反式聚异戊二烯/多壁碳纳米管复合材料的微观结构及物理机械性能

以氯化镁（MgCl_2）、经四氯化钛（TiCl_4）预处理的普通型多壁碳纳米管（MWCNTs）或羟基化多壁碳纳米管（MWCNTs-OH）为载体,采用高能球磨法制备了负载钛系催化剂,然后采用原位聚合法制备了反式聚异戊二烯（TPI）/MWCNTs纳米复合材料,表征了MWCNTs在催化剂中的分散性、纳米复合材料的微观结构,考察了2种MWCNTs含量对纳米复合材料物理机械性能的影响。结果表明,在负载钛系催化剂中,MWCNTs-OH或普通型MWCNTs无聚集且分散均匀;在2种TPI/MWCNTs复合材料中,TPI分子链紧密包覆MWCNTs表面,二者形成类似于核-壳管状结构,反式-1,4-结构质量分数均为99.1%,3,4-结构质量分数均为0.9%,MWCNTs的类型对复合材料的结构无显著影响;TPI/MWCNTs-OH复合材料的物理机械性能优于TPI/普通型MWCNTs复合材料及纯TPI材料,且当MWCNTs-OH的质量分数达到0.10%时,复合材料的拉伸强度及扯断伸长率较纯TPI分别提高了36%和49%。     

多壁碳纳米管改性聚碳酸酯型聚氨酯的研究

通过原位聚合法用多壁碳纳米管(MWCNTs)对聚碳酸酯型水性聚氨酯(CWPU)进行改性,讨论了MWCNTs的加入对CWPU/MWCNTs复合材料的低温性、耐热性、机械性能和耐水性等性能的影响。结果表明,加入质量分数为0.3%的MWCNTs,其在CWPU中分散情况较好;所制复合材料的Tg及耐热稳定性明显提高,加入MWCNTs质量分数0.3%的CWPU/MWCNTs复合材料,其热分解温度提高了近20℃;随着MWCNTs含量的增加,材料拉伸强度逐渐增加,而伸长率呈现先减少后增加的趋势;由于CWPU本身具有很好的耐水性能,MWCNTs的加入,进一步提高了聚氨酯材料的耐水性能。     

水下搅拌摩擦加工制备碳纳米管增强PE-HD结构与拉伸性能研究

通过水下搅拌摩擦加工技术制备多壁碳纳米管（MWCNTs）增强高密度聚乙烯（PE-HD）复合材料,并研究了旋转速度和MWCNTs含量对复合材料结构和性能的影响。结果表明,MWCNTs在基体中以云状形式分布,组织相对均匀;MWCNTs含量为从1 %（质量分数,下同）增加到2 %时,复合材料拉伸强度随着旋转速度的增加先增大后减小;MWCNTs含量为4 %时,复合材料拉伸强度随着旋转速度的增加而减小;PE-HD的结晶度随着MWCNTs含量的增加而下降。     

碳纳米管-聚酰胺纤维改性邻甲酚醛环氧树脂

多壁碳纳米管(MWCNTs) 经酸化处理后与聚酰胺66（PA66)共纺制备MWCNTs-PA66纳米纤维膜后与邻甲酚醛环氧树脂（o-CFER）进行复合固化,制备了o-CFER/MWCNTs-PA66复合材料,并对其微观结构、力学性能和热性能进行了研究。结果表明,酸化MWCNTs表面引入了含氧基团,使PA66纤维膜的直径增大;o-CFER/MWCNTs-PA66复合材料的冲击强度、拉伸强度随MWCNTs含量的增加先增大后降低;当MWCNTs含量为0.5 %（质量分数,以PA66质量为基准）时,冲击强度和拉伸强度均达到最大值分别为0.29 kJ/m2和1.96 MPa,冲击强度较o-CFER树脂提高了23.2 %,较o-CFER/PA66复合材料提高了16.3 %,拉伸强度较纯o-CFER树脂提高了74 %;MWCNTs-PA66复合纤维膜能够提高o-CFER的耐热性。     

