碳纳米管增强环氧树脂基复合材料的制备及其力学性能

通过对多壁碳纳米管进行表面处理,用超声分散和模具浇注成型法制备了碳纳米管/环氧树脂纳米复合材料。研究了碳纳米管含量和表面处理对碳纳米管/环氧树脂复合材料力学性能和断面形貌的影响,分析了碳纳米管对环氧树脂的增强机理。结果表明,随着碳纳米管含量的增加,碳纳米管/环氧树脂复合材料的拉伸强度和弯曲强度及模量先增加后减小;当碳纳米管的质量分数为0.5%时,复合材料的拉伸强度、弯曲强度和弯曲模量分别达到最大值69.8MPa、136.9MPa和3.72GPa,比纯环氧树脂提高了33.9%、29.3%和4.8%;当碳纳米管的质量分数为1.5%时,拉伸模量达到最大值2050.5MPa,比纯环氧树脂提高了7.3%。     

激光石墨化沥青基碳纤维的力学性能研究

为提升沥青基碳纤维的力学性能,采用自制的激光超高温石墨化装置对中间相沥青基碳纤维进行石墨化处理。通过改变实验过程中的激光功率、牵伸力及碳纤维直径等3个因素制备了多组样品,研究了沥青基碳纤维拉伸强度随温度的变化规律,并分析了石墨化过程中牵伸力及碳纤维直径对其力学性能的影响。结果表明：沥青基碳纤维石墨化能承受的最大激光功率为360 W,对应的温度约为3 050℃,在此条件下处理得到的碳纤维拉伸强度由1.0 GPa提升至2.5 GPa;在碳纤维的承受范围内,其力学性能随着温度、牵伸力的增加而提高;直径较小的碳纤维力学性能提升更大。     

Fabrication and characterization of poly(vinyl alcohol)/carbon nanotube melt-spinning composites fiber

A composite fiber based on carbon nanotube(CNT) and poly(vinyl alcohol)(PVA) was prepared by melt-spinning. Structural features and the mechanical performances of the PVA/CNT composite fiber were investigated as a function of draw condition. Initial moduli and tensile strengths of the drawn composite fibers are much higher than those of undrawn composite fiber. It is identified from XRD and 2D XRD that the composite fiber exhibits enhanced crystallinity and orientation degree with increasing the draw ratio. Accordingly, finger-like pores distributed along the axial direction homogeneous on the melt-spinning PVA fiber surface. After dry and hot-drawn, the hydrophobicity of PVA/CNT composites fiber decreased gradually.     

防腐剂预处理玉米秸秆皮/HDPE复合材料 制备及其力学性能研究

将不同防腐剂处理后的玉米秸秆皮(CSF)、高密度聚乙烯(HDPE)塑料和其他添加剂共混,熔融复合后,采用挤出成型制备CSF/HDPE复合材料。考察了玉米秸秆皮添加量、防腐剂种类及其处理浓度对复合材料力学性能的影响,并利用扫描电镜(SEM)和红外光谱(FTIR)对复合材料进行表征。结果表明:经氨溶铜季铵盐(ACQ)处理后,随ACQ浓度增加,复合材料力学性能逐渐降低; 玉米秸秆纤维质量分数为50%、ACQ质量分数为1%时,玉米秸秆皮/HDPE复合材料的力学性能最佳。经硼酸锌(ZB)处理后,随ZB浓度的增加,复合材料拉伸强度逐渐增强; 弯曲强度、弯曲模量、冲击强度均呈现先增大后减小的趋势; 玉米秸秆纤维质量分数为50%、ZB质量分数为2%时,CSF/HDPE复合材料的力学性能最佳。     

Magnetic Cotton Fabric Coated with Poly( vinyl alcohol )( PVA )/Magnetic Attapulgite( MAT ) Composite Solution

Magnetic fiber or fabric incorporating magnetic particles was widely used in the field of magnetic health-care.The cotton fabric was modified with poly(vinyl alcohol)(PVA)/magnetic attapulgite(MAT)composite solution by coating,which was the PVA solution blended with MAT.The mechanical and magnetic properties were characterized by scanning electronic microscopy(SEM),vibrating sample magnetometer(VSM)and tensile strength test.The results of SEM show that MAT can scatter uniformly in the PVA film and the PVA/MAT polymer film has good combination with cotton fabric.The results of other tests show that the addition of PVA/MAT polymer film not only brings uniform magnetism to cotton fabric,but also increases the mechanical strength of the material.Besides,the proportion of PVA/MAT and dipping time are studied in order to determine the best parameters for further study on magnetic cotton fabric.     

