Butadiene popcorn polymer

Abstract

Using a direct weight method, the rate of butadiene polymer growth has been found to be logarithmic with time and proportional to the initial mass of polymer seed present providing active polymer seeds are used. When solutions of potassium sulfide (0.005 and 0.0025 g. per ml.) were added to butadiene, the growth of popcorn polymer in the vapor phase was greatly inhibited. The final weights of 0.100 g. initial polymer seeds were 0.205 and 0.389 g. after 29.6 and 30.5 days at 60°C. respectively, for the two sulfide concentrations. This is to be compared with a normal growth of 2.85 g. after 13.5 days at 60° for a non‐sulfided test. Water does not inhibit popcorn polymer growth and may possibly accelerate it. The activity of the popcorn seeds for spontaneous growth in the presence of monomer depends on the seed generation or extent to which the seeds have grown. The growth activity of a definite mass of polymer increases with continued seed growth until a point is reached where there is a structural change from popcorn‐like to more glassy‐like polymer. The latter has lower growth activity. It is believed that the effect of variation of activity with seed generation is independent of peroxide content and that these tests were performed with peroxide‐free seeds.

The reactivity of 1,3-butadiene with butadiene-derived popcorn polymer

“…Butadiene can also react with oxygen (such as would be available from air intrusion into a process) to form a shocksensitive polyperoxide, which, upon continued exposure to butadiene, can produce a species commonly referred to as "popcorn polymer" [11,12]. This material grows through a free radical-catalyzed polymerization-like pathway, but forms in a manner that accumulates considerable molecular strain.…”

Relief system's last line of defense, only line of defense?

“…The Contractor engineers did not recognize that butadiene was a reactive chemical and that uninhibited butadiene in particular was more reactive than inhibited butadiene. This information was readily available in an MSDS that could have been easily obtained from the Client or from numerous sources in the literature [5–20].…”

Rapid build‐up of a pyrophoric polymer in ethylene plant deethanizer and depropanizer columns

“…Consequently, it was apparent that it would be necessary to analyze an impractically large number of samples from various locations in the columns in order to make a significant statistical analysis. However, from its appearance, some of the polymer formed in the columns appeared to be of the popcorn variety, which has been synthesized in glass tubes by exposing butadiene vapour to a mixture of water, rusty iron and benzoyl peroxide at 60°C (Miller et al, 1952). In the column locations, where the popcorn-like polymer was formed, it is likely that iron rust promoted polymerization.…”