Research On The Dispersion Of Carbon Nanotubes

Carbon nanotubes (CNTs) are a kind of material, with unique structure and excellent properties, which have a potential application in the area of mechanics, electricity, optical and electrochemistry. Composites using CNTs as reinforcement exhibit good strength, elasticity, fatigue resistance and isotropy, which may bring a qualitative leap in the performance of composite materials.CNTs with nano-size, large specific surface area and high length-diameter ratio, are easy to agglomerate and entangle due to high electrostatic interaction and van der Waals forces. Commercial CNTs purchased are seriously agglomerated and entangled in the package. The agglomeration of CNTs results in the decrease of the electrical and mechanic properties of composites utilizing CNTs as a part of reinforcement. If CNTs are to be utilized as effective reinforcements in polymer composites, proper dispersion has to be guaranteed.Characterization of the dispersion of carbon nanotube is also a problem. Conventional optical microscope is hardly able to observe a single nanotube due to the nano-dimension. So expensive and high precision instruments have to be employed. Because of high magnification, up to10000times and even to100000times, we can only observe few local nanotubes. Which means that fully characterization of the dispersion of nanotube is hardly achieved. Since the cylindrical shape with high aspect ratio up to1000, the diameter of carbon nanotubes aggregated is difficult to accurately measure.In view of the above questions, this paper studies the effects of ultra-sonication and dispersant TNEDIS on the dispersion of nanotube in the acetone solution. Ultrasonic time is set to20min,30min,40min,50min,60min,70min,80min,90min,100min,110min,120min,130min,140min,150min. the content of TNEDIS is set to0.8Wt%,1.0Wt%,1.2Wt%. A laser particle size analyzer and SEM&TEM are employed to measure the diameter of the aggregated aligned multi-wall carbon nanotubes from macro to micro dimension, comprehensively characterized the dispersion of aligned multi-wall carbon nanotube.Experimental results show that in the beginning of ultra-sonication, the average particle size of aggregated MWNTs aligned in acetone solution decrease with the time. The aggregated MWNTs with larger particle size are dispersed gradually while the percentage of aggregated MWNTs of smaller particle size increase. There would come to a time when all the aggregated MWNTs of larger particle size disappear suddenly. And finally the particle size of aligned MWNTs particles show an interval distribution with three different particle size interval. And the percentage of the particles belonging to every interval remain stable, which means that the average particle size of aggregated MWNTs no longer decreases with the time.In the beginning of ultra-sonication dispersion, under the same ultrasonic dispersion time, the average particle size of aggregated MWNTs in acetone solution decrease as the content of TNEDIS increases. There would come to a time when the average particle size of aggregated MWNTs remain stable. After90minutes of ultrasonic dispersion, the average particle size of aggregated MWNTs in acetone solution with different content of TNEDIS remain stable at about1.300um. TNEDIS accelerates the dispersion of aggregated MWNTs of large particle size which turn into the particles of...