Studies on graphite based conductive paint coatings

Electrically conductive coatings are mainly required for static charge dissipation and electromagnetic/radio frequency interference (EMI/RFI) shielding. Electrically conductive coatings are prepared by the incorporation of the metallic pigments/graphite onto the binder. In the present investigation graphite is used as the conductive filler and epoxy polymer as binder. Optimization of the solid content and pigment volume concentration (PVC) of the coating is done by varying the composition of the binder and pigment volume. To get the minimum resistivity value offered by the coating. The resistivity of the coating was measured by means of the four-probe resistivity method. The effect of inclusion of carbon black as additional pigment is also studied. The results are presented and discussed in this paper.     

UV-curable phthalazinone-based epoxy methacrylate antifouling coatings with <Emphasis Type="Italic">N</Emphasis>-vanillylnonanamide as antifoulant

A UV-curable solvent-free antifouling coating formulated by a novel epoxy methacrylate-containing phthalazinone moiety with reactive diluents and photoinitiator and non-toxic N-vanillylnonanamide as antifoulant was prepared. First, the basic performance of the cured films obtained was evaluated using Chinese National Standards. This environmentally friendly antifouling coating has excellent physical properties, with a pencil hardness of above 5H, an adhesion of grade 1, impact strength above 45 cm, and good resistance to alkali and salt but not acid. Then antifouling evaluation was carried out by the leaching rate of antifoulant, and by immersing samples in natural sea water, respectively. The results from the leaching rate of N-vanillylnonanamide from the antifouling coating shows that the release rate of 45 μg/m² day of the coating with 15% antifoulant is steady after a slight decrease, and this coating can effectively prevent marine organisms attaching for 6 months, which is also evidenced by field tests in natural sea water.     

Oxidation of carbons in the presence of chlorine

The oxidation reaction of carbon black, sucrose carbon and graphite in the presence of chlorine was studied by thermal analysis (TGA and DTA). The oxidation rate was shown to depend upon the characteristics of each carbon. Heating in chlorine caused different degrees of mass increase in each of the three carbons, with two reaction zones due to physisorption and chemisorption of chlorine on the carbon surface. Burning of the carbons in oxygen gave the following reactivity order: carbon black>sucrose carbon>graphite. Burning of the carbons in the presence of chlorine showed its inhibiting effect, being strongest in carbon black. Oxidation in absence of chlorine started at 525, 560 and 660°C for carbon black, sucrose carbon and graphite, respectively. When chlorine was present in the gaseous phase, oxidation started at 650, 590 and 770°C. Therefore, the reactivity order in the presence of oxygen was sucrose carbon>carbon black>graphite.     

Synergistic effects of carbon fillers in electrically and thermally conductive liquid crystal polymer based resins

Adding conductive carbon fillers to insulating thermoplastic resins increases composite electrical and thermal conductivity. Often, as much of a single type of carbon filler is added to achieve the desired conductivity, while still allowing the material to be molded into a bipolar plate for a fuel cell. In this study, varying amounts of three different carbons (carbon black, synthetic graphite particles, and carbon fiber) were added to Vectra A950RX Liquid Crystal Polymer. The resulting single filler composites were tested for electrical resistivity (1/electrical conductivity) and thermal conductivity. In addition, the effects of single fillers and combinations of two different carbon fillers were studied via a factorial design. The results indicated that for the composites containing only single fillers, synthetic graphite, followed by carbon fiber, cause a statistically significant decrease in composite electrical resistivity. Composites containing only synthetic graphite, followed by carbon black, and then carbon fiber cause a statistically significant increase in thermal conductivity. For the combinations of two different fillers, the composites containing carbon black/synthetic graphite and synthetic graphite/carbon fiber had a statistically significant and positive effect on thermal conductivity. It is possible that thermally conductive pathways are formed that “link” these carbon fillers, which results in increased composite thermal conductivity. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers     

Investigation of the conductivity of asphalt concrete containing conductive fillers

