碳纳米管/丁苯橡胶复合材料的电学性能

采用喷雾干燥法可制备不同配比的碳纳米管（Carbon nanotubes,CNTs）/粉末丁苯橡胶复合材料,观察CNTs在橡胶基体中的分散情况,检测复合材料的导电性能及介电性能,并进行了简要的理论分析。结果表明：CNTs在橡胶基体中获得了充分均匀的分散,有利于CNTs改性补强作用的发挥。与纯胶样品及填充炭黑（Carbon black,CB）样品相比, 填充CNTs样品在8~18GHz下具有较高的介电常数及低介电损耗。随着CNTs加入量的增加,CNTs/粉末丁苯橡胶复合材料的电导率逐渐升高,当CNTs加入量为60phr（per hundred rubber）时,与纯胶样品及添加60phr CB样品相比,电导率提高近10个数量级;复合材料内部导电同时存在隧道导电机制和渗逾导电机制。采用喷雾干燥法制备的CNTs/粉末丁苯橡胶复合材料,将是一种综合性能良好的新型纳米复合材料,有望在抗静电橡胶、电磁屏蔽及介电材料等领域获得应用。     

超声分散制备天然橡胶/丁苯橡胶/炭黑/碳纳米管纳米复合材料

通过超声分散制备了分散均匀的碳纳米管(CNTs)/天然橡胶母料,利用母料制备了天然橡胶(NR)/丁苯橡胶(SBR)/炭黑(CB)/碳纳米管复合材料。通过比较常规搅拌、双辊混炼和超声分散三种方法对碳纳米管的分散及对复合材料性能的影响,表明超声分散能实现碳纳米管在基体中均匀分散,CNTs和CB的协同作用提高了复合材料的力学性能,当CB/CNTs之比为37/3时力学性能最高,与未加CNTs增强的体系相比,拉伸强度提高了6.4%。当CNTs含量为7phr,与未加CNTs的体系相比,压缩模量提高了20%。     

碳纳米管/粉末丁苯橡胶复合材料的热学性能

将碳纳米管(CNTs)及其它配合剂制成悬浮液,与丁苯胶乳共混,然后利用喷雾干燥法制备CNTs/粉末丁苯橡胶复合材料,检测其热学性能,并进行相应的理论分析。结果表明,随着CNTs加入量的增加,橡胶复合材料的热分解温度逐渐增加,CNTs/橡胶复合材料的热导率逐渐提高,当CNTs体积百分比含量约为22%,即CNTs加入量为60 phr时,与纯胶样品相比,复合材料的热导率提高近1倍。理论分析表明,由于CNTs自身的弯曲和缠绕以及混酸氧化对CNTs自身导热性能的破坏,复合材料热导率的实测值与理论计算值存在一定差距。     

氯化聚乙烯/碳纳米管复合材料的制备及其性能研究

以三氯化铝(AlCl3)作催化剂,将多壁碳纳米管(MWNTS)悬浮在氯仿(CHCl3)溶液中,通过亲电加成反应,对MWNTS进行了侧壁化学修饰,并对化学修饰后的MWNTS作了红外光谱的分析.分别采用机械共混法和溶液共沉淀法制备了CPE/CNTs复合材料,对CPE/CNTs复合材料进行了拉伸性能及流变性能的测试,并利用扫描电子显微镜(SEM)观察了CPE/CNTs复合材料拉伸断面的形貌特征.结果表明:CPE/CNTs复合材料的拉伸强度随碳纳米管加入量的增加而增大,当碳纳米管的加入量为5份时,其拉伸强度最大,与纯氯化聚乙烯的拉伸强度相比,提高了75%;化学修饰后的碳纳米管在氯化聚乙烯基体中有了较好的分散性和相容性;CPE/CNTs复合材料的表观粘度随碳纳米管加入量的增加而逐渐增大.     

