Synthesis and characterisation of poly(arylene sulfides), 7. Transitional behavior of random and block copoly(arylene sulfides)

Differential scanning calorimetry was used to evaluate first and second order transition temperatures and % crystallinity of poly(1,4‐phenylene sulfide) (PPS), poly(2‐methyl‐1,4‐phenylene sulfide) (PMPS), their blends and random and block copolymers comprising thio‐1,4‐phenylene and thio‐2‐methyl‐1,4‐phenylene units. Results are discussed in terms of the miscibility of PPS and PMPS in the melt phase and disruption of the crystallisation of PPS units by PMPS units. Microphase separation in the block copolymers was shown to be dominated by crystallisation of the PPS blocks. The application of Krause's microphase separation theory to prediction of the transitional behaviour of the block copolymers is critically discussed.