多壁碳纳米管表面羧基化及其阻燃ABS的性能

采用硝酸氧化/低温等离子处理两步法,将多壁碳纳米管(MWCNTs)羧基化(MWCNTs-COOH),以改善其在ABS基体中的分散性。通过熔融共混的方法制备不同组分ABS/MWCNTs-COOH复合材料。利用红外、拉曼分析、扫描电镜对改性修饰后MWCNTs结构进行研究;利用扫描电镜、热重分析、极限氧指数、残炭分析、力学性能测试对ABS/MWCNTs-COOH复合材料分散性、热性能、阻燃性能、力学性能进行研究。实验结果表明,MWCNTs羧基化改性后提高了在ABS基体材料中的分散性;当MWCNTs-COOH含量为1%时,复合材料初始分解温度和最大分解温度分别提高了22.69℃和27.90℃,热稳定性提高,同时复合材料力学性能也得到改善,拉伸强度提高了18.3%;极限氧指数和残炭测试表明,MWCNTs-COOH加入提高了复合材料的极限氧指数,MWCNTs-COOH在复合材料燃烧过程中,会在材料表面形成网络状炭层,提高复合材料的阻燃性能。     

碳基聚丙烯导电复合材料的制备及性能研究

采用两步分散方法,即依次通过粉体预混和熔融共混两步法制备了碳基聚丙烯(PP)导电复合材料,利用不同的表征手段研究了碳基材料用量对PP复合材料性能的影响。结果表明:片状膨胀石墨(EG)和纤维状多壁碳纳米管(MWCNTs)在PP体系中形成了完整而稳定的导电网络,而且分散均匀,致使PP的拉伸强度和断裂伸长率明显提高,在EG/MWCNTs=0.1:0.1时,复合材料的拉伸强度和断裂伸长率达到最大。复合碳基材料的加入,影响了PP的结晶行为,改善了PP复合材料的耐热性能,显著提高了PP复合材料的导电性能,其逾渗阈值在EG/MWCNTs为0.1:0.1到0.5:0.5之间。     

Preparation and properties of graphene/multi-walled carbon nanotube/thermoplastic vulcanizate composites

通过熔融接枝共混制备了石墨烯（Ge）/多壁碳纳米管（MWCNTs）/聚丙烯（PP）母粒,然后与丁基橡胶动态硫化制备了Ge/MWCNTs/热塑性硫化胶（TPV）复合材料,考察了Ge/MWCNTs/TPV复合材料的相态结构、热电性能和力学性能。结果表明,Ge/MWCNTs作为异相成核剂能够提高PP的结晶温度;Ge/MWCNTs/TPV复合材料呈现“海-岛”结构,Ge和MWCNTs在PP相和橡塑两相界面分散均匀、与基体结合能力强。加入质量分数均为3%的Ge和MWCNTs时,Ge/MWCNTs/TPV复合材料的直流电导率提高5个数量级,热导率提高了36.7%,拉伸强度达17.3 MPa,扯断伸长率达260%。     

石墨烯/多壁碳纳米管/热塑性硫化胶复合材料的制备及性能（英文）

通过熔融接枝共混制备了石墨烯(Ge)/多壁碳纳米管(MWCNTs)/聚丙烯(PP)母粒,然后与丁基橡胶动态硫化制备了Ge/MWCNTs/热塑性硫化胶(TPV)复合材料,考察了Ge/MWCNTs/TPV复合材料的相态结构、热电性能和力学性能。结果表明,Ge/MWCNTs作为异相成核剂能够提高PP的结晶温度;Ge/MWCNTs/TPV复合材料呈现"海-岛"结构,Ge和MWCNTs在PP相和橡塑两相界面分散均匀、与基体结合能力强。加入质量分数均为3%的Ge和MWCNTs时,Ge/MWCNTs/TPV复合材料的直流电导率提高5个数量级,热导率提高了36.7%,拉伸强度达17.3 MPa,扯断伸长率达260%。     

