单壁碳纳米管在环氧导静电涂料面漆中的应用

通过使用单壁碳纳米管作为新的导电材料,研究了单壁碳纳米管对环氧导静电涂料的外观、表面电阻率及耐化学品性能等的影响。结果显示,单壁碳纳米管能够以极小的添加量便可以使涂料的表面电阻率达到传统导静电涂料的电阻率要求,并且对外观影响极小,同时兼顾环氧导静电涂料的表面装饰性,而且不影响涂料本身的性能。     

抗静电剂对单体浇铸尼龙性能的影响

采用己内酰胺、氢氧化钠、甲苯二异氰酸酯及抗静电剂为原料,通过阴离子聚合制备了抗静电单体浇铸尼龙(MC尼龙)。考察了抗静电剂种类及用量对MC尼龙的表面电阻率和体积电阻率的影响,并研究了其对MC尼龙力学性能的影响。结果表明,加入抗静电剂后有效地降低了MC尼龙的表面电阻率和体积电阻率,且在一定的用量范围内,对力学性能有一定的增强作用。     

掺杂氧化锌晶须对工程塑料抗静电性的影响

采用新的铝掺杂方法,降低了氧化锌晶须电阻率,研究了铝掺杂对氧化锌晶须电阻率的影响。含20%掺量的氧化铝使氧化锌晶须的表面电阻率从107～108Ω降低到1.6×106Ω,体积电阻率从108～109Ω·cm降低到7.1×105Ω·cm;研究了掺杂氧化锌晶须对塑料抗静电性能的影响,铝掺杂氧化锌晶须的添加量为8%(质量分数),使环氧树脂的表面电阻率降低到7.2×1010Ω;铝掺杂氧化锌晶须的添加量为12%(质量分数),使聚苯硫醚的表面电阻率降低到2.0×1010Ω。     

不同抗静电剂在丁腈橡胶中的应用研究

研究了抗静电剂种类和用量对丁腈橡胶制品各项物理机械性能和抗静电性能的影响,结果表明加入抗静电剂后焦烧时间变短,机械强度下降,耐磨性变差,但明显降低了胶料的表面电阻率和体积电阻率。随抗静电剂用量增加,表面电阻率和体积电阻率也越小,显著改善了丁腈橡胶的抗静电性能。     

阻燃型乙丙橡胶的电绝缘性能的研究

本文研究了硫化体系、阻燃剂类型、用量等因素对绝缘性能的影响。通过对体积电阻率和表面电阻率的测定,分析了几种类型的阻燃剂和用量对电绝缘性能的影响。     

PEEK抗静电复合材料表面电阻率均匀性的研究

研究了填料种类以及混合工艺对聚醚醚酮(PEEK)抗静电复合材料表面电阻率均匀性的影响。在此基础上,综合PEEK/CB(炭黑)复合材料与PEEK/CF(碳纤维)复合材料的优点制备了表面电阻率均匀、电阻率容易控制、力学性能良好的PEEK/CB/CF抗静电复合材料。     

聚乙烯树脂体积电阻率测量不确定度的评定

按照GB/T1410-2006《固体绝缘材料体积电阻率和表面电阻率试验方法》测量聚乙烯树脂的体积电阻率,分析了体积电阻率测量的影响因素。利用测试数据以及JJF1059.1-2012对体积电阻率测量不确定度进行分析评估,得到测量结果的相对扩展不确定度。     

不同抗静电剂对聚丙烯抗静电性能和力学性能的影响

通过熔融共混法制备不同配比的多元醇脂肪类抗静电剂、磺酸类抗静电剂改性聚丙烯（PP）抗静电材料;分别考察了两种抗静电材料的体积电阻率、表面电阻率、拉伸强度、冲击强度和表面硬度。结果表明：两种抗静电剂的加入都能够降低PP的表面电阻率,起到抗静电效果,而多元醇脂肪类抗静电剂的效果要比磺酸类抗静电剂突出;两种抗静电剂对PP体积电阻率影响都不大。此外,两种抗静电剂的加入会降低PP的拉伸强度和表面硬度,对冲击强度影响不大。在PP中添加6份多元醇脂肪类抗静电剂,抗静电效果最佳,其表面电阻率为4.7×1011Ω,拉伸强度为27.28MPa,冲击强度为4.9kJ/m2,邵氏硬度为64.8。     

抗静电高抗冲聚苯乙烯片材的研究

以高抗冲聚苯乙烯为基体、炭黑为导电填料,热塑性丁苯橡胶为增韧剂,制得抗静电高抗冲聚苯乙烯片材.通过表面电阻率的测试和SEM照片观测分析了影响表面电阻率的因素.结果表明:采用多相复合体系、低压缩比螺杆、低牵伸速度均有利于降低片材表面电阻率.     