Study on the Mechanical Properties of Carbon Nanotube/Polyacrylonitrile Composite Fibers

The method of preparing the multi-walled carbon nanotubes (MWNTs)-polyacrylonitriIe (PAN) composite fibers is described and the effects of draw ratio on the mechanical properties of CNT/PAN fibers have also been discussed. The results show that the degrees of MWNTs dispersion in the polymer matrix have much effect on the mechanical properties.     

Effect of Processing Parameters on Morphology and Mechanical Properties of Hollow Gel-Spun Lignin/Graphene Oxide/Poly (Vinyl Alcohol) Fibers

To investigate the influence of various processing parameters on the mechanical properties of fibers, lignin/graphene oxide(GO)/poly(vinyl alcohol)(PVA) fibers with different mass ratios of lignin and GO to PVA were prepared by gel spinning technique. Air drawing process and spinneret diameters were tuned as the main factors. The tensile strength increased up to 472 MPa with air drawing process applied in 30 L0.05 GO0.72 D-A PVA fibers(air-drawn PVA fibers reinforced by 30% lignin and 0.05% GO spun with a spinneret diameter of 0.72 mm), indicating 17.4% higher than that of the fiber without air drawing process(402 MPa). Similarly, at least a 14.6% increase in Young's modulus has been achieved for 30 L0.05 GO0.72 D-A fiber. In addition, a smaller spinneret diameter(0.72 mm) also led to a 24.9% increase in tensile strength and a 7.7% increase in Young's modulus in comparison with those of 5 L0.05 GO0.84 D-A fibers.     

Preparation of super-aligned carbon nanotube-reinforced nickel-matrix laminar composites with excellent mechanical properties

A homogeneous and compact super-aligned carbon nanotube(SACNT)-reinforced nickel-matrix composite was successfully prepared by electrodeposition. The mechanical properties of the laminar SACNT/Ni composites were substantially improved compared with those of pure nickel. With increasing content of SACNTs, the tensile strength of the composite increased and the elongation decreased because of the high-strength SACNTs bearing part of an applied load and the fine-grained strengthening mechanism. The nanohardness of the SACNT/Ni composites was improved from 3.92 GPa(pure nickel) to 4.62 GPa(Ni-4 vol%SACNTs). The uniform distribution of SACNTs in the composites and strong interfacial bonding between the SACNTs and the nickel matrix resulted in an improvement of the mechanical properties of the SACNT/Ni composites. The introduced SACNTs refined the nickel grains, increased the amount of crystal twins, and changed the preferred orientation of grain growth.     

植物纤维与聚乳酸制备生物质复合材料的研究

本文研究了以植物纤维与聚乳酸为原料制备生物质复合材料的工艺,探讨不同加工方式、纤维种类和添加量对植物纤维/聚乳酸复合材料拉伸性能及透湿性的影响,并利用扫描电镜对复合材料进行表征。研究结果表明:复合材料采用熔融挤出加工方式比物理混合的性能好,而蔗渣纤维作为填料是较好的选择;同时,当植物纤维添加量低于20%时,随着添加量的增加,材料的拉伸强度和断裂伸长率随之下降。     

新型MWNT-TiO2:Ni复合催化剂光催化分解甲醇水溶液制氢的研究

采用改进化学气相沉积法(CVD)合成了MWNT-TiO2:Ni复合光催化剂,利用扫描电镜(SEM)和拉曼光谱(Ra-man)对催化剂进行表征,考察催化剂的光催化分解甲醇水溶液制氢的活性,并对其光催化机理进行了初步分析.研究表明,多壁碳纳米管(MWNTs)原位生长能显著提高二氧化钛(TiO2)的光催化制氢能力.当MWNTs的含量为4.4%时,催化剂的紫外光催化活性达到最大,光量子效率为4.8%.其反应机理解释为MWNTs的"氢溢流"效应,促进光生电子从TiO2向MWNTs转移,降低光生电子-空穴对的快速复合;同时,MWNTs生长有利于提高复合光催化剂的光吸收能力.     

