GO/PF原位复合材料的摩擦磨损性能及力学性能

采用改进的Hummers法制备氧化石墨烯(GO),并与酚醛树脂(PF)进行原位聚合,将原位聚合树脂与固化剂、填料等通过辊炼、模压成型制备GO/PF原位复合材料.研究GO的含量对GO/PF原位复合材料的力学性能及摩擦磨损性能影响,使用扫描电子显微镜(SEM)观察复合材料的磨损面形貌.研究结果表明,GO通过原位聚合能在一定程度上提高复合材料的力学性能、摩擦磨损性能,当GO质量分数为0.25％时,GO/PF原位复合材料的冲击强度提高了18.6％,在250℃和300℃下,GO/PF原位复合材料的体积磨损率分别降低了20.0％和15.6％.     

原位聚合法制备酚醛树脂/氧化石墨烯复合材料

以自制的氧化石墨烯(GO)为改性填料,采用原位聚合法制备了酚醛树脂(PF)/GO复合材料,通过X射线衍射仪、红外光谱、扫描电镜、热重分析及力学性能测试研究了产物结构,GO在PF中的分散以及GO含量对PF/GO复合材料性能的影响。结果表明,GO在PF基体中的分散度可达到微米级,且未与PF发生化学反应。适量引入GO,可有效提高PF的力学性能和热稳定性,当GO的质量分数为1.0%时,PF/GO的冲击强度和弯曲模量达到最大值7.15 kJ/m~2和19.57 GPa,分别比纯PF提高了14.04%和17.96%,当GO质量分数为1.5%时,PF/GO热稳定性最好,T_(5%)、T_(max)和800℃残炭率分别比纯PF提高58.3℃,8.2℃和2%。     

BPR/PF复合材料的热性能和动态力学性能

采用硼酚醛树脂(BPR)与普通酚醛树脂(PF)熔融共混挤出制备BPR/PF树脂,通过模压成型工艺制备BPR/PF复合材料。利用热失重(TG)、动态力学性能(DMA)研究不同BPR含量对复合材料热性能、动态力学性能、蠕变和应力松弛性能的影响。结果表明,BPR能显著增强树脂的热性能。700℃,BPR加入质量分数50份时,BPR/PF的残炭率达到了58%,而PF的残炭率只有38.29%,共混复合材料的储能模量提高了28%;玻璃化转变温度提高了18.3℃;复合材料的蠕变和应力松弛性能也得到了提高。     

热致性液晶聚合物/酚醛树脂/氧化石墨烯混杂复合材料的性能研究

采用熔融挤出法将热致性液晶聚合物(TLCP)与酚醛树脂(PF)熔融挤出,分别加入改良Hummers法制备的氧化石墨烯(GO)、硅烷偶联剂改性GO(KH550 GO、KH560 GO),制备了TLCP/PF/GO混杂复合材料,研究了加入GO对TLCP/PF/GO混杂复合材料的力学性能、摩擦磨损性能的影响。结果表明,硅烷偶联剂处理的GO能一定程度提高复合材料的摩擦磨损性能和力学性能,特别是TLCP/PF/KH560 GO混杂复合材料的摩擦因数稳定,在150 ℃和250 ℃下的体积磨损率分别降低了20.6 %和23.1 %,材料的冲击强度提高了18.6 %。     

PHET/PF原位复合材料力学、动态力学和热性能研究

自行合成了端羟基的热致性聚酯液晶(PHET),采用原位复合的方法制备了热致性聚酯液晶(PHET)/酚醛树脂(PF)原位复合材料,研究了PHET的用量对PHET/PF原位复合材料的冲击强度、弯曲强度、动态力学性能、热性能等的影响。结果表明,PHET的加入可以提高PHET/PF原位复合材料的力学性能、动态力学性能和热性能,当PHET质量分数为7.5%时,原位复合材料的冲击强度、弯曲强度和玻璃化转变温度(Tg)分别提高了44.69%、44.68%和22.9℃。在200℃时,PHET/PF共混物中液晶丝状织态结构明显且分布连续。     