改性淀粉/丁苯橡胶复合材料的制备及性能研究

采用固相法制备了玉米淀粉接枝马来酸酐(MAH)和苯乙烯(St)的共聚物Starch-g-MAH-St(SMS)。采用机械共混法制备了接枝改性淀粉/丁苯橡胶(SMS/SBR)复合材料,研究了复合材料的力学性能、热空气老化性能、动态力学性能以及微观形态。结果表明,SMS/SBR复合材料的力学性能优于未改性淀粉/SBR复合材料和纯SBR。当苯乙烯和MAH单体用量都为原淀粉质量的10%且SMS的用量为20 g/100 g SBR时,SMS/SBR复合材料的力学性能最佳。经100℃热空气老化48 h后,复合材料的拉伸强度仍可达10 MPa。与纯SBR硫化胶相比,SMS/SBR复合材料的玻璃化转变温度(Tg)降低。微观形态分析显示,淀粉经改性后粒子尺寸减小,在SBR中的分散性得到了改善,与SBR基体的相容性得到了提高。     

叶蜡石基改性复合粉体部分替代N330对SBR/N330纳米复合材料性能的影响

利用工业化生产中通用的橡胶混炼工艺制备了丁苯橡胶(SBR)/N330/叶蜡石基改性复合纳米粉体(PBMCN)纳米复合材料.对改性的叶蜡石基复合纳米粉体在SBR/N330/PBMCN纳米复合材料中的分散性能及对SBR/N330/PBMCN体系纳米复合材料的力学和硫化性能的影响进行了研究.结果表明,PBMCN在SBR/N330/PBMCN复合材料中的分散效果良好.PBMCN取代N330 20%(质量分数)时,SBR/N330/PBMCN复合材料的拉伸强度、拉断伸长率及硫化性能都得到了改善.分析讨论了PBMCN在SBR/N330/PBMCN复合材料中的补强机理.     

CNTs含量对CNTs/Al微观组织及力学性能的影响

为增加碳纳米管(CNTs)在铝基体中的分散性,利用机械球磨-真空热压烧结工艺制备碳纳米管/铝(CNTs/Al)复合材料,采用扫描电子显微镜(SEM)、电子万能试验机和万能摩擦磨损实验机,研究了CNTs质量分数对CNTs/Al复合材料微观组织、力学性能及摩擦磨损性能的影响.结果表明:CNTs经超声波预先分散后分散性增加;当CNTs质量分数为2.0%时,复合材料中CNTs与Al粉之间表现出较好的相容性;随着CNTs含量进一步增加,CNTs团聚现象严重;热压烧结温度600℃时,随着CNTs添加量的增加,铝基复合材料的屈服强度和抗拉强度呈现出明显的先增大后降低的趋势,同时,CNTs/Al复合材料的摩擦因数和磨损率随CNTs含量的增大先减小后增加;CNTs质量分数为2.0%时,复合材料的屈服强度最大值为116 MPa,抗拉强度最大值为245 MPa,与纯Al基体相比,分别提高了78%和1.9倍.2.0%CNTs/Al复合材料可获得较好的摩擦磨损性能,其摩擦系数和磨损率呈现平缓趋势,复合材料的磨痕最浅.     

二氧化硅协同氧化石墨烯改性丁苯橡胶复合材料及性能研究

采用静电自组装法首先制备二氧化硅/氧化石墨烯复合粒子(SiO₂@GO),然后对改性后的复合粒子进行了傅里叶红外光谱(FT-IR)、热失重(TG)和X射线光电子能谱(XPS)的表征。最后，通过机械共混法制备得到了SiO₂@GO增强的丁苯橡胶(SBR)复合材料，并对复合材料的热性能和力学性能进行了研究。结果表明：与单独二氧化硅增强的SBR复合材料相比，SiO₂@GO/SBR的最小转矩、最大转矩、拉伸强度和撕裂强度均较大，硫化时间也较长，并随着复合粒子添加量的增加而变大。当加入质量分数约为13%的复合粒子时，增强后的橡胶拉伸强度、撕裂强度分别能达到5.40MPa、36.35kN/m,动态力学性能表明增强后SBR复合物的抗湿滑性和低滚动阻力较好。     

