Abstract
Variation in the molecular weight distribution of straight polymers, with a mean molecular weight of (1.1-2)×106, upon central, random, or terminal chain scisson was simulated. The peak in the molecular weight distribution was shown to shift to a lower molecular weight upon central or random chain scisson, and the randomly cut polymers were more widely distributed than the centrally cut polymers. A bimodal distribution was obtained upon terminal chain scisson. A parameter “n1” in a Rosin-Rammler plot, where molecular weight was substituted for particle size, stayed nearly constant for large t values duning central and random chain scisson. This constant n1 value was 2. 1-2.3 for central chain scisson and 1.3-1.7 for random chain scisson. n1 for terminal chain scisson decreased to zero with increasing t. The application of these simulation results to ball-milling of polyvinylpyrrolidone (PVP) in nitrogen showed that the terminal chain scisson of PVP was accompanied by its random chain scisson. It was also shown that the addition of phenothiazine or acridine increased the rate of random chain scisson.
