溴锑阻燃体系对PS-HI／有机蒙脱土复合材料的阻燃性研究

采用熔融法制备包括溴锑阻燃剂（TBBPA—Sb2O3）和有机蒙脱土（OMMT）并用体系的阻燃PS-HI复合材料；利用琏于耗氧原理的锥形量热仪测试并分析复合材料的燃烧性能，用扫描电子显微镜表征复合材料的微观结构肜貌，结果表明：TBBPA-Sb2O3与OMMT并用阻燃的PS-HI复合材料热释放速率、峰值热释放速率、平均热释放速率以技中烟速率均明显降低，火灾性能指数明显增加；形成的PS-HI／OMMT复合材料与TBBPA—Sb2O3体系之间具有阻燃协同效应，当TBPA—Sb2O3添加7．5份和2．5份，OMMT添加5份时，三者之间的阻燃协同作用最佳。     

丙烯酸酯橡胶柔性电极材料的制备及其性能研究

通过导电炭黑与多壁碳纳米管（MWCNT）并用制备丙烯酸酯橡胶（ACM）柔性电极材料,研究导电炭黑和MWCNT在ACM基体中的分散性及其并用比对柔性电极材料硫化特性、物理性能和导电性能的影响,并分析柔性电极材料与介电弹性体（DE）基体的粘合性能。结果表明：导电炭黑和MWCNT在ACM基体中具有良好的分散性;添加导电炭黑/MWCNT并用体系的ACM柔性电极材料的拉断伸长率远大于200%,满足DE发电机对于大形变的要求,且与仅添加导电炭黑的柔性电极材料相比,其硬度和弹性模量减小,柔韧性提高;随着MWCNT用量的增大,柔性电极材料的导电通路逐渐完善,导电性能提高;导电炭黑/MWCNT并用比为10/10的ACM柔性电极材料与ACM基DE基体共硫化后,两者的粘合强度达到5 N·mm^-1,且粘合稳定性较好。     

SBS/蒙脱土纳米复合材料耐热性能研究

采用溶液混合方法制备了苯乙烯/丁二烯三元嵌段共聚物（SBS）/有机蒙脱土（OMMT）纳米复合材料（NC）,对SBS/OMMT NC的热学性能进行了研究。结果表明,添加OMMT对于所有复合体系均提高了耐热性能,其中以SBS4402/OMMT-DK1B体系最为明显,热失重中心温度Tdc提高幅度达27℃;当OMMT用量为2.5质量份时,NC的Tdc最高,表明耐热性能最好,超过2.5质量份后,耐热性能下降;星型结构SBS耐热性能的提高明显高于线型SBS。     

OMMT对PE-HD/PA6合金的结晶性能和相容性的影响

研究了不同含量的有机蒙脱土（OMMT）对高密度聚乙烯/聚酰胺6（PE-HD/PA6）合金的结晶性能和微观结构的影响。X射线衍射和差示扫描量热仪分析表明,随着OMMT的含量的增加,PA6倾向于生成γ晶型;扫描电镜分析表明,对于PE-HD/PA6合金,PA6以球状分散在PE-HD基体中,相尺寸直径较大,为30~40 μm;添加OMMT后,PA6分子链的极性基团可以与OMMT层间表面产生强的相互作用,使得大分子链在熔融过程中进入OMMT层间,得到PE-HD/PA6/OMMT纳米复合材料。当添加3份OMMT后,复合材料中分散相PA6的相尺寸降低至10 μm,尺寸分布均匀,说明OMMT起到了相容剂的作用。同时,适量的OMMT提高了PE-HD/PA6合金对有机溶剂的阻透性。     