Carbon black, graphite and carbon fibre were employed to design and prepare electrically conductive asphalt mixtures containing single filler or mixed fillers of conductive powder plus carbon fibre. The effects of filler type, filler content and mixed fillers on the resistivity of asphalt concrete were investigated. Experimental results showed that the insulating-conductive percolation transition of the resistivity under the function of filler content appears in the single-filler composites and the percolation threshold is approximately 12%, 10%, and 5% by volume percentage of the binder phase for carbon black, graphite and carbon fibre respectively. The combination function of mixed fillers has appreciable advantages over single powder filler, but no obvious advantages over simple fiber in the conductivity improvement at the same total filler content. But the addition of small amounts of expensive fibers to larger amounts of cheaper CB or graphite can be a cost effective system. Scanning electron microscope images provide insight into the mechanisms of conductivity enhancement for mixed fillers. Conductive filler particles exhibit the short-range contacts or connections in asphalt concrete, whereas carbon fibres exhibit a long-range conductive bridging effect and short-circuit effect because of the high aspect ratio.     

Preparation and characterization of a novel conducting nanocomposite blended with epoxy coating for antifouling and antibacterial applications

In this study, novel epoxy-based paint was synthesized to be applied on carbon steel. The composition of the paint mainly contains epoxy mixed with an electronically conductive polymer, polyaniline (PANI), alone and combined with its nanocomposite derivation containing ZnO nanorods as an additive. The antifouling properties of the paint applied on carbon steel were investigated. The conductive nanocomposite was synthesized by an in situ chemical oxidative method of aniline in the presence of ZnO nanorods and then well characterized. The antifouling behavior was evaluated for 9 months in the Caspian Sea and Persian Gulf. Results revealed that epoxy/PANI–ZnO nanocomposite coating can prevent accumulation of marine macroorganisms on the coated panel. In addition, the epoxy coating comprising PANI–ZnO nanocomposite as well as the epoxy/ZnO coating exhibit significant antibacterial characteristics against (E. coli and S. epi). We interpret the antifouling and antibacterial behavior of the paint with (i) the presence of emeraldine salt structure in PANI which develops a surface pH in a range of 4–5 preventing the adhesion of microorganisms on the surface and (ii) the antibacterial and antifouling properties of zinc oxide nanorods that occurred by the production of hydrogen peroxide on the surface of the coating.     

纳米导电炭黑防静电PTFE涂层的研究

以纳米导电炭黑粉体XC-72R作为导电填料对高分子材料进行防静电处理。先对纳米导电炭黑粉体进行球磨分散,制得固含量为35wt%的高稳定性导电浆料,再将该浆料添加到聚四氟乙烯(PTFE)乳液中,并涂布到玻璃纤维布上,经380℃烧结制得防静电PTFE涂层。当炭黑粉体的添加量为3.98wt%时,涂层的电阻率可达106Ω.cm,具有很好的防静电效果。     

海洋防污涂料技术的研究现状及展望

叙述了海洋防污涂料类型与研究现状,介绍了新型环保的低表面能防污涂层技术在海洋方面的应用,介绍了异噻啉酮衍生物（MOP-OCI）对藻类生长的抑制作用,以此化合物为防污剂制备的海洋防污涂料,5个月的实海挂板几乎没有附着海洋污损生物。重点介绍了有机硅涂料、有机氟涂层以及绿色防污涂料的国内外研究进展和应用现状,并介绍了几种防污涂料的防污机理与加速评价方法,展望了海洋防污涂料发展趋势。     

The Microbial Mechanisms of a Novel Photosensitive Material (Treated Rape Pollen) in Anti-Biofilm Process under Marine Environment

