Cationic polymerization of indene and acenaphthylene

✍ Scribed by H.J. Prosser; R.N. Young

• Publisher: Elsevier Science
• Year: 1975
• Tongue: English
• Weight: 394 KB
• Volume: 11
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(75)90023-3

✦ Synopsis

The polymerizations of indene and acenaphthylene by TiC14-CCI3CO2H in dichloromethane take place in two stages, viz. a fast initial reaction followed by a slow stationary-state process. A mechanism involving the relaxation of active centres created by fast initiation to an equilibrium mixture of active and dormant centres satisfactorily accounts for the observed behaviour. Spectroscopy failed to reveal the presence of the acenaphthenium ion during polymerization, but paradoxically an ion of this type is slowly formed in large amounts after polymerization has ceased.

EXPERIMENTAL

An adiabatic calorimeter was constructed as a modified version of that designed by Plesch [t]; the principal differences (Fig. 1) were the use of (a} a thermistor as the sensor of temperature changes and (b) a breaker tube in place of the phials of the original. These modifications considerably simplified the glass-blowing and eliminated the need for frequent repair caused by unexpectedly strongwalled phials. A value of -55.7 k J/mole was obtained for the heat of polymerization of indene, in satisfactory agreement with the value of -58l kJ/mole obtained by Sigwalt [2] using an adiabatic calorimeter of Plesch's design.

Spectrophotometric studies were conducted using standard high vacuum techniques and a Perkin-Elmer 371 spectrophotometer.

Molecular weights were determined viscometrically using the literature parameters for polyindene [3] and polyacenaphthylene [4].