Preparation and characterization of PSA/nano-TiO2 composites and fibers

Polysulfonamide/nano titanium dioxide (PSA/nano-TiO₂) composite spinning solutions with various nano-TiO₂ mass fractions were prepared using the solution blending method. The corresponding composite fibers were developed by wet-spinning technology and the composite membranes were prepared using the digital spin-coating technique. The properties of PSA/nano-TiO₂ composite fibers and membranes were investigated by scanning electron microscope, Fourier transform infrared spectroscopy and X-ray diffraction, etc. The effects of nano-TiO₂ and its mass fractions on the mechanical properties, thermal stability and ultraviolet resistance of PSA composites were also analyzed. The experimental results showed that nano-TiO₂ with low mass fractions can be dispersed evenly in the PSA matrix; the blending of nano-TiO₂ had no obvious influence on the molecular structure and the chemical composition of PSA fiber; the crystallization in PSA fiber was promoted at low nanoparticles mass fractions because it can act as a nucleation agent; the mechanical properties and the thermal stability of PSA/nano-TiO₂ composites can be enhanced obviously by blending nano-TiO₂ into PSA matrix. The ultraviolet resistance of PSA composites can be improved significantly with the increasing nano-TiO₂ mass fractions and the 7 wt.% specimen showed the lowest UV transmittance.     

纤维素/碳纳米管复合纤维的制备及其功能化应用

针对导电材料填充纤维素复合纤维的强度与导电性能难以兼顾的问题,利用羧基改性碳纳米管能较好地分散在水中,以及低温(-10℃)条件下氢氧化钠/尿素溶液能较好地溶解纤维素这个特性,制备了纤维素/碳纳米管复合纺丝液,然后通过湿法纺丝制备了含有不同质量分数碳纳米管的复合纤维,对复合纤维的微观结构、力学性能以及电学性能进行表征。结果表明：由于纤维素与碳纳米管之间的强相互作用以及碳纳米管的取向,使复合纤维具有良好的力学性能和导电性能,当碳纳米管质量分数为20%时,复合纤维的断裂强度为165 MPa,电阻为3 kΩ;当电压升高到30 V时,复合纤维的温度在15 s内可上升到62.3℃,且吹气和浸入水中都能产生规律的电阻变化。     

Preparation and characterization of graphene enriched poly(vinyl chloride) composites and fibers

In this paper, poly(vinyl chloride)/graphene (PVC/G) composite fibers are extruded through a set of wet spinning unit for the purpose of properties improvement, including mechanical strength, thermal stability, and electrical conductivity. PVC/G composite membranes are also prepared using a spin-coating method for the analysis on the distribution of graphene in PVC composite. The PVC/G composite fibers are systematically characterized by means of Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, and X-ray Diffraction. The mechanical, thermal, and electrical properties of the prepared PVC/G composite fibers are also analyzed. The experimental results show that the graphene sheets at a low concentration of 1–5 wt% can be distributed homogeneously in the PVC matrix; the mechanical properties, thermal stability, and electrical conductivity of PVC can be enhanced significantly by the blending of graphene sheets.     

UHMWPE/PANI复合导电纤维的制备及其性能

采用原位聚合法制备了UHMWPE/PANI复合导电纤维。探讨了氧化剂种类及过硫酸铵浓度对复合纤维电导率及表面形态的影响,并研究了UHMWPE/PANI复合纤维的化学结构及力学性能。结果表明：纤维表面形成的聚苯胺导电层赋予了纤维一定的导电性能,以过硫酸铵为氧化剂制得的复合纤维的导电性能最强,其电导率可达10-1S/cm;随过硫酸铵浓度的增加,复合纤维的电导率呈现先增后减的趋势,以30g/L时制得的复合纤维的电导率最高。复合纤维是基质纤维与聚苯胺的共混体系,且导电处理未引起基质纤维分子链结构的变化。导电处理后,纤维的断裂强度较未处理前有少量增加,断裂伸长率基本保持不变。     

