Cat’s paw inspires impact-resistant composite

In current work, crosslinked polyborosiloxanes (PBS) were synthesized by the Piers-Rubinsztajn reaction based on polydimethylsiloxanes (PDMS) with terminal dimethylhydrosilyl or distributed methylhydrosilyl groups in the polymer chain and boronic or phenyl boronic acid methyl esters. Depending on the number and location of the methylhydrosilyl groups in the initial PDMS, as well as on the functionality of the boronic component (2 for phenyl boronic and 3 for boronic acid methyl esters), PBS with different macromolecular architecture and crosslinking density were obtained. PBS based on PDMS with terminal dimethylhydrosilyl groups, crosslinked with trimethyl borate, are soluble in common solvents such as THF, toluene and chloroform, whereas PBS based on PDMS with distributed methylhydrosilyl groups are non-soluble. Investigations in an environmental chamber showed hydrolytic stability of the PBS samples under experimental conditions, which was confirmed by gel permeation chromatography (GPC) and infrared spectroscopy (FTIR). In the investigations of thermal stability of obtained PBS, 5% weight loss was observed at 380–430 °C. Differential scanning calorimetry (DSC) experiments showed differences in phase behavior of PBS with different boronic crosslinks.