碳纳米管对羟基磷灰石基复合材料力学性能的影响

将力学性能优良的碳纳米管(CNTs)与羟基磷灰石(HA)生物陶瓷相复合,发展CNTs/HA复合材料来应用于骨组织修复领域,有望解决HA生物陶瓷力学性能的不足。通过3种不同的制备方法,即通过表面活性剂将CNTs分散在HA基体中、通过酸碱中和反应将CNTs与HA共沉淀以及通过体外浸泡在CNTs上矿化生长HA等方法来获得CNTs/HA复合材料。深入研究CNTs的表面结构和分散状态对CNTs/HA复合材料力学性能的影响。结果表明,CNTs的添加改变了HA的脆性,导致复合材料抗压力学性能得到提高。但是,由于复合材料制备方法的不同,导致CNTs在HA基体中的分散状态、表面结构的完整性以及与HA的界面结合情况不同,导致其抗压力学性能不同。其中,通过表面活性剂将CNTs分散在HA基体中而获得复合材料的抗压力学性能表现最好,而CNTs与HA通过共沉淀法所获得复合材料的抗压力学性能表现最差。     

聚甲基丙烯酸甲酯改性碳纳米管及其在聚合物中的应用

本文利用引发剂偶氮二异丁腈(AIBN)在碳纳米管(CNTs)表面引发甲基丙烯酸甲酯(MMA)聚合,使CNTS表面接枝聚甲基丙烯酸甲酯(PMMA),提高CNTs与基体的界面粘结力,改善CNTs在基体中的分散状态。通过熔融共混法制备PVDF/CNTs和PVDF/CNTs-PMMA复合材料。结果表明改性后的CNTs在PVDF中的分散更好,PVDF/CNTs复合材料的导电逾渗阈值为0.7 vol%,PVDF/CNTs-PMMA复合材料的导电逾渗阈值为0.28 vol%,降低了60%。这表明通过对填料化学改性是一种降低复合材料逾渗阈值的有效方法。     

高填充量碳纳米管/丁苯粉末橡胶机械混炼的物理化学机制

将用喷雾干燥法制备的碳纳米管(CNTs)/丁苯粉末橡胶复合材料在开炼机上机械混炼, 考察机械混炼对复合材料常规力学性能的影响, 并对机械混炼对CNTs增强丁苯橡胶复合材料力学性能的影响进行相应的理论研究和机理分析. 结果表明, 与混炼前的复合材料相比, 机械混炼有效地提高了CNTs/丁苯橡胶复合材料的力学性能, 特别是当CNTs加入量较大时, 提高幅度更为显著, 与填充传统补强剂CB复合材料相比, 具有较大的优势. 这是因为机械混炼一方面使CNTs在橡胶基体中获得了更为充分均匀的分散; 另一方面, 混炼过程中产生的自由基以及巨大的剪切力, 使得CNTs与橡胶基体间界面结合如物理吸附、氢键作用、化学结合等得到了进一步增强, 提高了CNTs/丁苯橡胶复合材料的结合橡胶含量, 更好地发挥了CNTs对丁苯橡胶的补强效应, 从而提高了复合材料的拉伸强度和撕裂强度等力学性能. CNTs补强丁苯橡胶复合材料力学性能的机理符合“强键和弱键学说”.     

聚碳酸酯/碳纳米管复合热电材料的制备与性能研究

本文首先通过溶液混合法将碳纳米管(CNTs)分散到聚碳酸酯(PC)基体中,然后将获得的PC/CNT絮状物通过高温模压的方法制备了一种柔性的高热电性能PC/CNT复合材料。PC/CNT复合材料断面形貌分析表明,CNTs均匀地分散在PC基体中。此外,PC/CNT复合材料的导电性随着CNTs含量的增加而急剧增加,而Seebeck系数几乎保持恒定,使得材料的功率因子随着CNTs含量的增加而快速增加,最大功率因子达到4.6μW·m^-1·K^-2。     