Marine biofouling is a worldwide problem in coastal areas and affects the maritime industry primarily by attachment of fouling organisms to solid immersed surfaces. Biofilm formation by microbes is the main cause of biofouling. Currently, application of antibacterial materials is an important strategy for preventing bacterial colonization and biofilm formation. A natural three-dimensional carbon skeleton material, TRP (treated rape pollen), attracted our attention owing to its visible-light-driven photocatalytic disinfection property. Based on this, we hypothesized that TRP, which is eco-friendly, would show antifouling performance and could be used for marine antifouling. We then assessed its physiochemical characteristics, oxidant potential, and antifouling ability. The results showed that TRP had excellent photosensitivity and oxidant ability, as well as strong anti-bacterial colonization capability under light-driven conditions. Confocal laser scanning microscopy showed that TRP could disperse pre-established biofilms on stainless steel surfaces in natural seawater. The biodiversity and taxonomic composition of biofilms were significantly altered by TRP (p < 0.05). Moreover, metagenomics analysis showed that functional classes involved in the antioxidant system, environmental stress, glucose–lipid metabolism, and membrane-associated functions were changed after TRP exposure. Co-occurrence model analysis further revealed that TRP markedly increased the complexity of the biofilm microbial network under light irradiation. Taken together, these results demonstrate that TRP with light irradiation can inhibit bacterial colonization and prevent initial biofilm formation. Thus, TRP is a potential nature-based green material for marine antifouling.     

Assessing the Antimicrobial Activity of Polyisoprene Based Surfaces

There has been an intense research effort in the last decades in the field of biofouling prevention as it concerns many aspects of everyday life and causes problems to devices, the environment, and human health. Many different antifouling and antimicrobial materials have been developed to struggle against bacteria and other micro- and macro-organism attachment to different surfaces. However the “miracle solution” has still to be found. The research presented here concerns the synthesis of bio-based polymeric materials and the biological tests that showed their antifouling and, at the same time, antibacterial activity. The raw material used for the coating synthesis was natural rubber. The polyisoprene chains were fragmented to obtain oligomers, which had reactive chemical groups at their chain ends, therefore they could be modified to insert polymerizable and biocidal groups. Films were obtained by radical photopolymerization of the natural rubber derived oligomers and their structure was altered, in order to understand the mechanism of attachment inhibition and to increase the efficiency of the anti-biofouling action. The adhesion of three species of pathogenic bacteria and six strains of marine bacteria was studied. The coatings were able to inhibit bacterial attachment by contact, as it was verified that no detectable leaching of toxic molecules occurred.     

聚氨酯/导电炭黑抗静电胶粘剂的制备与性能研究

制备了弹性聚氨酯(PU)/导电炭黑复合抗静电胶粘剂,通过体积电阻率的测定考察了该胶粘剂的导电性能,利用热重分析(TGA)和差示扫描量热(DSC)法研究了该胶粘剂的热性能,并采用湿热老化和温度冲击试验研究了该胶粘剂在加入复合抗氧剂前后的抗老化性能。结果表明:当w(导电炭黑)≥6.2%(相对于胶粘剂而言)时,该胶粘剂开始获得抗静电能力;当w(导电炭黑)≈7.0%(相对于胶粘剂而言)时,该胶粘剂的体积电阻率发生突跃式下降;该胶粘剂的热性能由PU基体所决定,导电炭黑对其热性能的影响不大;加入复合抗氧剂后,该胶粘剂具有良好的抗老化性能。     

Effect of some service conditions on the electrical resistivity of conductive styrene–butadiene rubber–carbon black composites

Conductive polymer composites were prepared using vulcanized styrene–butadiene rubber as a matrix and conductive carbon black as a filler. The filler loading was varied from 10 to 60 phr. The volume resistivity was measured against the loading of the carbon black to verify the percolation limit. The electrical conductivity of filled polymer composites is attributed to the formation of some continuous conductive networks in the polymer matrix. These conductive networks involve specific arrangements of conductive elements (carbon black aggregates) so that the electrical paths are formed for free movement of electrons. The effects of temperature and pressure on the volume resistivity of the composites were studied. The volume resistivity of all the composites increased with increase in temperature, and the rate of increase in the resistivity against temperature depended on the loading of carbon black. The change in volume resistivity during the heating and cooling cycle did not follow the same route, leading to the phenomena of electrical hysteresis and electrical set. It was found that the composites with 40 and 60 phr carbon black become more conductive after undergoing the heat treatment. Generally, all the composites showed a positive temperature coefficient of resistivity. The volume resistivity of all the composites decreased with increase in pressure. The relaxation characteristic of the volume resistivity of the composites was studied with respect to time under a constant load. It was found that the volume resistivity of the compressed specimen of the composites decreased exponentially with time. It was observed that initially a faster relaxation process and later a slower relaxation process occurred in these composites. Some mechanical properties of these composites were also measured to confirm the efficacy of these composites for practical applications. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2179–2188, 2004     

