高温热处理对HDPE/CB导电复合材料性能的影响

在高密度聚乙烯(HDPE)中加入适量的炭黑(CB)制备了HDPE/CB导电复合材料。通过对HDPE/CB导电复合材料热处理前后性能的研究,发现高温热处理可以消除成型加工对导电复合材料导电性的不利影响,显著改善未交联HDPE导电复合材料的导电性;并发现在热处理的温度上可以突破传统的将热处理温度限制在HDPE熔点之下的做法。而使材料的热处理温度超过熔点。     

炭黑复合导电高分子材料成型加工研究进展

概述了导电高分子材料的分类和性能特点，以及炭黑复合导电高分子材料的导电特性与机理。介绍了炭黑预处理。炭黑与基体混合，高分子材料加工方法及工艺条件等对炭黑复合导电高分子材料性能影响的国内外研究进展，总结了材料加工现有的技术难点。     

炭黑粒子偶联处理的HDPE复合材料PTC性能研究

研究了以HDPE为基体,工业炭黑（CB）为导电粒子的高分子复合材料的PTC（正温度系数）导电行为。考察了炭黑及偶联剂种类、用量对高分子PTC导电材料性能的影响,并探讨了偶联接枝机理,从理论上对改性效果进行了分析。结果表明,对炭黑,尤其是槽法炭黑 表面处理可显著提高复合材料的电导率及减小NTC（负温度系数）效应;钛酸酯偶联剂具有最佳改性效果,可明显改善炭黑粒子分散状态,增强材料的PTC效应,其最佳用量为1％质量份。     

偶联处理对HDPE/炭黑复合材料PTC性能的影响

以HDPE／工业炭黑(CB)复合材料为研究对象，考察了炭黑及偶联剂种类、用量对高分子PTC(正温度系数)导电材料性能的影响，并探讨了偶联接技机理，从理论上对改性效果进行了分析。结果表明，对炭黑(尤其是槽法炭黑)进行表面处理可显著提高复合材料的电导率，减小NTC(负温度系数)效应；钛酸配偶联剂具有最佳改性效果，可明显改善炭黑粒子分散状态，增强材料的PTC效应，其最佳用量为1％。     

炭黑／碳化硅复合导电涂料的制备及导电性能研究

制备了一种以炭黑、碳化硅为混合填料的复合导电涂层。研究了炭黑／碳化硅混合填料复合涂层的导电性能,重点研究了混合填料和炭黑种类对涂料导电性能的影响。试验结果表明,混合填料能够明显改善涂层的导电性能,混合填料的炭黑含量在5％时出现渗透阈值,当炭黑含量为25％时电阻率降至10．59Ω·cm。     

复合填料/PP复合材料正负温度系数效应的研究

采用熔融共混方法首先得到交联型炭黑／PE导电材料，将其碾磨粉碎和过筛得到新型的复合导电填料，再和PP经过熔融共混得到一种新的导电复合材料。由于HDPE和PP结晶相在各自的熔点的熔融行为，使复合材料发生热体积膨胀，从而使材料产生了双正温度系数(PTC)效应。同时，负温度系数效应(NTC)基本消除。复合导电材料扫描电镜(SEM)的形态结构进一步证实了这种结论。     

高导电粗旦聚乙烯纤维的制备及性能研究

以高密度聚乙烯(HDPE)和导电炭黑(CB)为原料,聚离子液体(P(MIMH-AD))为分散剂,利用熔融混合的方法制备导电母粒,并通过单螺杆纺丝机使导电母粒与HDPE切片进行熔融纺丝制得导电HDPE纤维,研究了聚离子液体对CB的分散作用,以及导电HDPE纤维的导电性能和力学性能。结果表明：聚离子液体P(MIMH-AD)不仅在水溶液中可以有效分散CB,在熔融状态下也可以通过π-π的相互作用使CB在导电母粒HDPE/CB/P(MIMH-AD)中均匀分散;制备的导电HDPE初生纤维经拉伸后,断裂强度提高约5倍,达到109 MPa,断裂伸长率达到124%,电导率提高至400.4Ω·m,但仍可以点亮灯泡,力学性能得到提高的同时,具有良好的导电性能。     

PE/CB/EPDM导电复合材料的研究

通过研究不同种类炭黑及基体树脂等对于导电复合材料电性能和力学性能的影响，确立了以HDPE为基材，导电炭黑为填料的导电复合体系。实验结果表明：当EPDM加入量为10－15份时，HDPE／CB／EPDM复合材料具有较好的综合性能。     

炭黑预处理对炭黑／HDPE导电复合材料性能的影响

通过用四种有代表性的处理剂对炭黑进行预处理，研究了处理后炭黑填充的HDPE复合材料的电性能、力学性能和流变性能。发现四种处理剂对复合材料的性能均有一定的改善。但也表现出各自的差异，在导电性能上表现的差异更为明显，如经钛酸酯偶联剂和硬脂酸处理的炭黑，在炭黑含量为15%时，可使复合材料的电阻率降低1-2个数量级。为此笔者分析了上述结果的原因。     

