Poly(vinyl alcohol) and poly(dimethylsiloxane)-based interpenetrating polymer networks via radical polymerisation

In this paper, interpenetrating polymer networks (IPNs) based on poly(vinyl alcohol) (PVA) and poly(dimethylsiloxane) with terminal vinyl groups (PDMS-vinyl) with both hydrophilic and hydrophobic features were prepared by radical reticulation. Specifically, an aqueous PVA solution was mixed with an alcoholic PDMS-vinyl solution in the presence of 2,2-dimethoxy-2-phenylacetophenone (DMPAP) and N’,N-methylenebisacrylamide (MBA) as initiating and reticulating agents, respectively, to obtain samples with the following PVA/PDMS-vinyl (w/w) compositions: 100/0, 75/25, 50/50, and 25/75. Confirmation of the IPN formation was done by a set of techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TG), differential scanning calorimetry (DSC), as well as theoretical calculations. The techniques used showed evidence of cross-linking reactions occurring in both PVA and PDMS-vinyl. Swelling experiments showed a proper balance of the resulting IPNs in swelling polar and apolar solvents, according to their composition and cross-linking. Tools of Theoretical Chemistry (Methods of Molecular Mechanics and Quantum Mechanics) were employed for the first time to investigate the cross-linking reaction between PVA and MBA and corroborate the experimental results. The PVA/PDMS IPNs showed a high capacity (up to 80 wt.%) to absorb water and may be characterised as hydrogels.