Polymers
·
2017
·Vol. 9
·期 1
·1
·
IF 3.364
Yanhua Song,Zhaoyang Sun,Lan Xu,Zhongbiao Shao
In the electrospinning process, a modified parallel electrode method (MPEM), conducted by placing a positively charged ring between the needle and the parallel electrode collector, was used to fabricate highly aligned carbon nanotubes/polyacrylonitrile (CNTs/PAN) composite nanofibers. Characterizations of the samples—such as morphology, the degree of alignment, and mechanical and conductive properties—were investigated by a combination of scanning electron microscopy (SEM), transmission electron microscopy (TEM), universal testing machine, high-resistance meter, and other methods. The results showed the MPEM could improve the alignment and uniformity of electrospun CNTs/PAN composite nanofibers, and enhance their mechanical and conductive properties. This meant the successful preparation of highly aligned CNT-reinforced PAN nanofibers with enhanced physical properties, suggesting their potential application in appliances and communication areas.Keywords:carbon nanotubes;highly aligned;composite nanofibers;electrospinning
研究领域:
材料科学
·
纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Applied Polymer Materials
·
2025
·
IF 4.7
Yikun Sun,Bo Niu,Hongxiang Cai,Hao Tian,Liang Li,Qixin Zhuang,Donghui Long
The filler content and distribution are the most significant factors affecting the thermal conductivity (TC) of polymer-matrix composites. Orienting the filler for alignment is the most widely adopted approach to enhance TC in these materials. However, traditional orientation strategies require external fields or additional conditions, resulting in complex processes and hindering the ability to achieve conformal orientation of heterogeneous structures. In this context, an orientation strategy is proposed based on dense packing and injection molding to fabricate high-orientation and shape-controllable composites, thereby reducing limitations related to temperature, pressure, molding shapes, and matrix types during composite preparation. Dense packing induces the transition of high diameter-to-thickness ratio (DTR) fillers from locally isotropic to anisotropic alignment, while the injection molding process drives the overall orientation of the composites. Using aluminum (Al) flakes and cyanate ester (CE) as representative materials, a systematic study was conducted on the influence of filler content and composite thickness on the orientation of fillers. As a result, Al/CE-40 exhibits remarkable flexibility and achieves a maximum tensile strength of 29.9 MPa with an Al flake content of 40 wt %. The prepared Al/CE composites exhibit a high orientation ratio of 0.868 and a TC of 5.9 W·m–1·K–1, even with only 30 wt % Al content. Notably, the Al/CE composites maintain a high orientation when formed into specific shapes. Furthermore, various sheet-like materials with a high DTR, such as silver and mica flakes, show considerable promise as thermal management materials suitable for injection molding.
研究领域:
材料科学
·
热管理材料
✓ 已验证
产品关联
DOI
高影响因子
Materials Today Communications
·
2022
·
IF 3.662
Jiangang Zhou,Congzhen Xie,Rui Wang,Huasong Xu,Bin Gou,Licheng Li
Thermally conductive polymeric materials have attracted great interest from academia and industry for several decades. Herein, we report a facile method to fabricate BNNS/PP composites with excellent properties, especially the in-plane thermal conductivity . SEM and XRD results show the orderly dispersion and high orientation of BNNS along the in-plane direction. Attractively, the in-plane thermal conductivity of BNNS/PP composites after 20 times of folding and hot pressing is dramatically improved to 4.08 W/mk at a BNNS content of only 19.1 vol%, which is 20 times higher than that of pure PP and 480% higher than that of single hot pressing composite at the same filler content. In addition, The Hashin-Shtrikman (HS) model and finite element simulations are introduced to interpret the improvement of in-plane thermal conductivity of BNNS/PP composites after repeated hot pressing. Meanwhile, the influence of parallel orientation and layered distribution of BNNS on the mechanical and dielectric properties of BNNS/PP composites has been investigated. This facile method presents a novel approach to design and fabricate polymer composites with excellent in-plane thermal conductivity.
研究领域:
材料科学
·
热传导工程
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED MATERIALS
·
2022
·Vol. 34
·期 37
·2204259
·
IF 32.086
Jingxuan Chen,Donglin Jia,Rongshan Zhuang,Yong Hua,Xiaoliang Zhang
Perovskite quantum dots (PQDs) have emerged as competitive optoelectronic materials for photovoltaic applications due to their ideal bandgap energy, high defect tolerance, and solution processability. However, the highly dynamic surface and imperfect cubic structure of PQDs generally result in unfavorable charge-carrier transport within the PQD solids and serious nonradiative recombination. Herein, a highly orientated PQD solid is demonstrated using precursor engineering accompanied by a chemical stripping treatment (CST). A combination of systematic experimental studies and theoretical calculations is conducted to fundamentally understand the resurfacing of PQDs using the CST approach. The results reveal that the highly ordered PQDs can result in a high orientation of PQD solids, significantly promoting charge-carrier transport within the PQD solids. Meanwhile, the ideal cubic-structured PQD with an iodine-rich surface dramatically decreases surface trap states, thereby substantially diminishing trap-assisted nonradiative recombination. Consequently, the inorganic PQD solar cell delivers a power conversion efficiency of up to 16.25%. This work provides a feasible avenue to construct highly orientated PQD solids with improved photophysical properties for high-performance optoelectronic devices.
研究领域:
材料科学
·
光伏技术
·
纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MACROMOLECULAR MATERIALS AND ENGINEERING
·
2020
·Vol. 305
·期 3
·1900691
·
IF 3.853
Yi Pu,Xue Yang,Yifei Zhang,Lujian Li,Yuze Xie,Bin He,Ding Yuan,Xin Ning
Here, highly-oriented poly(m-phenylene isophthalamide)/polyacrylonitrile multi-walled carbon nanotube (PMIA/PAN-MWCNT) composite nanofiber membranes with excellent mechanical strength and thermal stability are successfully produced using electrospinning. It is demonstrated that the cooperation of multi-walled carbon nanotubes (MWCNT) and high-speed rotating collection is beneficial to the acquisition of highly oriented fibers and effectively improves the mechanical strength of the membrane along the orientation direction. Specifically, the tensile stress of poly(m-phenylene isophthalamide)/polyacrylonitrile (PMIA/PAN) membrane is enhanced significantly from 10.6 to 20.7 MPa, benefiting from the highly oriented alignment of the fibers as well as the reinforcing effect of MWCNTs on the fibers. Furthermore, the stressing process of single fiber and fiber aggregates is carefully simulated, and the influence of MWCNTs on the mechanical properties of PMIA/PAN-MWCNT membranes is analyzed comprehensively, providing a meaningful auxiliary means for the study of mechanical properties. In addition, the composite nanofiber membrane has the advantages of both PMIA and PAN, possessing high temperature resistance, flame-retardancy, and chemical stability, for an ideal high-temperature material. In short, the as-prepared PMIA/PAN-MWCNT composite membrane with excellent comprehensive property emerges a promising application in many fields, especially in high-tech.
研究领域:
材料科学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）