Antioxidant Silicone Elastomers without Covalent Cross-Links

Improved sustainability is associated with elastomers that readily breakdown in the environment at end of life and, as importantly, that can be reprocessed/reused long before end of life arises. We report the preparation of silicone elastomers that possess both thermoplasticity-reprocessability-and antioxidant activity. A combination of ionic and H-bonding links natural phenolic antioxidants, including catechol, pyrogallol, tannic acid, and others, to telechelic aminoalkylsilicones. The mechanical properties of the elastomers, including their processability, are intimately linked to the ratio of [ArOH]/[H2NR] that was found to be optimal when the ratio exceeded 1:1.

High Refractive Index, Enantiopure Silicones Based on BINOL

The high refractive index aromatic compound, binaphthol (BINOL), is readily incorporated into silicone polymer chains using the Piers-Rubinsztajn reaction; alternating and random linear copolymers, and elastomers are available. The highest refractive index (RI) materials were BINOL rich. It was not possible to directly make high refractive index linear polymers with very short HSi-capped, telechelic silicone chains, as they did not react cleanly. However, chain extending short vinyl-capped BINOL macromers with simple arylsilanes using hydrosilylation led to polymers with molar mass up to 8000 and refractive indices up to 1.58. Elastomers were prepared using similar processes. The reactions are facile to practice and suggest BINOL could be harnessed in these and other processes to augment RI. This article is protected by copyright. All rights reserved.