In this study, barium ferrite (BaFe 12 O 19 ) was used as the basic microwave-absorbing material and compounded with graphene and PANI. Then, BaFe 12 O 19 , BaFe 12 O 19 /graphene, and BaFe 12 O 19 /graphene/PANI were mixed with waterborne polyurethane and coated on nylon fabrics by the cast coating method to prepare flexible microwave absorbing materials. The microwave absorbing performance of BaFe 12 O 19 /graphene/PANI coated fabric is significantly improved in comparison with BaFe 12 O 19 and BaFe 12 O 19 /graphene coated fabric, which mainly comes from the synergistic effects of magnetic loss, dielectric loss, and conductivity loss. The BaFe 12 O 19 /graphene/PANI coated fabric has a minimum reflection loss value of –37.36 dB (at 13.76 GHz) and an effective absorption bandwidth of 5.40 GHz (12.44–17.84 GHz) when the thickness is 1.2 mm. Consequently, the facile preparation route and excellent performance make the BaFe 12 O 19 /graphene/PANI composite a promising candidate for efficient microwave absorbence.

后新冠疫情时代,口罩已经成为人们在公共场合的必需品,聚丙烯熔喷布作为口罩三层结构中的重要组成,对防护效果和舒适程度起到了决定性的作用.本文通过系统测试随机收集的20个聚丙烯熔喷布样品的基本参数、微观形貌、过滤性能、通气阻力、透气性和透湿性,研究了熔喷布的纤维直径及其均匀程度和孔隙率等结构参数与上述性能之间的内在联系,得到如下结论:过滤效率、通气阻力和透气性均受熔喷布中纤维直径及其均匀程度的影响,纤维直径越小、越均匀,熔喷布的盐性/油性颗粒物过滤效率和透气性能越好,通气阻力越低,且熔喷布孔隙率与其通气阻力和透气性之间存在线性关系;纤维直径及其均匀程度对于透湿性的影响较小,过滤效率和透湿性与熔喷布孔隙率之间均未呈现稳定的变化趋势.

A novel strategy for the synthesis of conductive shear thickening fluids (STFs) which manifest both shear thickening behavior and strain-sensing properties.

利用热塑性聚氨酯(TPU)和碳化硅(SiC)涂覆芳纶织物,制备具有良好柔韧性和抗刺穿性能的防刺织物.测试了织物的刚柔性、层间剥离性能和准静态穿刺性能,探讨碳化硅含量、粒径大小对涂层织物防刺性能的影响.结果表明:添加碳化硅颗粒后的涂层溶液能够进一步提高织物的防刺性能,而且柔韧性下降较小;当碳化硅粒径相同时,涂层织物的防刺性能随着添加量的增加先增大后减小,当30 nm碳化硅质量分数为1％,或80 nm碳化硅质量分数为3％时,涂层织物有较好的防刺性能.

STFs impregnation is an effective method to prepare impact resistance fabrics without sacrificing their flexibility, and the structural features are essential factors affecting the puncture resistance behaviors of these fabrics. Since few studies focus on the quasi-static puncture resistance of 3D woven fabrics and their STFs-based composites, we developed a strategy to evaluate the anti-puncture efficiencies and established models to predict the puncture resistance characteristics of materials. The results show a significant linear relationship between the puncture resistance and layer numbers, and the maximum puncture force and energy dissipation could reach 1284.58 N and 7.22 J for the five-layer angle-interlock fabric after STFs impregnation. Given the inter-yarn slippage restriction by STFs, the maximum puncture force of the fabric with an FVF of 49.47% increases 132.84% after STFs treatment, but the anti-puncture efficiencies of fabrics, whose FVF is higher than 53.4%, drop more than 10% after impregnation. The layer-to-layer interweaving improves fabric's anti-puncture efficiency, but the overlarge binding warp inclination is detrimental to the mechanical usage of yarns and the maintenance of the compact structure.