Influence of alkaline treatment and fiber loading on the physical and mechanical properties of kenaf/polypropylene composites for variety of applications

Due to current trend and increasing interest towards natural based fiber products, Kenaf (Hibiscus cannabinus) fibers have been used for the developments of many products. Therefore, Kenaf fiber-reinforced composites have been widely used in engineering and industrial applications. The present work deals with the fabricating and characterization of untreated and treated kenaf/polypropylene (PP)-reinforced composites. Composites of PP reinforced with treated and untreated kenaf fibers were fabricated using the injection molding technique. Different fiber loadings of 10, 20, 30, 40, 50 wt% treated and untreated kenaf composites were also prepared. X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and thermo gravimetric analysis (TGA) were performed on the treated, untreated kenaf fibers and kenaf/PP composites. Moreover, the alkaline-treated kenaf composites exhibit better physical, morphological, and mechanical properties because of the compatibility of kenaf with PP. However, variations in tensile and flexural properties depend on treatment and kenaf fiber contents. The percentage increase in the mechanical properties of the treated kenaf/PP composites relative to that of PP was also measured. In addition, 40 wt% kenaf fiber loading resulted in higher mechanical properties. By contrast, kenaf/PP composite with 50% fiber loading was not successfully prepared because of improper mixing and the burning of kenaf fibers in the PP matrix. To conclude, 40% kenaf/PP composites with superior physical and mechanical properties may be used in variety of applications such as automotive, sports, construction, animal bedding, and mass production industries.     

纤维增强磷酸钾镁水泥砂浆力学性能研究

研究了PVA纤维、PP纤维、玻璃纤维三种纤维在不同的w_(S/C)下对磷酸钾镁水泥砂浆力学性能的影响.结果表明:三种纤维都能在一定程度上增强磷酸钾镁水泥砂浆的力学性能,对磷酸钾镁水泥砂浆早期力学性能的影响比较大,后期力学性能的影响会有所降低.其中,PVA的增强效果最为明显,PP纤维次之,玻璃纤维增强效果最弱.同时得出,在同种纤维条件下,w_(S/C)不是磷酸钾镁水泥砂浆抗折强度的主要影响因素,但是其抗压强度均随着w_(S/C)的增大而增大.     

撒布式混杂钢纤维再生混凝土力学性能

为了研究撒布式混杂钢纤维再生混凝土的力学性能,以混杂钢纤维撒布层数和掺量为参数,对混凝土试块进行抗压、劈拉及弹性模量试验。结果表明:随着混杂钢纤维撒布层数的增加,抗压强度整体变化不大,劈拉强度逐渐呈现上升趋势,弹性模量、拉压比、弹强比随层数变化规律不明显;但弹性模量均较普通再生混凝土降低,拉压比均较普通再生混凝土增大,弹强比有增大也有减小;随着混杂钢纤维掺量的增加,抗压强度先增大后减小,劈拉强度、弹性模量逐渐增大,拉压比、弹强比先减小后增大。撒布混杂钢纤维层后,再生混凝土的破坏由脆性转变为具有一定的塑性。     

集束PBO纤维增强UHPC性能的研究

钢纤维和PVA纤维是UHPC常用的增强纤维。但是,钢纤维易腐蚀,且容易扎伤人。PVA纤维力学强度不高,限制了其应用。采用集束PBO纤维增强UHPC,考察其流动度、力学强度和收缩性能,并与钢纤维-UHPC、PVA纤维-UHPC进行比较。结果显示集束PBO纤维增强UHPC的综合性能优于PVA纤维增强UHPC,且掺量为2%(体积百分比)时,集束PBO纤维增强UHPC的抗弯性能和收缩性能与钢纤维增强UHPC相当,抗压强度则低20%。     

高性能聚丙烯纤维对再生混凝土力学性能的影响

通过工作性能、立方体抗压、劈裂抗拉及弹性模量试验,研究了不同骨料取代率下的高性能聚丙烯纤维增强再生骨料混凝土(HPP fibers reinforced recycled aggregate concrete,HFRAC)随高性能聚丙烯(high performance polypropylene,HPP)纤维掺量增加...     

各向同性煤沥青制备炭/石墨纤维的研究

以各向同性煤沥青为原料,采用熔融纺丝工艺制备了直径为55μm的沥青纤维,经预氧化、炭化和石墨化处理后得到炭纤维和石墨纤维,并采用偏光显微镜、XRD和SEM等对其形貌、结构和性能进行表征。结果表明,炭/石墨纤维具有与沥青原料相似的各向同性光学结构;随热处理温度升高,炭/石墨纤维截面逐渐变粗糙,且内部石墨微晶逐步发育并长大,3 000℃下石墨化纤维微晶增大较明显,其堆积高度和平面尺寸分别约为5nm和11nm;1 600℃炭化纤维的力学性能较好,其拉伸强度和杨氏模量分别达到0.57GPa和32.19GPa,进一步提高热处理温度,纤维拉伸强度逐步降低,但是其杨氏模量逐渐增加,3 000℃石墨化纤维的拉伸强度和杨氏模量分别为0.26GPa和40.57GPa;炭/石墨纤维室温轴向电阻率随热处理温度的升高而降低,1 000℃炭化纤维室温轴向电阻率为47.78μΩ.m,3 000℃石墨化纤维室温轴向电阻率降至21.98μΩ.m。     