氧化石墨烯纳米带-碳纳米管/TPU复合材料薄膜的制备及表征

将不同维度纳米填料同时复合,采用纵向氧化切割MWCNTs法制得不同含量比的氧化石墨烯纳米带-碳纳米管(GONRs-CNTs)2种维度纳米材料复合体,随后将上述填料加入到TPU基体中制得GONRsCNTs/TPU复合材料薄膜.采用FTIR、XRD、TG、XPS、TEM和FE-SEM研究了不同反应条件下所得GONRsCNTs复合体的结构及性能,并结合复合材料薄膜的氧气透过率和拉伸测试以及表面形貌观察,研究了GONRs与CNTs的协同作用、二者的含量比对TPU复合材料薄膜阻隔和力学性能的影响.研究表明,GONRs与CNTs的协同效应明显优于MWCNTs,同时当所加GONRs-CNTs复合体中GONRs与CNTs的含量比约为67∶33时,GONRs-CNTs/TPU复合材料薄膜的氧气透过率和拉伸强度相比纯TPU薄膜分别降低51.3%和提高29.3%,阻隔性能和力学性能均得到明显改善.     

具有隔离结构的聚丙烯/碳纳米管复合材料的制备及电磁屏蔽性能

通过共挤出包覆-热压法制备了具有隔离结构的聚丙烯(PP)/碳纳米管(CNTs)电磁屏蔽复合材料。 其中,CNTs随机分布于PP基体中形成导电相,该导电复合物作为包覆层包敷在纯PP颗粒表面,形成包覆复合粒子,经热压后形成隔离导电网络。 结果表明,所制备的隔离结构复合材料呈现良好的导电性能,可获得较低的导电逾渗值0.28%(体积分数);在CNTs质量分数为5.6%时,该复合材料电磁屏蔽性能达到25.6 dB,同时具有良好的力学性能。 本文结果表明,共挤出包覆-热压法制备隔离结构导电复合材料方法简单可控、绿色环保,对开发高性能电磁屏蔽复合材料具有重要指导意义。     

原位沉析法制备磁性氧化铁羟基磷灰石/壳聚糖棒材

首先通过化学沉淀法制备磁性氧化铁羟基磷灰石(Fe3O4/HA),然后以壳聚糖(CS)为基体,利用原位沉析法将Fe3O4/HA与CS复合,制得磁性Fe3O4/HA/CS复合材料.经XRD、粒径分布和PPMS测试,结果表明了Fe3O4/HA复合物的生成.系统研究了磁性Fe3O4/HA/CS棒材力学性能的影响因素,最终确定Fe3O4与HA质量比为3∶17,磁性Fe3O4/HA与CS质量比为9∶91时,棒材的力学性能最优,弯曲强度可达到87.0 MPa,弯曲模量1.57 GPa.     

聚合物/纳米碳酸钙复合材料的制备

提出了一种制备聚合物/碳酸钙复合材料的技术.即先将纳米碳酸钙粒子在温和条件下分散到水溶液中,再在较弱的外场作用下混合分散到聚合物熔体中,使用此方法制备的4种典型聚合物(聚乙烯、聚丙烯、聚碳酸酯和聚脂)的纳米复合材料,通过扫描电镜观察纳米粒子以纳米尺寸均匀分布于树脂基体中.聚碳酸酯复合材料的相对分子质量变化不大,而且复合材料的某些力学性能有所提高,证明此种方法可用于极性与非极性聚合物制备纳米复合材料.     

纳米Ag/CNTs复合材料的制备、表征及对环三亚甲基三硝胺热分解的影响

采用银镜法和水热法制备了两种纳米Ag/CNTs(碳纳米管)复合材料, 利用傅里叶变换红外(FTIR)光谱、粉末X射线衍射(XRD)、透射电子显微镜(TEM)、扫描电子显微镜及能量散射光谱仪(SEM-EDS)对复合物的物相、组成、形貌和结构进行分析表征, 并运用差示扫描量热法(DSC)研究了纳米Ag/CNTs 复合材料对环三亚甲基三硝胺(RDX)热分解特性的影响. 结果表明: 纳米Ag 以10-80 nm的不规则球形“粘附”于纳米CNTs 表面,分散较均匀, 水热法制得的复合物表面纳米Ag较大、且负载的Ag粒子较多; 纳米Ag/CNTs 复合材料的加入改变了RDX的热分解过程, 使原有占主导的液相分解变为二次的气相反应加剧, RDX主分解峰形发生了明显的改变; 纳米Ag/CNTs 复合材料对RDX热分解的催化主要表现为分解温度的降低.     

