In this study of side chain crystallinity, methacrylate and acrylate monomers, with «-alkyl groups containing from 12 to 18 carbon atoms, were synthesized, polymerized and copolymerized; dilatometric measurements were made on these polymers to determine the changes in specific volume with temperature and time; spacings were obtained from Debye-Scherrer patterns taken at small and wide angles. The following results were noted: the specific volume-temperature plots were S-shaped, typical of first-order transitions; crystallization was rapid and accompanied by very little supercooling; melting ranges were short except for the mixed long chain copolymers; long and short spacings were found in the X-ray patterns. The melting ranges of the polymers did not depend on the temperature of the cooling bath.

The solubilities of reaction mixtures of calcium oxide, silica, and water, and hydrated tricalcium silicate in water were investigated. It was concluded from the results that several solid phases exist in the system Ca0-Si02-H20 at 25°: (1) silica and silica that has partially reacted with calcium hydroxide at Ca0-Si02 mole ratios less than 0.14, (2) partially reacted silica and CaH2Si04 at mole ratios between 0.14 and 1, (3) CaH2Si04 with varying amounts of calcium hydroxide dissolved in it for over-all Ca0-Si02 mole ratios greater than 1, and (4) CaH2Si04'roCa(0H)2 and calcium hydroxide at over-all Ca0-Si02 ratios above about 1.75. The evidence for a phase Ca(H3Si04)2 is not conclusive. The solubility product for CaH2Si04 and the ratio of the activity of the calcium hydroxide dissolved in CaH2Si04 (in moles of calcium hydroxide per mole of CaH2Si04) to that in the solution are constants which describe the system in the CaO-Si02 mole ratio range 1-1.75.

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This paper describes a light scattering study of the formation of polysilicic acid in basic media prepared by mixing very clean solutions of ammonium acetate and sodium metasilicate. The growth of the colloidal silica sols was observed by t,wbidity, dissymmetry and depolarization measurements. The rate of polymerization of silicic acid was followed in equivolume mixtures of 3% ammonium acetate and sodium metasilicate solutions whose concentrations varied from 0.1 to 10%. It was found that the rate increased with silicate concentration up to 1%.Similarly, equivolume mixtures of 1% sodium silicate and 1, 3, 6 and 10% solutions of ammonium acetate showed an increase in rate with ammonium acetate concentration. Measurements of the pH of the solutions show that the reaction does not proceed above the pH of 11 and increases in rate as the pH is lowered to 8.6. Depolarization and dissymmetry measurements indicate that the particles are large isotropic spheres.Above this concentration the rates were lower.Mechanisms of polymerization and aggregation are discussed.