Sequence distribution and miscibility of SMA copolymers

✍ Scribed by J. Pionteck; V. Reid; W. J. Macknight

• Publisher: John Wiley and Sons
• Year: 1995
• Tongue: English
• Weight: 668 KB
• Volume: 46
• Category: Article
• ISSN: 0323-7648
• DOI: 10.1002/actp.1995.010460210

✦ Synopsis

We have investigated the miscibility of poly(styrene-co-maleic anhydride) (SMAISMA) blends, i.e. blends of two SMA copolymers which have different maleic anhydride (MA) contents. 33 SMA copolymers with MA contents between 2 and 29 vol.% were used. The MA contents were determined by two different techniques: FTIR using a titration technique for calibration and DEPT NMR, which was also employed to determine the triad sequence distribution of the SMA copolymers investigated.The miscibility was determined by the single TE criterion as measured by DSC after annealing at 220 "C for 2 min. After normalization of the polymerization degree to N = 1000 kcr =0.002), we found miscibility for such blends (1:l by weight) where the difference in the MA contents d [MA] is less than or equal to 2.5 vol.%.At higher differences in MA content the copolymers are immiscible. The miscibility is independent of the overall MA content.The resulting interaction parameterx,, MA is equal to 3 at 220 "C. A comparison of the miscibility window determined experimentally with calculated miscibility windows where special interaction energies are assigned to the different triad-triad combinations does not show any evidence for an influence of the sequence distribution on the miscibility of SMAISMA blends.