Novel PVA/Methoxytrimethylsilane elastic composite membranes: preparation, characterization and DFT computation

A modified composite membranes (PVA/Si-OH/Si-OC) were made via solution-casting process using different 1:1, 1:2, 1:3 and 1:4 volume ratios of polyvinyl alcohol (PVA):methoxytrimethylsilane (MTMS). Moreover, FT-infrared and energy-dispersive X-ray spectroscopy (EDX) were mesured to account for the network structural rearrangements involving silicon within PVA matrices. The addition of MTMS has improved the thermal and mechanical properties of the composite membranes as compared to pristine PVA. In addition, the crystallinity and the morphological changes of PVA/MTMS composites was studied using X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. Three structures were suggested based on trimethyl silanol (I) wet out condensation (II and III) with the dopped PVA followed by and H-bonding interactions (IV). The outcomes of B3LYP/6-31G(d) frequency calculations favors a threedimensional SiOC linked network (III). Nevertheless, EDX reveals, the 3D SiOC links are not observed on the surface of composite membranes, however, is found dominant in the bulk, [(CH3)(3)SiOCH2CH2CH2O](n). Moreover, the solubility, density, and refractive index of the synthesized composites were measured and found depended on the ratio of PVA in the composite membranes. The current results are compared with that published earlier including dimethoxydimethylsilane at the same conditions. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

A modified composite membrane was prepared using different ratios of PVA and MTMS, resulting in improved thermal and mechanical properties compared to pristine PVA. The study also examined the crystallinity and morphological changes of the composite materials. Based on the experimental findings, a three-dimensional structure of SiOC linked network was proposed.