表面改性对酚醛树脂/氧化石墨烯复合材料的力学性能与摩擦性能的影响

采用硅烷偶联剂KH550对氧化石墨烯(GO)进行表面改性,制备改性的氧化石墨烯(MGO),采用FTIR和XRD对MGO进行结构表征,通过共混、混炼、模压成型工艺制备酚醛树脂(PF)/MGO复合材料,研究GO的表面改性对PF复合材料的力学性能、动态力学性能和摩擦性能的影响,采用扫描电子显微镜(SEM)对复合材料的磨损表面进行形貌分析。结果表明:GO的表面改性对提高PF复合材料的力学和动态力学性能、摩擦学性能具有明显效果,相比于未改性的PF/GO复合材料,其冲击强度提高了24.32%,弯曲强度提高了10.95%,弯曲模量提高了21.21%,松弛模量提高了42.22%,形变率降低了40.79%,同时改性的PF/MGO复合材料具有较高的摩擦系数和磨损率;扫描电镜观察结果显示,复合材料的磨损表面显得平整、光滑。     

剑麻纤维素微晶/酚醛树脂力学性能和动态力学性能的研究

采用硅烷偶联剂KH550对从剑麻中提取的剑麻纤维素微晶(SFCM)进行改性,对SFCM与酚醛树脂(PF)进行熔融共混、用模压成型工艺制备SCFM/PF复合材料,研究SFCM含量对复合材料的力学性能、动态力学性能、蠕变和应力松弛性能的影响。结果表明,与PF相比,SFCM/PF复合材料的冲击强度和弯曲强度分别提高了54.94%,31.37%,储能模量提高了30%,玻璃化转变温度提高了41℃,蠕变和应力松弛性能也得到了提高。     

BPR含量对BPR/SF/PF复合材料摩擦磨损性能和力学性能的影响

将硼酚醛树脂(BPR)与普通酚醛树脂(PF)熔融共混,再加入经过碱处理的剑麻纤维(SF),通过模压成型工艺制备BPR/SF/PF复合材料。利用定速式摩擦试验机和电子万能试验机研究了BPR含量对复合材料摩擦磨损性能及力学性能的影响,采用扫描电镜观察了复合材料磨损表面的形貌。结果表明:在BPR/PF=50/100时,与普通PF/SF复合材料相比,BPR/SF/PF复合材料在300℃下的磨损率降低了42%,冲击强度提高了14%,弯曲强度和弯曲模量分别提高了25%和36%;复合材料磨损面形貌显示,加入BPR后,复合材料由疲劳磨损转变为磨粒磨损。     

聚丙烯/氧化石墨烯(PP/GO)复合材料的制备及性能

通过原位聚合法制备了聚丙烯/氧化石墨烯(PP/GO)复合材料,并以此为母料与聚丙烯溶液共混,制备了不同氧化石墨烯含量的PP/GO复合材料,研究了GO对复合材料力学性能、电性能及热性能的影响。力学性能测试发现,石墨烯能显著提高复合材料的刚性,同时,使其韧性降低。当GO的含量为2. 5%时,复合材料的弹性模量和拉伸强度分别提高了700%和82%,而断裂伸长率降低了93%。电性能测试结果发现,PP/GO的渗流阈值为1. 5%,在此含量条件下,复合材料的电导能达到10-2S/m,与PP相比,提高了11个数量级;同时,PP/GO的快速降解温度也提高了250℃。     

CE/BMI/GO复合材料的制备与性能

以双马来酰亚胺树脂(BMI)预聚体改性氰酸酯树脂(CE)(CE/BMI)作为基体树脂,以氧化石墨烯(GO)作为增强体,通过浇铸成型工艺制备了CE/BMI/GO复合材料。研究了GO的质量分数对CE/BMI/GO复合材料力学和摩擦学性能的影响。结果表明,GO的加入有益于复合材料力学性能和摩擦学性能的提高。GO的质量分数为0.8%时复合材料获得最好的韧性和耐磨性。对比基体树脂,CE/BMI/GO复合材料的冲击强度和弯曲强度分别提高了33.6%和27.6%;摩擦系数和磨损率分别降低了22.5%和77.6%。     

