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。     

UHMWPE/炭黑抗静电复合材料的研究

制备了导电炭黑(CB)填充UHMWPE抗静电复合材料。实验结果表明,在经表面固相接枝改性的UHMWPE/CB复合体系中,炭黑渗滤区含量为5%~7%,表面电阻ρs从1014Ω下降到107Ω,较低的炭黑含量确保了复合材料优异的耐磨性;同时扫描电镜(SEM)表征证明炭黑在改性UHMWPE中达到纳米分散,形成双重纳米导电网络结构,这种双重纳米导电结构提高了复合材料的抗静电性能、力学性能和热变形温度。     

碳纤维增强聚醚醚酮复合材料力学性能研究

通过热压成型方法制备出碳纤维增强聚醚醚酮(CF/PEEK)复合材料,研究了CF含量和退火处理对拉伸力学性能的影响,CF含量对压缩力学性能的影响。结果表明:随着CF含量的增加,拉伸力学性能先增加后下降。退火处理在CF含量较低时增加了CF/PEEK复合材料的拉伸力学性能,在高CF含量时,对拉伸力学性能起到负面的影响。随着CF含量的增加,CF/PEEK复合材料的压缩性能先上升后下降,且碳纤维含量在10%时压缩性能达到最大值503.56 MPa。     

选择性激光烧结聚醚砜树脂/碳纤维/炭黑复合材料的性能研究

采用选择性激光烧结(SLS)技术制备聚醚砜树脂/碳纤维/炭黑(PES/CF/CB)复合粉末烧结件,研究CB质量分数为2%,将CF质量分数从0增加到3%时,PES/CF/CB烧结件显微组织、力学性能、导电性能及表面质量的变化。结果表明,当加入CF质量分数为1.5%时,对PES/CF/CB复合粉末烧结件的力学性能具有一定的增强作用;CF的添加能够起到增强烧结件导电性能的作用,烧结件的电导率从5×10^-3 S/m提高至15×10^-3 S/m;随着CF质量分数的增加,烧结件表面质量呈现变差的趋势。     

低温环境下PEEK/CF复合材料结构和性能研究进展

分析了碳纤维(CF)增强聚合物(CFRP)复合材料特别是CF增强聚醚醚酮(PEEK/CF)复合材料在新一代可重复使用航天运载器(RSLVs)低温燃料贮箱上应用的优势,并根据RSLVs低温燃料贮箱对材料的要求,介绍了低温环境及低温-室温热循环处理对PEEK/CF复合材料内部结构、气体渗透性能和力学性能影响的研究进展.在此...     

CF增强PEEK/Cu复合材料的制备与性能

采用模压法制备碳纤维(CF)增强聚醚醚酮(PEEK)/Cu复合材料,研究了CF等离子处理时间、CF用量和热处理工艺对PEEK/Cu/CF复合材料力学性能的影响。结果表明:随着未处理CF用量增加,PEEK/Cu/CF复合材料的力学性能逐渐下降;当CF等离子处理时间小于等于4 min时,PEEK/Cu/CF复合材料的拉伸强度和冲击强度随处理时间增加而提高;等离子处理4 min,随CF用量的增加,PEEK/Cu/CF复合材料的拉伸强度提高,但其冲击强度下降。与未处理的复合材料相比,热处理Ⅱ和Ⅲ这2种处理工艺的复合材料结晶度和熔点均提高,且热处理Ⅲ的提高幅度大于热处理Ⅱ的。     

PEEK层间增韧碳纤维环氧树脂基复合材料的性能研究

为了改善碳纤维/环氧树脂(CF/EP)层合板层间断裂韧性较差的问题,采用预浸料层间涂层和模压工艺制备聚醚醚酮(PEEK)层间增韧CF/EP层合板。探究PEEK含量对CF/EP层合板Ⅱ型层间断裂韧性和冲击强度的影响。结果表明:PEEK的加入有效提高CF/EP层合板的Ⅱ型层间断裂韧性和冲击强度。当PEEK含量为2%,层合板的断裂韧性和冲击强度分别达到1 253 J/m²和259 kJ/m²,与纯层合板相比分别提高61.5%和32.8%。实验分析PEEK增韧机理,为研究高附加值复合材料产品提供参考。     

PEEK/CF复合材料中PEEK结晶行为研究进展

对聚醚醚酮（PEEK）/碳纤维（CF）复合材料界面结晶研究现状进行综述,分析PEEK在复合过程中的结晶形态演变,总结影响PEEK在CF表面形成横晶结构的关键因素。PEEK横晶结构的生成与CF和PEEK的微观结构匹配性、导热性能匹配性,以及复合材料的热处理条件密切相关。诱导PEEK在CF表面形成横晶结构有助于提高二者的界面结合强度,进而提升复合材料的拉伸强度和杨氏模量。     

HDPE／EAA／GF／CB四元抗静电复合体系性能研究

采用原位复合的方法制备了一种具有双渗滤结构的新型低碳含量高密度聚乙烯/乙烯丙烯酸共聚物/玻璃纤维/炭黑(HDPE/EAA/GF/CB)四元抗静电复合材料,研究了所得材料的电性能与力学性能.SEM测试表明:材料中EAA相包覆在GF上,形成一个特殊的纤维状结构分散在HDPE中,EAA与HDPE有明显界限,这种结构使材料产生了双渗滤行为,体积电阻率大大下降.同时,研究了GF、CB对材料力学性能的影响,表明纤维的增强作用,使材料的拉伸强度提高20 MPa.     