基于氟碳表面活性剂插层水滑石的聚酰亚胺纳米复合材料的制备与性能

以氟碳表面活性剂全氟辛基磺酸钾为插层剂, 通过离子交换制备插层水滑石, 并以其为填料, 通过原位插层聚合方法, 制备了水滑石/氟碳表面活性剂/聚酰亚胺纳米复合材料. 用X射线衍射、 红外光谱和热失重等方法分析插层水滑石结构. 结果表明, 全氟辛基磺酸钾插层水滑石后, 水滑石的层间距由0.76 nm增加到2.52 nm, 在水滑石层间构建了氟碳链的微环境. 这种氟化水滑石可剥离分散于聚酰亚胺基体中, 改善了纳米复合材料的气体阻隔性能、 介电性能和机械性能. 这种影响不仅体现无机纳米片层的杂化效果, 而且展示出氟碳链的特点.     

碳纳米管/聚丙烯腈原液的制备及可纺性

通过原位聚合的方法制备了碳纳米管／聚丙烯腈复合材料原液,并采用湿纺成型工艺制得碳纳米管／聚丙烯腈复合材料纤维。与共混工艺相比较,采用该方法制得的碳纳米管／聚丙烯腈复合材料碳纳米管在聚丙烯腈基中分散均匀,具有较好的可纺性。     

碳纳米管/聚合物复合材料

本文简要介绍了碳纳米管的纯化和表面改性方法,着重对碳纳米管/聚合物复合材料的制备方法、微观结构表征及其力学、电学、光学等性能的研究进行了综述;简述了此类复合材料在电学、电磁屏蔽材料及吸波隐身材料、纤维材料以及航天工业等领域的应用,探讨了该研究领域所面临的一些问题及今后的发展方向。     

Effect of Different Hybrid Method on Properties of Carbon Nanotubes/Dolomite Hybrid Filled Phenolic Composites

Hybridization of multi wall carbon nanotubes (MWCNTs) with other filler in polymer matrix composites (PMC) is one of the techniques for combining different properties of fillers for making more unique composites. In this work, the hybrid filler (CNTs–dolomite) are prepared via chemical vapour deposition (CVD hybrid) and the milling method (physically hybrid). The effect of different hybrid method on properties of multi wall carbon nanotubes/dolomite hybrid filled phenolic composites were studied. Phenolic/CVD hybrid composites and phenolic/physically hybrid composites with different filler loadings were prepared using hot mounting press. The prepared samples were characterized for their thermal conductivity and hardness. The thermal conductivity was measured using the Transient Plane Source (TPS) method, using a Hot-DiskTM Thermal Constant Analyzer and the hardness was measured using Rockwell micro-hardness. The results showed that at 5% filler loading, the phenolic/CVD hybrid composites were capable of increasing the thermal conductivity and micro-hardness up to 7.22% and 101.6% respectively compared to pure phenolic.     

层状双金属氢氧化物/碳纳米管复合物的制备及在有机溶剂中的分散

通过硝酸处理在碳纳米管(CNTs)表面生成了羧基(-COOH)基团, 随后采用尿素法在其水悬浮液中原位合成了层状双金属氢氧化物(LDH), 获得了层状双金属氢氧化物/碳纳米管复合物(LDH/CNTs), 考察了CNTs用量对LDH形貌与结构的影响. 结果表明, CNTs的用量对LDH的产率及结构无显著影响; 但当CNTs用量较低(<0.2 g/L)或过高(>4.0 g/L)时, 会导致LDH的粒径分布变宽. 对LDH/CNTs进行氯化及有机化处理, 获得了十二烷基苯磺酸根离子(DBS)插层的DBS-LDH/CNTs. 对DBS-LDH/CNTs在不同有机溶剂中分散及剥离程度的研究发现, DBS-LDH/CNTs在丁醇、 乙醇及二甲苯中均可良好分散且其悬浮液较稳定, LDH在不同溶剂中的剥离程度为丁醇>乙醇>二甲苯>四氢呋喃.     