炭黑填充HDPE复合型导电塑料的阻燃化

采用具有阻燃功能的高分子改性剂M_L、有机阻燃剂多溴代烷和无机阻燃剂Sb_2O_3对炭黑/HDPE复合材料的燃烧性能研究后表明:三种阻燃剂均可使炭黑填充HDPE复合型导电塑料阻燃化,但性能上有所差异。     

PA1 01 O/CB、PE/CB体系的PTC效应研究

研究了炭黑(CB)含量对LDPE、HDPE、PA1010电阻率的影响,以及LDPE/CB、HDPE/CB、PA101/CB复合体系的电阻-温度特性,发现PA101/CB体系的正温度系数(PTC)转变温度较高,但与HDP/CB体系相比,其PTC强度却很低,不适于制备PTC材料.HDPE/CB体系在160℃附近具有较高的PTC效应,且辐射交联可消除其负温度系数(NTC)效应,容易加工成型,是制备低温区PTC材料的较好体系.     

复合型PE自限温发热材料的形态及电热特性

研究了炭黑的含量对复合型聚乙烯自限温发热材料发热行为的影响,发现发热温度最高的发热材料的炭黑含量即为导电渗流区上限的含量。采用透射电子显微镜、扫描电子显微镜分别表征了炭黑的微观形态及其发热材料的微观网状结构。将材料的渗滤行为、发热特性以及特定的网状结构形态进行了关联。结果表明,这种由颗粒构成的网状结构既具有优异的导电性,又保持了良好的力学性能,     

高密度聚乙烯导电复合材料介电性能的研究

用熔融共混和热压工艺制备了CB/HDPE,MWNT/HDPE聚合物基复合材料,研究了填料体积含量,测试电压,填料形貌尺寸对复合体系介电性能的影响.实验表明,当导电填料含量达到渗流阈值附近时复合材料的介电常数达到最大,测试电压达到一定值时,渗流阈值附近的复合材料介电损耗会迅速增加,相同填料体积含量的MWNT/HDPE复合体系比CB/HDPE体系具有更高的介电常数,利用渗流理论、Maxwell-Wagner界面极化效应和微电容模型解释了实验现象.     

炭黑填充HDPE的力学性能和微波加热性能

为了提高HDPE（高密度聚乙烯）的微波加热性能，将炭黑和HDPE共混制备了复合试样，测试了试样的微波加热性能和机械性能，并用扫描电镜（SEM）观察了试样的断面形态。结果表明，当试样中炭黑用量超过一个临界值后，试样的升温速率随着炭黑用量的增加而显著上升。该临界值和作用微波的功率有关，当微波功率为100W时，临界炭黑的质量分数为9％，200W时为7％，400W时为3％。试样的拉伸强度和模量在炭黑的质量分数低于13％时保持不变，在超过13％后，拉伸强度和模量随着炭黑用量的增加而升高。试样的断裂伸长率在炭黑的质量分数小于7％时保持不变，在炭黑的质量分数超过7％以后下降非常快。     

Impedance spectra of carbon black filled high‐density polyethylene composites

Carbon black (CB) filled high‐density polyethylene (HDPE) composites are prepared by ordinary blending for use as an electrical conductive polymer composite. The composite changes from an electrical insulator to a conductor as the CB content is increased from 10 to 20 wt %, which is called the percolation region. For explanatory purposes, three models, namely, “conduction via nonohmic contacting chain,” “conduction via ohmic contacting chain,” and a mixture of them corresponding to the conductions in the percolation region, high CB loading region, and limiting high CB loading are proposed by the reasonable configurations of aggregate resistance, contact resistance, gap capacitance, and joining aggregates induction. The characters of the impedance spectra based on the three models are theoretically analyzed. In order to find some link between the electrical conductivity and the CB dispersion manner in the composites, the impedance spectra of three samples, HDPE/15 wt % CB (the center of the percolation region), HDPE/25 wt % CB (a typical point in the high CB loading region), and HDPE/19 wt % CB (the limiting high CB loading region), are measured by plotting the impedance modulus and phase angle against the frequency and by drawing the Cole–Cole circle of the imaginary part and real part of the impedance modulus of each sample. The modeled approached spectra and the spectra measured on the three samples are compared and the following results are found: the measured impedance spectrum of HDPE/15 wt % CB (percolation region) is quite close to the model of conduction via nonohmic contacting chain. The character of the measured spectrum of HDPE/25 wt % CB consists of the form of the model of conduction via ohmic contacting chain. The impedance behavior of HDPE/19 wt % CB exhibits a mixture of the two models. From the comparisons, it is concluded that the electrical conducting network in the percolation region of the CB filled HDPE composite is composed of aggregate resistance, nonohmic contact resistance, and gap capacitance, and that of the high CB loading region consists of continuously joined CB aggregate chains, which are possibly wound and assume helix‐like (not straight lines) conductive chains, acting as electrical inductions as the current passes through. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1344–1350, 2005     

