今日更新:Composites Part A: Applied Science and Manufacturing 3 篇,Composites Science and Technology 2 篇
Enhancing mechanical properties and thermal conductivity in polymer bonded explosives by multi-scale surface modification of carbon fibers
He Guansong, Wang Peng, Zhong Ruolei, Li Xin, Yin Huamo, Chen Jie, Liu Shijun, Yang Zhijian
doi:10.1016/j.compositesa.2023.107918
通过对碳纤维进行多尺度表面改性,提高聚合物粘合炸药的机械性能和导热性能
Poor interfacial interaction and strength largely restrict the overall performance and practical application of carbon fibers (CFs) reinforced composites. The favorable interfacial properties were the key to realize superior mechanical properties in composites. Herein, we reported a novel multi-scale surface modification strategy of CFs to strengthen interfacial properties. Based on chemical oxidation treatment, the surface of CFs was further in situ grafted by a crosslinked high-strength polymer network consisting of aromatic diisocyanate, graphene oxide (GO) and polyethylenen glycol (PEG), which significantly improved the interfacial bonding and mechanical strength of interface layer itself. Benefitting from this multi-scale surface treatment, a high-efficiency mechanical enhancement of polymer bonded explosives (PBX) was achieved. With only 0.3 wt% fiber content, the maximum tensile and compressive strength PBX composites were both significantly improved, which were 63% and 39% higher than those of pure PBX, respectively. Meanwhile, the thermal conductivity was also enhanced, yielding a significant synergistic enhancement effect. The interface failure mechanism of the composite under stress was clarified by the fracture morphology characterization. This study sheds a light for exploring novel surface modification and has the potential application in in high performance polymer composites.
界面相互作用和强度差在很大程度上限制了碳纤维(CFs)增强复合材料的整体性能和实际应用。良好的界面性能是实现复合材料优异机械性能的关键。在此,我们报告了一种新型的多尺度碳纤维表面改性策略,以增强界面性能。在化学氧化处理的基础上,进一步在 CF 表面原位接枝由芳香族二异氰酸酯、氧化石墨烯(GO)和聚乙二醇(PEG)组成的交联高强度聚合物网络,从而显著提高了界面层本身的界面结合力和机械强度。得益于这种多尺度表面处理,实现了聚合物结合炸药(PBX)的高效机械增强。在纤维含量仅为 0.3 wt% 的情况下,PBX 复合材料的最大拉伸强度和抗压强度都得到了显著提高,分别比纯 PBX 复合材料高出 63% 和 39%。同时,热导率也得到了提高,产生了明显的协同增强效应。通过断口形貌表征,阐明了复合材料在应力作用下的界面失效机理。这项研究为探索新型表面改性提供了启示,具有在高性能聚合物复合材料中应用的潜力。
Shape-memory polyurethane elastomer originated from waste PET plastic and their composites with carbon nanotube for sensitive and stretchable strain sensor
Zhou Xing, Wang Guosheng, Li Dexiang, Wang Qi, Zhu Keming, Hao Yaya, Xu Yueyang, Li Neng
doi:10.1016/j.compositesa.2023.107920
利用废 PET 塑料制成的形状记忆聚氨酯弹性体及其与碳纳米管的复合材料,用于灵敏且可拉伸的应变传感器
Chemical recycling of polyethylene terephthalate (PET) bottles is prospective for reducing waste plastics. The transformation of waste PET into valuable composites in high efficiency still remains a formidable challenge. Here we report the synthesis of polyurethane elastomer (PUE) by using the degraded products from waste PET via one-pot chain extended process. Then, the composites composed of PUE as substrate with carbon nanotubes as fillers are applied in fabricating stretchable strain sensor. The results show that the degraded product was successfully introduced into the polyurethane chains. The PUE chains showed disordered stacking as the degraded product content increased, with the modulus and elongation at break were up to 763.9 %. The composites assembled strain sensors exhibited stable sensing performance and excellent durability after 1000 cycles at 20 % tensile strain. This may supply a path to efficiently recycle waste PET plastic into valuable and functional composites, and even devices.
