hangzhou310014 China

With science and technology developing rapidly nowadays, intellective, carriable, and wearable electronic devices have also developed quickly. So far, the demand for composite films with remarkable electromagnetic interference (EMI) shielding performance is increasingly urgent. In this paper, a sandwich-like EMI shielding composite film was prepared by alternating vacuum-assisted filtration method, where hollow polyaniline (h-PANI)/cellulose nanofiber (CNF) in the surface layers and MXene/CNF in the intermediate layer. Due to the successful construction of the sandwich structure, when the proportion of MXene is just 8 wt% and h-PANI is 24 wt%, the EMI SE of the sandwich-structured composite films achieved 35.3 dB, which is better than that of the homogeneously blended film (17.3 dB) and the improvement of the SET is mainly caused by the increase of SEA. Besides, the EMI SE of the composite film did not reduce observably even after ultrasonic, stripping, bending and other treatments, indicating that it has good EMI shielding stability. More interestingly, the absorption coefficient of the sandwich-structured composite films with h-PANI was improved by 325% contradistinguish to that of the pure CNF layer structure. This novel sandwich composite film exhibits excellent EMI shielding performance with broad application prospects in intelligent, portable, and wearable fields. © 2023 Elsevier B.V.

关键词： Signal interference

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What is the key Factor of Forming the "Core-Shell" Structure in the Blends of Two Polymers? "Entanglement Degree" or "Viscosity"

SSRN

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SSRN 2024年

作者： Shi, Yanqin Ni, Leikun Ma, Meng Chen, Si He, Huiwen Zhu, Yulu Wang, Xu College of Materials Science and Engineering Zhejiang University of Technology Hangzhou310014 China Key Laboratory of Plastic Modification and Processing Technology Research of Zhejiang Province Hangzhou310014 China

The key factor of forming a "core-shell" structure in the blends of two polymers after flowing in pipelines was revealed. The "core-shell" structure of high viscosity PP coated low viscosity PE was prepared by blending PP(T30S) and PE(2200J), PP(H2150) and PE(2200J) in a capillary rheometer at different shear rates. The results were not consistent with the principle of minimum viscous dissipation, while they were consistent with the principle of normal stress balance on the layered interface due to the entanglement degree of both PP(T30S) and PP(H2150) being higher than that of PE(2200J). However, the viscosity ratio of the two polymers had an effect on the integrity of the coating structure. Moreover, the core-shell structure could be obtained in a wider range of shear rates and was more complete when the volume ratio of PP(H2150) to PE(2200J) decreased from 2:1 to 1:2. It may be related to the fact that the small amount of PP could migrate to the outer layer in a shorter time. The "core-shell" structure could also be obtained by mixing high-polarity PA6(1010C2) with PP(T30S) or PP(H2150). The formation of a "core-shell" structure in both PA6(1010C2)/PP(T30S) and PA6(1010C2)/PP(H2150) complied with the high entanglement degree PA6 coated the low entanglement degree. The worse the compatibility of the two composites, the better the core-shell structure. The results meant the entanglement degree was the key factor in determining which polymer coated the other polymer. The principle of normal stress balance on the layered interface was more suitable for guiding the preparation of the core-shell structure blends. © 2024, The Authors. All rights reserved.

关键词： Polymer blends

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Laser-Directed Energy Deposition of Low-Carbon Low-Temperature Ultra-Fine Bainitic Steel: Multi-Physical Modelling, Metallurgy and Performance Studies

SSRN

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SSRN 2023年

作者： Guo, Yanbing Wu, Dongsheng Chen, Yuan Wang, Lyuyuan Chi, Yuanqing Feng, Kai Li, Zhuguo Ma, Ninshu College of Ocean Science and Engineering Institute of Marine Materials Science and Engineering Shanghai Maritime University Shanghai201306 China Osaka University 11-1 Mihogaoka Osaka Ibaraki567-0047 Japan Key Laboratory of Crop Harvesting Equipment Technology of Zhejiang Province Jinhua Polytechnic Jinhua321017 China School of Materials Science and Engineering Nanjing University of Science and Technology Nanjing210094 China School of Mechanical and Electrical Engineering Guangdong University of Technology Guangzhou510006 China Shanghai Key Lab of Materials Laser Processing and Modification School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai200240 China

An innovative iron-based alloy powder characterized by reduced carbon content and elevated Mn content was developed, leading to the fabrication of iron-based ultrafine bainitic steel with exceptional mechanical properties utilizing laser-directed energy deposition (L-DED). The layers' morphology, microstructure, phase composition, and elemental distribution were analyzed, indicating that the melting depth of the layer was deep and ultra-fine dendrite formed in the top region. A multi-physical powder and melt pool simulation was conducted to analyze the melt flow and pool solidification characteristics, showing that the strong downward flow inside the molten pool caused by the powder impingement leaded to the increase of the melting depth. The cooling rate G×R, where G was the temperature gradient and R was the solidification rate, was higher at the top pool boundary, which facilitated the ultra-fine dendrite formation at this location. Following subsequent low-temperature isothermal heat treatment, a refined bainitic microstructure emerged within the deposited layer. The bainitic plates in the 573K isothermally transformed bainite were interspersed with film-retained austenite (RA). Conversely, the bainitic plates formed at a lower temperature (523K) exhibited a coalesced morphology, stemming from the diminished stability of super-cooled austenite. The bainite plates underwent growth and coalescence, ultimately giving rise to the bainitic microstructure. The 523K transformed coatings demonstrated superior hardness (509.2 HV), strength (1435 MPa), and elongation (11.5%) compared to the 573K transformed coatings (456.5 HV, 1241 MPa, 10.1%). This research holds significant implications for the advancement of low-carbon bainitic materials with remarkable comprehensive mechanical properties in additive manufacturing applications. © 2023, The Authors. All rights reserved.

关键词： Bainite

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