INFLUENCE OF AGING ON THE ORDERING PHENOMENA OF SYNDIOTACTIC POLYSTYRENE

The crystallization from the glassy state of different samples of syndiotactic polystyrene (sPS) was investigated with different techniques, such as differential scanning calorimetry, infrared analysis, and polarized optical microscopy. The different samples of sPS were obtained by ageing the glassy sPS films at room temperature and at 70-degrees-C; the behaviour of these films was compared with that of the fresh sample, put at the crystallization temperature as soon as prepared. The temperature of crystallization was 120-degrees-C; at this temperature, besides the crystalline phase, a fraction of mesophase is formed. All the techniques investigated to follow the crystallization phenomenon show that the fresh sample crystallizes much sooner than the others; the sample aged at 70-degrees-C takes the longest time to crystallize, whereas an intermediate behaviour characterizes the sample aged at room temperature. This result was correlated with the initial structural organization of the glassy amorphous samples.