# Mechanistic Study of Substituent Effect on Photoinduced O-C Bond Activation in Polycarbonate

## TL;DR

This paper studies how chemical groups on polycarbonate affect the breaking of specific bonds when exposed to light.

## Contribution

The study reveals how substituent position and electronic properties influence photoinduced bond cleavage in polycarbonate.

## Key findings

- Electron-donating groups in meta- or ortho-positions promote carbonate O-C bond cleavage.
- Electron-withdrawing groups suppress bond cleavage in these positions.
- Ortho-positioned substituents have a stronger effect on bond scission.

## Abstract

Photodegradation of polycarbonate (PC) is investigated based on quantum chemical methods with PC models to clarify the effect of substituents at different positions of phenyl rings on the carbonate O-C bond cleavage. Compared to the results without substituents on phenyl rings, the breakage of the carbonate O-C bond is promoted or suppressed when the electron-donating or electron-withdrawing group is placed on the meta- or ortho-positions of the gem-dimethyl groups of phenyl rings, respectively. Moreover, the promotion and suppression of carbonate O-C bond scission are more significant if the substituents are located on the ortho-positions of the gem-dimethyl groups.