Novel hybrid organic/inorganic poly(thiourethane) covalent adaptable networks

[Display omitted] •New hybrid covalent adaptable networks have been prepared.•They consist of multifunctional POSS structures and poly(thiourethanes) as the matrix.•Octathiol POSSs were synthesized at atmospheric and autogenic pressure.•The presence of POSS accelerates the relaxation process of poly(thiourethane)s. Organic-inorganic hybrid materials combine the advantages of both phases: hardness and strength of inorganic phase and elasticity and toughness of the organic matrix. In the present study, we have prepared nanocomposites with a poly(thiourethane) polymeric matrix and silsesquioxane-type structures, with thiols as reactive groups (POSS-A or POSS-B, synthesized in different pressure conditions), looking for a covalent interaction between both phases, and good dispersion. Due to the click behavior of the reaction between the isocyanate and the thiol groups, highly homogeneous materials are obtained. Both monomers, catalyst (dibutyltin dilaurate, DBTDL), and the POSS precursor (3-mercaptopropyl trimethoxysilane, MPTMS), are commercially available, which present the advantage of being industrially scalable. The incorporation of POSS leads to an increase in glassy and rubbery storage moduli and the temperature of the maximum of tan δ curve. The vitrimeric behavior of the poly(thiourethanes) improved with the POSS incorporation, getting lower relaxation times. With a higher proportion of closed cages, POSS-B leads to the most significant improvements. All the materials prepared showed high transparency and the fracture of POSS modified materials indicates an improved toughness.