Electrical conductivity of carbon‐filled polypropylene‐based resins

Adding conductive carbon fillers to insulating thermoplastic resins increases composite electrical conductivity. Often, as much of a single type of carbon filler is added to achieve the desired conductivity and still allow the material to be molded into a bipolar plate for a fuel cell. In this study, various amounts of three different carbons (carbon black, synthetic graphite particles, and carbon nanotubes) were added to polypropylene resin. The resulting single‐filler composites were tested for electrical resistivity (1/electrical conductivity). The effects of single fillers and combinations of the different carbon fillers were studied via a factorial design. The percolation threshold was 1.4 vol % for the composites containing only carbon black, 2.1 vol % for those containing only carbon nanotubes, and 13 vol % for those containing only synthetic graphite particles. The factorial results indicate that the composites containing only single fillers (synthetic graphite followed closely by carbon nanotubes and then carbon black) caused a statistically significant decrease in composite electrical resistivity. All of the composites containing combinations of different fillers had a statistically significant effect that increased the electrical resistivity. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Modification of sisal fiber by in situ coating steam explosion and electromagnetic interference shielding effectiveness of sisal fiber/PP composites

The technology of steam explosion was adopted to modify sisal fiber (SF) material and two different carbon particles, expanded graphite and conductive carbon black (CCB), were in situ coated on the surface of SF during steam explosion process. The DC conductivity and electromagnetic interference shielding effectiveness (SE) of the modified SF/polypropylene (PP) composites were studied and the measurement of electromagnetic interference (EMI) SE was conducted in two frequency ranges of 400–1,000 MHz and 1–18 GHz. The experimental results showed that this novel coating technology could improve the SE of the modified SF/PP composites significantly, which has a strong dependence on the loadings of the expanded graphite modified sisal fiber (SF‐EG) and conductive carbon black modified sisal fiber (SF‐CCB). When the loadings of SF‐EG and SF‐CCB reached 50 wt%, the maximum values of the SE were 33 dB and 51 dB, respectively. For the modified SF/PP composites, the experimental EMI SE values are in good correlation with the theoretical calculation values in far field of electromagnetic radiation. POLYM. COMPOS., 35:1038–1043, 2014. © 2013 Society of Plastics Engineers     

填充型NBR/EPDM导电复合材料的研究

研究了石墨/炭黑填充的NBR/EPDM导电复合材料力学性能、动态力学性能和压阻、温阻特性。结果表明,随NBR用量的减少,复合材料拉伸强度、撕裂强度和拉断伸长率均降低;与纯胶相比,填料在NBR/EPDM中分散性变差,复合材料Payne效应和损耗因子都增大。电阻率测试结果表明,NBR/EPDM并用胶电阻率明显低于纯胶;恒温下其电阻率随压力的增大先减小后增大;恒压下其电阻率随温度的升高而减小;NBR/EPDM并用比不同时,复合材料电阻率随压力、温度的变化趋势不尽相同。     

Urushiol titanium polymer-based composites coatings for anti-corrosion and antifouling in marine spray splash zones

Seawater is highly corrosive, and the alternating dry and wet environment can cause severe corrosion in metal equipment. Moreover, marine equipment is also seriously affected by marine biofouling. These harsh conditions pose a serious threat to the integrity of marine equipment as well as their associated maritime activities and necessitate the development of effective coatings to minimize damage to the equipment. Urushiol titanium polymer/acrylic resin (UTP/AR) composite materials were developed. Then, marine anti-corrosion and antifouling coatings were prepared from the UTP/AR composite materials using rosin-modified Cu₂O as an antifoulant. The composite coating with a UTP:AR mass ratio of 1:1 (UTP/AR3) showed the best chemical resistance and light aging resistance. UTP/AR3 also exhibited a good corrosion current density (2.009 × 10⁻⁷ A cm⁻²) and corrosion potential (−0.5007 V), further indicating that the UTP/AR composite coatings have excellent anti-corrosive properties. Marine field tests showed that the UTP/AR/Cu₂O composite coatings with rosin-modified Cu₂O contents less than 20% showed stable, long-term antifouling performance after immersion in seawater for 360 day. Briefly, the UTP/AR/Cu₂O composite coatings have broad application prospects in the marine industry for materials in the spray splash zone.     

