THERMAL-DEGRADATION OF POLY(ARYLENE SULPHIDE)S .3. VACUUM PYROLYSIS OF POLY(1,4-PHENYLENE SULFIDE) IN THE PRESENCE OF POLYSTYRENE - THE RESIDUE AND THE GASEOUS FRACTION

Mixed samples of poly(1,4-phenylene sulphide) (PPS) and polystyrene (PS) (1:1 by wt) have been subjected to vacuum pyrolysis at 280 to 450-degrees-C. Samples of the two polymers have also been degraded separately, but simultaneously, in a dual-cavity sample tube, so that volatiles from one polymer passed over the other. The results of degradation have been compared with results from similar studies conducted separately on the homopolymers. PPS residues from all the PPS-PS system behaved in a similar manner to those from the parent homopolymer, indicating that the PPS was little affected by the degradation of PS. PS residues from the unmixed systems behaved in a similar manner to the parent homopolymer, espectially at temperatures <350-degrees-C. For the mixed system, the drop in M(n) of the PS residues was much larger and the polydispersity increased steadily from an initial value of 1.20 to 1.79 at 350-degrees-C. Mechanisms are proposed to account for these observations.