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The intrinsic viscosities of low molecular weight fractions of atactic poly(acry1ic acid) at 50% and 100% neutralization and at several concentrations of added sodium chloride is studied. In salt-free solutions the 100% neutralized polymer assumes the rigid rod form. The results at concentrations of sodium chloride higher than 0,02mol/l can be interpreted in terms of a non-draining random coil polymer.The values of K Q are determined using the Stockmayer-Fixman method; there is an increase in K Q on going from poly(acry1ic acid) in dioxane through the 50% neutralized form in O ,~M sodium chloride solution to the 100% neutralized form in 1 , 5~ sodium chloride solution, indicating the continued effect of short-range electrical forces at the @-point. ZUSAMMENFASSUNG:Das Verhalten der Viskositatszahl von Fraktionen niedrigen Molekulargewichtes ataktischer Polyacrylsaure bei 50% und 100% Neutralisation und verschiedenen Konzentrationen hinzugefugten Natriumchlorids wird untersucht. In salzfreier Losung nimmt das lOO%ig neutralisierte Polymere die Gestalt eines starren Stabchens an. Die Ergebnisse bei NaC1-Konzentrationen uber 0,02 mol/l lassen sich durch ein undurchspultes statistisches Knauel interpretieren.Die Werte von K Q werden nach der Methode von Stockmayer-Fixman bestimmt. Dabei nimmt K e fur Polyacrylsaure in Dioxan von der zu 50% neutralisierten Form in O ,~M Natriumchloridlosung zu der zu 100% neutralisierten Form in 1 , 5 M Natriumchloridlosung zu. Dies weist darauf hin, dalJ ein Effekt kurzreichender elektrischer Krafte auch am O-Punkt weiterbesteht.

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To reduce the amount of carbon dioxide released from transportation the EU has implemented legislation to mandate the renewable content of petrol and diesel fuels. However, due to the complexity of the combustion process the addition of renewable content, such as biodiesel and ethanol, can have a detrimental effect on other engine emissions. In particular the engine load can have a significant impact on the emissions. Most research that have studied this issue are based on steady state tests that are unrealistic of real world driving and will not capture the difference between full and part loads. This study aims to address this by investigating the effect of renewable fuel blends of diesel, biodiesel and ethanol on the emissions of a compression ignition engine tested over the World Harmonised Light Vehicle Test Procedure (WLTP). Diesel, biodiesel and ethanol were blended to form binary and ternary blends, the ratios were determined by Design of Experiments (DoE). The total amount of emissions for CO, CO 2 and NO x as well as the fuel consumption, were measured from a 2.4 L compression ignition (CI) engine running over the WLTP drive cycle. The results depicted that percentages smaller than 10 % of ethanol in the fuel blend can reduce CO emissions, CO 2 emissions as well as NO x emissions, but increases fuel consumption with increasing percentage of ethanol in the fuel blend. Blends with biodiesel resulted in minor increases in CO emissions due to the engine being operated in the low and medium load regions over the WLTP. CO 2 emissions as well as NO x emissions increased as a result of the high oxygen content in biodiesel which promoted better combustion. Fuel consumption increased for blends with biodiesel as a result from biodiesel's lower heating value. All the statistical models describing the engine responses were significant and this demonstrated that a mixture DoE is suitable to quantify the effect of fuel blends on an engine's emissions response. An optimised ternary blend of B2E9 was found to be suitable as a 'drop in' fuel that will reduce harmful emissions of CO emissions by approximately 34 %, NO x emissions by 10 % and CO 2 emissions by 21 % for transient engine operating scenarios such as the WLTP drive cycle.