高导电强韧性聚乳酸/多壁碳纳米管复合材料的制备及其结构调控

为了探究聚乙二醇丙烯酸酯(PEGDA)的引入对多壁碳纳米管/聚乳酸(MWCNT/PLA)复合材料结晶性能、热力学稳定性、导电性能和力学性能的影响,首先采用了化学改性的方法将小分子量PEGDA单体原位接枝到线型PLA分子链上,实现了具有一定柔性结构聚乳酸(GPLA)的改性制备;其次利用熔融加工的方法实现了多壁碳纳米管在PLA/GPLA/MWCNT复合材料内部的均匀富集分布,促进了复合材料内部导电网络的构筑。结果表明,通过化学原位接枝法可以成功将PEGDA接枝到PLA分子链上,形成长链结构,并且长链结构的形成能够提高复合材料的复数黏度、结晶性能和热力学稳定性。导电数据表明,随着MWCNT含量的增加,PLA/MWCNT复合材料的导电性能逐步改善,导电逾渗阈值约为0.8%;并且复合材料内部GPLA的引入,可以充分利用GPLA的异相成核能力和“晶体排斥”效应,促使PLA/MWCNT/GPLA复合材料的导电性能表现出了先升高后降低的现象,这主要是因为高含量的GPLA的引入,导致了复合材料内部的复数黏度提高,使复合材料内部MWCNT的团聚体表现出了不同的分布状态。当GPLA的含量增加到15%时,复合...     

NR／BR／OMMT纳米复合材料的研究（Ⅱ）纳米蒙脱土在工业配方中的应用

选用前期优选出的有机蒙脱土（OMMT）牌号,利用机械共混法制备了不同OMMT含量的天然橡胶（NR）/顺丁橡胶（BR）/OMMT纳米复合材料。利用透射电子显微镜研究了复合材料的亚微观结构,观察结果显示制备出了分散均匀的剥离型的NR/BR/OMMT纳米复合材料;力学性能测试表明,当OMMT的用量为3份时,其复合材料的综合力学性能最佳;耐溶剂实验表明,随着OMMT含量的逐渐增加,NR/BR/OMMT纳米复合材料的耐溶剂性能明显提高并不断提高;而OMMT在轮胎工业配方中的优异性能表明其在轮胎工业中具有良好的应用前景。     

高气体阻隔性ECO/OMMT纳米复合材料的性能研究

采用熔体共混方法制备氯醚橡胶（ECO）／有机蒙脱土（OMMT）纳米复合材料，研究其微观结构、拉伸性能和气体阻隔性能。结果表明，即使在OMMT用量较大（100份）的情况下。ECO／OMMT纳米复合材料仍能够形成插层结构≠在OMMT用量较大的情况下，ECO／OMMT纳米复合材料中OMMT聚集形成刚性很强的填料网络，使复合材料的应力一应变行为趋向于塑料和短纤维补强橡胶复合材料。同时绝大多数橡胶大分子链被分隔在OMMT片层之间，显著提高了材料的气体阻隔性能。     

多壁碳纳米管薄膜增强聚间二甲苯己二酰胺复合材料

多壁碳纳米管薄膜（BP）可以提升材料的力学性能和导热、导电性能，在制备热塑性复合材料方面具有巨大的应用潜力。采用先溶液浸渍后热压成型的方法制备了聚间二甲苯己二酰胺（MXD6）/BP复合材料，研究了BP含量对复合材料热导率、电导率、拉伸强度的影响。利用傅里叶变换红外光谱（FTIR）证实了碳纳米管和MXD6之间存在的π-π共轭效应，并用扫描电子显微镜（SEM）观察了MXD6在碳纳米管周围的分布。使用差示扫描量热（DSC）法和热重（TG）分析表征了复合材料的结晶性能和热稳定性，使用热导率仪、万用表和微机控制电子万能试验机测试了复合材料的导热性能、导电性能和力学性能。研究表明，在加入了碳纳米管后，MXD6的热导率、电导率和拉伸强度有了显著的提升。当复合材料中MXD6的质量分数为94.84%时，复合材料的拉伸强度达到了540.3 MPa，提高了6倍，并且复合材料的电导率达到24.814 S/cm，热导率为1.453 W/(m·K)，有效地拓展了MXD6的应用范围。     

硅橡胶基高导电复合材料的制备及其性能研究

以导电炭黑、片状微米银、碳纳米管为填料制备甲基乙烯基硅橡胶（MVQ）基高导电复合材料并研究其性能。结果表明：导电炭黑在MVQ中的逾渗阈值为8～12份（体积分数3.33%～4.92%）,导电炭黑用量为12份时导电炭黑/MVQ复合材料的交联网络最稳定;在添加12份导电炭黑的基础上添加150份片状微米银时,导电炭黑/片状微米银/MVQ复合材料在50%应变后的导电网络恢复程度最大;导电炭黑/片状微米银/碳纳米管/MVQ复合材料在50%应变后的电导率为1.2×104 S·m-1,电导率变化率为18%。     

