Poly(dimethylsiloxane), bis(3-aminopropyl) terminated,20 - 30 cSt

Riehle, Natascha, et al. Data in brief 18 (2018): 1784-1794.

Polysiloxane urea elastomers (PSU) were prepared by two-step polymerization using aliphatic diisocyanate 4,4'-methylbis(cyclohexyl isocyanate) (H 12 MDI), siloxane chain extender 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane (APTMDS) and Poly(dimethylsiloxane), bis(3-aminopropyl) terminated (PDMS) or polydimethyl-methyl-phenyl-siloxane-co- (PDMS-Me,Ph), respectively.
The required amount of H12 MDI was dissolved in THF in a 250 mL four-necked round-bottom reaction flask equipped with a PTFE oval magnetic stirring bar, dropping funnel, nitrogen inlet and outlet, and an inserted ATR probe. Start collecting spectra and record the initial NCO concentration by tracking the height of the NCO absorption peak at 2263 cm -1. Then, 31.5 g of undiluted PDMS are quickly (within 38 seconds) added to the H 12 MDI solution via a dropping funnel. Once the NCO peak height is constant again, about 50 mL of THF (used to rinse the dropping funnel) is added to the prepolymer solution. Finally, the entire amount of chain extender APTMDS (calculated according to the reaction stoichiometry) is quickly added via syringe. A transient increase in viscosity indicates the formation of PSU. Therefore, the PSU solution is diluted with THF to a final concentration of 17% (w/w).