AbstractsChemistry

The viscosity stability of polyvinyl acetate in mustard gas and in Bis(2-chloroethyl)Ether has been investigated and the effect of the addition of various salts and cosolvents determined. Iron has been shown to cause large viscose changes with ageing. Precipitation of the polymer solution has revealed that a molecular weight change occurs with ageing. An investigation of the structure of gelling solutions has indicated that the molecular weight change in a solution with increasing viscosity is a result of cross bridging between polymer chains. A cell has been designed to determine the osmotic pressures of heterogeneous polyvinyl acetate samples. The molecular weight of Gelva 15 was found to be higher then that expected from intrinsic viscosity measurements. It is shown that the discrepancy is due to the Staudinger constant assigned to polyvinyl acetate. A study of the pro-knock activity of various compounds revealed that this action is mainly a counteraction of the lead tetraethyl in the fuel. The results indicate that the pro-knock molecules preferentially attack the lead tetraethyl-hydrocarbon complex associated with chain branching. A few compounds such as chloropicrin exhibit a small effect on unleaded gasolines. The decrease in efficiency due to a 10 octane drop is of the order of 5% of the total power developed by the engine.