Carbon black–filled immiscible blends of poly(vinylidene fluoride) and high density polyethylene: Electrical properties and morphology

The electrical conductivity, current-voltage characteristics and morphology of carbon black–filled immiscible blends of poly(vinylidene fluoride)(PVDF) and high density polyethylene (HDPF) were investigated. Carbon black (CB) had stronger affinity to HDPE than to PVDF, resulting in its selective localization in the HDPE phase. The CB content and PVDF/HDPE volume ratio were the two main factors influencing the electrical conductivity, current-voltage characteristics, and morphology. At a fixed PVDF/HDPE volume ratio of 1/1, a percolation threshold of 0.037 volume fraction of CB was observed, and that value was much lower than that for conventional CB-filled polymer composites. At a fixed CB content (10 wt% CB), a maximum electrical conductivity was observed at a PVDF/HDPE volume ratio of 2.75. An increase in CB content in the composites with a fixed PVDF/HDPE volume ratio (1/1) and an increase in PVDF content in composites with a fixed CB content (10 wt%) greatly decreased the domain size of the PVDF phase. A positive-temperature-coefficient effect was used to determine the location of CB in the blends.     

Effect of the carbon black structure on the stability and efficiency of the conductive network in polyethylene composites

Composites of high‐density polyethylene (HDPE) with different kinds of carbon black (CB) were prepared through melt blending. The influence of the CB structure on the stability and efficiency of the conductive network in HDPE/CB composites were mainly investigated. Scanning electron microscopy was used to observe the morphology of the CB primary aggregates. The relationship between the temperature‐resistivity behaviors of the composites and the crystallization behaviors of the matrix were also investigated. High‐structure CB built an effective conductive network at a low filler content compared to the low‐structure one because of its branched morphology. Therefore, the composite containing high‐structure CB revealed a lower percolation threshold. The composite containing low‐structure CB obtained a stronger positive temperature coefficient (PTC) intensity because the cluster network was fragile and easily damaged during matrix melting. The reproducibility of the results of PTC effect of the composite containing high‐structure CB was better than that of the composite containing a low‐structure one. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Preparation and characterization of isotactic polypropylene/high‐density polyethylene/carbon black conductive films with strain‐sensing behavior

Novel conductive films with a unique strain (ε)‐sensing behavior and based on a blend of isotactic polypropylene (iPP), high‐density polyethylene (HDPE), and carbon black (CB) were fabricated by an extrusion casting method. The morphology and ε‐sensing behavior of the films were investigated. Scanning electron microscope images showed that the oriented lamellae with a growing direction perpendicular to the extrusion direction were obtained in the HDPE phase and were accompanied by a cocontinuous structure of the iPP phase and HDPE/CB phase. The conductive percolation threshold (m_c) and resistivity–ε behavior of the thin films are affected by the drawing ratio during the process of film preparation. The m_c and electrical resistance of the iPP/HDPE/CB composite films increased with the drawing ratio. The gauge factor of the films within the elastic region decreased with increasing drawing ratio. Furthermore, the result of iPP/(HDPE/CB) 40/60 with a high drawing ratio shows that a reversible conductivity was obtained during the cyclic tensile testing (ε = 10%), but an irreversible conductivity makes the film fail during use at the applied ε values of up to 15%. This makes them good piezoresistive candidates for ε‐sensing materials. Moreover, a simple structural model was proposed to describe the reversible and irreversible phenomena in the electrical resistance behavior of the iPP/HDPE/CB films under tensile loading. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40686.     

固相法改性淀粉／炭黑／丁苯橡胶复合材料的制备与性能研究

采用固相法制备了淀粉接枝马来酸酐（MAH）和丙烯酸丁酯（BA）的共聚物Starch-gMAH／BA（SMB）。采用机械共混法用15phr的改性淀粉（SMB）代替等量的炭黑（CB）,制备了改性淀粉／炭黑／丁苯橡胶复合材料（SMt3／CB／SBR）,研究了复合材料的力学性能、热氧老化性能、动态力学性能以及微观形态。结果表明,SMB／CB／SBR复合材料的力学性能优于未改性淀粉／CB／SBR复合材料,拉伸强度及扯断伸长率等性能优于SBR／CB复合材料;且SMB／CB／SBR复合材料具有更好的耐热氧老化性能;与SBR／CB复合材料相比,SMB／CB／SBR复合材料具有更低的滚动阻力;微观形态显示,淀粉经改性后粒子尺寸减小,在SBR基体中的分散性得到改善,与SBR基体的相容性得到提高。