Techniques for the measurement of natural product incorporation into an antifouling coating

The control of biofouling can be achieved by a variety of methods but for an open system, such as a ship's hull, a protective paint coating is the most adopted method. The incorporation of a natural product extract directly into a coating has received little previous attention. This study has investigated a combination of the antifouling compound (a natural product extract) and the delivery system (control depletion polymer) investigated together. It was necessary to investigate the natural product incorporation into a coating and finally assess the antifouling system including the primer layers in the natural marine environment. Natural products must first be practical as antifoulants to be developed further into a functional system by their incorporation into surfaces or coatings. To demonstrate this, the natural product under investigation was homogenised into a blank proprietary antifouling paint system binder, applied to primed and un-primed ship grade steel and immersed in marine environments. Electrochemical techniques were used to investigate the effects of natural product incorporation into a coating. In addition, optical and scanning electron microscopes were used to assess the physical characteristics of the coating system. The most rigorous test for an antifouling system is a field trial. Field trials were completed at a raft exposure facility, in estuarine dock conditions at the Empress dock, National Oceanography Centre, Southampton, UK.     

Preparation and properties of a new coating method for preparing conductive polyester fibers with permanent conductivity

A new coating method based on dissolution (the dissolving‐coating method) was designed to prepare carbon black–coated electrically conductive polyester fibers. The effects of the composition of the coating mixture on the volume resistivity of the fibers were investigated. The mechanical properties and conductive permanence of the coated fibers were studied. The coated fibers prepared by the dissolving‐coating method had the characteristics of lower volume resistivity (9.6 × 10⁰ Ω cm) and permanent conductivity. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2685–2691, 2006     

Electrically and thermally conductive nylon 6,6

Increasing the thermal and electrical conductivity of typically insulating polymers, such as nylon 6,6, opens new markets. A thermally conductive resin can be used for heat sink applications. An electrically conductive resin can be used in static dissipative and Electromagnetic Interference/Radio Frequency Interference shielding applications. This research focused on adding various carbon based conductive fillers and a chopped glass fiber to nylon 6,6. These materials were extruded and injection molded into test specimens. Tensile tests as well as in-plane electrical resistivity, in-plane thermal conductivity, and through-plane thermal conductivity tests were conducted. One successful formulation consisted of 10% 3.2 mm chopped E-glass fiber/15% Thermocarb (high quality synthetic powdered graphite)/5% carbon black/70% nylon 6,6 (all % in wt%). For this formulation, the in-plane electrical resistivity was reduced from 10¹⁵ ohm-cm (neat nylon 6,6) to 15 ohm-cm. The through-plane thermal conductivity increased from 0.25 W/mK (neat nylon 6,6) to 0.7 W/mK. The tensile elongation at failure was 1.4%.     

Application of marine biotechnology in the production of natural biocides for testing on environmentally innocuous antifouling coatings

The widely recognized biofouling phenomenon has many negative consequences for artificial structures that are in contact with seawater in the form of structural defects and additional expenses for maritime companies due to cleaning and prevention processes. After having analyzed the serious environmental problems caused by an indiscriminate use of highly toxic biocides coming from organic derivatives of tin compounds and the uncontrolled emissions of volatile organic compounds (VOC) to the atmosphere, the evolving technology of antifouling paintings (further mandated by current environmental standards) aims to develop environmentally innocuous water-based coverings in which extracts of the very same marine world are used as biocide compounds. Water-based coatings are being developed that use low-toxic elements and natural biocides, where bacteria is isolated from surfaces immersed in the marine environment, creating a promising source of natural antifouling compounds. The result is a new environmentally friendly antifouling coating that is able to mitigate the problem of biofouling without affecting the surrounding medium, and which may be applied on any artificial structure in contact with seawater. An erratum to this article can be found at