高能球磨法制备的CNTs/Al-5%Mg复合材料的力学性能及断裂特性

采用高能球磨法制备了不同质量分数碳纳米管(CNTs)与Al-5%Mg(质量分数)粉末的复合粉末,用热压烧结工艺制备了CNTs/Al-5%Mg复合材料。结果表明:高能球磨法可以将CNTs均匀的分散到基体中,并与其产生良好结合;CNTs具有细化复合粉末晶粒尺寸的作用,当CNTs含量为3%时,复合粉末的平均晶粒尺寸达到最小值为63.6nm,继续增加CNTs的含量,复合粉末平均晶粒尺寸增大;当CNTs含量为2%时,复合材料的抗拉强度和硬度达到最大值,与基体材料相比分别提高了42.39%和36.5%;CNTs/Al-5%Mg复合材料的强化机制为细晶强化和载荷传递。     

CNTs强化碳纤维/环氧复合材料界面过渡层及其对界面性能的影响

采用上浆的方法将碳纳米管(CNTs)引入到碳纤维表面,制备CF/CNTs/环氧多尺度复合材料。相比上浆处理前,复合材料的层间剪切强度及弯曲强度分别提高了13.54%和12.88%。采用力调制原子力显微镜及扫描电镜的线扫描功能对复合材料界面相精细结构进行分析。结果表明:CNTs的引入在纤维和基体间构建了一种CNTs增强环氧树脂的界面过渡层。该界面过渡层具有一定厚度,且其模量和碳元素含量呈梯度分布。在固化成型前对含有CNTs的复合材料进行超声处理,促使碳纤维表面的CNTs向周围树脂中分散,发现复合材料的界面过渡层被弱化,其层间剪切强度及弯曲强度较超声处理前分别下降了7.33%和5.34%,验证了CNTs强化的界面过渡层对于提高复合材料界面性能的重要作用。     

Preparation and properties of the powder SBR composites filled with CNTs by spray drying process

Carbon nanotubes (CNTs) filled powder styrene-butadiene rubber (SBR) composites were prepared by spray drying of the suspension of CNTs in SBR latex. The powder was spherical like and uniform with an average diameter of less than 10 μm. The dispersion of CNTs in the rubber matrix was improved remarkably compared with that in the rubber composites obtained by the conventional mechanical mixing method. Further study about the effect of CNTs on the prepared SBR composites was performed by analyzing the vulcanization process of the SBR powder, thermal and mechanical properties of the vulcanized SBR composites. Differential scanning calorimeter (DSC) analysis indicated that the glass transition temperatures of SBR composites increased with the increasing ratio of CNTs. The vulcanization process showed that CNTs could decelerate the vulcanization of the SBR composites. Dynamic mechanical analysis indicated that the storage modulus of the composites was improved with the CNTs additions, especially when the CNTs addition exceeded 30 phr. Compared with pure SBR composites, the hardness, tensile and tear strengths of the composites filled with 60 phr CNTs enhanced 73.9%, 327.7% and 191.1%, respectively, which should be ascribed to the excellent mechanical properties of CNTs and uniform dispersion of CNTs in the rubber matrix.     

Preparation and properties of powder styrene-butadiene rubber composites filled with carbon black and carbon nanotubes

Carbon nanotubes (CNTs) and carbon black (CB) filled powder styrene-butadiene rubber (SBR) composites were prepared by spray drying of the suspension of CNTs and CB in SBR latex. The powders were sphere like and fine with uniform diameters of 10-15 μm. Experimental results showed that the introduction of CNTs into the matrix was beneficial to improve the security of the vulcanization of the rubber composites, and the dynamic and basic mechanical properties of the CNTs/SBR composites were better than those of CB/SBR and neat SBR composites. Observations on the microstructure of the composites indicated that CNTs were well dispersed in the matrix. Morphology of the fracture confirmed that the bonding between CNTs and rubber matrix was strong and load can be transferred to CNTs efficiently during the mechanical property tests. Moreover, the powder SBR composites containing well-dispersed CNTs could be perfect candidate as additives for other polymers.     

New Fabrication and Mechanical Properties of Styrene-Butadiene Rubber/Carbon Nanotubes Nanocomposite

A novel technology to prepare styrene-butadiene rubber(SBR)/carbon nanotubes(CNTs) composites was developed by combining a spray drying method and a subsequent mechanical mixing process.The cross-linking degrees of the vulcanized composites increased gradually with the additive CNTs contents.By comparing with those of the pure SBR composites,the mechanical properties such as tensile strength,tear strength and hardness of the composites filled with CNTs at certain contents were dramatically improved almost b...     