BR/CB/OMMT纳米复合材料的结构与性能研究

采用溶液插层法与双辊混炼法制备了顺丁橡胶/炭黑/有机蒙脱土（BR/CB/OMMT）纳米复合材料,用透射电子显微镜（TEM）以及X射线衍射（XRD）方法对复合材料的亚微观结构进行了表征,并研究了复合材料的力学特性、耐磨耗性能以及硫化特性。结果表明：BR/CB/OMMT为插层型纳米复合材料;在OMMT含量小于4份时,BR/CB/OMMT纳米复合材料具有优异的力学性能和耐磨耗性能;OMMT起到了硫化促进剂的作用,降低了BR的焦烧时间（TS）和正硫化时间（T90）;低填充量OMMT可提高复合材料的交联密度。     

Synthesis of glass fiber‐multiwall carbon nanotube hybrid structures for high‐performance conductive composites

The conductive polyamide 66 (PA66)/carbon nanotube (CNT) composites reinforced with glass fiber‐multiwall CNT (GF‐MWCNT) hybrids were prepared by melt mixing. Electrostactic adsorption was utilized for the deposition of MWCNTs on the surfaces of glass fibers (GFs) to construct hybrid reinforcement with high‐electrical conductivity. The fabricated PA66/CNT composites reinforced with GF‐MWCNT hybrids showed enhanced electrical conductivity and mechanical properties as compared to those of PA66/CNT or PA66/GF/CNT composites. A significant reduction in percolation threshold was found for PA66/GF‐MWCNT/CNT composite (only 0.70 vol%). The morphological investigation demonstrated that MWCNT coating on the surfaces of the GFs improved load transfer between the GFs and the matrix. The presence of MWCNTs in the matrix‐rich interfacial regions enhanced the tensile modulus of the composite by about 10% than that of PA66/GF/CNT composite at the same CNT loading, which shows a promising route to build up high‐performance conductive composites. POLYM. COMPOS. 34:1313–1320, 2013. © 2013 Society of Plastics Engineers     

Graphene nanoplate and multiwall carbon nanotube–embedded polycarbonate hybrid composites: High electromagnetic interference shielding with low percolation threshold

This study has reported the preparation of polycarbonate (PC)/graphene nanoplate (GNP)/multiwall carbon nanotube (MWCNT) hybrid composite by simple melt mixing method of PC with GNP and MWCNT at 330°C above the processing temperature of the PC (processing temperature is 280°C) followed by compression molding. Through optimizing the ratio of (GNP/MWCNT) in the composites, high electromagnetic interference shielding effectiveness (EMI SE) value (∼21.6 dB) was achieved at low (4 wt%) loading of (GNP/MWCNT) and electrical conductivity of ≈6.84 × 10⁻⁵ S.cm⁻¹ was achieved at 0.3 wt% (GNP/MWCNT) loading with low percolation threshold (≈0.072 wt%). The high temperature melt mixing of PC with nanofillers lowers the melt viscosity of the PC that has helped for better dispersion of the GNPs and MWCNTs in the PC matrix and plays a key factor for achieving high EMI shielding value and high electrical conductivity with low percolation threshold than ever reported in PC/MWCNT or PC/graphene composites. With this method, the formation of continuous conducting interconnected GNP‐CNT‐GNP or CNT‐GNP‐CNT network structure in the matrix polymer and strong π–π interaction between the electron rich phenyl rings and oxygen atom of PC chain, GNP, and MWCNT could be possible throughout the composites. POLYM. COMPOS., 37:2058–2069, 2016. © 2015 Society of Plastics Engineers     

Effect of multiwall carbon nanotubes on thermomechanical and electrical properties of poly(trimethylene terephthalate)