RGO改性MC尼龙导电复合材料的制备及表征

采用溶剂预分散的方法分散还原氧化石墨烯(RGO)微片,再结合硅烷偶联剂等处理RGO表面,并以原位聚合法制备RGO改性MC尼龙导电复合材料。研究了RGO含量、表观密度及表面处理方法对RGO改性MC尼龙导电复合材料电性能的影响;分析了RGO添加后对MC尼龙热性能的影响。结果表明,随着RGO含量的增加,RGO改性MC尼龙导电复合材料的表面电阻率和体积电阻率呈现逐渐减小趋势,电性能得到提高;RGO质量分数1.5%为RGO改性MC尼龙导电复合材料的渗滤阈值;当RGO质量分数达到2.5%时,RGO改性MC尼龙导电复合材料的表面电阻率达到1.04×102Ω,体积电阻率达到1.35×102Ω·m。     

Studies on Electrical Properties of Natural Fiber: HDPE Composites

Abstract:

The composites of banana, hemp, and agave with HDPE resin were separately prepared in different ratios, 60:40, 55:45, 50:50, and 45:55 (wt/wt). These fibers were also treated with maleic anhydride and the effect of maleic anhydride was studied on surface resistivity and volume resistivity of wood polymer composites. The surface resistivity decreases with an increase in fiber content in the composites, while volume resistivity increases. The maximum surface and volume resistivities were observed in untreated banana fiber composite, while minimum surface resistivity and volume resistivity were found in maleic anhydride-treated agave fiber composite. The decrement in volume resistivity and surface resistivity is due to the increment in cross-linking between polymer and fiber by treatment with maleic anhydride.     

Esterification Effect of Maleic Anhydride on Surface and Volume Resistivity of Natural Fiber/Polystyrene Composites

The natural fibers (banana, hemp and sisal) and polystyrene (PS) were taken for the preparation of natural fiber polymer composites in the different ratios of 40:60, 45:55, 50:50 and 55:45 (wt/wt), respectively. These fibers were esterified with maleic anhydride (MA) and the effect of esterification of maleic anhydride was studied on surface resistivity and volume resistivity of natural fiber/polystyrene composites. It was found that the untreated fibers composites show more surface resistivity and volume resistivity in comparison to maleic anhydride treated fibers composites. An untreated hemp fibers composite shows maximum surface and volume resistivity while maleic anhydride treated sisal fibers composites show minimum surface and volume resistivity.     

Effect of processing parameters on the surface resistivity of ethylene–vinyl acetate copolymer/multiwalled carbon nanotube nanocomposites

In this study, ethylene–vinyl acetate (EVA) copolymer was melt‐mixed with multiwalled carbon nanotube (MWCNT). To realize full‐scale application of MWCNT to the polymer industries, the effect of melt‐processing parameters on the surface resistivity in the polymer/MWCNT nanocomposites should be well‐understood. The effect of mixing time, rotor speed, compression molding time, and temperature on the surface resistivity was investigated. Increasing the rotor speed and longer mixing time lead to an improvement of dispersion of MWCNT in polymer matrix, resulting in a decrease of surface resistivity. The surface resistivity of EVA/MWCNT nanocomposites is also sensitive to the press temperature and time. However, the dominant processing parameters to affect surface resistivity depend on the amount of MWCNT. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Effect of the viscosity and processing parameters on the surface resistivity of polypropylene/multiwalled carbon nanotube and ethylene–propylene–diene/multiwalled carbon nanotube nanocomposites