聚对苯二甲酸乙二酯(PET)瓶的化学回收利用在减少废塑料方面前景广阔。如何高效地将废弃 PET 转变为有价值的复合材料仍是一项艰巨的挑战。在此,我们报告了利用废弃 PET 的降解产物,通过一锅扩链工艺合成聚氨酯弹性体(PUE)的过程。然后,以聚氨酯弹性体为基材,碳纳米管为填料组成的复合材料被应用于制造可拉伸应变传感器。结果表明,降解产物被成功引入到聚氨酯链中。随着降解产物含量的增加,聚氨酯链出现了无序堆叠,模量和断裂伸长率高达 763.9%。组装应变传感器的复合材料在 20% 拉伸应变条件下循环使用 1000 次后,显示出稳定的传感性能和出色的耐用性。这为将废弃 PET 塑料有效回收利用为有价值的功能性复合材料甚至设备提供了一条途径。
The simultaneously achieved high permittivity and low loss in tri-layer composites via introducing negative permittivity layer
Song Xiaoting, Zhang Zidong, Fan Guohua, Liu Yao, Fan Runhua
doi:10.1016/j.compositesa.2023.107921
通过引入负介电常数层,在三层复合材料中同时实现高介电常数和低损耗
Dielectric composites with excellent power densities have garnered significant attentions in electrical systems and pulsed energy storage. However, the low permittivity and high dielectric loss are greatly limit their applications. Herein, we present a novel approach involving tri-layer composites, where a middle negative-έ layer is sandwiched between outer positive-έ layers. This design aims to realize the balance of comprehensive performances by the interfacial polarization and synergistic effect between positive and negative-έ layers. Amazingly, the composite with content 3-5-3 with the thickness ratio of 1:20:1 shows remarkable permittivity of 679 coupled with a low loss tangent of 0.017 @ 10kHz, which is approximately 141 times higher than PI matrix with 4.8 of permittivity. Remarkably, the composite with content 3-5-3 (1:1:1) exhibited an improved Ud and high η of 1.35 J/cm3 and 94.5%, respectively. This work presents a new class of tri-layer composites with negative-έ layer, whose design method is applicable in high-property dielectric composites.
具有出色功率密度的介电复合材料在电气系统和脉冲储能领域备受关注。然而,低介电常数和高介电损耗极大地限制了它们的应用。在此,我们提出了一种涉及三层复合材料的新方法,即在外层正έ层之间夹入中间负έ层。这种设计旨在通过界面极化和正负έ层之间的协同效应实现综合性能的平衡。令人惊奇的是,厚度比为 1:20:1 且含量为 3-5-3 的复合材料显示出 679 的显著介电常数和 0.017 @ 10kHz 的低损耗正切,这比介电常数为 4.8 的 PI 基体高出约 141 倍。值得注意的是,3-5-3(1:1:1)含量的复合材料显示出更高的 Ud 值和更高的η 值,分别为 1.35 J/cm3 和 94.5%。这项研究提出了一种新型负έ层三层复合材料,其设计方法适用于高特性介电复合材料。
Interfacial reinforcement of carbon fiber composites through a chlorinated aramid nanofiber interphase
Mamolo Steven U., Sodano Henry A.
doi:10.1016/j.compscitech.2023.110351
通过氯化芳纶纳米纤维间相实现碳纤维复合材料的界面加固
Carbon fiber-reinforced polymers (CFRPs) rely on a strong interfacial bond between the reinforcing fibers and polymeric matrix to yield the high strength and toughness expected by a composite material. Poor interfacial strength leads to sub-optimal load transfer and introduces stress concentrations, which can reduce overall performance and result in catastrophic failure. Aramid nanofibers (ANFs) have shown significant promise for interfacial reinforcement in polymeric composite systems due to their high tensile strength, large specific surface area, and abundant polar functional groups. However, due to the chemically inert nature of carbon fibers, ANFs do not readily bond to their surface – thus limiting their application to CFRPs. In this work, we demonstrate that chlorination of ANFs and oxygen plasma treatment of carbon fibers enables the formation of a chlorinated ANF (Cl-ANF) interphase through chemical and physical adsorption using a simple dip-coating process, while fully preserving the tensile strength of the carbon fibers. The Cl-ANF interphase yielded a 79.8 % increase in interfacial shear strength and a 33.7 % increase in short beam strength. By enhancing the interfacial bond between fiber and matrix without degradation of the fiber's tensile strength, this method provides a rapid and reliable process to improve the mechanical properties of CFRP composites.
