Many amines have the ability to decompose organic peroxides, but in peroxide-catalyzed emulsion polymerization only a limited number of amines have an activating effect so powerful that it is possible by adding them to the system to bring about rapid polymerization at a low temperature. Particularly effective are polyethylene and polypropylene polyamines when the peroxide catalyst is of the class represented by cumene hydroperoxide. A comparison
Vol. 50 chloride. The methylcreatinine hydrochloride thus obtained melted with slight decomposition at 234-236°, as reported. All attempts to condense this product with benzaldehyde, either by the usual procedure or with longer heating and increased proportions of sodium acetate and of acetic anhydride, were completely unsuccessful.At this stage it was thought worth while to show that the methylation could not have taken place with the introduction of a second methyl group on the 1-nitrogen.The methylcreatinine was accordingly hydrolyzed and found to yield sarcosine and methylamine. Since it was thus clear that the substance must have one of the two structures represented by VIII and IX, it was sought to convert it into a mixture of these two isomers (see discussion) in the hope that at least one of them might be condensed with benzaldehyde. The mixture obtained, however, gave no benzal derivative.
Table IRubber 100, sulfur 7.5, zinc oxide 5, cured at 115°C. with various proportions of piperidinium pentamethylenedithiocarbamate ,-(a) 0.25 part P. P.-s ^-(6) 0.33 part P. P.-> ) 0.50 part P. P.-.,-(d) 0.66 part P. P.-.
The polymerization in solution of a variety of water‐soluble monomers with a variety of water‐soluble redox initiators is described and a detailed study is reported on the polymerization, in aqueous solution, of methyl vinyl ketone and of methyl methacrylate under the influence of potassium sulfate‐silver nitrate. Keeping the persulfate concentration constant and varying the silver nitrate or, conversely, keeping the silver nitrate constant and varying the persulfate, it is found that, except at very high concentration of catalyst, both the rate of polymerization and the molecular weight of the polymer bear a linear relation to the square root of the catalyst concentration, in harmony with the general theory of catalyzed bulk and emulsion polymerization. The molecular weight of the polymer formed diminishes with increase in the temperature of polymerization. The study of redox polymerization in water, without emulsifier, has been extended to the case of a mixture of a water‐soluble and a water‐insoluble monomer, and it has been found that copolymerization proceeds at a reasonable rate and frequently forms a stable latex. The copolymerization of styrene and 5 or 10 per cent of its weight of methacrylonitrile in water under the influence of a water‐soluble persulfate‐bisulfite redox pair has been examined with some closeness. Polymerization is apparently initiated in the aqueous solution, since, contrary to the state of affairs in emulsion polymerization, water‐soluble retarders are more effective than oil‐soluble ones, when the retarder is added at the outset. If the retarder is added at a later stage of polymerization, oil‐soluble reagents are more effective than water‐soluble ones. The water‐soluble monomer enters into the polymer at a greater rate than the water‐insoluble one, but it appears that, even at the earliest stage at which it is practicable to take samples co‐polymerization occurs. The influence of catalyst concentration on the rate of polymerization, the molecular weight of the polymer, and the latex particle size was examined.
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