Structure/property relationship of polyvinyl alcohol/dimethoxydimethylsilane composite membrane: Experimental and theoretical studies

Alaa Fahmy; Tarek A Mohamed; Mohamed Abu-Saied; Hisham Helaly; Farid El-Dossoki

doi:10.1016/j.saa.2019.117810

Structure/property relationship of polyvinyl alcohol/dimethoxydimethylsilane composite membrane: Experimental and theoretical studies

Spectrochim Acta A Mol Biomol Spectrosc. 2020 Mar 5:228:117810. doi: 10.1016/j.saa.2019.117810. Epub 2019 Nov 23.

Authors

Alaa Fahmy¹, Tarek A Mohamed², Mohamed Abu-Saied³, Hisham Helaly⁴, Farid El-Dossoki⁵

Affiliations

¹ Chemistry Department, Faculty of Science, Al-Azhar University, Nasr City, 11884 Cairo, Egypt; BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, 12205 Berlin, Germany.
² Chemistry Department, Faculty of Science, Al-Azhar University, Nasr City, 11884 Cairo, Egypt. Electronic address: tarek_ama@azhar.edu.eg.
³ Polymeric Materials Research Department, Advanced Technology and New Materials Research Institute, City of Scientific Research & Technological Applications, New Borg Al-Arab City, 21934 Alexandria, Egypt.
⁴ TCI SANMAR Group Company, Port Said, Egypt.
⁵ Chemistry Department, Faculty of Science, Port-Said University, Port Said, Egypt.

PMID: 31791909
DOI: 10.1016/j.saa.2019.117810

Abstract

A novel mixed matrix composite has been prepared using solution-casting method at different volume concentrations of polyvinyl alcohol; PVA (50, 67, 75 and 80%) and fixed amount of dimethoxydimethylsilane in air atmosphere. The hydrolyzed dimethyldisilanol acts as in-situ cross linker through a wet-out condensation between the hydroxyl moieties of Si_OH and PVA_OH. Such process improves the mechanical properties of composite membranes as compared to pristine PVA which has been determined as function of varied membrane components to evaluate the structure/property relationships. Furthermore, DFT (B3LYP)/6-31G(d) geometry and frequency computations were carried out for the suggested dimeric PVA structures via 1,3-diol linkage followed by condensation and hydrogen bonding interaction. Vibrational interpretations of composite membranes were proposed based on the computed wavenumbers, Cartesian coordinates displacements for the suggested hydrolyzed products involving the dominant PVA/Si_OH/Si_OC/Si_OSi functional groups compared with those given in literatures. FTIR and EDX provide clear evidences for incorporating silicon to 3D network. Meanwhile, the infrared de-convoluted spectral interpretations ensure 17-30% cross-linked SiOC within the network of composite membranes.

Keywords: DFT calculations; Dimethoxydimethylsilane; Membrane; Polymer composites; Polyvinyl alcohol.