聚醚醚酮／碳纤维复合材料热性能和电性能的研究

通过熔融共混法制备了聚醚醚酮/碳纤维(PEEK/CF)复合材料.采用差示扫描量热分析法(DSC)、扫描电子显微镜(SEM)、动态热机械分析仪(DMA)、微欧计、高阻计等考察了复合材料的热性能和电性能.结果表明:聚醚醚酮/碳纤维复合材料的熔点比聚醚醚酮高,但是复合材料的结晶度小于聚醚醚酮.通过SEM照片、DSC曲线和DMA曲线可以证明:聚醚醚酮和碳纤维结合较好,这对复合材料导电性能产生一定影响,即随着碳纤维质量分数增加到10%,复合材料导电性能呈现出逾渗效应,但是逾渗值较高,在经过热处理后,碳纤维含量较高的复合材料电阻率呈现七升趋势,一定碳纤维含量的复合材料表现出明显的PTC效应.     

聚丙烯/炭黑复合材料的导电逾渗行为和PTC特性

以聚丙烯(PP)为基体、炭(黑CB)为填料制备复合材料,研究了不同CB种类的PP/CB复合材料的导电逾渗行为和电阻正温度系数效(应PTC)特性,同时利用扫描电镜对复合材料的微观形态进行了分析。结果表明:CB的结构性越高,比表面积越大,则其填充的复合材料逾渗阈值越低,PP/VulcanXC-72体系的逾渗阈值约为2.5%,而PP/40B2体系约为3.5%;CB的比表面积越小,结构性越低,则相同质量分数时其填充的复合体系的PTC强度越大P,P/40B2体系的PTC强度大于PP/VulcanXC-72体系。     

Electrical conductivity and percolation threshold of hybrid carbon/polymer composites

The electrical conductivity and percolation threshold of single and hybrid carbon filled composites are experimentally investigated. Polystyrene, carbon fiber (CF) and carbon black (CB) at three CF/CB ratios of 1.67, 3.33, 6.67 were compounded in a twin screw extruder micro‐compounder and compression molded into sheets. The through‐plane and in‐plane electrical conductivity of the composites are measured by 2 and 4 probe techniques. The percolation threshold of the single filler and hybrid composites are determined from the experimental results using a percolation model. The hybrid composites have a higher value of electrical conductivity and lower percolation threshold than the single CF filler composite except for the CF/CB ratio of 6.67. The percolation threshold for the cases of single filler and hybrid composites are modeled. The hard core / soft shell model is used and it is assumed that the percolation in a particle filled system depends on the ratio of tunneling distance to particle diameter. This ratio is determined by modeling single filler composites using the experimental data and kept constant in the modeling of the hybrid system. Finite size scaling is used to determine the percolation threshold for the infinite size hybrid system containing (nanosize) particles and micron size fibers for three CF/CB ratios. The simulation results show that the percolations of hybrid composites have the same trends observed in the experimental results. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41744.     

环氧化橡胶对PTC导电高分子复合材料的改性作用

炭黑用环氧化天然橡胶（ENR）胶乳处理后，与高密度聚乙烯混炼，制得导电复合材料，对复合材料的电性能、力学性能和形态进行了研究。结果表明，ENR使导电复合材料的渗逾区间和转折温度等有所改变，可使材料的PTC强度提高1－2个数量级；同时力学性能也有改善。SEM观察证明，ENR有利于炭黑的分散性，并使导电复合材料中炭黑和基体间的相互作用明显增大，对高填充的材料效果尤为显著。     

炭黑在沥青基短切碳纤维补强天然橡胶中的作用

研究炭黑及沥青基短切碳纤维表面臭氧改性对碳纤维填充天然橡胶(NR)硫化胶物理性能的影响。结果表明:臭氧改性后,碳纤维的涂覆层基本去除且表面粗糙度明显增加;碳纤维/NR复合材料拉伸断面中碳纤维表面光滑且与NR发生明显脱粘,复合材料物理性能较低;填充30份炭黑N330后,碳纤维/NR复合材料物理性能显著提高,炭黑/短纤维/NR复合材料和炭黑/臭氧改性碳纤维/NR复合材料的拉伸强度分别达到18.6和26.9 MPa,较碳纤维单独填充时分别提高了431%和627%;碳纤维与炭黑具有类似的微观结构,炭黑在碳纤维补强NR时起到桥梁作用,从而大大增强了两者间的界面强度。     