多壁碳纳米管协效复合膨胀阻燃剂阻燃EVA的研究

以乙烯-乙酸乙烯酯共聚物(EVA)为基体树脂,大分子磷氮复合阻燃剂(NPS)为主阻燃剂,以多壁碳纳米管(MWCNTs)为协效剂,制备了低烟无卤阻燃EVA复合材料。采用极限氧指数(LOI)、热重分析(TGA)、扫描电镜(SEM)、力学性能和动态热力学性能(DMA)测试等手段对复合材料进行测定,重点考察了MWCNTs对膨胀阻燃EVA体系的影响,探讨了其作用机理。结果表明:MWCNTs对阻燃EVA体系具有很好的协同效应;MWCNTs的加入提高了膨胀炭层在高温时的热稳定性,增加了高温时的残炭量;MWCNTs可以改善膨胀炭层的形貌,提高炭层的隔热性能;0.5%的MWCNTs与29.5%的NPS复配,试样的LOI达到33.6%,拉伸强度达到12.37 MPa;MWCNTs用量在3%以内时,体系仍能保持较好的电绝缘性。     

热处理对PEEK/MWCNTs复合材料性能影响

对聚醚醚酮(PEEK)/多壁碳纳米管(MWCNTs)复合材料进行热处理,研究热处理温度对PEEK/MWCNTs复合材料力学性能和热性能的影响。结果表明:热处理可明显提升复合材料力学性能,与未热处理相比,拉伸强度和弯曲强度分别提升了9.2%和18.6%。热处理可明显提高复合材料熔点和结晶度,250℃下热处理的复合材料熔点升到348.13℃,结晶度升到31.5%。同时热处理可明显提高PEEK/MWCNTs复合材料储能模量。最佳热处理温度为250℃,最佳热处理时间为2h。     

In vitro degradation of poly(l-lactide)/poly(ε-caprolactone) blend reinforced with MWCNTs

The physical and mechanical properties of poly(l-lactide)/poly(??-caprolactone) (PLLA/PCL) blends reinforced with multiwalled carbon nanotubes (MWCNTs) before and after in vitro degradation were investigated. Because of brittleness, PLLA needs to be plasticized by PCL as a soft polymer. The MWCNTs are used to balance the stiffness and the flexibility of PLLA/PCL blends. The results showed that with incremental increase in concentration of MWCNTs in composites, the agglomerate points of MWCNTs were increased. The physical and mechanical properties of prepared PLLA/PCL blends and MWCNT/PLLA/PCL nanocomposites were characterized. The X-ray diffraction analysis of the prepared blends and composites showed that MWCNTs, as heterogeneous nucleation points, increased the lamella size and therefore the crystallinity of PLLA/PCL. The mechanical strength of blends was decreased with incremental increase in PCL weight ratio. The mechanical behavior of composites showed large strain after yielding and high elastic strain characteristics. The tensile tests results showed that the tensile modulus and tensile strength are significantly increased with increasing the concentration of MWCNTs in composites, while, the elongation-at-break was decreased. The in vitro degradation rate of polymer blends in phosphate buffer solution (PBS) increased with higher weight ratio of PCL in the blend. The in vitro degradation rate of nanocomposites in PBS increased about 65% when the concentration of MWCNTs increased up to 3% (by weight). The results showed that the degradation kinetics of nanocomposites for scaffolds can be engineered by varying the contents of MWCNTs.     

Effect of proton irradiation on mechanical properties of low‐density polyethylene/multiwalled carbon nanotubes composites

The mechanical properties of low‐density polyethylene/multiwalled carbon nanotubes (LDPE/MWCNTs) composites without and with 170 keV proton irradiation were studied by tensile tests. Mechanisms of changes of mechanical properties were examined by means of small angle X‐ray scattering (SAXS), wide angle X‐ray diffraction (WAXD), Raman spectroscopy, and scanning electron microscopy (SEM). The tensile curve of LDPE exhibits three characteristic regions, while those for LDPE/MWCNTs composites only give the first and the second ones. The tensile curves of all samples with 170 keV proton irradiation have no obvious yield phenomenon. The addition of MWCNTs increases the ultimate tensile strength and decreases the elongation at break. Moreover, the ultimate tensile strengths of both LDPE and LDPE/MWCNTs composites with 170 keV proton irradiation are enhanced, and the elongations at break for them are decreased. Based on the analyses of SAXS, WAXD, Raman spectroscopy, and SEM, both the loading of MWCNTs and the proton irradiation can change the mechanical properties of LDPE/MWCNTs composites by a number of factors including the homogeneous distribution of MWCNTs in LDPE matrix, the aberrance zone between MWCNTs, and LDPE matrix, the interaction between MWCNTs and LDPE matrix, and the crystallinities of samples. POLYM. COMPOS., 36:278–286, 2015. © 2014 Society of Plastics Engineers     

