ISSN:
0449-296X
Keywords:
Physics
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The kinetics of polymerization of acrylamide and methacrylamide, photoinitiated by azidopentamminecobalt(III) chloride in homogeneous aqueous acid medium was studied systematically. Monochromatic wavelengths 365, 405, and 435 mμ were employed for irradiation. Polymerization proceeded without any induction period, and the reaction was followed by measurements of rate of monomer disappearance (bromometrically), rate of complex disappearance (spectrophotometrically), and the chain lengths of the polymer formed (viscometrically). The dependences of the rate of polymerization on variables like light intensity, light absorption fraction by the complex, wavelength, monomer concentration, hydrogen ion concentration, nature of the acid used (HClO4, HNO3, and H2SO4), etc., were studied. The rate of polymerization of acrylamide depended on the unit power of monomer concentration and on the square root of light absorption fraction kε and light intensity I. The rate of methacrylamide polymerization was proportional to the unit power of monomer concentration and fractional powers of 0.25 and 0.30 of kε and I, respectively. A kinetic reaction scheme is proposed and discussed in the light of the experimental results, and it has been concluded that (1) the primary photochemical act is an electron transfer reaction from the azide ion to Co(III) in the complex, (2) initiation of polymerization is by azide radical, (3) termination is by mutual destruction of polymer radicals.
Additional Material:
8 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1968.150061204
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