Hybrid electro-conductive composites with improved toughness, filled by carbon black

The influence of both carbon black (CB), and an ethylene-propylene copolymer grafted by maleic anhydride (EP-g-MA), on the static mechanical properties, impact strength, peel and shear strengths as well as on the electrical conductivity of composites based on high-density polyethylene (HDPE) matrix, was investigated in this paper. It was found that CB improves the stress at yield, the stress at break, and Young’s modulus, as well as the shear strength and peel strength, of the HDPE/CB composites. The percolation threshold was found at 4.5 vol.% of CB. The addition of EP-g-MA to the HDPE/CB composites improves their impact strength, the peel and shear strengths, and the electrical conductivity.     

新型炭黑填充抗静电和导电聚丙烯复合材料

以炭黑为导电填料,在聚丙烯中加入适量的环氧树脂和玻璃纤维,制备了新型的抗静电和导电聚丙烯复合材料。测定了不同复合体系的渗滤阈值,用扫描电镜(SEM)对相形貌进行了观察,并研究了环氧树脂和玻璃纤维用量对体积电阻率的影响。SEM照片表明在新型复合材料中,炭黑优先分布在环氧树脂中,环氧树脂包覆在玻璃纤维表面,通过玻璃纤维间的搭接形成导电通路。这种独特的结构使该复合材料的渗滤阈值低于聚丙烯/炭黑和聚丙烯/环氧树脂/炭黑复合体系的渗滤阈值。玻璃纤维和环氧树脂含量分别需要达到约10%,复合材料才能具有抗静电和导电作用。     

抗静电半硬质PVC材料的制备及性能

通过SEM、拉伸断裂行为、表面电阻、DMA(动态热机械分析)和维卡软化温度测试,研究了半硬质PVC/炭黑(CB)材料力学性能、电性能、热性能和微观形态。结果表明:随着炭黑添加量增加,PVC/CB的导电性能和拉伸强度提高,而体系的断裂伸长率降低。当炭黑添加量仅为4份时,PVC/CB即有逾渗现象发生,表面电阻大幅度降低。当炭黑的添加量为7份时,材料的表面电阻降至1×105Ω,即可满足矿山材料抗静电的要求,而材料的综合力学性能良好。炭黑可使PVC材料的玻璃化转变温度向高温区域移动,材料的耐热性能提高。     

Structure and properties of electrically conducting composites consisting of alternating layers of pure polypropylene and polypropylene with a carbon black filler

Electrically conducting composites consisting of alternating polypropylene (PP) and carbon black (CB)-filled polypropylene (PPCB) layers were prepared by multilayered coextrusion. The co-continuous structure with selective location of CB in PPCB layers was controllable by changing the number of multiplying elements, and decreased the percolation threshold and electrical resistivity of multilayered composites because of the double percolation effect. This double percolation could be achieved in a single polymer matrix using multilayered coextrusion, whereas it can only be produced in two different polymeric matrices by conventional approaches. Results showed that the dispersion of CB aggregates in PPCB layers was greatly affected by the shearing forces induced by the horizontal spreading flow and vertical recombination occurring during the multilayered coextrusion. The electrical resistivity, positive temperature coefficient effect and mechanical properties of multilayered composites depended strongly on their number of layers. A brittle-ductile transition occurred in PPCB layer compared with the conventional composites. The interesting positive and negative temperature coefficient effects occurred during crystallization and depended on the number of layers. A mechanism is proposed to explain these phenomena.     

Dynamic percolation phenomenon of poly(methyl methacrylate)/surface fluorinated carbon black composite

The electrical resistivity of polymer filled with conductive filler, such as carbon black (CB) particles, is greatly decreased by incorporating the conductive filler. This is called the percolation phenomenon and the critical CB concentration is called the percolation threshold concentration (Φ*). For CB particle–filled insulating polymer composite at lower than Φ*, the conductive CB network is constructed in the polymer matrix when the composite is maintained at a temperature higher than the glass‐transition temperature or the melting temperature of the polymer matrix. This phenomenon is called dynamic percolation and the time to reach the substantial decrease in resistivity is called percolation time (t_p). To investigate the relationship between the dynamic percolation process and the surface state of CB particles, we used three kinds of carbon black particles such as original carbon black (CB0) and fluorinated carbon black (FCB010 and FCB025)–filled poly(methyl methacrylate) (PMMA). It was observed that the dynamic percolation curves for CB0‐filled PMMA and FCB‐filled PMMA composites shifted to a shorter percolation time with increases in both the annealing temperature and the filler concentration. However, the dynamic percolation curves of FCB‐filled PMMA showed a gradually decreasing trend compared to that of CB0‐filled PMMA composites. The activation energy calculated from an Arrhenius plot of the t_p against the inverse of the annealing temperature was decreased by surface fluorine treatment. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1151–1155, 2003