Abstract
A concentrated aqueous solution of acrylamide was dispersed in carbon tetrachloride using emulsifier, and polymerization was carried out in the emulsion at 30°C by using redox initiator under nitrogen atmospher.
The polymerization proceeded smoothly at the comparatively low temperature without any side reactions, because heat of reaction was readily eliminated by stirring.
Molecular weight of polyacrylamide was able to be easily controlled by adding some chain transfer agent. The chain transfer coefficients of isopropyl alcohol, tert-butyl alcohol and n-dodecyl mercaptane were found to be 2×10-4, 0.44×10-4 and 0.90×10-4 respectively.
Microscopic obserbation showed that fine particles of random forms of polyacrylamide flocculate rapidly to almost globular and porous particles of about 1.5_??_2μ in diameter uniformly at a time the polymerization is near completion.
From the reaction mixture, the polyacrylamide may be precipitated by smaller amount of precipitant such as methanol than that needed in usual solution polymerization, and powder of watersoluble polymer of required molecular weight was obtained conveniently.