Influence of Dispersion of Nano-ZnO Particles in Polymer Matrices on Properties of Relevant Nano Composite Fibers

IntroductionIt is well knownthat nanoparticles have rich propertiesand are useful for functional composites . The nanometricsize ,leading to huge specific surface area up to or morethan1 000m2/g ,andtheir unique properties have attractedintensive interests . Thus many articles have elucidated thepreparation of polymer matrix nanocomposites( PMNC)[1 6]. Polymers are very i mportant matricesbecause of their flexibility and easy processing .Nanoparticles i mpart larger-size congeries because of…     

7tBA／PtBA133-b—PS20／MWNT纳米复合材料的合成及性能

通过原子转移自由基聚合（ATRP）方法，制备了一组不同Ps嵌段长度的聚丙烯酸叔丁酯-b-聚苯乙烯（PtBA113-b—PSn）两亲性嵌段聚合物，研究发现，Ps嵌段聚合度较小的PtBAl33-b—PS。嵌段聚合物可以在乙醇中有效地分散多壁碳纳米管（MWNT）．以此嵌段聚合物作为分散剂首先在乙醇中分散MWNT，得到不同MWNT含量的均相溶液，然后与特定分子量的PtBA均聚物进行溶液共混，制备了一组不同MWNT含量的PtBA／MWNT纳米复合材料．透射电镜（TEM）观察表明嵌段聚合物分散的MWNT在乙醇溶液中几乎呈单根分散状态．利用偏光显微镜（PLM）对不同MWNT含量的复合材料中MWNT的分散状态进行观察表明，MWNT在PtBA基体中分散均匀，相容性良好，没有明显的团聚现象发生．用动态热机械分析（DMTA）对所得材料的力学性能和热性能进行了表征，结果表明，随着复合材料中MWNT含量的增加，材料的弹性模量逐渐增大，同时玻璃化转变温度也有显著提高．     

PVDF-SiO_2中空纤维复合膜的制备和表征

采用相转化法制备聚偏氟乙烯(PVDF)-二氧化硅(SiO2)中空纤维复合膜,讨论了纳米SiO2粒子对PVDF膜结构和性能的影响。通过扫描电子显微镜、能谱、傅里叶红外光谱、热分析、材料试验、接触角测量和超滤实验分别对不同膜的微观结构、化学组成、热稳定性、机械强度、亲水性以及分离性能、抗污染能力进行了联合表征。结果表明:添加SiO2粒子有利于PVDF由α相向β相转变,复合膜的性能与纯PVDF膜相比有明显改善。当w(SiO2)=3%时,纳米颗粒分散较均匀,膜断裂强度为纯PVDF膜的2.7倍,纯水通量由81.6 L/(h.m2)提高到160.0 L/(h.m2),热稳定性、亲水性和抗污染性显著提高;但过高的SiO2含量(w3%)会引起纳米颗粒团聚而导致膜的各项指标下降。     

搅拌铸造法制备石墨烯增强铝基复合材料的组织和力学性能研究

石墨烯增强铝基复合材料满足轻量化用材的同时兼具良好的力学性能,是一种极具应用前景的复合材料。通过粉末混合、压坯和热还原,制备了含石墨烯的预制块,并将其作为中间体在搅拌铸造过程中加入,成功制备了石墨烯增强铝基复合材料。通过扫描电子显微镜、拉曼光谱、X射线衍射仪等表征了复合材料的微观组织结构;通过力学性能测试,研究了石墨烯含量对复合材料力学性能的影响。表征结果表明,搅拌铸造法制备的石墨烯增强铝基复合材料中石墨烯结构完整,复合材料的晶粒得到明显细化。拉伸试验表明,石墨烯质量分数为0.4%的铝基复合材料的综合力学性能最佳,抗拉强度、屈服强度和维氏硬度分别较同条件下制备的纯铝提高了55%、47%和63%。断裂机制研究结果表明,随着石墨烯含量的增加,复合材料由韧性断裂转变为脆性断裂。