为进一步了解警用防刺服用织物增强柔性防刺复合材料,提升现有柔性防护装备的防刺性能水平,以复合材料的柔性基体作为切入点,系统介绍了剪切增稠型、硬质颗粒涂层型和树脂增强型等多种类型的柔性防刺复合材料的结构特点、性能特征及其主要影响因素,并从柔性基体的结构特征出发,总结了织物增强柔性防刺复合材料在防刺机制研究方面的最新进展;最后针对防护装备在穿着灵活性和舒适性方面的不足,提出了整合不同类型柔性防刺复合材料在结构性能特征和防刺机制方面的优势,开发复合型织物增强柔性防刺复合材料的发展方向.

Magnetic nanoparticles are attracting significant attention for their wide application as biomaterials and magnetic storage materials. As an environmentally friendly adhesive, reactive polyurethane hot-melt adhesive (PUR) is a biocompatible polymer with a wide range of applications. In this paper, chitosan (CS)-surface-modified magnetic Fe3O4 nanoparticles were synthesized by the sol-gel method. Surface modification of the Fe3O4 nanoparticles with CS enhanced their mechanical properties in PUR. The nanoparticles were characterized by Fourier transform infrared (FTIR) and X-ray diffraction (XRD) analyses, while their surface morphology was elucidated using scanning electron microscopy (SEM) and projection electron microscopy (TEM) techniques. Subsequently, PUR/CS-Fe3O4 magnetic nanocomposite films were prepared using an in situ method, wherein different amounts of CS-surface-modified magnetic Fe3O4 nanoparticles were doped into the PUR and coated on the films. The thermal, UV resistance and mechanical properties of the PUR/CS-Fe3O4 magnetic nanocomposite films were investigated by TGA, UV spectrometer and tensile testing. CS-Fe3O4 nanoparticles were successfully prepared using the sol-gel method and CS to modify the surface of the Fe3O4 nanoparticles. The results show that the mechanical properties and UV resistance of PUR/CS-Fe3O4 magnetic nanocomposites are improved by almost 50%, so the constructed PUR/CS-Fe3O4 magnetic nanocomposites have good UV-resistant properties and mechanical properties. The as-synthesized CS-Fe3O4 magnetic nanocomposites show great potential for application to mechanical and textile development.

鉴于利器砍杀式暴恐袭击事件的频繁发生,以及公安武警对于轻便舒适型防刺装备的迫切需求,近年来高性能织物增强柔性防刺材料的研究开发发展迅猛.系统地回顾了近年来国内外织物增强柔性防刺材料领域相关的研究成果,重点梳理以机织物、针织物和非织造织物为预制件的柔性防刺材料的结构特征和防刺机理.其中:机织物中经纬纱之间的滑移作用成为材料失效的重要因素;针织物的线圈结构使其具有自锁紧和缓冲吸能的作用;非织造织物由于具有面内各向同性的性能特征,多与其他类型织物复合制备柔性防刺材料.基于此,对复合织物柔性防刺材料研究现状进行分析与展望,为今后织物增强柔性防刺材料的研发与应用提供了一些意见和建议.

为了提高废弃玉米苞叶的再利用率,降低育果袋的生产成本,该研究采用碱煮法将玉米苞叶脱胶后提取玉米苞叶纤维,运用湿法成网技术将(5±0.5)mm的玉米苞叶纤维与废旧书本纸屑按1.5:1的配比快速成型制备了育果袋材料样品,并对其和市场具有代表性的5种育果袋的透气、保温、遮光性能以及水份管理能力等相关性能进行测试分析.结果表明:与市场参比样品相比,所制备的材料具有优良的套袋相关性能,其透气率和透气量分别达到了73.5 mm/s和173.7 L/m2·s;热量损失仅为265 kJ/h;可见光和紫外光范围内透过率分别为0.4％和0.09％;不仅如此,所制备的材料在30 min内芯吸高度达到了31 mm,平均湿蒸发速率为0.1165 g/h,保水性能明显优于市场葡萄专用育果袋样品.