Polysiloxane Networks Modified by Nitrogen-Containing Organic Compounds

Area of Science:

• Polymer Chemistry
• Materials Science
• Organic Chemistry

Background:

• Amine-functionalized polysiloxanes offer diverse applications, including toxic metal ion extraction and catalyst support.
• Poly(hydromethylsiloxane) (PHMS) is a versatile polymer backbone for functionalization.

Purpose of the Study:

• To synthesize and characterize PHMS networks functionalized with N-allylaniline (Naa), N-allylcyclohexylamine (Nach), and N-allylpiperidine (Nap).
• To compare the efficacy of a two-step versus a one-step synthesis method for amine functionalization of PHMS.

Main Methods:

• Synthesis of PHMS networks via two-step (pre-crosslinking then amine reaction) and one-step (simultaneous cross-linking and amine reaction) procedures.
• Characterization using Fourier-transform infrared (FTIR) spectroscopy, 29Si magic-angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy, and elemental analysis.

Main Results:

• The one-step method yielded higher degrees of PHMS network functionalization compared to the two-step method.
• The one-step method effectively hindered undesirable side reactions like hydrolysis and condensation of Si-H/SiOH groups.
• Amine basicity influenced the extent of side reactions, particularly in the two-step procedure.

Conclusions:

• The one-step synthesis is a more advantageous method for preparing amine-functionalized PHMS networks.
• This optimized method leads to improved material properties and purity.
• The findings provide insights into controlling functionalization and minimizing side reactions in polysiloxane chemistry.