ISSN:
0021-8995
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
A new initiating system, named the Veroxathionite system, for the copolymerization of butadiene (75)-styrene (25) is described. At 0°C., with the recipe: butadiene, 75 parts; styrene, 25 parts; water, 180 parts; potassium myristate, 5 parts; potassium pyrophosphate, 1 part; sulfole mercaptan, 0.3 part; 0.66 mmole of phenylcyclohexane hydroperoxide, 0.001 M ferric versenate, and 0.1 part of sodium dithionite, conversions of 45, 87, and 100% were reached in 1, 2, and 3 hours, respectively. The rate can be varied within wide limits by changing the concentration of iron. With only 10-4 M ferric versenate and 0.06 part of dithionite, 71% conversion is attained in 12 hours. The amount of dithionite must be adjusted to the amount of hydroperoxide and, to a lesser extent, to the amount of iron. With much more than one mole of dithionite per mole of hydroperoxide, dead-stops occur at low conversion due to exhaustion of hydroperoxide. The rate is determined by the concentration of ferric versenate, and an excess of versene over ferric iron has no effect. The addition of potassium pyrophosphate yields a latex which is of normal fluidity and free of precoagulation up to 80% conversion. The effects of polymerization variables are described. With methanol as antifreeze, a recipe is described which yields 75% conversion in 8 hours at -20°C. The reaction mechanism is very involved. It is concluded that an induced reaction between hydroperoxide and dithionite is responsible for the low efficiency of the radicals produced in this recipe.
Additional Material:
10 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/app.1959.070010211
Permalink