Multiwalled carbon nanotubes (MWCNTs) were synthesized using chemical vapor deposition and poly(trimethylene terephthalate) (PTT)/MWCNT composites with varying amounts of MWCNTs were prepared by melt compounding using DSM micro‐compounder. Morphological characterization by SEM and TEM showed uniform dispersion of MWCNTs in PTT matrix upto 2% (w/w) MWCNT loading. Incorporation of MWCNTs showed no effect on percent crystallinity but affected the crystallite dimensions and increased the crystallization temperature. Dynamic mechanical characterization of composites showed an increase in storage modulus of PTT upon incorporation of MWCNTs above glass transition temperature. The electrical conductivity of PTT/MWCNT composites increased upon incorporation of MWCNTs and percolation threshold concentration was obtained at a loading of MWCNTs in the range of 1–1.5% (w/w). © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Low percolation threshold in polycarbonate/multiwalled carbon nanotubes nanocomposites through melt blending with poly(butylene terephthalate)

Here, we demonstrate an easy method for the preparation of highly electrically conductive polycarbonate (PC)/multiwalled carbon nanotubes (MWCNTs) nanocomposites in the presence of poly(butylene terephthalate) (PBT). In the presence of MWCNTs, PC and PBT formed a miscible blend, and the MWCNTs in the PC matrix were uniformly and homogeneously dispersed after the melt mixing of the PC and PBT–MWCNT mixture. Finally, when the proportion of the PC and PBT–MWCNT mixture in the blend/MWCNT nanocomposites was changed, an electrical conductivity of 6.87 × 10^?7 S/cm was obtained in the PC/PBT–MWCNT nanocomposites at an MWCNT loading as low as about 0.35 wt %. Transmission electron microscopy revealed a regular and homogeneous dispersion and distribution of the MWCNTs and formed a continuous conductive network pathway of MWCNTs throughout the matrix phase. The storage modulus and thermal stability of the PC were also enhanced by the presence of a small amount of MWCNTs in the nanocomposites. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Preparation of conductive polyphenylene sulfide/polyamide 6/multiwalled carbon nanotube composites using the slow migration rate of multiwalled carbon nanotubes from polyphenylene sulfide to polyamide 6

Conductive polyphenylene sulfide (PPS)/polyamide 6 (PA6)/multiwalled carbon nanotube (MWCNT) composites having 10–30 wt % PA6 and 1 wt % MWCNTs are prepared by melt mixing at 300°C for 8 min using a high concentration PPS/MWCNT masterbatch approach, and the migration kinetics of MWCNTs from thermodynamically unfavored PPS to favored PA6 was investigated. The morphology of the composites was investigated by field emission scanning electron microscopy and transmission electron microscopy, showing the localization of most MWCNTs in the PPS phase and at the interface, being different from the case of direct melt mixing where non‐conductive materials were obtained with most MWCNTs found in the PA6 phase and at the interface. The electrical resistivity and morphology of the materials as a function of time were investigated, showing that the conductive materials can be prepared within a mixing time of 4–16 min because of the slow migration rate of MWCNTs from PPS toward PA6, and MWCNTs can eventually migrate into the PA6 phase after a long mixing time of 30 min. The slow migration rate of MWCNTs was attributed to the high viscosity ratio of the two phases. This article shows a good example where the migration of MWCNTs was slow enough to control and can be used to prepare conductive polymer blends. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42353.     

The electrical properties and crystallization of stereocomplex poly(lactic acid) filled with carbon nanotubes

Multi-walled carbon nanotubes (MWCNTs) filled poly(l-lactic acid) (PLLA) and PLLA/poly(d-lactic acid) (PDLA) composites were prepared through a directly melt mixing process. A special crystalline structure of stereocomplex was formed by PLLA and PDLA, which was easily found when mixing two polymers with identical chemical composition but different steric structures. The electrical conductivities were greatly improved by the formation of stereocomplex compared to that of PLLA/MWCNT composites at same MWCNT content. The percolation threshold of the PLLA/PDLA/MWCNT composite at a PLLA/PDLA weight ratio of 50/50 was 0.35 wt%, while being 1.43 wt% of PLLA/MWCNT composites. The X-ray diffraction, non-isothermal and isothermal crystallization results showed that the formation of stereocomplex greatly increased the crystallinity of the composites, meanwhile MWCNTs acted as heterogeneous nucleating agent, which significantly accelerated the nucleation and spherulite growth. Therefore, the PLLA/PDLA/MWCNT composites have a very low percolation threshold due to the volume exclusion effect.     