聚苯胺/聚丙烯腈导电纤维的结构与性能

将十二烷基苯磺酸掺杂的聚苯胺(PANI-DBSA)与聚丙烯腈(PAN)共混,通过常规腈纶湿法成型技术制备出PANI-DBSA/PAN复合导电纤维。采用扫描电镜及透射电镜对PANI-DBSA在PAN中的分散情况进行了分析,探讨了PANI-DBSA含量对复合纤维力学性能及导电性能的影响。结果表明:PANI-DBSA在PAN基体中分散均匀,呈纳米尺寸分散,在较低的PANI-DBSA含量下复合纤维中的导电网络已经形成;PANI-DBSA的质量分数为5%时,复合导电纤维具有良好的力学性能,电导率可达10-3S/cm。     

Effects of Coir Fiber and Maleic Anhydride Modification on the Properties of Thermoplastic Starch/PLA Composite Laminates

Coir fiber reinforced composite laminates made of poly(lactic acid) (PLA) with a thermoplastic starch (TPS) were fabricated. Modified thermoplastic starch (MTPS) was prepared by reactive blending of TPS with maleic anhydride (MA). The effect of coir fibers was of our main interest. The tensile properties, water absorption, and morphological properties of the fabricated composite laminates were investigated. The composite laminates between PLA and starch TPS were prepared using coir fiber as reinforcing core, and the physical, mechanical, and morphological properties were studied. The results suggested that the optimum fiber contents for maximum tensile strength for TPS/PLA and MTPS/PLA composites were 20 and 30 wt%, respectively. Using MA for chemical modification of TPS for PLA composites could reduce the PLA content of about 10 wt%, and improve the tensile about 20%. The volume swelling for the MTPS/PLA composites was much lower than that for the TPS/PLA composites, and the swelling reduced with increasing coir fiber content. Based on compressive strength, the pallets produced using MTPS/PLA composites showed a high potential to replace the commercial urea-formaldehyde/PLA composites. It clearly appeared that MA modification to TPS not only improve the mechanical properties of fiber reinforced PLA composites, but also made the PLA composites bio-degrade more quickly.     

二维过渡金属碳/氮化合物复合纤维在智能可穿戴领域的应用进展

针对传统纤维难以满足当前智能可穿戴设备需求,现有复合纤维大都不能兼具导电性能好、力学性能优、储能特性强等问题,归纳总结了一种新型二维过渡金属碳/氮化合物(MXene)复合纤维在智能可穿戴领域中的研究进展。首先从纤维制备角度介绍了MXene复合纤维的制备方法,包括涂覆法、双辊法、静电纺丝法和湿法纺丝法等,并分析了各种方法的优劣;然后对制备的MXene复合纤维在现阶段电磁屏蔽、超级电容器、柔性传感器等领域的应用进行系统介绍;最后对MXene复合纤维在智能可穿戴领域的未来发展进行展望,为新一代导电性高、力学性能优异、高能量储存复合纤维的研究提供新的思路。     

PTT/PANI复合导电纤维的制备与性能

采用原位聚合法制备了PTT/PANI复合导电纤维,探讨了反应时间、等离子预处理、拉伸状态对复合纤维电导率的影响,并研究了PTT/PANI复合纤维的表面形貌、热学性能及力学性能。结果表明：纤维表面形成的聚苯胺导电层赋予了纤维优良的导电性能,其电导率可达10-2S/cm;对纤维进行氧气等离子预处理可明显提高复合纤维的电导率;反应时间对复合纤维的电导率也有较大影响;PTT/PANI复合纤维经拉伸后导电性能明显下降。复合纤维的热稳定性在高于430℃时优于基质纤维并在一定程度上提高了基质纤维的力学性能。     

