ISSN:
0022-3832
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
The present paper describes the preparation and evaluation of the effectiveness as modifiers of a number of compounds of bis-type structure - principally aryl disulfides - in bulk styrene and emulsion butadiene polymerizations. This work endeavors to explore some of the objectives described in the first paper of this series, and deals primarily with attempts to gain quantitative information on the effect of the nature and location of substituting groups with respect to the dissociating bond. The compounds examined include both those containing reactive groups attached and those lacking such groups. A number of the preparations are now compounds. Evaluations in 50°C. bulk styrene were carried out with the objective of eliminating the complications of the diffusion factor always present in emulsion systems. Generally speaking, the correlation between effectiveness in bulk styrene and 50°C. emulsion butadiene was quite good, though there were exceptions. It was found that the modifier activity of many compounds in emulsion butadiene could be enhanced by predispersing them in the aqueous phase - presumably a result of minimizing the importance of diffusion rate. Some of the modifiers were also tested in a low temperature butadiene emulsion system. Aryl disulfides continue to offer the most promise from the standpoint of combining the features of attaining high transfer constants and ease of incorporating desired reactive groups. Some compounds had adequate activity in emulsion butadiene polymerizations for use as practical modifiers. However, it has not yet been established that these compounds cleave to give one-half the molecule on each end of the butadiene polymer chain, as has been done for styrene polymers.
Additional Material:
3 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1955.120178501
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