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1 Polish Journal of Chemical Technology

1 1999

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The Solid state postpolycondensation of poly(bisphenol a carbonate) in the presence of thermally unstable poly(propylene carbonate)

Kuran W., Dębek C., Wielgosz W., Kuczyńska L., Sobczak M.

Polish Journal of Chemical Technology

1999

Vol. 1, nr 1

26-30

The process for the synthesis of high-molecular-weight poly(bisphenol A carbonate) (PBC) by the solid-state postpolycondensation (SSP) process using 5-20 wt % of thermally unstable poly(propylene carbonate) (PPC) was investigated and compared with the analogous process without addition of the thermally unstable polymer. An application of poly(propylene carbonate) for the SSP process was found to enable the process to be carried out with poly(bisphenol A carbonate) not being precrystallized prior to postpolycondensation. It does mean that the inconvenient stage of crystallization of the prepolymer could be omitted. PBC of M v 48 000 g/mol was obtained by the standard procedure of SSP process starting with a prepolymer crystallized in acetone (for 192 h at a condensation temperature of 230-255°C and pressure of 0.07 mmHg). Instead, in the presence of 20 wt % PPC (without the inconvenient phase of crystallization of the prepolymer), PBC of Mv 42 000 g/mol with inconspicuous content of PPC was obtained. The results have been discussed in terms of propylene carbonate appearing in the postpolycondensation system due to the thermal decomposition of poly(propylene carbonate) under conditions applied. Propylene carbonate probably acts as a swelling agent which makes the prepolymer chain mobility and increased crystallization as well as the removal of condensation low-molecular-weight by-products more facile.