Special morphology and its role in mechanical enhancement of linear low‐density polyethylene/multiwalled carbon nanotubes composites

In this work, multiwalled carbon nanotubes (MWCNTs), as reinforcing agent, were blended with linear low‐density polyethylene (LLDPE), then molded by hot compression molding to prepare LLDPE/MWCNTs composites. Tensile tests indicate that the strength, Young's modulus, and toughness are all improved for LLDPE/MWCNTs composites containing 1 and 3 wt % MWCNTs. Compared with LLDPE, the Young's modulus of LLDPE/MWCNTs composites rises from 144.8 to 270.8 MPa at 1 wt % MWCNTs content. At the same time, increases of 18.5% in tensile strength and 16.6% in yield strength are achieved. Additionally, its toughness is enhanced by 26.7% than that of LLDPE. Microstructure characterizations, including differential scanning calorimetry, X‐ray diffraction, and scanning electron microscopy were performed to investigate the variations of microstructure and further to establish the relationship between microstructure and mechanical properties. Homogeneous dispersion of MWCNTs, network formation, and development of an oriented nanohybrid shish‐kebab structure contribute to the enhanced strength and toughness. The increased crystallinity is beneficial to the reinforcement and increased modulus. Additionally, the thermal stability of the LLDPE/MWCNTs composites is enhanced as well. This work suggests a promising routine to optimize polymer/MWCNTs composites by tailoring the structural development. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45525.     

Synergetic effects of graphene platelets and carbon nanotubes on the mechanical and thermal properties of epoxy composites

A remarkable synergetic effect between the multi-graphene platelets (MGPs) and multi-walled carbon nanotubes (MWCNTs) in improving the mechanical properties and thermal conductivity of epoxy composites is demonstrated. Stacking of individual two-dimensional MGPs is effectively inhibited by introducing one-dimensional MWCNTs. Long and tortuous MWCNTs can bridge adjacent MGPs and inhibit their aggregation, resulting in a high contact area between the MGP/MWCNT structures and the polymer matrix. Scanning electron microscope images of the fracture surfaces of the epoxy matrix showed that MWCNT/MGP hybrid nanofillers exhibited higher solubility and better compatibility than individual MWCNTs and MGPs did. The tensile strength of GD400-MWCNT/MGP/epoxy composites was 35.4% higher than that of the epoxy alone, compared to only a 0.9% increase in tensile strength for MGP/epoxy composites over the epoxy compound. Thermal conductivity increased by 146.9% using GD400-MWCNT/MGP hybrid fillers and 23.9% for MGP fillers, compared to non-derivatised epoxy.     

Enhanced shape memory effect of poly(L-lactide-co-ε-caprolactone) biodegradable copolymer reinforced with functionalized MWCNTs

Data from comprehensive thermomechanical tests of poly(L-lactide-co-ε-caprolactone) biodegradable shape memory polymer (SMP) reinforced with pristine and functionalized multiwalled carbon nanotubes (MWCNTs) are reported. The SMP specimens tested up to 500% strain and between 25 °C and 70 °C temperatures. The incorporation of functionalized MWCNTs leads to the best overall reinforcing effect in tensile modulus, yield stress, tensile strength and elongation at failure. Thermo mechanical experiments resulted that the functionalized MWCNTs increased the glass transition range of composites and changed the melting point of composites slightly. The crystallinity of composites was increased with increment of MWCNTs in composites. The shape fixity and shape recovery of composites increased slightly, while the recovery stress increased 46%. It is found that the functionalized MWCNTs prepare an effective physical cross linking and switching segments in polymer composites.     