碳纤维增强聚合物(CFRP)依靠增强纤维与聚合物基体之间牢固的界面结合力来实现复合材料所期望的高强度和韧性。界面强度差会导致载荷传递效果不理想,并引起应力集中,从而降低整体性能并导致灾难性故障。芳纶纳米纤维(ANFs)具有拉伸强度高、比表面积大和极性官能团丰富等特点,因此在聚合物复合材料体系中的界面加固方面大有可为。然而,由于碳纤维的化学惰性,ANFs 不易与碳纤维表面结合,因此限制了其在 CFRP 中的应用。在这项工作中,我们证明了对 ANFs 进行氯化处理和对碳纤维进行氧等离子体处理后,可通过简单的浸涂工艺,利用化学和物理吸附作用形成氯化 ANF(Cl-ANF)相,同时完全保持碳纤维的抗拉强度。Cl-ANF 中间相使界面剪切强度提高了 79.8%,短束强度提高了 33.7%。通过增强纤维与基体之间的界面结合力而不降低纤维的抗拉强度,这种方法为提高 CFRP 复合材料的机械性能提供了一种快速可靠的工艺。
Optimizing energy storage density of the multi–layer composite of poly(vinylidene fluoride) and nano–Ni plated CaCu3Ti4O12 with an ultralow filling content
Gao Liang, Zhang Yuting, Xiao Qianqian, Gao Zhengwu, Wang Xuan
doi:10.1016/j.compscitech.2023.110353
优化超低填充物含量的聚偏氟乙烯和纳米镍镀层 CaCu3Ti4O12 多层复合材料的储能密度
Surface modification of nanoceramics with high dielectric constant can increase dielectric constant of polymer composites voiding excessive dielectric loss, however, low discharged energy density (Ud) of composites at a low loading limits potential applications in high–energy–storage devices under low electric field. Herein, Ni–plated CaCu3Ti4O12 nanoparticle (CCTO@Ni) is used to improve the electric properties of the poly(vinylidene fluoride) monolayer composites (C/PVDF), and an ultralow loading of 0.5 vol% promotes the largest Ud of 2.53 J/cm3 at 230 MV/m, resulting from MWS interface polarization and Coulomb barrier effect included by CCTO@Ni fillers, which is used to further prepare three kinds of multi–layer structured C/PVDF composites by solution casting layer by layer. Comprehensive testing shows that the PVDF–C/PVDF–PVDF–C/PVDF–PVDF five–layer film (P–C–P–C–P) enhances the dielectric constant and breakdown strength to contribute the maximal Ud of 6.65 J/cm3 at 297.8 MV/m, which is 118% larger than that of pure PVDF. Above excellent characteristics are attributed to the interface polarization of the middle C/PVDF layer and the alleviating and blocking effect of the middle and outer PVDF layers, which are clarified in depth by the finite element simulation and enhanced breakdown model.
对具有高介电常数的纳米陶瓷进行表面改性可以提高聚合物复合材料的介电常数,从而避免过多的介电损耗,然而,复合材料在低负载时的低放电能量密度(Ud)限制了其在低电场下高能量存储设备中的潜在应用。在本文中,镀镍的 CaCu3Ti4O12 纳米粒子(CCTO@Ni)被用来改善聚偏氟乙烯单层复合材料(C/PVDF)的电性能,0.5 vol% 的超低负载可使其在 230 MV 下的最大放电能量密度达到 2.53 J/cm3。 CCTO@Ni 填料在 230 MV/m 时产生的 MWS 界面极化和库仑势垒效应,进一步通过逐层溶液浇注制备了三种多层结构的 C/PVDF 复合材料。综合测试结果表明,PVDF-C/PVDF-PVDF-C/PVDF-PVDF 五层薄膜(P-C-P-C-P)提高了介电常数和击穿强度,在 297.8 MV/m 时的最大 Ud 为 6.65 J/cm3,比纯 PVDF 大 118%。上述优异特性归功于中间 C/PVDF 层的界面极化以及中间和外层 PVDF 层的缓解和阻挡作用,有限元模拟和增强击穿模型深入阐明了这一点。