Understanding the Microstructure Connectivity in Photopolymerizable Aluminum-Phosphate-Silicate Sol-Gel Hybrid Materials for Additive Manufacturing

Tayama, Gabriel Toshiaki [UNESP]; Santagneli, Silvia Helena [UNESP]; de Oliveira Junior, Marcos; Messaddeq, Younes [UNESP]

Understanding the Microstructure Connectivity in Photopolymerizable Aluminum-Phosphate-Silicate Sol-Gel Hybrid Materials for Additive Manufacturing

Data

2023-02-09

Autores

Tayama, Gabriel Toshiaki

Santagneli, Silvia Helena

de Oliveira Junior, Marcos

Messaddeq, Younes

Tipo

Artigo

Resumo

In this paper, we report the synthesis and structural characterization of transparent and photopolymerizable aluminum-phosphate-silicate hybrid materials obtained via the sol-gel route, with different aluminum/phosphate (Al/P) ratios. We explored the system Si(1-x)-(Al/P) (x) with x varying from 0.3 to 1, and atomic ratios of Al/P are 1:3, 1:1, and 3:1. All compositions contain high inorganic mass content (up to 40 wt %). Furthermore, they are compatible with vat-photopolymerization platforms. The structural evolution of the hybrid materials with the silicon concentration was investigated by SEM, phase-contrast AFM, and solid-state NMR techniques, using single- and double-resonance experiments. The structure follows the build-up principle using aluminum-phosphate species and alkoxysilane chains as fundamental building blocks. These aluminum-phosphate species were identified as monomeric and dimeric chain structures by comparing different parameters obtained from NMR data to compound models. Monomeric and dimeric aluminum-phosphate chain structures were predominant in 3:1 and 1:3 Al/P ratio samples, respectively, promoting and hindering the heterocondensation with the alkoxysilane precursor, respectively. The photopolymerization mechanism leads to the percolation of the inorganic networks through a parallel polymethylmethacrylate network, resulting in a material with structural heterogeneities in the range of 5 nm, evidenced by phase-contrast AFM.