Sensitized Radiation-Induced Polymerization of Indene with 1,1,2,2-Tetrachloroethane

Area of Science:

• Polymer Chemistry
• Radiation Chemistry

Background:

• Radiation-induced polymerization is a method for polymer synthesis.
• Indene polymerization typically proceeds via cationic or free radical mechanisms.
• Sensitizers can alter polymerization kinetics and yields.

Purpose of the Study:

• To investigate the effect of 1,1,2,2-tetrachloroethane (TCE) as a sensitizer on radiation-induced indene polymerization.
• To compare sensitized polymerization with bulk and uncensored radiation-induced polymerization.
• To analyze the impact of TCE on polymerization kinetics, yield, and molecular weight.

Main Methods:

• Gamma radiation was used to induce polymerization of indene monomer at a dose rate of 3 kGy/h.
• Polymerization was conducted both with and without the sensitizer TCE.
• Polyindene yield, polymerization kinetics, molecular weight (via end-group analysis and glass transition temperature), and mechanism were analyzed.
• Spectroscopic techniques including electronic absorption spectroscopy and FT-IR were employed.

Main Results:

• TCE significantly increased polyindene yield and accelerated polymerization kinetics compared to uncensored polymerization.
• The radiation chemical yield (G_p) increased with dose in sensitized polymerization, unlike in the absence of TCE.
• TCE promoted both cationic and free radical polymerization mechanisms.
• Despite enhanced yield and kinetics, TCE resulted in polyindene with lower molecular weight.

Conclusions:

• TCE acts as an effective sensitizer for radiation-induced indene polymerization, enhancing yield and kinetics.
• The presence of TCE influences the polymerization mechanism, promoting both cationic and radical pathways.
• A trade-off exists between increased polymerization efficiency and reduced molecular weight when using TCE as a sensitizer.