# Novel Hydroxyl-Functional Aliphatic CO2-Based Polycarbonates: Synthesis and Properties

## TL;DR

Researchers synthesized new CO2-based polycarbonates with hydroxyl groups, showing unique properties like low glass transition temperatures and easy breakdown.

## Contribution

A new method for synthesizing hydroxyl-functional polycarbonates using CO2 and mild depolymerization conditions.

## Key findings

- The terpolymers had molecular weights from 20,000 to 100,000 with narrow dispersities.
- Adding water led to a unimodal molecular weight distribution with dispersity of 1.11.
- Hydroxyl-functional polycarbonates cyclodepolymerized under milder conditions than protected ones.

## Abstract

A series of novel functional polycarbonates, specifically poly(solketal glycidyl ether carbonate-co-propylene carbonate)s with varying compositions, were synthesized through the ring-opening copolymerization of solketal glycidyl ether, propylene oxide, and carbon dioxide. The reaction was catalyzed by rac-(salcy)CoIIIX complexes with bis(triphenylphosphine)iminium salts as co-catalysts, achieving high selectivity. The resulting terpolymers exhibited number-average molecular weights ranging from 2 × 104 to 1 × 105 and a narrow, bimodal molecular weight distribution, with dispersities of 1.02–1.07 for each mode. Interestingly, the addition of a small amount of water to the reaction mixture yielded a terpolymer with a unimodal molecular weight distribution and a dispersity of 1.11. Subsequent acidic hydrolysis of the solketal protective groups produced poly(glyceryl glycerol carbonate-co-propylene carbonate). All terpolymers were amorphous, with Tg near or below room temperature. The hydroxyl-functional polycarbonates underwent cyclodepolymerization under milder conditions compared to polycarbonates with protected hydroxyl groups.