碳纳米管/聚合物温差发电复合纺织材料的制备及其性能

为得到一种新型的柔性可穿戴温差发电织物,通过聚（3,4?乙烯二氧噻吩）与聚苯乙烯磺酸（PEDOT/PSS）将 碳纳米管（CNTs）均匀分散,采用浸渍烘干法,制备 CNTs/PEDOT/PSS 温差发电复合材料。借助扫描电子显微镜、X 射线衍射仪表征了该温差发电复合纺织材料的表面形貌和结晶情况,测试了不同质量分数 CNTs 下的 Seebeck 系数、 电导率和热导率,通过计算热电优值讨论了其热电性能,并研究了透湿性、折皱回复性等服用性能。结果表明：随着 CNTs 质量分数的增加,Seebeck 系数和电导率增大,热导率保持在较低的水平,热电优值增加,热电性能逐渐增强,透 湿性稍有下降,折皱回复性得到提高;在CNTs 质量分数为0.4% 时,热电优值达到2.99 ×10-9。     

Photoreactive TiO2/carbon nanotube composites: synthesis and reactivity

Electron-hole recombination limits the efficiency of TiO2 photocatalysis. We have investigated the efficacy with which anatase/carbon nanotube (CNT) composite materials reduce charge recombination and enhance reactivity. We synthesized nanostructured assemblies composed of different proportions of anatase (5 or 100 nm) and either single-or multi-walled CNTs. The composites were prepared using a simple low temperature process in which CNTs and anatase nanoparticles were dispersed in water, dehydrated at 80 degrees C, and dried at 104 degrees C. The structures of the various TiO2/CNT composites were characterized by scanning electron microscopy (SEM) and their function was tested by phenol oxidation. Charge recombination was compared by measuring the photoluminescence spectra of select composites. We found that a nanostructured composite assembled from the 100 nm anatase and single-walled CNTs (SWCNTs) exhibited enhanced and selective photocatalytic oxidation of phenol in comparison to both pure anatase and Degussa P25. A mechanism for the enhanced reactivity is proposed in which electrons are shuttled from TiO2 particles to the SWCNTs as a result of an optimal TiO2/ CNT arrangement that stabilizes charge separation and reduces charge recombination. In addition, the SWCNT assembly provides better catalyst-support (dispersal and connection) than multi-walled CNTs.     

PLA/PBAT/CNTs-COOH防静电包装材料的制备与性能研究

可降解防静电包装材料在保留传统防静电材料性能的前提下,可完全生物降解,符合环保要求。为了制备具有优异力学和导电性能的可生物降解防静电包装材料,本研究先对碳纳米管(CNTs)进行羧基化,然后通过熔融共混法制备PLA/PBAT/CNTs-COOH复合材料。采用傅立叶变换红外光谱仪(FTIR)和差示扫描量热仪(DSC)对制备的复合材料的链结构和热性能进行表征,并且通过万能材料试验机、数字冲击试验机和多功能数据采集仪研究了复合材料的力学和导电性能。结果表明:将CNTs-COOH引入PLA/PBAT体系中,可在不降低拉伸强度的同时,有效提高冲击强度,降低表面电阻率,CNTs-COOH的最佳添加量为1wt%~1.5wt%。该PLA/PBAT/CNTs-COOH复合材料可用于静电敏感产品的防静电包装。     

聚氨酯基碳纳米管-液态金属导电纤维的制备及其性能

为改善碳纳米管(CNT)作为导电填料弹性性能不足的问题,以CNT和液态金属(LM)为导电填料,热塑性聚氨酯(TPU)为基体,选用N,N-二甲基甲酰胺(DMF)作为溶剂,去离子水为凝固浴,通过湿法纺丝制备了CNT/LM/TPU导电纤维,并研究了LM和CNT 2种导电填料对纤维结构和性能的影响。结果表明:当导电填料LM质量分数为40%,CNT质量分数为10%时,CNT/LM/TPU纤维的力学性能大幅度提升,断裂强度为10.16 MPa,断裂伸长率为252%;CNT/LM/TPU纤维具有良好的导电性能,其电导率为5.41 S/m,可以用作导线点亮电路,在100%和200%的拉伸应变下电路仍有电流通过,且经20次循环拉伸后仍具有稳定的电阻回复性;此外,该纤维还具有良好的抗菌性能,对金黄色葡萄球菌的抑菌率达到92.61%。     

