Spherical Particle Formation that Deteriorates Thixotropic Property and its Suppression Strategy for Diamide-Based
Yuki Mashiyama1, Haruka Maruyama1, Eiichi Satou2
1Graduate School of Science and Engineering, Saitama University.
Abstract:
Spherical particle formation degrades the performance of castor-oil-derived thixotropic additives, which are widely used to a dripping preventing agent in automobile paints and household waste oil treatment agent. Double-chain-type diamide is a heat-resistant thixotropic additive that causes nanofibrosis; its entanglement and gelation embracing solvent molecules-originating from the abundant intermolecular hydrogen bonds-and easy forming/rupturing tendency result in spherical particle formation, which can be confirmed by the temperature and time of reserve heating. Diamides with two hydrocarbons that have undergone thermal treatment leading to spheroidization were found exhibit significantly different sublimation/pyrolysis temperature, melting temperature, and crystal orientation than non-treated diamides. By comparing with the change observed under more extreme heating conditions, it can be considered that the amide bond site would increase the bond length and suppress the degree of freedom of rotation just before bond cleavage. In this state, verification of the origin of spherical particle formation by using the Langmuir-Blodgett method revealed that anisotropic suppression of hydrogen bonding occurs. In addition, it was found that spheroidization can be suppressed by adding a growth aid when preheating is conducted under a certain condition.
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