ISSN:
0360-6376
Keywords:
Physics
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Kinetics of solution polymerization of styrene was studied using pyridine as solvent and BZ2O2 and azobisisobutyronitrile (AIBN) as initiators at 60°C. Normal kinetic features (Rp ∝ [AIBN]0.5 · [styrene]1.0) were observed for the AIBN-initiated polymerization, with pyridine playing the role of an inert diluent; but in the BZ2O2-initiated polymerization, the monomer exponent was found to vary from a low value of 0.45 at a relatively low initiator concentration (1 × 10-2 mole/liter) to a value higher than the usual value of unity (1.18) at a much higher concentration of the initiator (16 × 10-2 mole/liter). The initiator exponent value was found to be 0.5 (usual) up to 20% v/v dilution with pyridine, but it showed a tendency to decrease with increase in pyridine content beyond 20% v/v. The kp2/kt value for each initiator system, however, was found to remain constant over the whole concentration range of pyridine. The unusual kinetic features were explained on the basis of predominance of one or the other of two competitive reactions in BZ2O2-initiated system: (a) higher rate of decomposition of BZ2O2 in pyridine and (b) primary radical depletion by reaction with pyridine, depending upon the concentration of BZ2O2 and pyridine.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1979.170170227
