Stabilizing Effects of Cross-Linked Polyethylenepolyamine Base Copolymer Type Multi-Branched Nonionic Surface Active Agents on Various Types of COM

Evaluation was made of the stabilizing effects on various types of COM of multi-branched nonionic surface active agents with high molecular weight prepared by copolymerizing propylene oxide and ethylene oxide to polyethylenepolyamine and then cross-linking 2 mol of the product with 1 mol of tolylenediisocyanate. In the tests, 15 types of COM were prepared using various coal samples such as bituminous coal, subbituminous coals and lignites and various types of heavy oils. After being combined with the agents mentioned above at a concentration of 0.125%, COM samples were subjected to 30d still storage at 70°C15 d still storage at 70°C followed by reagitation and 7 d still storage, or 7 d still storage after heating to 100°C or cooling down to 0°C, for measurement of physical properties such as coal concentration, viscosity and specific gravity of COM. It was found that the above surface active agent was capable of imparting stabilizing effects to the various types of COM, under the severe heating, cooling and reagitation conditions that are generally encountered in the practical utilization of COM.