角蛋白/多壁碳纳米管复合纤维的制备

为促进废旧羊毛的回收利用,采用L-半胱氨酸还原法溶解羊毛提取角蛋白,将羊毛再生角蛋白溶于碳酸钠/碳酸氢钠缓冲溶液中配置成纺丝液,并且向其中添加由傅克反应制备的功能化多壁碳纳米管,通过湿法纺丝制备再生角蛋白/功能化碳纳米管复合纤维。研究结果表明：碳纳米管均匀的分散在复合纤维中,没有发生团聚现象,并且与角蛋白基体有着良好的界面作用;碳纳米管加入对纤维的结晶度有所提高,并且能够诱导角蛋白内部形成较多的β-折叠的二级结构构象;随着碳纳米管的加入,复合纤维的拉伸断裂强度增加,当碳纳米管质量分数为0.15 wt%时,拉伸断裂强度达到最大（91.5±12.6） MPa,比纯角蛋白纤维提高了139%。     

Structures and flammability properties of polyethylene terephthalate(PET) fibers containing encapsulated carbon materials

In this paper, carbon nanotubes (CNTs) and carbon microspheres (CMSs) have been microencapsulated to obtain microencapsulated carbon nanotubes (MCNTs) and microencapsulated carbon microspheres (MCMSs). Moreover, a series of PET fibers with CNTs/CMSs or MCNTs/MCMSs were prepared by melt spinning. Morphologic structures, mechanical, thermal, and flame retardant properties of MCNTs/MCMSs /PET fibers have been studied by TEM, SEM, electronic tension meter, DSC, TG, limiting oxygen index (LOI), and vertical flammability instruments. The results show that the tensile strength of MCNTs/MCMSs/PET fibers are increased because of better dispersion and compatibility of MCNTs/MCMSs in PET and enhanced orientation degrees of fibers, compared with CNTs/CMSs/PET fibers. Moreover, the highest values of mechanical properties are observed with 0.4 wt% content. Meanwhile, the MCNTs/MCMSs/PET fibers have good thermal stabilities and their fabrics have higher LOI value of 25.3%, reaching B1 class of China standard GB 17591-2006. Overall, this method endowed the MCNTs/MCMSs/PET fibers with the good mechanical and flame-retardant properties.     

功能化碳纳米管复合薄膜及其膜卷纱的电热性能

碳纳米管(CNT)具有优异的电学性能,为了更好地将其应用于纺织品加热领域,采用加捻CNT薄膜的方法制备膜卷纱,并通过预喷涂导电聚合物聚(3,4-乙烯二氧噻吩):聚(苯乙烯磺酸盐) (PEDOT:PSS)溶液的方式进一步优化CNT膜卷纱的电热性能;随后分析PEDOT:PSS喷涂浓度对CNT薄膜及其膜卷纱的结构和导电性能的影响,以及施加不同电压条件下CNT薄膜及其膜卷纱的温度变化。结果表明:随着PEDOT:PSS质量分数从0.01%增加至1.4%,所喷涂的CNT薄膜电导率由344.2 S/cm逐渐增大至668.9 S/cm;当PEDOT:PSS质量分数为0.07%时,所制备的CNT复合膜卷纱具有优异的电热性能,当在其两端施加电压时,温度可到达214 ℃,响应时间为5 s,发热温度是其未加捻薄膜的1.6倍,具有较好的应用潜力和开发价值。     

Mechanical,morphological, and thermogravimetric analysis of alkali-treated Cordia-Dichotoma natural fiber composites

ABSTRACT

Usage of composites with natural fiber reinforcement is drastically increasing in recent times because of their low density, biodegradable nature, and low cost. However, natural fibers have certain core problems such as poor adhesion between the fiber and matrix and a relatively high degree of moisture absorption. Alkaline treatment of natural fibers is aimed at improving the adhesive strength so that effective stress transferability takes place in the composite. In the present work, Cordia-Dichotoma fibers were treated with sodium hydroxide (NaOH) and composites were prepared with different weight ratios of these fibers reinforced with epoxy. The prepared composites were tested for their tensile and flexural strengths (mechanical properties). Besides, for a comprehensive material characterization, IR spectroscopy (FT-IR), scanning electron microscope, and thermogravimetric analysis were carried out. This work investigates the influence of aforementioned NaOH treatment on thermal, mechanical, and morphological properties of the composite material.     

