Sonication studies, carbon

SWNTs were prepared by high-pressure CO decomposition over the Fe catalyst (HiPco method [13]) at Carbon Nanotechnologies Inc. Houston, Texas, USA. The raw sample was purified by controlled thermal oxidation in air followed by sonication in HC1. The purity estimated by elemental analysis, TGA, XRD and TEM gave in result 99% content of SWNT in the samples studied [4],... 

The same thermosetting polystyrene SMP was used in this study. In addition to the 40% by volume of glass microbaUoons, 0.15% by volume of multiwalled carbon nanotubes was also added, which was the same as in Reference [38]. The multiwaUed carbon nanotubes (Cheap Tubes Inc.) have a density of 2.1 g/cm, diameter of 20-30 nm, and length of 20-30 pm. Similar to Reference [38], a two-step procedure was used to prepare the syntactic foam. First, the carbon nanotubes were added to Part A of the polymer. The mixture was mixed with the assistance of an ultrasound mixer for 30 minutes at a frequency of 20 kHz (Sonics Vibracell VC 750W) and a three-roll mill for one pass (NETZSCH type 50) (see Rgure 3.26). Second, microballoons and hardener (Part B of the polymer) were added to the carbon nanotube/Part A mixture and mixed with a spatula for 15 minutes. It was then poured into an aluminum mold of... 

In the earher studies, chlorinated solvents (methylene chloride or carbon tetrachloride) and ethyl ether were used due to their excellent abilities to partition a large spectrum of plasticizers. Today, hexane or its 1 1 mixture with methanol are likely used for extraction. It is also important to increase the surface area of a sample and its contact with the solvent. This is best achieved by cryogenic grinding and sonication. With this technology of plasticizer extractiorr, 79.6 to 99.5% of plasticizers were recovered from blank matrix and 55 to 94% from spiked samples. 

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