Significantly enhanced the properties of PE/GO composites with segregated structures via two-step compound

Conductive polymer composites (CPCs) have generated significant academic and industrial interest due to the wide applications in anti-static materials, electromagnetic interface, sensor, and conductors. Nonetheless, the CPCs fabricated by conventional melt-mixing applied to the scalable production generally have a very high percolation threshold, which always suffer from the various draw backs such as, high melt viscosities, low economic affordability, inferior mechanical properties, and solution compounding by reducing the viscosity improves the uniformity of nano-particles. This work aims at building a segregated structure in polyethylene to enhance mechanical properties and electrical conductivity, by taking advantage of the solution compounding and melt-blending methods. Based on the segregated structure, the composites showed the enhanced mechanical properties, thermal stabilities and antistatic properties with a low percolation threshold. In addition, the composite mechanism between graphene oxide and polyethylene and the structure-performance relationship of the CPCs were elucidated and explored by SEM, TEM, and FTIR.     

Anisotropy of functional properties of SiC composites with GNPs,GO and in-situ formed graphene

This paper reports on anisotropy of functional properties of different silicon carbide-graphene composites due to preferential orientation of graphene layers during sintering. Dense silicon carbide/graphene nanoplatelets (SiC/GNPs) and silicon carbide/graphene oxide (SiC/GO) composites were sintered in the presence of yttria (Y₂O₃) and alumina (Al₂O₃) sintering additives at 1800 °C in vacuum by the rapid hot pressing (RHP) technique. It is found that electrical conductivity of SiC/GNPs and SiC/GO composites increases significantly in the perpendicular direction to the RHP pressing axis, reached up to 1775 S/m in the case of SiC/GO (for 3.15 wt.% of rGO). Also, thermal diffusivity was found to increase slightly by the addition of GNPs in the SiC/GNPs composites in the perpendicular direction to the RHP pressing axis. But, in the parallel direction, the addition of GNPs showed a negative effect. The formation of graphene domains was observed in reference sample SiC-Y₂O₃-Al₂O₃ sintered by RHP, without any addition of graphene. Their presence was confirmed indirectly by increasing electrical conductivity about three orders of magnitude in comparison to the reference sample sintered by conventional hot press (HP). Raman, SEM and TEM analysis were used for direct evidence of presence of graphene domains in RHP reference sample.     

A study of the effects of the matrix epoxy resin and graphene oxide (GO) manufacturing process on the tensile behaviour of GO-epoxy nanocomposites

This work comprises a study of the reinforcement capacity provided by the addition of different types of nano-reinforcements of graphene oxide (GO) to epoxy matrices. A range of nanocomposites, resulting from the use of two epoxy matrices (a mono-component system and a bi-component system) and different types of GOs, at different weight percentages were studied and tensile tests were performed on specimens of these materials in order to quantify the variations in their elastic constants and tensile strength. The GO reinforcements used were obtained by means of the modified Hummers method followed by thermal reduction at different temperatures. The aim was to quantify the effect of carbon/oxygen ratio on the reinforcement capacity of GO in order to optimise the manufacturing process. The stiffness of the nanocomposites improved with the addition of TRGO for both matrices, but the tensile strength depended on the matrix.     

聚苯乙烯/氧化石墨纳米复合材料的制备

天然石墨在浓硫酸中用高锰酸钾氧化成氧化石墨(GO),在含有氧化石墨的苯乙烯乳液中进行自由基聚合,可以得到层间插入聚苯乙烯(PS)的石墨纳米复合材料。研究发现,在聚合过程中不仅发生了苯乙烯均聚反应,而且存在插入聚合反应,并用FTIR、XRD、TEM等手段进行表征。     

SiCNO–GO composites with the negative temperature coefficient of resistance for high‐temperature sensor applications

We report the synthesis of silicon oxycarbonitride ceramic‐graphene oxide (SiCNO–GO) composites by using polyvinylsilazne (PVSZ) and GO as precursors through cross‐linking processes, in which GO organizes into microspheres in the SiCNO matrix. The formation of GO microspheres significantly enhances the electrical conductivity of SiCNO. The electrical resistivity of SiCNO–GO composites shows a negative temperature coefficient in the range from 25°C to 600°C. We demonstrate the application of SiCNO–GO composites as the functional component of high‐temperature sensors.     