In this study, relatively large amounts of polypropylene (PP) and ethylene–propylene–diene (EPDM) were melt‐mixed with multiwalled carbon nanotubes (MWCNTs). Although the melt‐compounding method has many advantages, the uniform dispersion of carbon nanotubes in the polymer matrix is still the most challenging task. Because the electrical conductivity of composites is strongly influenced by the filler's state of dispersion and the extent of filler breakage during processing, the effects of the viscosity and processing conditions, such as the mixing time, rotor speed, and cooling rate, on the surface resistivity were studied. The PP/MWCNT nanocomposites displayed a high dependence of surface resistivity on the cooling rate, and the EPDM/MWCNT nanocomposites displayed a higher surface resistivity at the same content of MWCNTs and less dependence of surface resistivity on the cooling rate compared with PP/MWCNT nanocomposites. The increased surface resistivity of the EPDM/MWCNT nanocomposites was observed when EPDM with higher viscosity was used to prepare the EPDM/MWCNT nanocomposites. By increasing the rotor speed, lower surface resistivity was obtained in the PP/MWCNT nanocomposites. However, by increasing the rotor speed, a higher surface resistivity was obtained in the EPDM/MWCNT nanocomposites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Effect of Soaking Time on the Temperature Coefficient of Resistivity of Semiconducting Barium Titanate PTCR Ceramics

The influence of soaking time at 1200°C on the temperature coefficient of resistivity (TCR) of semiconducting barium titanate ceramics has been investigated. It is found that soaking duration has influence on the room-temperature resistivity, the maximum resistivity, the temperature ( T _max) at which the maximum resistivity appears, and TCR of the positive temperature coefficient of resistivity (PTCR) ceramics. The increased room-temperature resistivity with the increase of soaking time is contributed mainly by the increase of grain boundary resistivity examined by the complex-plane impedance method. The obtained surface acceptor density ( N _s) by capacitance–voltage measurement is found to increase with the soaking duration. The higher N _s contributes to higher built-in potential and results in lower T _max and higher maximum resistivity. Therefore, the increased surface acceptor density from increasing the soaking time at 1200°C increases the temperature coefficient of resistivity of PTCR ceramics.     

Effect of processing parameters on the surface resistivity of ethylene propylene diene terpolymer/multiwalled carbon nanotube nanocomposites

In this study, ethylene propylene diene terpolymer (EPDM) is melt‐mixed with multiwalled carbon nanotube (MWCNT). To realize full‐scale application of MWCNT to the rubber industries, the effect of melt‐processing parameters on the surface resistivity in the rubber/MWCNT nanocomposites should be well understood. The effect of rotor speed, mixing temperature, and annealing time on the surface resistivity of the EPDM/MWCNT nanocomposites has been investigated. The surface resistivity of EPDM/MWCNT nanocomposites with 3 phr MWCNT increases with increasing the rotor speed and decreasing the mixing temperature. Tensile strength and tensile modulus of EPDM/MWCNT (3 phr) nanocomposites are higher than those of EPDM, respectively. For the nanocomposite with 3 phr MWCNT loadings, surface resistivity increases as the annealing time at room temperature increases. This is the first report that surface resistivity of rubber/MWCNT nanocomposites increases significantly on annealing at room temperature. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40129.     

Using field theory to measure surface resistivity of high-resistance polymeric films

Theoretical expressions based on Ohm's law for field theory were derived to measure surface resistivity of high-resistance polymer films using parallel plate and concentric circular electrodes. Experimental measurements of resistivity were compared to experimental measurements using conventional expressions based on Ohm's law for circuit theory. Expressions based on Ohm's law for circuit theory were found to be inadequate for measuring surface resistivity. The surface resistivity of high-resistance films can be accurately measured if electric field theory is used to include the effects of electrode structure, if relative humidity (RH) and temperature are controlled, if the level of applied voltage is limited, and if the measuring system is shielded from extraneous electric and magnetic fields. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2856–2862, 2001     

The effects of graphene on the properties of acrylic pressure-sensitive adhesive

Graphene was examined as a conductive filler to reduce the surface resistivity of an acrylic pressure-sensitive adhesive (PSA). The graphene effectively reduced the surface resistivity; however it also reduced the peel strength of the PSA. This peel strength reduction could be minimized when the graphene was not mixed homogeneously but embedded in the PSA as a separate layer. In addition, the surface resistivity was reduced much more effectively. Typically, the surface resistivity reduced to one-millionth, when 1 part of graphene was imbedded as a separate layer in 100 parts of PSA, compared to that of homogeneously dispersed composite.     

海泡石纤维／不饱和聚酯复合材料研究

研究了海泡石纤维／不饱和聚酯(UP)复合材料制备中纤维松解、表面处理、纤维用量、增稠剂和炭黑的加入等因素的作用及影响。探讨了复合材料成型工艺参数，研究了海泡石纤维／UP复合材料的性能，并与短切玻璃纤维／UP复合材料进行了比较。发现海泡石纤维／UP复合材料密度稍大，常态体积电阻稍小，硬度接近，表面电阻及沸煮后的体积电阻值则较高。