Preparation of Polylactide/Poly(ether)urethane Blends with Excellent Electro-actuated Shape Memory via Incorporating Carbon Black and Carbon Nanotubes Hybrids Fillers

In this work, hybrid conductive fillers of carbon black(CB) and carbon nanotubes(CNTs) were introduced into polylactide(PLA)/thermoplastic poly(ether)urethane(TPU) blend(70/30 by weight) to tune the phase morphology and realize rapid electrically actuated shape memory effect(SME). Particularly, the dispersion of conductive fillers, the phase morphology, the electrical conductivities and the shape memory properties of the composites containing CB or CB/CNTs were comparatively investigated. The results suggested that both CB and CNTs were selectively localized in TPU phase, and induced the morphological change from the sea-island structure to the co-continuous structure. The presence of CNTs resulted in a denser CB/CNTs network, which enhanced the continuity of TPU phase.Because the formed continuous TPU phase provided stronger recovery driving force, the PLA/TPU/CB/CNTs composites showed better shape recovery properties compared with the PLA/TPU/CB composites at the same CB content. Moreover, the CB and CNTs exerted a synergistic effect on enhancing the electrical conductivities of the composites. As a result, the prepared composites exhibited excellent electrically actuated SME and the shape recovery speed was also greatly enhanced. This work demonstrated a promising strategy to achieve rapid electrically actuated SME via the addition of hybrid nanoparticles with self-networking ability in binary PLA/TPU blends over a much larger composition range.     

A Review Featuring Fabrication,Properties and Applications of Carbon Nanotubes (CNTs) Reinforced Polymer and Epoxy Nanocomposites

Carbon nanotubes (CNTs) have long been recognized as the stiffest and strongest man-made material known to date.In addition,their high electrical conductivity has roused interest in the areas of electrical appliances and communication related applications.However,due to their miniature size,the excellent properties of these nanostructures can only be exploited if they are homogeneously embedded into light-weight matrices as those offered by a whole series of engineering polymers.In order to enhance their chemical affinity to engineering polymer matrices,chemical modification of the graphitic sidewalls and tips is necessary.The mechanical and electrical properties to date of a whole range of nanocomposites of various carbon nanotube contents are also reviewed in this attempt to facilitate progress in this emerging area.Recently,carbonaceous nano-fillers such as graphene and carbon nanotubes (CNTs) play a promising role due to their better structural and functional properties and broad range of applications in every field.Since CNTs usually form stabilized bundles due to van der Waals interactions,they are extremely difficult to disperse and align in a polymer matrix.The biggest issues in the preparation of CNTs reinforced composites reside in efficient dispersion of CNTs into a polymer matrix,the assessment of the dispersion,and the alignment and control of the CNTs in the matrix.An overview of various CNT functionalization methods is given.In particular,CNT functionalization using click chemistry and the preparation of CNT composites employing hyperbranched polymers are stressed as potential techniques to achieve good CNT dispersion.In addition,discussions on mechanical,thermal,electrical,electrochemical and applications ofpolymer/CNT composites are also included.     

熔体自由基反应法制备聚丙烯/碳纳米管复合材料

以2,5-二甲基-2,5-双（叔丁基过氧基）己烷（DHBP）在聚丙烯体系中引发形成自由基,以二硫化四甲基秋兰姆（TMTD）调控自由基反应,通过熔融共混一步法制备了共价接枝的聚丙烯/碳纳米管（PP/CNTs）复合材料。 通过拉曼光谱和透射电子显微镜证明发生了共价接枝反应,并研究了PP/CNTs的结晶性能、热性能与力学性能。 结果表明,发生共价接枝的PP/CNTs与未接枝的PP/CNTs及PP相比,其结晶温度分别提高了2.6和12.0 ℃,热分解温度T5%分别提高了6.4和34.8 ℃,其拉伸强度和拉伸模量略有提高,冲击强度分别提高了56.7%和58.1%。