聚酰胺基碳纳米管复合纤维的研究现状与进展北大核心CSCD

碳纳米管的力学、电学及热学等性能可赋予聚酰胺纤维良好功能,且聚酰胺基碳纳米管复合纤维能够保持其功能的稳定性。然而,如何提高碳纳米管在聚酰胺基体中的分散效果、降低碳纳米管应用成本,是碳纳米管复合纤维及其纺织品的重要研究方向。因此,本文结合现阶段国内外聚酰胺基碳纳米管复合纤维及纺织品的研究现状,探讨影响聚酰胺基碳纳米管复合纤维结构性能的主要因素和应用前景,为推进碳纳米管在纺织领域中的发展应用提供参考。     

PPTA@ZnO NWs的功能化修饰及导热绝缘纸基材料的制备与研究

为了提高芳纶纤维纸基材料的导热性,通过水热合成法在对位芳纶纤维(PPTA)表面生长氧化锌纳米线(ZnO NWs),进一步用硅烷偶联剂KH550对PPTA@ZnO NWs进行功能化修饰,采用湿法造纸技术制备PPTA@ZnO NWs-KH550纸基复合材料并研究其导热性能、绝缘性能及力学性能。结果表明,ZnO NWs成功地均匀包覆在PPTA表面。与PPTA纸基复合材料相比,PPTA@ZnO NWs纸基复合材料的导热系数可达0.455W/(m·K),提高115.64%,且介电强度满足绝缘要求。经硅烷偶联剂KH550功能化修饰后,PPTA@ZnO NWs-KH550纸基复合材料导热系数较修饰前基本保持不变,呈现优异的绝缘性和良好的力学性能,介电强度增加3.69%,拉伸强度提高58.75%。     

基于N-甲基吗啉-N-氧化物溶剂制备聚芳砜酰胺/纤维素阻燃纤维

为制备兼具阻燃和吸湿性能的纤维,采用N-甲基吗啉-N-氧化物(NMMO)水溶液为共溶剂,分别将纤维素(cellulose)和聚芳砜酰胺(PSA)溶解后进行共混制备纺丝液,通过干喷湿法纺丝制备PSA/cellulose共混纤维,并对纺丝液及共混纤维的结构和性能进行表征与分析。结果表明:NMMO对PSA具有良好的溶解性能,纺丝液均质、稳定,制备的共混纤维呈现出PSA富集于纤维表层的类皮-芯结构;PSA/cellulose纤维具有良好的阻燃性能、吸湿性能和力学性能,当纤维素质量分数达到30%时,共混纤维仍可达到阻燃纤维标准,其断裂强度为2.08 cN/dtex,无需后道牵伸处理就能达到较高的强度,此时PSA/cellulose纤维的回潮率提高为8%,具有良好的可染性。     

Development of electrically conductive composites based on recycled resources

Abstract

The current study was focused on the development of electrically conductive composites of carbon particle filled cotton fabric/epoxy systems. The carbon particles were refined to the scale of micro/nanoparticles using ball milling and morphological properties were studied by Malvern zetasizer and SEM. The influence of different concentrations of carbon particles in green epoxy resin for electrical conductivity was studied. Additionally, the electrical conductivity and electromagnetic shielding ability of conductive composites were analyzed. Waveguide method at high frequency (i.e. at 2.45?GHz) was used to investigate the EMI shielding. Similarly, the effect of different concentrations of carbon particles in composites was also studied for mechanical strength (tensile and flexural). A comprehensive study showed the improvements in electrical and mechanical properties with increase in the concentration of carbon particles and their even distribution in resin. The composites with higher carbon filler concentration showed maximum electrical conductivity (1.0E–02), shielding effectiveness 23.13?dB and mechanical properties.