The changes in oxidation stability of two grades of crankcase lube oil, monograde (SAE 40) and multigrade (SAE 20W50), and their base oils were monitored by measuring their carbonyl peak index with respect to time in order to corroborate the results of sludge deposit and soluble acidity characteristics. The carbonyl peak index was calculated as the difference in the ratios of the absorbance of the carbonyl band at 1700 cm -1 and of the basic peak methyl stretching vibration at around 3000 cm -1 at oxidation time t and the start of the experiment. The results showed that the base oils were oxidized to a greater extent than the formulated oils. The monograde oil and its base oil had higher carbonyl peak indexes than their respective multigrade counterparts, showing that the monograde oils were less resistant to oxidation than the multigrade oils. However, results of sludge deposits and soluble acidity showed that the multigrade oils formed more oxidation products than the monograde oils, which also incidentally suggests that the multigrade oils deteriorate faster. The two conflicting observations therefore suggest that the types of oxidation products formed from the two oils were different even though initiated by similar mechanisms. The effects of metals (zinc, nickel, and aluminum), as well as the effect of water (on the activity of the metals), on the overall carbonyl peak index are reported.

No abstract

No abstract

No abstract

Graft copolymerization of ethyl acrylate onto starch initiated by ceric ion in an aqueous medium was studied at 29 "C. It was found that the grafting frequencies and molecular weights of grafted poly(ethy1 acrylate) changed from 2 graft polymer molecules per lo4 anhydroglucose units (AGU) and 3.03 lo5 to 34 and 6.80 -lo5, respectively, when the starch content was varied from 1.0 wt.-Yo to 0.2 wt.-Yo. The influence of dilution of ceric ion on the extent and rate of graft polymerization of ethyl acrylate onto starch was also examined. ZUSAMMENFASSUNGDie durch Cer(1V)-Ionen initiierte Pfropfcopolymerisation von Ethylacrylat auf Starke wurde bei 29 "C in waBrigem Medium untersucht. Durch Variieren des Starkegehalts zwischen 1 und 0,2 Gew.-Yo lnderte sich die Pfropffrequenz von 2 auf 34 Pfropfpolymermolekiile pro lo4 Anhydroglucose-Einheiten (AGU) und das Molekulargewicht des gepfropften Poly(ethylacry1ats) von 3,05 I@ auf 6,80 * lo5. Der EinfluR der Cer(1V)-Konzentration auf Grad und Geschwindigkeit der Pfropfpolymerisation von Ethylacrylat auf Starke wurde ebenfalls untersucht.