Polymer/graphene oxide (GO) thermoset composites with GO as a crosslinker

Composites have historically been of intense interest due to their potential to replace glass, wood and metal at a fraction of the weight. Of the many choices of fillers, graphene oxide (GO) is generally attractive for its versatility and tunability in terms of surface functionality, size and shape. While the majority of GO has been incorporated into polymers and polymer precursors by physical mixing, this review focuses on research where GO has served as both a property enhancer and multifunctional crosslinker in thermosets. Methods for preparing GO (with and without additional functionalization) and incorporating it appropriately into thermosets are described. A review of characterization techniques, typically applied before and after GO is incorporated into thermosets and analytical methods for confirming important chemical reactions during crosslinking, is also provided. Finally, the resulting composite thermoset properties are surveyed throughout to connect preparation and characterization methods to their potential practical importance.     

聚酰亚胺/氧化石墨烯复合材料的制备及其性能

以自制的氧化石墨烯(GO)为改性填料,通过原位聚合法制备了聚酰亚胺(PI)/GO复合材料,并对其形貌、结构和性能进行了表征和测试。结果表明:GO的引入未对PI结构产生破坏作用,且有效提高了PI的力学性能、热稳定性和介电性能,降低了吸水率;当GO质量分数为1.5%时,PI/GO复合材料的拉伸强度达126.9 MPa,较PI提高了55.7%;吸水率由3.65%降至0.92%,质量损失5%时的温度较PI提高了5.8℃;当GO质量分数为2.0%时,介电常数(0.1 MHz)较PI提高了83.1%。     

优化气相色谱法测定香蕉中三唑醇残留量

[方法]优化测定香蕉中三唑醇残留量的气相色谱法。香蕉样品用乙腈提取,氟罗里硅土固相萃取小柱净化,不同比例的正己烷-丙酮溶液淋洗去杂质和洗脱,浓缩定容,用气相色谱仪测定。[结果]三唑醇的峰形尖锐,无杂质干扰,响应灵敏度高,标准工作曲线的线性相关系数为0.9997,最小检出限为4.0μg/kg,回收率均为87.0%~96.0%,相对标准偏差为4.4%~5.6%。[结论]样品提取、净化效率、回收率高,而且简便、重现性好,适合大批量样品的检测。     

携手走向未来

成功的品牌打造既要靠过硬的产品质量,还要靠广泛的媒体宣传和广告来配合;反之,媒体的成功也要依靠企业和读者的合作与支持。离开企业及读者的合作与支持,媒体就成了无源之水、无本之木。媒体与企业犹如鱼和水一样,密不可分。特别是在商品经济高度发达的今天,媒体与企业的相互支撑与合作显得更加迫切和必要。国内外知名的商家对于媒体历来非常重视,也非常配合。为了     

A Review on Composite Papers of Graphene Oxide,Carbon Nanotube,Polymer/GO,and Polymer/CNT: Processing Strategies,Properties, and Relevance

In this review, particular importance is given to the fabrication and properties of carbon nanotube and graphene oxide-based paper-like materials (buckypapers). Different strategies for the reduction and functionalization of graphene oxide were also discussed. The chemistry of buckypapers is conversed with special emphasis on structure and essential characteristics of buckypaper. Various techniques for buckypaper processing have been critically reviewed including significance of each method. Moreover, importance of polymer/graphene oxide and polymer/carbon nanotube composite papers has been highlighted. Due to outstanding physical, thermal, and electrical properties, polymer-based buckypapers are potentially important as nanofilters, fuel cell components, and miniaturization of electrical connections.