Synthesis of uniformly dispersed carbon nanotube reinforcement in Al powder for preparing reinforced Al composites

In order to obtain homogeneously dispersed carbon nanotube (CNT) reinforcement with well structure in Al powder, a novel and simple approach was developed as a means of overcoming the limits of traditional mixing methods. This process involves the even deposition of Ni catalyst onto the surface of Al powder by impregnation route with a low Ni content (0.5 wt.%) and in situ synthesis of CNTs in Al powder by chemical vapor deposition. The in situ synthesized CNTs with well-crystallized bamboo-like structure in the composite powders can obviate the reaction with Al below 1000 °C. The feasibility of fabricating CNT/Al composites with high mechanical properties using the as-prepared composite powders was proved by our primary test, which indicated that the compressive yield stress and elastic modulus of 1.5 wt.%-CNT/Al composites synthesized by hot extrusion are 2.2 and 3.0 times as large as that of the pure Al matrix.     

High electrical performance of carbon nanotubes/rubber composites with low percolation threshold prepared with a rotation-revolution mixing technique

The present study demonstrates a novel mixing approach for achieving a good dispersion of carbon nanotubes (CNTs) in a styrene-butadiene rubber (SBR), which leads to a significant improvement in electrical properties. Our mixing technique consists of (1) pretreatment by ultrasonication to disentangle the bundles of CNTs in organic solvent and (2) “rotation-revolution” mixing of the CNTs with SBR without mechanical shear, which prevents CNTs from collapsing during the mixing process. The present mixing method does not require the addition of any dispersing agents (amphiphilic molecules) or chemical modification of the CNTs to obtain a good dispersion. Compared with a conventional Banbury mixing technique, our method leads to a significant decrease in the percolation threshold (less than 1 phr), where the electrical conductivity suddenly increases due to the formation of percolation networks of CNTs in SBR. This is because the aspect ratio of the CNTs was maintained even after the mixing process, whereas CNTs were broken during the conventional Banbury mixing. The effect of using different types of CNTs on electrical conductivity was also investigated. The results show that the percolation threshold is largely related to the structural quality (graphitization) of the CNTs as well as their aspect ratio.     

γ辐射对麦秸粉/PBSPBAT复合材料性能的影响

为了提高聚丁二酸丁二醇酯（PBS）基复合材料的性能,降低生产成本,采用熔融共混法制备了麦秸粉/PBS-聚己二酸-对苯二甲酸丁二醇共聚酯（PBAT）复合材料,利用⁶⁰Co-γ射线对该复合材料进行了辐射改性。研究了辐射改性对麦秸粉/PBS-PBAT复合材料力学性能、热稳定性和热变形温度的影响,并采用FTIR和SEM表征了复合材料的结构和断面形貌。结果表明：当三烯丙基异氰脲酸酯（TAIC）的含量为1wt%时,复合材料经30 kGy剂量辐射后,其拉伸强度、弯曲强度和冲击强度分别提高了20%、23.5%和6.5%;辐射改性提高了复合材料的高温分解速率,使其热变形温度上升了约11℃,并增强了复合材料组分间的粘结性。     

多壁碳纳米管填充丁苯橡胶复合材料的研究

采用浓硝酸(HNO3)氧化处理后的多壁碳纳米管(MWNTs)与丁苯橡胶(SBR)及其他配合剂在开炼机上进行混炼加工制备MWNTs／橡胶复合材料，并与炭黑补强橡胶体系进行对比，进而研究了MWNTs／橡胶复合材料的物理性能，并初步探讨了该材料微观结构与性能之间的关系。结果表明：随着MWNTs质量百分含量的增加，橡胶复合材料的力学性能也随之增高；MWNTs／橡胶复合材料的抗撕裂强度(25．9kN／m)、硬度(58)、磨耗(0．22mL/1．61km)性能较炭黑／橡胶体系要好。由MWNTs补强的橡胶对开发具有低滚动滞后性和抗疲劳损失的轮胎胎面胶将有很大的实用潜力。