CRYSTALLIZATION OF SYNDIOTACTIC POLYSTYRENE IN BETA-FORM .2. QUANTIFICATION OF STACKING-FAULTS IN THE SOLUTION-GROWN SINGLE-CRYSTALS

The probability of the presence of stacking faults in the p-form singl e crystals of syndiotactic polystyrene, which were grown isothermally from a dilute solution at a temperature ranging from 150 to 210 degree s C, was estimated from the mean half-breadth of the streaked reflecti ons. The probability was also estimated by counting the number of the faults recorded in the dark-field and the high-resolution electron mic roscopic images. The probability showed weak dependence on crystalliza tion temperature, with its maximum value at 165 degrees C. When the si ngle crystals grown at 165 degrees C were annealed isothermally even a t 260 degrees C, only a small decrease in the amount of stacking fault s was detected. The molecular mechanism of and difficulty in eliminati ng the stacking faults by annealing were discussed on the basis of the structural model of the fault.