Electrical and piezoresistive properties of multi-walled carbon nanotube/polymer composite films aligned by an electric field

Aligned multi-walled carbon nanotube (MWCNT)/polymer composite films are prepared by solution casting in the presence of an alternating electric field. Application of 7 kV/m at a frequency of 60 Hz to the polymer composite melt induces MWCNT alignment in the direction of the applied field, which is maintained after polymer crystallization. The electrical conductivity and piezoresistive response of electric-field-aligned and randomly oriented 0.1–0.75 wt% MWCNT/polysulfone films are evaluated. Electrical conductivity is 3–5 orders of magnitude higher for composites with electric-field-aligned MWCNTs than for randomly oriented composites. MWCNT alignment inside the polymer matrix also increases the film piezoresistive sensitivity, enhancing the strain sensing capabilities of the composite film.     

Electrical properties of multi walled carbon nanotubes/ poly(vinylidene fluoride/trifluoroethylene) nanocomposites

Poly(vinylidene fluoride-trifluoroethylene) (PVDF-TrFE)/multi-walled carbon nanotube (MWCNT) nanocomposites were prepared by the method of solution mixing/casting. The dispersity of the MWCNTs in the PVDF-TrFE matrix was investigated using transmission electron microscopy (TEM), revealing that MWCNT are well distributed in the PVDF matrix. Both individual and agglomerations of MWCNT’s were evident. The electrical properties were characterized by ac conductivity measurements. The conductivity was found to obey a percolation-like power law with a percolation threshold below 0.30 wt. %. The electrical conductivity of the neat PVDF-TrFE could be enhanced by seven orders of magnitude, with the addition of only 0.3 wt. % MWCNTs, suggesting the formation of a well-conducting network by the MWCNT’s throughout the insulating polymer matrix. The intercluster polarization and anomalous diffusion models were used to explain the dielectric behaviors of the composites near the percolation threshold, and the analyses of ac conductivity and dielectric constant imply that the intercluster polarization is more applicable to our systems.     

The electrical conductivity and electromagnetic interference shielding of injection molded multi-walled carbon nanotube/polystyrene composites

Multi-walled carbon nanotube (MWCNT)/polystyrene (PS) composites were injection molded into a mold equipped with three different cavities. A high alignment of MWCNTs in PS was achieved by applying high shear force to the melt. The effects of gate and runner designs and processing conditions, i.e., mold temperature, melt temperature, injection/holding pressure and injection velocity, on the volume resistivity of the composites were investigated in both the thickness and in-flow directions. The experiments showed that volume resistivity could be varied up to 7 orders of magnitude by changing the processing conditions in the injection molded samples. The electromagnetic interference shielding effectiveness (EMI SE) of the molded composites was studied by considering the alignment of the MWCNTs. The EMI SE decreased with an increase in the alignment of the injection-molded MWCNTs in the PS matrix. This study shows that mold designs and processing conditions significantly influence the electrical conductivity and shielding behavior of injection molded CNT-filled composites.     

Improvement in properties of multiwalled carbon nanotube/polypropylene nanocomposites through homogeneous dispersion with the aid of surfactants

The effects of different surfactants on the properties of multiwalled carbon nanotubes/polypropylene (MWCNT/PP) nanocomposites prepared by a melt mixing method have been investigated. Sodium dodecyl sulfate (SDS) and sodium dodecylbenzene sulfonate (NaDDBS) were used as a means of noncovalent functionalization of MWCNTs to help them to be dispersed uniformly into the PP matrix. The effects of these surfactant‐treated MWCNTs on morphological, rheological, thermal, crystalline, mechanical, and electrical properties of MWCNT/PP composites were studied using field emission scanning electron microscopy, optical microscopy, rheometry, tensile, and electrical conductivity tests. It was found that the surfactant‐treatment and micromixing resulted in a great improvement in the state of dispersion of MWCNTs in the polymer matrix, leading to a significant enhancement of Young's modulus and tensile strength of the composites. For example, with the addition of only 2 wt % of SDS‐treated and NaDDBS‐treated MWCNTs, the Young's modulus of PP increased by 61.1 and 86.1%, respectively. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012