Reinforcement of styrene-butadiene-styrene tri-block copolymer by multi-walled carbon nanotubes via melt mixing

Styrene-butadiene-styrene tri-block copolymer (SBS) was reinforced with multi-walled carbon nanotubes (MWCNTs) by the interaction through melt mixing. The tensile strength of SBS/MWCNT composites increased with increasing MWCNT content. The interactions between SBS and MWCNTs were characterized by solubility of MWCNTs in tetrahydrofuran, dynamic mechanical analysis, X-ray photoelectron microscope, ultraviolet spectra and transmission electron microscopy. The results showed that there were interactions between MWCNTs and SBS occurred during melt mixing, leading to an improvement of the mechanical properties of SBS/MWCNT composites, as well as the homogeneous dispersion of MWCNTs in SBS. The interactions between MWCNTs and SBS were supposed to consist of the π-π interaction between MWCNTs and the phenyl groups of SBS, as well as the chemical bonding of polybutadiene segments with MWCNTs.     

碳纳米管/石墨烯协同改性碳纤维复合材料的制备及性能

利用偶联剂（KH570）改性的石墨烯（GO）和酸化的多壁碳纳米管(MWCNTs)协同改性聚丙烯腈（PAN）基碳纤维制备得到PAN/MWCNTs/GO基碳纤维（MPG）,以此为原料,采用湿法造纸技术,制备PAN/MWCNTs/GO基碳纤维复合材料（MPG P）。利用傅里叶变换红外光谱仪、扫描电子显微镜,对MPG纤维进行表征,并利用四探针测试仪、万能试验机和多孔材料分析仪,研究了MPG-P材料的导电性能、力学性能、孔径分布以及孔隙率。结果表明,当MWCNTs/GO含量为0.2 %（质量分数,下同）时,MPG P表现出最佳的拉伸强度(37.21 MPa),电阻率为13.17 mΩ·cm,孔隙率为63.7 %;当MWCNTs/GO=1/2（质量比,下同）时,表现出最佳的拉伸强度(40.13 MPa),比纯PAN复合材料(30.18 MPa)提高了32.97 %,电阻率为13.52 mΩ·cm,孔隙率为65.2 %。     

Toughening of cycloaliphatic epoxy resin by multiwalled carbon nanotubes

The toughness of cycloaliphatic epoxy resin 3,4‐epoxycyclohexylmethyl‐3′,4′‐epoxycyclohexane carboxylate (ERL‐4221) has been improved by using multiwalled carbon nanotubes (MWCNTs) treated by mixed acids. The MWCNT/ERL‐4221 composites were characterized by Raman spectroscopy and their mechanical properties were investigated. A significant increase in the tensile strength of the composite from 31.9 to 55.9 MPa was obtained by adding only 0.05 wt % of MWCNTs. And a loading of 0.5 wt % MWCNTs resulted in an optimum tensile strength and cracking energy, 62.0 MPa and 490 N cm, respectively. Investigation on the morphology of fracture surface of the composites by field emission scanning electron microscopy demonstrated the crack pinning‐front bowing and bridging mechanisms of toughening. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Structural,mechanical and thermal studies of double‐molded isotactic polypropylene nanocomposites with multiwalled carbon nanotubes

Nanocomposites of isotactic polypropylene (iPP) and multiwalled carbon nanotubes (MWCNTs) with various contents of MWCNTs were fabricated by double molding techniques. X‐ray diffraction measurements reveal a development of α‐crystal with lamellar stacks having a long period of 150 Å in the neat iPP that increases to 165 Å in 2 wt % MWCNTs‐loaded composites, indicating that MWCNTs enhance crystallization of iPP as a nucleating factor. Mechanical properties, such as tensile strength, flexural strength, Young's modulus, tangent modulus, and microhardness are found to increase with increasing MWCNTs content. Thermal analyses represent an increase of crystallization and melting temperatures and a decrease of thermal stability of the composites with increasing MWCNTs. Changes in structural, mechanical, and thermal properties of the composites due to the addition of MWCNTs are elaborately discussed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010